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Late oligocene amphictids (Mammalia: Carnivora) from La Milloque, Aquitaine Basin, France
LATE OLIGOCENE AMPHICTIDS (MAMMALIA : CARNIVORA) FROM LA MILLOQUE, AQUITAINE BASIN, FRANCE
EDITH CIROT & MIECZYSLAW WOLSAN CIROT E. & WOLSAN M. 1995. Late Oligocene amphictids (Mammalia : Carnivora) from La Milloque, Aquitaine Basin, France. [Les amphictid6s (Mammalia : Carnivora) de l'Oligoc~ne sup6rieur de La Milloque (Bassin d'Aquitaine, France)]. GEOBIOS, 28, 6 : 757-767. Villeurbanne le 31.12.1994. Manuscrit ddpos6 le 23.03.1994 ; accept6 d6finitivement le 24.11.1994. ABSTRACT Two incomplete mandibles and several isolated upper and lower teeth of Amphictis milloquensis (HELBING, 1928) and M2 of Amphictis ambigua (GERVAIS, 1872) are described from the Late Oligocene (MP 29) of La Milloque (Lot-et-Garonne) in the Aquitaine Basin, south-western France. No significant differences in size of teeth or their form were detected between the fossil population of Amphictis milloquensis from La Milloque and that from Dieupentale (MP 29). Although the M2 of Amphictis ambigua from La Milloque is congruent in morphology with those of this species from Pech Desse and Pech du Fraysse (MP 28), it exceeds the corresponding teeth from both the localities in size, providing supporting evidence for a progressive trend towards size increase through time in
Amphictis ambigua. KEY-WORDS : CARNIVORA,AMPHICTIS,OLIGOCENE, FRANCE. R]~SUM]~ Deux mandibules incompl~tes et quelques dents sup6rieures et inf6rieures isoldes d'Amphictis milloquensis (HELBING, 1928) et une M2 d'Amphictis ambigua (GERVAIS, 1872) sont d6crites. Ce mat6riel a 6t~ d6couvert dans le gisement de l'Oligoc~ne sup6rieur (MP 29) de La Milloque dans le Bassin d'Aquitaine (Lot-et-Garonne). Aucune diff6rence dans la taille et la forme des dents n'a 6t6 reconnue entre la population fossile d'Amphictis milloquensis de La Milloque et celle de Dieupentale (MP 29). Bien que la M2 d'Amphictis ambigua de La Milloque ne poss~de aucune diff6rence morphologique compar6e aux M2 de la m6me esp~ce d6couvertes dans les gisements plus anciens (MP 28) de Pech Desse et de Pech du Fraysse, une taille nettement plus 61ev6e est observ6e pour la dent de La Milloque, confirmant ainsi une 6volution allant vers un accroissement de taille ~ l'int~rieur de l'esp~ce Amphic-
tis ambigua. MOTS-CLt~S : CARNIVORA,AMPHICTIS,OLIGOC]~NE,FRANCE.
INTRODUCTION The continental Oligocene formations of the Aquitaine Basin in south-western France are known of two principal facies types : limestones and molasses. The "molasse de l'Agenais" has yielded n u m e r o u s faunas of fossil vertebrates (Richard 1948). The especially abundant assemblage of Late Oligocene mammals, attributed to t h e reference level MP 29 (Schmidt-Kittler, ed. 1987), has been collected in the second h a l f of 19th c e n t u r y (Richard 1948) and recently (Bru-
net 1979) in La Milloque (Lot-et-Garonne). This paper presents a description of t he amphictid remains from both the old and new collections.
Collection a b b r e v i a t i o n s - FSP, Facult6 des Sciences, Poitiers, France ; MNHN, I n s t i t u t de Pal6ontologie, Mus6um National d'Histoire Naturelle, Paris, France ; NMB, Naturhistorisches Museum Basel, Switzerland ; PDV, private collection of D. Vidalenc, Saint Gaudens, France.
758
SYSTEMATICS Order CARNIVORA Bowdich, 1821 Suborder CANIFORMIA Kretzoi, 1945 Infraorder ARCTOIDEA Flower, 1869 Order-group taxon ARCTOMORPHA Wolsan, 1993 Order-group taxon MUSTELIDA Tedford, 1976 Family AMPHICTIDAE Winge, 1895 Because the phylogenetic relationships of the type genus of the Amphictidae, the genus Amphictis, are uncertain within the Mustelida (Wolsan 1993), we regard this family as monotypic. The Amphictidae is distinguished from the other mustelidan arctomorphs by a combination of the following features (emended diagnosis) : suprameatal fossa shallow (i.e. its anterior and lateral walls are neither excavated into the squamosal nor perpendicular to the roof of the external auditory meatus) ; epitympanic recess expanded laterad, so t h a t its lateral part anterior to the fossa for the incudal processus brevis is floored by the squamosal ; meatal trough of the ossified ectotympanic not differentiated or short (i.e. its smallest medio-lateral dimension is smaller t h a n onethird of the bulla width) ; caudal entotympanic unexpanded posteriorad, so t h a t the smallest width of the auditory bulla between the stylomastoid foramen and fossa leading to the posterior lacerate foramen is smaller t h a n the greatest diameter of the stylomastoid foramen ; posterior carotid foramen joined to the fossa leading to the posterior lacerate foramen ; alisphenoid canal present ; palate extended posteriorad, so that its posterior margin is situated behind the posteriormost upper teeth ; p4 protocone (not the whole protocone wing) not differentiated or crescentic (i.e. completely formed by the cingulum) ; M 1 not smaller t h a n P~ ; anterior and posterior cingula of M 1 continuous around the lingo2al base of the protocone ; buccal border of the M crown positioned behind the buccal half of M 1 " M 2 with three or two roots ; anterior and posterior halves of the lingual wall of the Ms talonid subequal in height to each other ; talonid basin of M2 distinctly longer t h a n the trigonid basin.
angular processes, with the anterior fragment of P4 and intact M1 and M2 ; FSP LM 1969 MC 2, right dentary missing its ante-premolar end and ramus, preserving virtually complete P3-M1 and a posteriorly damaged M2 ; FSP LM 1969 MC 3, left p4 without its protocone wing and anterior roots ; FSP LM 1969 MC 4, right M 1 with damages to t h e cingulum ; FSP LM 1969 MC 5, left M1 ; FSP LM 1969 MC 6, left M1 crown ; FSP LM 1969 MC 7, right M1 trigonid with a damaged protoconid ; FSP LM 1969 MC 8, right M1 lacking its talonid and posterior root ; FSP LM 1969 MC 9, right M1 trigonid.
Description Mandible (Fig. 1, Tab. 1 ; Helbing 1928 : pl. IV, figs 3-5) - The body (or horizontal part) of the dentary bone, viewed from above, is almost straight in the type specimen, whereas in FSP LM 1969 MC 2 it arches laterad. Viewed from the side, the body tapers anteriorad, only slightly in the holotype but quite distinctly in FSP LM 1969 MC 2 ; in both the specimens the alveolar (or dorsal) and ventral borders of the body are arched ventrad. The side-walls of the body are convex in cross section (the lateral wall in particular) except the ventral part of the medial wall behind the alveoli for P3, where the surface of the
0
lO, mm
Genus Arnphictis POMEL, 1853
AMPHICTIS MILLOQUENSIS (HELBING, 1928) 1928 - Plesictis milloquensis
HELBING,
p. 46.
M a t e r i a l - NMB LM 554 (holotype), left dentary lacking the ante-premolar end, dorsal part of the ramus, and distal portions of th,e condyloid and
Figure 1 - A m p h i c t i s m i l l o q u e n s i s , F S P LM 1969 MC 2, partial right d e n t a r y w i t h P3-M2 (M2 d a m a g e d posteriorly) : a, dorsal view ; b, medial view ; c, lateral view. A m p h i c t i s m i l l o q u e n s i s , F S P L M 1969 M C 2, m a n d i b u l e droite incomplete avec P3-M2 (M2 cassde postdrieurement) : a, r u e dorsale ; b, rue rnddiale ; c, vue latdrale.
759
NMB LM 554 Greatest distance from posterior-most point of C1 alveolar rim to condyloid process Least distance from posterior-most point of C1 alveolar rim to indentation between condyloid and angular processes Distance between posterior-most points of C1 alveolar rim and angular process Distance between posterior-most points of C1 and M2 alveolar rims Greatest distance between alveolar rims for M1 and M2 Greatest distance from posterior-most point of M2 alveolar rim to condyloid process Least distance from posterior-most point of M2 alveolar rim to indentation between condyloid and angular processes Distance between posterior-most points of M2 alveolar rim and angular process Length of P1 alveolus (greatest diameter of P1 alveolar rim) Width of P1 alveolus (least diameter of P1 alveolar rim) Length of P2 alveoli (greatest distance between rims of anterior and posterior alveoli for P2) Width of P2 alveoli (least distance from line connecting lingual-most points of P2 alveolar rims to buccal-most point of these rims) Length of P3 alveoli (greatest distance between rims of anterior and posterior alveoli for P3) Width of P3 alveoli (least distance from line joining lingual-most points of P3 alveolar rims to buccal-most point of these rims) Length of P4 alveoli (greatest distance between rims of anterior and posterior alveeli for P4) Width of P4 alveoli (least distance from line connecting lingual-most points of P4 alveolar rims to buccal-most point of these rims) Length of M1 alveoli (greatest distance between rims of anterior and posterior alveoli for M1) Length of M2 alveoli (greatest distance between rims of anterior and posterior alveoli for M2) Greatest horizontal distance between lateral and medial walls of dentary below M1 perpendicular to long axis of dentary Least distance from alveolar border of dentary between P3 and P4 to its ventral border, measured on medial side Least distance from alveolar border of dentary between M1 and M2 to its ventral border, measured on medial side
FSP LM 1969 MC 2
64.0+ 60.5 62.1+ 38.6 15.1 25.7+
40.6 15.8
22.0 23.7+ 3.3 1.5 4.9
3.6 1.6 4.7
1.7 5.7
1.8 5.0
1.7 6.8
6.7
2.5 10.1 4.6
10.1 5.8
5.0
4.9
9.4
10.7
10.0
Ii.9
Table 1 - Mandible measurements (in mm) ofAmphictis milloquensis from La Milloque "+" indicates a minimum measurement on an incomplete structure. Dimensions (en ram) des mandibules d'Amphictis milloquensis de La Milloque ; "+" indique des mesures minimum d'une structure incomplete.
d e n t a r y is s o m e w h a t d e p r e s s e d along t h e v e n t r a l border. T h e b o d y a t t a i n s to its g r e a t e s t laterom e d i a l b r e a d t h b e n e a t h M1 ( N M B LM 554) or at t h e s y m p h y s i s ( F S P L M 1969 MC 2). T h e m a n d i b u l a r r o w of t h e p o s t - c a n i n e alveoli is n e a r l y s t r a i g h t in t h e holotype, w h e r e a s in F S P L M 1969 MC 2 it a r c h e s n o t i c e a b l y l a t e r a d . T h e p o s t - i n c i s o r alveoli a r e a r r a n g e d one b e h i n d t h e o t h e r a n d closely s p a c e d except for s e p a r a t i o n s b e t w e e n t h e alveoli for C1 a n d P1 in b o t h specim e n s e x a m i n e d (1.9 m m ) , b e t w e e n t h o s e for P1 a n d P2 in F S P L M 1969 MC 2 (1.0 m m ) , b e t w e e n t h o s e for P2 a n d P3 in F S P L M 1969 MC 2 (2.4 m m ) , a n d b e t w e e n t h o s e of M1 a n d M2 in N M B L M 554 (1.2 m m ) . O f t h e p r e s e r v e d t e e t h in F S P L M 1969 MC 2, P3 a n d P4 n e i t h e r t o u c h n o r o v e r l a p e a c h other, P4 a n d M1 a r e not in direct c o n t a c t as well b u t slightly o v e r l a p e a c h other, w h i l e M1 a n d M2 p a r t i a l l y a d h e r e e a c h o t h e r ant e r o - p o s t e r i o r l y ; in t h e t y p e s p e c i m e n , M1 a n d M2 a r e little i s o l a t e d f r o m e a c h other, b u t t h i s is a p p a r e n t l y b e c a u s e of t h e artificially i m p e r f e c t f i t t i n g of d e n t a r y p o r t i o n s b r o k e n b e t w e e n t h e s e t e e t h . P1 is r e p r e s e n t e d b y a single e l o n g a t e alveolus. T h e r e a r e p a i r s of alveoli for P2-M2. T h e
a n t e r i o r alveolus of e a c h p a i r is s m a l l e r t h a n t h e p o s t e r i o r one. T h e r e a r e two elliptical, a n t e r o - p o s t e r i o r l y elong a t e m e n t a l f o r a m i n a lying 4.5 m m ( N M B L M 554) or 6.5 m m ( F S P L M 1969 MC 2) a p a r t . T h e a n t e r i o r of t h e f o r a m i n a , 1.7 m m ( F S P L M 1969 MC 2) or 1.9 m m ( N M B L M 554) in g r e a t e s t diam e t e r , is placed below t h e s p a c e b e t w e e n t h e alveoli for P1 a n d P2, facing a n t e r o - l a t e r a d . T h e m o r e p o s t e r i o r f o r a m e n , m e a s u r i n g a l m o s t 1.4 m m in g r e a t e s t d i a m e t e r , is l o c a t e d below t h e space b e t w e e n t h e alveoli of P2 a n d P3 in t h e t y p e s p e c i m e n or slightly p o s t e r i o r to t h i s location, below t h e a n t e r i o r m a r g i n of P3, in F S P L M 1969 MC 2 ; t h i s f o r a m e n faces a n t e r o - l a t e r o - d o r s a d (NMB LM 554) or p o s t e r o - l a t e r o - d o r s a d ( F S P L M 1969 MC 2). T h e m a n d i b u l a r s y m p h y s i s is u n f u s e d in b o t h s p e c i m e n s u n d e r s t u d y a n d e x t e n d s to t h e level of t h e a n t e r i o r alveolus for P2. T h e r a m u s (or v e r t i c a l p a r t ) of t h e h o l o t y p e dent a r y , v i e w e d f r o m t h e side, is e x c a v a t e d v e n t r a l l y a n d p o s t e r i o r l y b e t w e e n t h e a n g u l a r a n d condyloid processes. I t e x h i b i t s a deep, w e l l - m a r k e d m a s s e t e r i c f o s s a t h a t e x t e n d s a n t e r i o r l y to t h e le-
760 vel of the posterior alveolus for M2 (in F S P LM 1969 MC 2 the fossa ends behind M2). The smallest latero-medial width or thickness of the ramus at the masseteric fossa is about 0.5 mm. From the level of the alveolar margin of the body ventrad, the ramus becomes broader medio-laterally forming at its ventral border a 3-4.5 mm broad, medially rounded shelf that terminates posteriorly in a tapering angular process positioned approximately at the level of the mental foramiha. The condyloid process of the type specimen is situated above the level of the mandibular alveolar border, nearly 7 mm dorsal to the angular process. The neck supporting the capitulum of the condyloid process is short and twisted through some 90 degrees. The long axes of the capitulum and dentary converge at an internal angle of about 65 degrees. Lower teeth P3-4 (Fig. 1, Tab. 2) - Both the teeth are doublerooted in F S P LM 1969 MC 2, with the posterior root being larger than the anterior one, which was also true for the type specimen judging from the alveoli. In P3 and P4 of F S P LM 1969 MC 2, much of the crown consists of a large blade-like cusp that is compressed bucco-lingually and som e w h a t deflected linguad. The tip of this principal cusp is positioned close behind the anterior third of the tooth length in P3, whereas in P4 the cusp culminates slightly more posteriorly, so that P4 has a more symmetric appearance in side view than it is for P3. Either of the teeth shows a small accessory cusp, which is better developed on P4, established along the basal half of the posterior edge of the principal cusp. In both teeth, wear has broken through the enamel of the accessory cusp occlusally. A cingulum is present only anteriorly and posteriorly on both teeth. The anterior cingulum of P3 represents the baso-lingual continuation of the anterior edge of the principal cusp, so that the tooth bears the anterior cingulum only on the lingual side. The anterior cingulum on P4 is also continuous with the anterior edge of the principal cusp, but unlike the condition in P3 it is prolon-
ged on the buccal side. Nevertheless, the lingual portion of the anterior cingulum is much stronger than the buccal one, creating a tiny cuspule slightly lingual to the place of junction with the anterior edge of the principal cusp. This cingular cusplet also occurs on the preserved fragment of P4 in the holotype where it is better pronounced. The posterior cingulum is better developed than the anterior one on both disputed teeth. It is more prominent on P4 where it terminates in two tiny, barely distinguishable elevations separated by a much larger, low cingular elevation culminating on the lingual side. The posterior cingular region is little deflected linguad on both teeth but especially on P4. M1 (Fig. 1, Tab. 3 ; Helbing 1928 : pl. IV, figs 3-6) - The crown of this tooth is supported by two strong roots of which the anterior root is somewhat smaller than the posterior one. In all specimens at hand, a well-marked cingulum runs along the buccal base of the trigonid from the anterior end of the paraconid to about mid-length of the protoconid. Another fragment of the buccal cinguhim is present on the anterior part of the hypoconid base. In F S P LM 1969 MC 7 and F S P LM 1969 MC 9, a short lingual cingulum additionally occurs, bordering the valley between the paraconid and metaconid lingually. The trigonid is notably arched buccad, making its lingual contour concave when viewed from above. The carnassial blade comprises the buccal ridge of the paraconid and the anterior ridge of the protoconid that are divided by a deep, slit-shaped carnassial notch. Except for F S P LM 1969 MC 9 that is almost unworn, the remaining referred trigonids display a more or less worn shearing surface on the buccal side of the paraconid and protoconid. In F S P LM 1969 MC 2, F S P LM 1969 MC 5, FSP LM 1969 MC 8, and partly also in FSP LM 1969 MC 6, the carnassial blade is deeply worn, particularly on the paraconid, exposing dentine facets. Viewed from the occlusal surface, the carnassial edge of the paraconid abruptly turns anteriorly into a short but trenchant lingual ridge descending towards the metaconid from which it is set off by a deep valley. The car-
Length (from anterior-most to posterior-most points of crown) Width (greatest distance between buccal and lingual borders of crown perpendicular to antero-posterier length of tooth) Height (least distance from occlusal-most point of tooth to basal margin of crown, measured on buccal side)
P3
P4
5.6
6.8
2.3
3.1
2.9
4.2
Table 2 - M e a s u r e m e n t s (in mm) of P3 and P4 (FSP LM 1969 MC 2) ofAmphictis milloquensis from La Milloque. Dimensions (en ram) des P3 et P4 (FSP LM 1969 MC 2) d'Amphictis milloquensls de La Milloque.
761
Length (from anterior-most to posterior-most points of crown) Width (least distance from buccal-most point of crown to line joining lingual-most points of paraconid wing and talanid) Trigonid length (least distance from anterior-most point of crown to line connecting notch between protoconid and hypoconid with notch posterior to metaconid) Least distance between buccal and lingual borders of crown across carnassial notch Talonid length (least distance from posterior-most point of crown to line connecting notch between protoconid and hypoconid with notch posterior to metaconid) Talonid w i d t h (greatest distance between buccal and lingual borders of talonid perpendicular to antero-posterior length of tooth) Paraconid height (least distance from occlusal-most point of paraconid to basal margin of crown, measured on lingual side) Protoconid height (least distance from occlusal-most point of protoconid to basal margin of crown, measured on buccal side) Metaconid h e i g h t (least distance from occlusal-most point of metaconid to basal m a r g i n of crown, measured on lingual side) Hypoconid height (least distance from occlusal-most point of hypoconid to basal margin of crown, measured on buccal side) Entoconid height (least distance from ocdusal-most point of entoconid to basal m a r g i n of crown, measured on lingual side)
NMB LM 554
FSP LM 1969 MC 2
FSP LM 1969 MC 5
FSP LM 1969 MC 6
FSP LM 1969 MC 7
FSP LM 1969 MC 8
FSP LM 1969 MC 9
10.0
10.0
8.6
10.6
4.8
4.8
4.1
5.1
4.3+
4.4+
4.3+
7.0
7.1
5.8
7.1
6.0e
6.7e
6.6e
3.8
4.0
3.7
4.1
3.5
3.7
3.6
3.0
2.9
2.8
3.5
4.6
4.3
3.8
4.7
3.6
3.5+
3.1+
3.8
3.1
3.2
3.3
5.9
6.1+
4.9+
6.2
6.0
6.0
4.2
4.0
3.7+
4.2
4.0
4.3
2.5
2.3+
1.7+
2.5+
1.8
1.6
1.5+
2.1+
3.4
Table 3 - Measurements (in mm) of M1 in Amphictis milloquensis from La Milloque ; %" indicates a m i n i m u m m e a s u r e m e n t on an incomplete structure, "e" indicates an estimated value. Dimensions (en mm) des M1 d'Amphietis milloquens@ de La Milloque ; %" indique des mesures minimum d'une structure incomplete, "e" indique des dimensions estimges.
nassial edge of the protoconid curves posteriorly at an about right angle to continue into a sharp ridge falling obliquely down until it meets the metaconid. In addition to the anterior and lingual ridges, the protoconid exhibits another two ridges that begin and terminate on its posterior wall. The occlusal and longer of these posterior ridges descends from about the top of the protoconid basad and is poorly differentiated and blunt, being in most specimens partially or completely removed by wear affecting the posterior surface of the trigonid. The basal ridge, by contrast, is very short but trenchant and ascends occlusad and slightly linguad from the anterior end of the hypoconid. The basal ridge of the protoconid is entirely worn out in F S P LM 1969 MC 6. The metaconid stands in part behind the protoconid, so that its posterior edge is visible in buccal view and the posterior wall of the trigonid is concave in occlusal view. The metaconid is stout, well detached from the protoconid, more or less deflected linguad, and higher than the paraconid,
resembling an equilateral triangle when viewed from the lingual side. Its tip in F S P LM 1969 MC 5 is worn away, exposing a dentine facet. The anterior face of the metaconid, which flanks postero-lingually a deep, spacious valley that sets it and the protoconid off from the paraconid, is widely rounded and blunt except for a short, edged occluso-basal crest found in F S P LM 1969 MC 2, F S P LM 1969 MC 7, and NMB LM 554. The buccal slope of the metaconid is angulated into a trenchant ridge that is united with the lingual crest of the protoconid at a prominent, slit-like notch. The posterior profile of the metaconid is made up by a sharp ridge that is about twice longer than the buccal ridge. It forms an angle of some 105-110 degrees with the occlusal margin of the lingual wall of the talonid, being slightly more oblique than the posterior profile of the protoconid. The talonid is rather deeply basined and somewhat deflected buccad, giving the buccal margin of the crown a remarkably concave outline be-
762 tween the protoconid and hypoconid when viewed from above. All the talonids available show an extensive wear facet on the buccal surface adjacent to this concavity. In addition to this facet there is another one in FSP LM 1969 MC 2 and FSP LM 1969 MC 5, placed more posteriorly and thus occupying the postero-buccal part of the talonld wall. The hypoconid is the largest and highest cusp on the talonid. It is elongate antero-posteriorly and has a conspicuously inclined buccal wall, making the talonid basin shifted linguad in occlusal view, especially in FSP LM 1969 MC 2. The anterior end o f the hypoconid is delimited by a V-shaped notch separating the anterior hypoconid crest from the basal posterior ridge of the protoconid. The hypoconid is followed postero-lingually by a weakly differentiated, tiny hypoconulid. In the talonids studied, excepting that of the holotype, wear has breached the enamel along both the hypoconid and hypoconulid. The posterior wall of the talonid, incorporating the hypoconulid, is lower t h a n the buccal and lingual walls. The latter, being detached from the metaconid by a small but distinct slit-shaped notch (rounded by wear in FSP LM 1969 MC 5), is produced occlusally into two (FSP LM 1969 MC 6) or three (NMB LM 554, FSP LM 1969 MC 2, and FSP LM 1969 MC
5) low elevations. The largest and highest of these elevations, the entoconid, lies most posteriorly at the postero-lingual corner of the talonid. This cusp in FSP LM 1969 MC 6 and both it and the elevation adjoining the metaconid in FSP LM 1969 MC 5 expose small wear facets of dentine occlusally.
M2 (Fig. 1, Tab. 4 ; Helbing 1928 : pl. IV, figs 3-5) - This tooth is two-rooted ; the anterior root is distinctly smaller t h a n the posterior one. The trigonid is larger t h a n the talonid. The latter is deflected occlusad and buccad. The buccal border of the crown is slightly excavated when viewed from the occlusal surface. A cingulum is present only on the buccal side anteriorly and posteriorly as shown by the holotype. In FSP LM 1969 MC 2, much of the antero-buccal cingulum has been removed by wear ; the postero-buccal part of this crown has been broken away. The protoconid and metaconid are salient. The latter is situated partly behind the former. The protoconid is higher t h a n the metaconid, but both the cusps are approximately equal in size when viewed from above. Each of t h e m is angulated by three ridges sloping anteriorly, medially, and posteriorly. The medial ridges in the type specimen are basally joined to each other at a V-shaped
Length (from anterior-most to posterior-most points of crown) Width (least distance from lingual-most point of crown to line joining buccal-most points of trigonid and talonid) Trigonid length (least distance between anterior-most point of crown and line t h a t is perpendicular to antero-posterior length of tooth and passes across notch separating protoconid from hypoconid) Trigonid width (greatest distance between buccal and lingual borders of trigonid perpendicular to antero-posterior length of tooth) Trigonid basin length (from anterior-most point of trigonid basin to notch between protoconid and metaconid) Talonid length (least distance between posterior-most point of crown and line t h a t is perpendicular to antero-posterior length of tooth and passes across notch separating protoconid from hypoconid) Talonid width (greatest distance between buccal and lingual borders of talonid perpendicular to antero-posterior length of tooth) Talonid basin length (from posterior-most point of talonid basin to notch between protoconid and metaconid) Protoconid height (least distance from occlusal-most point of protoconid to basal margin of crown, m e a s u r e d on buccal side) Metaconid height (least distance from occlusal-most point of metaconid to basal margin of crown, m e a s u r e d on lingual side) Hypoconid height (least distance from occlusal-most point of hypoconid to basal margin of crown, m e a s u r e d on lingual side)
NMB LM 554
FSP LM 1969 MC 2
FSP LM 1969 MC 1
5.1
5.6+
7.2
3.7
3.9
4.7
3.3
3.4
4.2
3.7
3.9
4.7
2.0
2.0
2.4
1.8
2.2+
3.0
2.8
3.0+
3.8
2.7
3.3e
4.4
2.3
2.6
1.7+
2.0
2.0
2.6
1.6
1.7+
Table 4 - Measurements (in mm) of M2 in Amphictis milloquensis (NMB LM 554 and FSP LM 1969 MC 2) and Amphictis ambigua (FSP LM 1969 MC 1) from La Milloque ; '%" indicates a m i n i m u m m e a s u r e m e n t on an incomplete structure, "e" indicates an estimated value. Dimensions (en ram) des M2 d'Amphictis milloquensis (NMB L M 554 et F S P L M 1969 MC 2) et Amphictis a m b i g u a (FSP L M 1969 MC 1) de La Milloque ; "+" indique des mesures minimum d'une structure incomplete, "e" indique des dimensions estimdes.
763 notch ; they are sharp except for the occlusal part of the protoconid where the medial slope is blunt. In F S P LM 1969 MC 2, the medial slopes of both the cusps are more or less rounded by wear, while the notch is heavily worn basally. The anterior ridges of the protoconid and metaconid originate at the tips of the cusps and are trenchant (that on the protoconid in F S P LM 1969 MC 2 is considerably worn along its basal half). They are connected by a low but edged, widely arched crest delimiting the trigonid basin anteriorly. There are four tiny elevations established along this crest in the holotype, of which the second counting from the metaconid is largest, whereas that adjacent to it buccally is smallest. The anterior trigonid crest in F S P LM 1969 MC 2, judging from the state of its preservation, was originally produced into two elevations only. The lingual of them, exposing an extensive dentine facet occlusally, was evidently prominent and conspicuously larger than the buccal one that is less worn. The posterior ridge of the protoconid is sharp and present about mid-way up the posterior slope of the cusp. Buccally of this ridge, the posterior face of the protoconid is worn in both specimens at hand. In F S P LM 1969 MC 2, this wear facet is larger and extends posteriorly onto the preserved buccal surface of the hypoconid. In addition to this facet, F S P LM 1969 MC 2 displays another extensive area of wear occupying the buccal wall of the trigonid in front of the tip of the protoconid. The posterior ridge of the metaconid is blunt and takes its rise at the tip of the cusp. It is continuous with a low, occlusally round crest that gently ascends postero-buccad and then buccad along the talonid margin to culminate at the posterior end of the crown where it meets both the posterobuccal cingulum and the posterior ridge of the hypoconid. This culmination represents the hypoconulid and can be seen in the holotype. In F S P LM 1969 MC 2, the corresponding portion of the crown has been broken off.
The hypoconid occupies much of the talonid area. Relative to the protoconid and metaconid, it is larger in F S P LM 1969 MC 2 than that of the holotype, being distinctly lower t h a n either of these cusps in both referred specimens. The hypoconid is sharpened occlusally into the anteroposteriorly oriented edge separated from the posterior ridge of the proteconid by a small b u t distinct, V-shaped notch. The trigonid and talonid are basined b u t of little depth. The trigonid basin is antero-posteriorly shorter but bucco-lingually broader than that of the talonid, so that both the basins are approximately equal in size. When viewed from the occlusal surface, the trigonid basin in the type specimen lies almost centrally, whereas in F S P LM 1969 MC 2 it appears to be displaced linguad in consequence of a greater lingual inclination of the protoconid. The talonid basins of both the specimens are distinctly shifted linguad.
U~pp er teeth P (Fig. 2, Tab. 5) - As deduced from F S P LM 1969 MC 3, this tooth had originally three major roots : two smaller (broken) placed side by side anteriorly and the largest one (preserved) located posteriorly. Moreover, a tiny accessory root occurs directly behind the remnant of the antero-buccal root. The preserved part of the crown is surrounded by a well-developed cingulum except for the posterior end of the crown and the buccal base of the paracone where it is faint or absent. The antero-buccal (or parastyle) wing is small but well defined. The lingual half of this wing bears a small but distinct parastyle that stands out from the cingulum. The paracone, which is a dominant cusp on the crown, displays four ridges passing from its tip basad. The buccal and antero-lingual ridges are widely rounded and blunt ; the former vanishes near the buccal cingulnm about at the level of the accessory root, whereas the latter ends artifidally at the broken surface of the protocone wing. The antero-buccal ridge is more trenchant
Figure 2 - A m p h i c t i s m i l l o q u e n s i s , FSP LM 1969 MC 3, left p4 (protocone wing broken away) : a, occlusal view ; b, lingual view ; c, buccal view. A m -
?
,smm
phictis milloquensis, FSP L M 1969 M C 3, P4 g a u c h e (aile de protocone cassde) : a, r u e occlusale ; b, vue linguale ; c, rue buccale.
764
Length (from anterior-most point of parastyle wing to posterior-most point of crown) Least distance from posterior-most point of crown to indentation between parastyle and protocone wings Least distance between buccal and lingual borders of crown across carnassial notch Paracone height (least distance from occlusal-most point of paracone to basal margin of crown, measured on buccal side)
8.5 8.1 3.3 4.9
Table 5 - Measurements (in mm) of p4 (FSP LM 1969 MC 3) ofAmphictis milloquensis from La Milloque. Dimensions (en mm) de i°4 (FSP L M 1969 M C 3) d ' A m p h i c t i s m i l l o q u e n s i s de La MiUoque.
0
5mm Figure 3 - Amphictis milloquensis~ FSP LM 1969 MC 4, right M (damaged antero-lingually) : a, occlusal view ; b, anterior view ; c, posterior view. A m p h i c t i s m i l l o q u e n sis, F S P L M 1969 M C 4, M1 droite (cassde ant~ro-lingualement) : a, rue occlusale ; b, rue antdrieure ; c, rue postdrieure.
a
Length (least distance from anterior border of crown to posterior-most point of metacone wing) Width (from buccal-most to lingual-most points of crown) Trigon length (greatest distance between margins of parastyle and metacone wings) Least distance between anterior and posterior borders of crown across notch separating protocone from paraconule Least distance from occlusal-most point of hypoconal cingulum to basalmargin of crown, measured on lingual side)
6.2 10.0 6.8 4.6 1.8
Table 6 - Measurements (in mm) of M1 (FSP LM 1969 MC 4) of Amphictis milloquensis from La Milloque. Dimensions (en ram) de M1 (FSP L M 1969 M C 4)
d'Amphictis mUloquensis de La Milloque.
a n d joins to t h e p a r a s t y l e . T h e p o s t e r i o r ridge c o n s t i t u t e s t h e a n t e r i o r p a r t of t h e c a r n a s s i a l blade, b e i n g d e t a c h e d f r o m t h e p o s t e r i o r p a r t b y a conspicuous, slit-like c a r n a s s i a l notch. T h e p o s t e r i o r (or m e t a c o n e - m e t a s t y l e ) w i n g is deflected buccad, giving t h e buccal m a r g i n of t h e c r o w n a concave c o n t o u r a n d m a k i n g the c a r n a s sial b l a d e n o t a b l y c u r v e d in occlusal view. T h e p o s t e r i o r p a r t of t h e c a r n a s s i a l b l a d e is c o m p o s e d of t h e m e t a c o n e a n d m e t a s t y l e t h a t are d e m a r c a t e d b y a s h a l l o w groove e s t a b l i s h e d on t h e buccal s u r f a c e occlusally. T h e m e t a c o n e is h i g h e r a n d shorter antero-posteriorly than the metastyle. T h e s h e a r i n g surface on t h e lingual side of t h e m e t a c o n e , m e t a s t y l e , a n d also p a r a c o n e is moder a t e l y worn. M 1 (Fig. 3, Tab. 6) - This t o o t h p o s s e s s e s two roots b u c c a l l y a n d one l i n g u a l l y ; t h e l i n g u a l root is l a r g e s t , a n d t h e p o s t e r o - b u c c a l one s u p p o r t i n g t h e m e t a c o n e is s m a l l e s t . A p a r t f r o m f r a g m e n t s affected b y d a m a g e , t h e c r o w n of F S P L M 1969 MC 4 is encircled b y a s t r o n g cingulum. T h e par a c o n e is l a r g e r a n d h i g h e r t h a n t h e m e t a c o n e .
B o t h t h e cusps a r e c o m p r e s s e d bucco-lingually giv i n g t h e m a blade-like form. T h e p a r a c o n e blade, w h i c h is a b o u t 2.8 m m long, is a n t e r o - b u c c a l l y contiguous to t h e p a r a s t y l e , w h i l e t h e m e t a c o n e blade, m e a s u r i n g a b o u t 2.2 m m in l e n g t h , is post e r i o r l y continued into t h e m e t a s t y l e c r e s t ; t h e p a r a s t y l e is b e t t e r p r o n o u n c e d t h a n t h e m e t a s tyle. T h e p a r a s t y l e a n d m e t a s t y l e crests, e a c h less t h a n 1 m m long, a r e c o n t i n u o u s w i t h t h e buccal c i n g u l u m at t h e a n t e r o - b u c c a l a n d posterobuccal corners of t h e crown, respectively. T h e par a c o n e is deflected b u c c a d following t h e p a r a s tyle, so t h a t t h e p a r a c o n e - p a r a s t y l e w i n g projects a n t e r o - b u c c a d and, w h e n v i e w e d f r o m t h e occlusal surface, the buccal b o r d e r of t h e c r o w n is rem a r k a b l y e x c a v a t e d at t h e level of a p r o m i n e n t V - s h a p e d n o t c h dividing t h e p a r a c o n e f r o m t h e m e t a c o n e . T h e l i n g u a l b a s e of t h e p a r a c o n e exhibits a short, low ridge t h a t r u n s t o w a r d s t h e par a c o n u l e to d i s a p p e a r n e a r b y its base. T h e p a r a conule f o r m s a s m a l l e l e v a t i o n on a p r o m i n e n t crest connecting t h e a n t e r i o r c i n g u l u m w i t h t h e protocone. T h e r e is a h e a v y - w e a r facet incised into t h e crest b e t w e e n t h e p a r a c o n u l e a n d proto-
765
0
Figure 4 - A m p h i c t i s ambiF S P LM 1969 MC 1, r i g h t M2 : a, occlusal view ; b, lingual view ; c, buccal view.
gua,
Amphictis
ambigua, FSP L M 1969 M C 1, M 2 droite : a, r u e occlusale ; b, uue linguale ; c, rue buccale.
cone. The protocone culminates at the level of the paracone and is produced posteriorly into a very low and wide, barely distinguishable ridge passing postero-buccad to reach the posterior cingulum at the place where wear has breached the enamel for a minute, ovate area that seems to be a r e m n a n t of a tiny metaconule. The talon is deflected posteriorad and occlusad, giving the posterior margin of the crown a noticeably concave outline in occlusal view and making the hypoconal cingulum conspicuously swollen. None the less, no differentiated hypocone can be identified except that wear has slightly broken through the enamel along the hypoconal cingulum posteriorly.
metastyle, and somewhat worn posterior portion of the buccal cinguhim. Its width across carnassial notch is 3.3 mm, while the height of its paracone measured more t:han 4.9 mm originally. There are no significant differences in size or shape between the teeth from Dieupentale and their counterparts from La Milloque.
AMPHICTIS AMBIGUA (GERVAIS, 1872) 1872 - Viverra (Arnphictis) ambigua GERVAIS, p. 266. 1887 -Amphictis Gervaisi SCHLOSSER, p]. 9, figs 46, 47 (not fig. 18). M a t e r i a l - FSP LM 1969 MC 1, right M2.
Discussion This species was originally described from La Milloque by Helbing (1928) who referred it to the genus Plesictis POMEL, 1846. Wolsan (1993) has recently re-diagnosed the mustelidan genera of the European Oligocene and Early Miocene, including Plesictis and Amphictis, and placed the holotype of Amphictis miUoquensis in his list of fossil specimens assigned to Amphictis. He therefore included this species, though not explicitly, in the genus Amphictis. Our comparison of the morphology of known remains ofAmphictis milloquensis with the emended diagnoses of Plesictis and Amphictis provided by Wolsan (1993) plainly supports the inclusion of this species in the genus
Amphictis. Additional records of Amphictis miUoquensis involve two other Late Oligocene localities in the Aquitaine Basin : Dieupentale, attributed to the reference level MP 29 by Duranthon (1991), and Th6zels (MP 30, Schmidt-Kittler, ed. 1987). For Th~zels, the species was only mentioned but undescribed by de Bonis & Guinot (1987). The material from Dieupentale includes three isolated teeth : M1 (PDV Dp 245 ; length = 8.6 mm, width = 4.5 mm) and M2 (PDV Dp 247 ; length = 5.8 mm, width = 3.7 mm) described by Crouzel et al. (1977 : figs 2!-24), and an undescribed, partial left p4. This p4 (PDV Dp 256) lacks its protocone and parastyle wings and anterior roots, and has a dentine facet at the paracone tip, well worn shearing surface of the paracone, metacone, and
Description (Fig. 4, Tab. 4) - The M2 has two roots of which the anterior root is considerably smaller than the posterior one. The trigonid is larger than the talonid. The latter is somewhat deflected buccad, giving the buccal margin of the tooth a smoothly concave outline when viewed from above. Wear has polished the surface of the crown, making the tips of the cusps and the ridges round and blunt. There is no trace of a cingulum. The dominant cusps of the crown are the protoconid, metaconid, and hypoconid. The protoconid is positioned buccal and slightly anterior to the metaconid and exactly anterior to the hypoconid. The metaconid and hypoconid appear to be little smaller than the protoconid when viewed from the occlusal surface. Although wear has significantly contributed to the heights of the cusps, affecting particularly the protoconid and hypoconid on which the dentine is exposed, occlusally, it can be inferred that the metaconid was also originally the highest cusp of the crown and that the protoconid was higher than the hypoconid. The protoconid and metaconid each have three ridges that pass down their slopes anteriorly, medially, and posteriorly, whereas the hypoconid has only two, anteriorly and posteriorly. The place where the medial ridges of the protoconid and metaconid meet each other is rounded by wear, but was apparently notched originally. The anterior ridges of the protoconid and metaconid
766
5.0
I
•
La Miltoque + Pech du Fraysse • Pech Desse
e
4, 4-44-4-
EE4. 0.
+ 4-
044-
4,
4.
44-
3.04~
+
4-+ • 4• 44-
5'.0
eb
Length, mm
7.'0
Figure 5 - Relationship between the length and width of M2 in A m p h i c t i s a m b i g u a . Data for Pech Desse and Pech du Fraysse from Cirot (1992). Relations entre la longueur et la largeur des M2 d ' A m p h i c t l s a m b l g u a . Les dimensions des M 2 de Pech Desse et Pech du Fraysse sont de Cirot (1992).
A comparison of the M2 from La Milloque with the holotype of Amphictis ambigua (MNHN Qu 9243) and the corresponding teeth of this species from Pech Desse and Pech du Fraysse (housed in FSP and described by Cirot 1992) revealed no significant differences in morphology. The relatively large dimensions of this tooth, however, placing it at the upper limit of the known range of size variation for the species (Fig. 5), suggest a larger average size in members of the La Milloque population as compared with t h a t for the Pech du Fraysse population and, in particular, t h a t for the population of Pech Desse. Because the faunal assemblage of La Milloque is stratigraphically younger t h a n t h a t from Pech du Fraysse (Schmidt-Kittler, ed. 1987), and the latter fauna is younger t h a n t h a t of Pech Desse (MSdden 1993), the data presented in Fig. 5 provide supporting evidence for a progressive trend towards size increase through time in Amphictis ambigua, postulated by Cirot (1992).
CONCLUSION are continued with a low crest t h a t broadly arches along the anterior border of the crown and is produced into four weakly differentiated, low elevations. The posterior ridge of the protoconid is separated from the anterior hypoconid ridge by a distinct depression, now rounded by wear but plausibly notched originally. The posterior ridge of the metaconid is continuous with a low crest t h a t runs postero-buccad along the slightly convex lingual border of the talonid. This low crest constitutes a tiny elevation t h a t culminates posteriorly and presumably represent the entoconid. Between this elevation and the posterior ridge of the hypoconid, at the posterior end of the crown, there is a small cuspule corresponding in its position to the hypoconulid. This cusplet is barely visible at the state of wear of the crown but it is well indicated by a tiny, ovoid dentine facet. The trigonid and talonid basins are shallow ; the latter is almost twice as extensive as the former. The basin of the trigonid is situated nearly centrally, whereas t h a t on the talonid appears to be little shifted linguad in occlusal view. - This species was erected by Gervais (1872) based on a partial mandible from Concots (Phosphorites du Quercy) in south-western France. The exact age of the fossil is unknown. However, the recent excavations in the Quercy area, involving the Late Oligocene localities Pech Desse and Pech du Fraysse (MP 28, Schmidt-Kittler, ed. 1987), have yielded an abundant material of Amphictis ambigua (de Bonis 1976 ; Cirot 1992 ; Cirot & de Bonis 1993). Discussion
1. The populations of Amphictis milloquensis from La Milloque and Dieupentale did not differ significantly. 2. The characteristic trait in evolution of Amphictis ambigua was a progressive size increase. Acknowledgments - We thank M. Brunet (Poitiers) and D. Vidalenc (Saint Gaudens) for the contribution of amphictid remains from a new collection of La Milloque and from Dieupentale, respectively. The drawings of the fossils are by S. Riffault (Poitiers). This study was supported by the State Committee for Scientific Research grant 6 P204 051 05 (Poland) and the Swiss National Science Foundation.
REFERENCES Bo~s L. de 1976 - D~couverte d'un crane d'Amphictis (Mammalia, Carnivora) dans l'Oligoc~ne sup~rieur des Phosphorites du Quercy (Lot). Comptes Rendus hebdomadaires des Sgances de l'Acadgmie des Sciences (Paris), Sgrie D, 283 : 327-330. BONIS L. de & GUINOTY. 1987 - Le gisement de Vertebras de Th~zels (Lot) et la limite Oligo-Mioc~ne dans les formations continentales du bassin d'Aquitaine. Mi~nchner Geowissenschaftliche Abhandlungen, Reihe A, 10 : 49-57. BOWDICHT.E. 1821 - An analysis of the natural classifications of Mammalia, for the use of students and travellers. J. Smith, Paris : 115 p. BRUNET M. 1979 - Les grands Mammi~res chefs de file de l~immigration Oligoc~ne et le p robl~rne de la limite Eoc~ne-Oligoc~ne en Europe. Editions de la Fondation Singer-Polignac, Paris : 281 p.
767 CIROT E. 1992 - t~tude phylog6n6tique de quelques g e n r e s d'Arctoidea de l'Oligoc6ne eurasiatique. C o m p a r a i s o n des donn6es morphologiques et mol6culaires. 2 vols. Th6se, Universit6 de Poitiers, 496 : 1-152. CIROT E. • BONIS L. de 1993 - Le cr~ne d'Amphictis ambiguus (Carnivora, M a m m a l i a ) : son i m p o r t a n c e pour la compr6hension de la phylog6nie des Must6loides. Comptes Rendus de l'Acaddmie des Sciences (Paris), Sdrie H, 316 : 1327-1333. CROUZEL F., GINSBURG L. & VIDALENC D. 1977 - Les C a r n i v o r e s fissip6des du S t a m p i e n t e r m i n a l de D i e u p e n t a l e (Tarn-et-Garonne). Bulletin de la Socidtd d'Histoire naturelle de Toulouse, 112 (1976) : 207-229. DURANTHON F. 1991 - Biozonation des molasses contin e n t a l e s oligo-mioc6nes de la r6gion toulousaine p a r l'6tude des mammif'eres. A p p o r t s ~ la connaissance d u b a s s i n d ' A q u i t a i n e (France). Comptes Ren-
dus de l'Acaddmie des Sciences (Paris), Sdrie II, 313: 965-970. FLOWER W.H. 1869 - On the v a l u e of t h e c h a r a c t e r s of t h e b a s e of the c r a n i u m in t h e classification of t h e o r d e r Carnivora, a n d on t h e s y s t e m a t i c position of Bassaris a n d o t h e r d i s p u t e d forms. Proceedings of
the Scientific Meetings of the Zoological Society of London, 1869 : 4-37. GERVAIS P. 1872 - S u r les MammiFeres dont les ossem e n t s a c c o m p a g n e n t les d6pSts de chaux phosphat6e des d 6 p a r t e m e n t s de T a r n - e t - G a r o n n e et du Lot. Journal de Zoologie (Paris), 1 : 261-268. HELBING H. 1928 - C a r n i v o r e n des oberen Stampien.
Abhandlungen der Schweizerischen Palaeontologischen Gesellschaft, 47 (4) : 1-83. KRETZOI M. 1945 - B e m e r k u n g e n fiber das Raubtiersystem. Annales Historico-Naturales Musei Nationalis Hungarici, 38 : 59-83. MODDEN C. 1993 - Revision d e r A r c h a e o m y i n i Schlosser (Rodentia, M a m m a l i a ) des europfiischen Oberoligoz~n. Schweizerische Paliiontologische Abhandlungen, 115 : 1-83. POMEL A. 1846 - M6moire pour servir h la g6ologie pa16ontologique des t e r r a i n s t e r t i a i r e s du d6partem e n t de l'Allier. Bulletin de la Socidtd gdologique de France, Sdrie 2, 3 (1845-1846) : 353-373.
POMEL A. 1853 - Catalogue des vert6br6s fossiles (suite.). Annales Scientifiques, Littdraires et IndustrieUes de l'Auvergne, 26 : 81-229. RICHARD M. 1948 - Contribution ~ l'6tude du B a s s i n d'Aquitaine. Les g i s e m e n t s de Mammif'eres tertiaires. Mdmoires de la Socidtd gdologique de France, Nouvelle Sgrie, 24 (52) : 1-380. SCHLOSSER M. 1887 Die Affen, Lemuren, Chiropteren, Insectivoren, M a r s u p i a l i e r , Creodonten u n d Carnivoren des europ~iischen Terti~irs u n d deren Beziehungen zu i h r e n l e b e n d e n u n d fossilen aussereuropfiischen V e r w a n d t e n . Beitr~ige zur
Paldontologie Osterreich-Ungarns und des Orients, 6 : 1-224. SCHMIDT-KITTLER N. (ed.) 1987 - E u r o p e a n reference levels a n d correlation tables. Mi~nchner Geowissenschaftliche Abhandlungen, Reihe A, 10 : 13-31. TEDFORD R.H. 1976 - Relationship of p i r m i p e d s to other carnivores (Mammalia). Systematic Zoology, 2 5 : 363-374. WINGE H. 1895 - J o r d f u n d n e og n u l e v e n d e Rovdyr (Carnivora) fra Lagoa S a n t a , Minas Geraes, Brasilien. Med U d s i g t over Rovdyrenes i n d b y r d e s Staegtskab. In LOTKEN C.F. (ed.) : E Museo Lundii.
En Samling af Afhandlinger om de i det indre Brasiliens Kalkstenshuler af Professor Dr. Peter Vilhelm Lund udgravede og i den Lundske palaeontologiske Afdeling af Kjbenhavns Universitets zoologiske Museum opbevarede Dyre- og Menneskeknogler, Bind 2 (2, 4). H. H a g e r u p s Boghandel, Copenh a g e n : 1-130. WOLSAN M. 1993 - Phylogeny a n d classification of early E u r o p e a n M u s t e l i d a ( M a m m a l i a : Carnivora). Acta Theriologica, 38 : 345-384. E. CIROT
Facult6 des Sciences Laboratoire de G6obiologie, Biochronologie et Pal6ontologie Humaine 40, avenue du Recteur Pineau F-86022 Poitiers Cedex M. WOLSAN Instytut Paleobiologii, Polska Akademia Nauk Aleja Zwirki i Wigury 93 02-089 Warszawa, Poland
EDITH CIROT & MIECZYSLAW WOLSAN CIROT E. & WOLSAN M. 1995. Late Oligocene amphictids (Mammalia : Carnivora) from La Milloque, Aquitaine Basin, France. [Les amphictid6s (Mammalia : Carnivora) de l'Oligoc~ne sup6rieur de La Milloque (Bassin d'Aquitaine, France)]. GEOBIOS, 28, 6 : 757-767. Villeurbanne le 31.12.1994. Manuscrit ddpos6 le 23.03.1994 ; accept6 d6finitivement le 24.11.1994. ABSTRACT Two incomplete mandibles and several isolated upper and lower teeth of Amphictis milloquensis (HELBING, 1928) and M2 of Amphictis ambigua (GERVAIS, 1872) are described from the Late Oligocene (MP 29) of La Milloque (Lot-et-Garonne) in the Aquitaine Basin, south-western France. No significant differences in size of teeth or their form were detected between the fossil population of Amphictis milloquensis from La Milloque and that from Dieupentale (MP 29). Although the M2 of Amphictis ambigua from La Milloque is congruent in morphology with those of this species from Pech Desse and Pech du Fraysse (MP 28), it exceeds the corresponding teeth from both the localities in size, providing supporting evidence for a progressive trend towards size increase through time in
Amphictis ambigua. KEY-WORDS : CARNIVORA,AMPHICTIS,OLIGOCENE, FRANCE. R]~SUM]~ Deux mandibules incompl~tes et quelques dents sup6rieures et inf6rieures isoldes d'Amphictis milloquensis (HELBING, 1928) et une M2 d'Amphictis ambigua (GERVAIS, 1872) sont d6crites. Ce mat6riel a 6t~ d6couvert dans le gisement de l'Oligoc~ne sup6rieur (MP 29) de La Milloque dans le Bassin d'Aquitaine (Lot-et-Garonne). Aucune diff6rence dans la taille et la forme des dents n'a 6t6 reconnue entre la population fossile d'Amphictis milloquensis de La Milloque et celle de Dieupentale (MP 29). Bien que la M2 d'Amphictis ambigua de La Milloque ne poss~de aucune diff6rence morphologique compar6e aux M2 de la m6me esp~ce d6couvertes dans les gisements plus anciens (MP 28) de Pech Desse et de Pech du Fraysse, une taille nettement plus 61ev6e est observ6e pour la dent de La Milloque, confirmant ainsi une 6volution allant vers un accroissement de taille ~ l'int~rieur de l'esp~ce Amphic-
tis ambigua. MOTS-CLt~S : CARNIVORA,AMPHICTIS,OLIGOC]~NE,FRANCE.
INTRODUCTION The continental Oligocene formations of the Aquitaine Basin in south-western France are known of two principal facies types : limestones and molasses. The "molasse de l'Agenais" has yielded n u m e r o u s faunas of fossil vertebrates (Richard 1948). The especially abundant assemblage of Late Oligocene mammals, attributed to t h e reference level MP 29 (Schmidt-Kittler, ed. 1987), has been collected in the second h a l f of 19th c e n t u r y (Richard 1948) and recently (Bru-
net 1979) in La Milloque (Lot-et-Garonne). This paper presents a description of t he amphictid remains from both the old and new collections.
Collection a b b r e v i a t i o n s - FSP, Facult6 des Sciences, Poitiers, France ; MNHN, I n s t i t u t de Pal6ontologie, Mus6um National d'Histoire Naturelle, Paris, France ; NMB, Naturhistorisches Museum Basel, Switzerland ; PDV, private collection of D. Vidalenc, Saint Gaudens, France.
758
SYSTEMATICS Order CARNIVORA Bowdich, 1821 Suborder CANIFORMIA Kretzoi, 1945 Infraorder ARCTOIDEA Flower, 1869 Order-group taxon ARCTOMORPHA Wolsan, 1993 Order-group taxon MUSTELIDA Tedford, 1976 Family AMPHICTIDAE Winge, 1895 Because the phylogenetic relationships of the type genus of the Amphictidae, the genus Amphictis, are uncertain within the Mustelida (Wolsan 1993), we regard this family as monotypic. The Amphictidae is distinguished from the other mustelidan arctomorphs by a combination of the following features (emended diagnosis) : suprameatal fossa shallow (i.e. its anterior and lateral walls are neither excavated into the squamosal nor perpendicular to the roof of the external auditory meatus) ; epitympanic recess expanded laterad, so t h a t its lateral part anterior to the fossa for the incudal processus brevis is floored by the squamosal ; meatal trough of the ossified ectotympanic not differentiated or short (i.e. its smallest medio-lateral dimension is smaller t h a n onethird of the bulla width) ; caudal entotympanic unexpanded posteriorad, so t h a t the smallest width of the auditory bulla between the stylomastoid foramen and fossa leading to the posterior lacerate foramen is smaller t h a n the greatest diameter of the stylomastoid foramen ; posterior carotid foramen joined to the fossa leading to the posterior lacerate foramen ; alisphenoid canal present ; palate extended posteriorad, so that its posterior margin is situated behind the posteriormost upper teeth ; p4 protocone (not the whole protocone wing) not differentiated or crescentic (i.e. completely formed by the cingulum) ; M 1 not smaller t h a n P~ ; anterior and posterior cingula of M 1 continuous around the lingo2al base of the protocone ; buccal border of the M crown positioned behind the buccal half of M 1 " M 2 with three or two roots ; anterior and posterior halves of the lingual wall of the Ms talonid subequal in height to each other ; talonid basin of M2 distinctly longer t h a n the trigonid basin.
angular processes, with the anterior fragment of P4 and intact M1 and M2 ; FSP LM 1969 MC 2, right dentary missing its ante-premolar end and ramus, preserving virtually complete P3-M1 and a posteriorly damaged M2 ; FSP LM 1969 MC 3, left p4 without its protocone wing and anterior roots ; FSP LM 1969 MC 4, right M 1 with damages to t h e cingulum ; FSP LM 1969 MC 5, left M1 ; FSP LM 1969 MC 6, left M1 crown ; FSP LM 1969 MC 7, right M1 trigonid with a damaged protoconid ; FSP LM 1969 MC 8, right M1 lacking its talonid and posterior root ; FSP LM 1969 MC 9, right M1 trigonid.
Description Mandible (Fig. 1, Tab. 1 ; Helbing 1928 : pl. IV, figs 3-5) - The body (or horizontal part) of the dentary bone, viewed from above, is almost straight in the type specimen, whereas in FSP LM 1969 MC 2 it arches laterad. Viewed from the side, the body tapers anteriorad, only slightly in the holotype but quite distinctly in FSP LM 1969 MC 2 ; in both the specimens the alveolar (or dorsal) and ventral borders of the body are arched ventrad. The side-walls of the body are convex in cross section (the lateral wall in particular) except the ventral part of the medial wall behind the alveoli for P3, where the surface of the
0
lO, mm
Genus Arnphictis POMEL, 1853
AMPHICTIS MILLOQUENSIS (HELBING, 1928) 1928 - Plesictis milloquensis
HELBING,
p. 46.
M a t e r i a l - NMB LM 554 (holotype), left dentary lacking the ante-premolar end, dorsal part of the ramus, and distal portions of th,e condyloid and
Figure 1 - A m p h i c t i s m i l l o q u e n s i s , F S P LM 1969 MC 2, partial right d e n t a r y w i t h P3-M2 (M2 d a m a g e d posteriorly) : a, dorsal view ; b, medial view ; c, lateral view. A m p h i c t i s m i l l o q u e n s i s , F S P L M 1969 M C 2, m a n d i b u l e droite incomplete avec P3-M2 (M2 cassde postdrieurement) : a, r u e dorsale ; b, rue rnddiale ; c, vue latdrale.
759
NMB LM 554 Greatest distance from posterior-most point of C1 alveolar rim to condyloid process Least distance from posterior-most point of C1 alveolar rim to indentation between condyloid and angular processes Distance between posterior-most points of C1 alveolar rim and angular process Distance between posterior-most points of C1 and M2 alveolar rims Greatest distance between alveolar rims for M1 and M2 Greatest distance from posterior-most point of M2 alveolar rim to condyloid process Least distance from posterior-most point of M2 alveolar rim to indentation between condyloid and angular processes Distance between posterior-most points of M2 alveolar rim and angular process Length of P1 alveolus (greatest diameter of P1 alveolar rim) Width of P1 alveolus (least diameter of P1 alveolar rim) Length of P2 alveoli (greatest distance between rims of anterior and posterior alveoli for P2) Width of P2 alveoli (least distance from line connecting lingual-most points of P2 alveolar rims to buccal-most point of these rims) Length of P3 alveoli (greatest distance between rims of anterior and posterior alveoli for P3) Width of P3 alveoli (least distance from line joining lingual-most points of P3 alveolar rims to buccal-most point of these rims) Length of P4 alveoli (greatest distance between rims of anterior and posterior alveeli for P4) Width of P4 alveoli (least distance from line connecting lingual-most points of P4 alveolar rims to buccal-most point of these rims) Length of M1 alveoli (greatest distance between rims of anterior and posterior alveoli for M1) Length of M2 alveoli (greatest distance between rims of anterior and posterior alveoli for M2) Greatest horizontal distance between lateral and medial walls of dentary below M1 perpendicular to long axis of dentary Least distance from alveolar border of dentary between P3 and P4 to its ventral border, measured on medial side Least distance from alveolar border of dentary between M1 and M2 to its ventral border, measured on medial side
FSP LM 1969 MC 2
64.0+ 60.5 62.1+ 38.6 15.1 25.7+
40.6 15.8
22.0 23.7+ 3.3 1.5 4.9
3.6 1.6 4.7
1.7 5.7
1.8 5.0
1.7 6.8
6.7
2.5 10.1 4.6
10.1 5.8
5.0
4.9
9.4
10.7
10.0
Ii.9
Table 1 - Mandible measurements (in mm) ofAmphictis milloquensis from La Milloque "+" indicates a minimum measurement on an incomplete structure. Dimensions (en ram) des mandibules d'Amphictis milloquensis de La Milloque ; "+" indique des mesures minimum d'une structure incomplete.
d e n t a r y is s o m e w h a t d e p r e s s e d along t h e v e n t r a l border. T h e b o d y a t t a i n s to its g r e a t e s t laterom e d i a l b r e a d t h b e n e a t h M1 ( N M B LM 554) or at t h e s y m p h y s i s ( F S P L M 1969 MC 2). T h e m a n d i b u l a r r o w of t h e p o s t - c a n i n e alveoli is n e a r l y s t r a i g h t in t h e holotype, w h e r e a s in F S P L M 1969 MC 2 it a r c h e s n o t i c e a b l y l a t e r a d . T h e p o s t - i n c i s o r alveoli a r e a r r a n g e d one b e h i n d t h e o t h e r a n d closely s p a c e d except for s e p a r a t i o n s b e t w e e n t h e alveoli for C1 a n d P1 in b o t h specim e n s e x a m i n e d (1.9 m m ) , b e t w e e n t h o s e for P1 a n d P2 in F S P L M 1969 MC 2 (1.0 m m ) , b e t w e e n t h o s e for P2 a n d P3 in F S P L M 1969 MC 2 (2.4 m m ) , a n d b e t w e e n t h o s e of M1 a n d M2 in N M B L M 554 (1.2 m m ) . O f t h e p r e s e r v e d t e e t h in F S P L M 1969 MC 2, P3 a n d P4 n e i t h e r t o u c h n o r o v e r l a p e a c h other, P4 a n d M1 a r e not in direct c o n t a c t as well b u t slightly o v e r l a p e a c h other, w h i l e M1 a n d M2 p a r t i a l l y a d h e r e e a c h o t h e r ant e r o - p o s t e r i o r l y ; in t h e t y p e s p e c i m e n , M1 a n d M2 a r e little i s o l a t e d f r o m e a c h other, b u t t h i s is a p p a r e n t l y b e c a u s e of t h e artificially i m p e r f e c t f i t t i n g of d e n t a r y p o r t i o n s b r o k e n b e t w e e n t h e s e t e e t h . P1 is r e p r e s e n t e d b y a single e l o n g a t e alveolus. T h e r e a r e p a i r s of alveoli for P2-M2. T h e
a n t e r i o r alveolus of e a c h p a i r is s m a l l e r t h a n t h e p o s t e r i o r one. T h e r e a r e two elliptical, a n t e r o - p o s t e r i o r l y elong a t e m e n t a l f o r a m i n a lying 4.5 m m ( N M B L M 554) or 6.5 m m ( F S P L M 1969 MC 2) a p a r t . T h e a n t e r i o r of t h e f o r a m i n a , 1.7 m m ( F S P L M 1969 MC 2) or 1.9 m m ( N M B L M 554) in g r e a t e s t diam e t e r , is placed below t h e s p a c e b e t w e e n t h e alveoli for P1 a n d P2, facing a n t e r o - l a t e r a d . T h e m o r e p o s t e r i o r f o r a m e n , m e a s u r i n g a l m o s t 1.4 m m in g r e a t e s t d i a m e t e r , is l o c a t e d below t h e space b e t w e e n t h e alveoli of P2 a n d P3 in t h e t y p e s p e c i m e n or slightly p o s t e r i o r to t h i s location, below t h e a n t e r i o r m a r g i n of P3, in F S P L M 1969 MC 2 ; t h i s f o r a m e n faces a n t e r o - l a t e r o - d o r s a d (NMB LM 554) or p o s t e r o - l a t e r o - d o r s a d ( F S P L M 1969 MC 2). T h e m a n d i b u l a r s y m p h y s i s is u n f u s e d in b o t h s p e c i m e n s u n d e r s t u d y a n d e x t e n d s to t h e level of t h e a n t e r i o r alveolus for P2. T h e r a m u s (or v e r t i c a l p a r t ) of t h e h o l o t y p e dent a r y , v i e w e d f r o m t h e side, is e x c a v a t e d v e n t r a l l y a n d p o s t e r i o r l y b e t w e e n t h e a n g u l a r a n d condyloid processes. I t e x h i b i t s a deep, w e l l - m a r k e d m a s s e t e r i c f o s s a t h a t e x t e n d s a n t e r i o r l y to t h e le-
760 vel of the posterior alveolus for M2 (in F S P LM 1969 MC 2 the fossa ends behind M2). The smallest latero-medial width or thickness of the ramus at the masseteric fossa is about 0.5 mm. From the level of the alveolar margin of the body ventrad, the ramus becomes broader medio-laterally forming at its ventral border a 3-4.5 mm broad, medially rounded shelf that terminates posteriorly in a tapering angular process positioned approximately at the level of the mental foramiha. The condyloid process of the type specimen is situated above the level of the mandibular alveolar border, nearly 7 mm dorsal to the angular process. The neck supporting the capitulum of the condyloid process is short and twisted through some 90 degrees. The long axes of the capitulum and dentary converge at an internal angle of about 65 degrees. Lower teeth P3-4 (Fig. 1, Tab. 2) - Both the teeth are doublerooted in F S P LM 1969 MC 2, with the posterior root being larger than the anterior one, which was also true for the type specimen judging from the alveoli. In P3 and P4 of F S P LM 1969 MC 2, much of the crown consists of a large blade-like cusp that is compressed bucco-lingually and som e w h a t deflected linguad. The tip of this principal cusp is positioned close behind the anterior third of the tooth length in P3, whereas in P4 the cusp culminates slightly more posteriorly, so that P4 has a more symmetric appearance in side view than it is for P3. Either of the teeth shows a small accessory cusp, which is better developed on P4, established along the basal half of the posterior edge of the principal cusp. In both teeth, wear has broken through the enamel of the accessory cusp occlusally. A cingulum is present only anteriorly and posteriorly on both teeth. The anterior cingulum of P3 represents the baso-lingual continuation of the anterior edge of the principal cusp, so that the tooth bears the anterior cingulum only on the lingual side. The anterior cingulum on P4 is also continuous with the anterior edge of the principal cusp, but unlike the condition in P3 it is prolon-
ged on the buccal side. Nevertheless, the lingual portion of the anterior cingulum is much stronger than the buccal one, creating a tiny cuspule slightly lingual to the place of junction with the anterior edge of the principal cusp. This cingular cusplet also occurs on the preserved fragment of P4 in the holotype where it is better pronounced. The posterior cingulum is better developed than the anterior one on both disputed teeth. It is more prominent on P4 where it terminates in two tiny, barely distinguishable elevations separated by a much larger, low cingular elevation culminating on the lingual side. The posterior cingular region is little deflected linguad on both teeth but especially on P4. M1 (Fig. 1, Tab. 3 ; Helbing 1928 : pl. IV, figs 3-6) - The crown of this tooth is supported by two strong roots of which the anterior root is somewhat smaller than the posterior one. In all specimens at hand, a well-marked cingulum runs along the buccal base of the trigonid from the anterior end of the paraconid to about mid-length of the protoconid. Another fragment of the buccal cinguhim is present on the anterior part of the hypoconid base. In F S P LM 1969 MC 7 and F S P LM 1969 MC 9, a short lingual cingulum additionally occurs, bordering the valley between the paraconid and metaconid lingually. The trigonid is notably arched buccad, making its lingual contour concave when viewed from above. The carnassial blade comprises the buccal ridge of the paraconid and the anterior ridge of the protoconid that are divided by a deep, slit-shaped carnassial notch. Except for F S P LM 1969 MC 9 that is almost unworn, the remaining referred trigonids display a more or less worn shearing surface on the buccal side of the paraconid and protoconid. In F S P LM 1969 MC 2, F S P LM 1969 MC 5, FSP LM 1969 MC 8, and partly also in FSP LM 1969 MC 6, the carnassial blade is deeply worn, particularly on the paraconid, exposing dentine facets. Viewed from the occlusal surface, the carnassial edge of the paraconid abruptly turns anteriorly into a short but trenchant lingual ridge descending towards the metaconid from which it is set off by a deep valley. The car-
Length (from anterior-most to posterior-most points of crown) Width (greatest distance between buccal and lingual borders of crown perpendicular to antero-posterier length of tooth) Height (least distance from occlusal-most point of tooth to basal margin of crown, measured on buccal side)
P3
P4
5.6
6.8
2.3
3.1
2.9
4.2
Table 2 - M e a s u r e m e n t s (in mm) of P3 and P4 (FSP LM 1969 MC 2) ofAmphictis milloquensis from La Milloque. Dimensions (en ram) des P3 et P4 (FSP LM 1969 MC 2) d'Amphictis milloquensls de La Milloque.
761
Length (from anterior-most to posterior-most points of crown) Width (least distance from buccal-most point of crown to line joining lingual-most points of paraconid wing and talanid) Trigonid length (least distance from anterior-most point of crown to line connecting notch between protoconid and hypoconid with notch posterior to metaconid) Least distance between buccal and lingual borders of crown across carnassial notch Talonid length (least distance from posterior-most point of crown to line connecting notch between protoconid and hypoconid with notch posterior to metaconid) Talonid w i d t h (greatest distance between buccal and lingual borders of talonid perpendicular to antero-posterior length of tooth) Paraconid height (least distance from occlusal-most point of paraconid to basal margin of crown, measured on lingual side) Protoconid height (least distance from occlusal-most point of protoconid to basal margin of crown, measured on buccal side) Metaconid h e i g h t (least distance from occlusal-most point of metaconid to basal m a r g i n of crown, measured on lingual side) Hypoconid height (least distance from occlusal-most point of hypoconid to basal margin of crown, measured on buccal side) Entoconid height (least distance from ocdusal-most point of entoconid to basal m a r g i n of crown, measured on lingual side)
NMB LM 554
FSP LM 1969 MC 2
FSP LM 1969 MC 5
FSP LM 1969 MC 6
FSP LM 1969 MC 7
FSP LM 1969 MC 8
FSP LM 1969 MC 9
10.0
10.0
8.6
10.6
4.8
4.8
4.1
5.1
4.3+
4.4+
4.3+
7.0
7.1
5.8
7.1
6.0e
6.7e
6.6e
3.8
4.0
3.7
4.1
3.5
3.7
3.6
3.0
2.9
2.8
3.5
4.6
4.3
3.8
4.7
3.6
3.5+
3.1+
3.8
3.1
3.2
3.3
5.9
6.1+
4.9+
6.2
6.0
6.0
4.2
4.0
3.7+
4.2
4.0
4.3
2.5
2.3+
1.7+
2.5+
1.8
1.6
1.5+
2.1+
3.4
Table 3 - Measurements (in mm) of M1 in Amphictis milloquensis from La Milloque ; %" indicates a m i n i m u m m e a s u r e m e n t on an incomplete structure, "e" indicates an estimated value. Dimensions (en mm) des M1 d'Amphietis milloquens@ de La Milloque ; %" indique des mesures minimum d'une structure incomplete, "e" indique des dimensions estimges.
nassial edge of the protoconid curves posteriorly at an about right angle to continue into a sharp ridge falling obliquely down until it meets the metaconid. In addition to the anterior and lingual ridges, the protoconid exhibits another two ridges that begin and terminate on its posterior wall. The occlusal and longer of these posterior ridges descends from about the top of the protoconid basad and is poorly differentiated and blunt, being in most specimens partially or completely removed by wear affecting the posterior surface of the trigonid. The basal ridge, by contrast, is very short but trenchant and ascends occlusad and slightly linguad from the anterior end of the hypoconid. The basal ridge of the protoconid is entirely worn out in F S P LM 1969 MC 6. The metaconid stands in part behind the protoconid, so that its posterior edge is visible in buccal view and the posterior wall of the trigonid is concave in occlusal view. The metaconid is stout, well detached from the protoconid, more or less deflected linguad, and higher than the paraconid,
resembling an equilateral triangle when viewed from the lingual side. Its tip in F S P LM 1969 MC 5 is worn away, exposing a dentine facet. The anterior face of the metaconid, which flanks postero-lingually a deep, spacious valley that sets it and the protoconid off from the paraconid, is widely rounded and blunt except for a short, edged occluso-basal crest found in F S P LM 1969 MC 2, F S P LM 1969 MC 7, and NMB LM 554. The buccal slope of the metaconid is angulated into a trenchant ridge that is united with the lingual crest of the protoconid at a prominent, slit-like notch. The posterior profile of the metaconid is made up by a sharp ridge that is about twice longer than the buccal ridge. It forms an angle of some 105-110 degrees with the occlusal margin of the lingual wall of the talonid, being slightly more oblique than the posterior profile of the protoconid. The talonid is rather deeply basined and somewhat deflected buccad, giving the buccal margin of the crown a remarkably concave outline be-
762 tween the protoconid and hypoconid when viewed from above. All the talonids available show an extensive wear facet on the buccal surface adjacent to this concavity. In addition to this facet there is another one in FSP LM 1969 MC 2 and FSP LM 1969 MC 5, placed more posteriorly and thus occupying the postero-buccal part of the talonld wall. The hypoconid is the largest and highest cusp on the talonid. It is elongate antero-posteriorly and has a conspicuously inclined buccal wall, making the talonid basin shifted linguad in occlusal view, especially in FSP LM 1969 MC 2. The anterior end o f the hypoconid is delimited by a V-shaped notch separating the anterior hypoconid crest from the basal posterior ridge of the protoconid. The hypoconid is followed postero-lingually by a weakly differentiated, tiny hypoconulid. In the talonids studied, excepting that of the holotype, wear has breached the enamel along both the hypoconid and hypoconulid. The posterior wall of the talonid, incorporating the hypoconulid, is lower t h a n the buccal and lingual walls. The latter, being detached from the metaconid by a small but distinct slit-shaped notch (rounded by wear in FSP LM 1969 MC 5), is produced occlusally into two (FSP LM 1969 MC 6) or three (NMB LM 554, FSP LM 1969 MC 2, and FSP LM 1969 MC
5) low elevations. The largest and highest of these elevations, the entoconid, lies most posteriorly at the postero-lingual corner of the talonid. This cusp in FSP LM 1969 MC 6 and both it and the elevation adjoining the metaconid in FSP LM 1969 MC 5 expose small wear facets of dentine occlusally.
M2 (Fig. 1, Tab. 4 ; Helbing 1928 : pl. IV, figs 3-5) - This tooth is two-rooted ; the anterior root is distinctly smaller t h a n the posterior one. The trigonid is larger t h a n the talonid. The latter is deflected occlusad and buccad. The buccal border of the crown is slightly excavated when viewed from the occlusal surface. A cingulum is present only on the buccal side anteriorly and posteriorly as shown by the holotype. In FSP LM 1969 MC 2, much of the antero-buccal cingulum has been removed by wear ; the postero-buccal part of this crown has been broken away. The protoconid and metaconid are salient. The latter is situated partly behind the former. The protoconid is higher t h a n the metaconid, but both the cusps are approximately equal in size when viewed from above. Each of t h e m is angulated by three ridges sloping anteriorly, medially, and posteriorly. The medial ridges in the type specimen are basally joined to each other at a V-shaped
Length (from anterior-most to posterior-most points of crown) Width (least distance from lingual-most point of crown to line joining buccal-most points of trigonid and talonid) Trigonid length (least distance between anterior-most point of crown and line t h a t is perpendicular to antero-posterior length of tooth and passes across notch separating protoconid from hypoconid) Trigonid width (greatest distance between buccal and lingual borders of trigonid perpendicular to antero-posterior length of tooth) Trigonid basin length (from anterior-most point of trigonid basin to notch between protoconid and metaconid) Talonid length (least distance between posterior-most point of crown and line t h a t is perpendicular to antero-posterior length of tooth and passes across notch separating protoconid from hypoconid) Talonid width (greatest distance between buccal and lingual borders of talonid perpendicular to antero-posterior length of tooth) Talonid basin length (from posterior-most point of talonid basin to notch between protoconid and metaconid) Protoconid height (least distance from occlusal-most point of protoconid to basal margin of crown, m e a s u r e d on buccal side) Metaconid height (least distance from occlusal-most point of metaconid to basal margin of crown, m e a s u r e d on lingual side) Hypoconid height (least distance from occlusal-most point of hypoconid to basal margin of crown, m e a s u r e d on lingual side)
NMB LM 554
FSP LM 1969 MC 2
FSP LM 1969 MC 1
5.1
5.6+
7.2
3.7
3.9
4.7
3.3
3.4
4.2
3.7
3.9
4.7
2.0
2.0
2.4
1.8
2.2+
3.0
2.8
3.0+
3.8
2.7
3.3e
4.4
2.3
2.6
1.7+
2.0
2.0
2.6
1.6
1.7+
Table 4 - Measurements (in mm) of M2 in Amphictis milloquensis (NMB LM 554 and FSP LM 1969 MC 2) and Amphictis ambigua (FSP LM 1969 MC 1) from La Milloque ; '%" indicates a m i n i m u m m e a s u r e m e n t on an incomplete structure, "e" indicates an estimated value. Dimensions (en ram) des M2 d'Amphictis milloquensis (NMB L M 554 et F S P L M 1969 MC 2) et Amphictis a m b i g u a (FSP L M 1969 MC 1) de La Milloque ; "+" indique des mesures minimum d'une structure incomplete, "e" indique des dimensions estimdes.
763 notch ; they are sharp except for the occlusal part of the protoconid where the medial slope is blunt. In F S P LM 1969 MC 2, the medial slopes of both the cusps are more or less rounded by wear, while the notch is heavily worn basally. The anterior ridges of the protoconid and metaconid originate at the tips of the cusps and are trenchant (that on the protoconid in F S P LM 1969 MC 2 is considerably worn along its basal half). They are connected by a low but edged, widely arched crest delimiting the trigonid basin anteriorly. There are four tiny elevations established along this crest in the holotype, of which the second counting from the metaconid is largest, whereas that adjacent to it buccally is smallest. The anterior trigonid crest in F S P LM 1969 MC 2, judging from the state of its preservation, was originally produced into two elevations only. The lingual of them, exposing an extensive dentine facet occlusally, was evidently prominent and conspicuously larger than the buccal one that is less worn. The posterior ridge of the protoconid is sharp and present about mid-way up the posterior slope of the cusp. Buccally of this ridge, the posterior face of the protoconid is worn in both specimens at hand. In F S P LM 1969 MC 2, this wear facet is larger and extends posteriorly onto the preserved buccal surface of the hypoconid. In addition to this facet, F S P LM 1969 MC 2 displays another extensive area of wear occupying the buccal wall of the trigonid in front of the tip of the protoconid. The posterior ridge of the metaconid is blunt and takes its rise at the tip of the cusp. It is continuous with a low, occlusally round crest that gently ascends postero-buccad and then buccad along the talonid margin to culminate at the posterior end of the crown where it meets both the posterobuccal cingulum and the posterior ridge of the hypoconid. This culmination represents the hypoconulid and can be seen in the holotype. In F S P LM 1969 MC 2, the corresponding portion of the crown has been broken off.
The hypoconid occupies much of the talonid area. Relative to the protoconid and metaconid, it is larger in F S P LM 1969 MC 2 than that of the holotype, being distinctly lower t h a n either of these cusps in both referred specimens. The hypoconid is sharpened occlusally into the anteroposteriorly oriented edge separated from the posterior ridge of the proteconid by a small b u t distinct, V-shaped notch. The trigonid and talonid are basined b u t of little depth. The trigonid basin is antero-posteriorly shorter but bucco-lingually broader than that of the talonid, so that both the basins are approximately equal in size. When viewed from the occlusal surface, the trigonid basin in the type specimen lies almost centrally, whereas in F S P LM 1969 MC 2 it appears to be displaced linguad in consequence of a greater lingual inclination of the protoconid. The talonid basins of both the specimens are distinctly shifted linguad.
U~pp er teeth P (Fig. 2, Tab. 5) - As deduced from F S P LM 1969 MC 3, this tooth had originally three major roots : two smaller (broken) placed side by side anteriorly and the largest one (preserved) located posteriorly. Moreover, a tiny accessory root occurs directly behind the remnant of the antero-buccal root. The preserved part of the crown is surrounded by a well-developed cingulum except for the posterior end of the crown and the buccal base of the paracone where it is faint or absent. The antero-buccal (or parastyle) wing is small but well defined. The lingual half of this wing bears a small but distinct parastyle that stands out from the cingulum. The paracone, which is a dominant cusp on the crown, displays four ridges passing from its tip basad. The buccal and antero-lingual ridges are widely rounded and blunt ; the former vanishes near the buccal cingulnm about at the level of the accessory root, whereas the latter ends artifidally at the broken surface of the protocone wing. The antero-buccal ridge is more trenchant
Figure 2 - A m p h i c t i s m i l l o q u e n s i s , FSP LM 1969 MC 3, left p4 (protocone wing broken away) : a, occlusal view ; b, lingual view ; c, buccal view. A m -
?
,smm
phictis milloquensis, FSP L M 1969 M C 3, P4 g a u c h e (aile de protocone cassde) : a, r u e occlusale ; b, vue linguale ; c, rue buccale.
764
Length (from anterior-most point of parastyle wing to posterior-most point of crown) Least distance from posterior-most point of crown to indentation between parastyle and protocone wings Least distance between buccal and lingual borders of crown across carnassial notch Paracone height (least distance from occlusal-most point of paracone to basal margin of crown, measured on buccal side)
8.5 8.1 3.3 4.9
Table 5 - Measurements (in mm) of p4 (FSP LM 1969 MC 3) ofAmphictis milloquensis from La Milloque. Dimensions (en mm) de i°4 (FSP L M 1969 M C 3) d ' A m p h i c t i s m i l l o q u e n s i s de La MiUoque.
0
5mm Figure 3 - Amphictis milloquensis~ FSP LM 1969 MC 4, right M (damaged antero-lingually) : a, occlusal view ; b, anterior view ; c, posterior view. A m p h i c t i s m i l l o q u e n sis, F S P L M 1969 M C 4, M1 droite (cassde ant~ro-lingualement) : a, rue occlusale ; b, rue antdrieure ; c, rue postdrieure.
a
Length (least distance from anterior border of crown to posterior-most point of metacone wing) Width (from buccal-most to lingual-most points of crown) Trigon length (greatest distance between margins of parastyle and metacone wings) Least distance between anterior and posterior borders of crown across notch separating protocone from paraconule Least distance from occlusal-most point of hypoconal cingulum to basalmargin of crown, measured on lingual side)
6.2 10.0 6.8 4.6 1.8
Table 6 - Measurements (in mm) of M1 (FSP LM 1969 MC 4) of Amphictis milloquensis from La Milloque. Dimensions (en ram) de M1 (FSP L M 1969 M C 4)
d'Amphictis mUloquensis de La Milloque.
a n d joins to t h e p a r a s t y l e . T h e p o s t e r i o r ridge c o n s t i t u t e s t h e a n t e r i o r p a r t of t h e c a r n a s s i a l blade, b e i n g d e t a c h e d f r o m t h e p o s t e r i o r p a r t b y a conspicuous, slit-like c a r n a s s i a l notch. T h e p o s t e r i o r (or m e t a c o n e - m e t a s t y l e ) w i n g is deflected buccad, giving t h e buccal m a r g i n of t h e c r o w n a concave c o n t o u r a n d m a k i n g the c a r n a s sial b l a d e n o t a b l y c u r v e d in occlusal view. T h e p o s t e r i o r p a r t of t h e c a r n a s s i a l b l a d e is c o m p o s e d of t h e m e t a c o n e a n d m e t a s t y l e t h a t are d e m a r c a t e d b y a s h a l l o w groove e s t a b l i s h e d on t h e buccal s u r f a c e occlusally. T h e m e t a c o n e is h i g h e r a n d shorter antero-posteriorly than the metastyle. T h e s h e a r i n g surface on t h e lingual side of t h e m e t a c o n e , m e t a s t y l e , a n d also p a r a c o n e is moder a t e l y worn. M 1 (Fig. 3, Tab. 6) - This t o o t h p o s s e s s e s two roots b u c c a l l y a n d one l i n g u a l l y ; t h e l i n g u a l root is l a r g e s t , a n d t h e p o s t e r o - b u c c a l one s u p p o r t i n g t h e m e t a c o n e is s m a l l e s t . A p a r t f r o m f r a g m e n t s affected b y d a m a g e , t h e c r o w n of F S P L M 1969 MC 4 is encircled b y a s t r o n g cingulum. T h e par a c o n e is l a r g e r a n d h i g h e r t h a n t h e m e t a c o n e .
B o t h t h e cusps a r e c o m p r e s s e d bucco-lingually giv i n g t h e m a blade-like form. T h e p a r a c o n e blade, w h i c h is a b o u t 2.8 m m long, is a n t e r o - b u c c a l l y contiguous to t h e p a r a s t y l e , w h i l e t h e m e t a c o n e blade, m e a s u r i n g a b o u t 2.2 m m in l e n g t h , is post e r i o r l y continued into t h e m e t a s t y l e c r e s t ; t h e p a r a s t y l e is b e t t e r p r o n o u n c e d t h a n t h e m e t a s tyle. T h e p a r a s t y l e a n d m e t a s t y l e crests, e a c h less t h a n 1 m m long, a r e c o n t i n u o u s w i t h t h e buccal c i n g u l u m at t h e a n t e r o - b u c c a l a n d posterobuccal corners of t h e crown, respectively. T h e par a c o n e is deflected b u c c a d following t h e p a r a s tyle, so t h a t t h e p a r a c o n e - p a r a s t y l e w i n g projects a n t e r o - b u c c a d and, w h e n v i e w e d f r o m t h e occlusal surface, the buccal b o r d e r of t h e c r o w n is rem a r k a b l y e x c a v a t e d at t h e level of a p r o m i n e n t V - s h a p e d n o t c h dividing t h e p a r a c o n e f r o m t h e m e t a c o n e . T h e l i n g u a l b a s e of t h e p a r a c o n e exhibits a short, low ridge t h a t r u n s t o w a r d s t h e par a c o n u l e to d i s a p p e a r n e a r b y its base. T h e p a r a conule f o r m s a s m a l l e l e v a t i o n on a p r o m i n e n t crest connecting t h e a n t e r i o r c i n g u l u m w i t h t h e protocone. T h e r e is a h e a v y - w e a r facet incised into t h e crest b e t w e e n t h e p a r a c o n u l e a n d proto-
765
0
Figure 4 - A m p h i c t i s ambiF S P LM 1969 MC 1, r i g h t M2 : a, occlusal view ; b, lingual view ; c, buccal view.
gua,
Amphictis
ambigua, FSP L M 1969 M C 1, M 2 droite : a, r u e occlusale ; b, uue linguale ; c, rue buccale.
cone. The protocone culminates at the level of the paracone and is produced posteriorly into a very low and wide, barely distinguishable ridge passing postero-buccad to reach the posterior cingulum at the place where wear has breached the enamel for a minute, ovate area that seems to be a r e m n a n t of a tiny metaconule. The talon is deflected posteriorad and occlusad, giving the posterior margin of the crown a noticeably concave outline in occlusal view and making the hypoconal cingulum conspicuously swollen. None the less, no differentiated hypocone can be identified except that wear has slightly broken through the enamel along the hypoconal cingulum posteriorly.
metastyle, and somewhat worn posterior portion of the buccal cinguhim. Its width across carnassial notch is 3.3 mm, while the height of its paracone measured more t:han 4.9 mm originally. There are no significant differences in size or shape between the teeth from Dieupentale and their counterparts from La Milloque.
AMPHICTIS AMBIGUA (GERVAIS, 1872) 1872 - Viverra (Arnphictis) ambigua GERVAIS, p. 266. 1887 -Amphictis Gervaisi SCHLOSSER, p]. 9, figs 46, 47 (not fig. 18). M a t e r i a l - FSP LM 1969 MC 1, right M2.
Discussion This species was originally described from La Milloque by Helbing (1928) who referred it to the genus Plesictis POMEL, 1846. Wolsan (1993) has recently re-diagnosed the mustelidan genera of the European Oligocene and Early Miocene, including Plesictis and Amphictis, and placed the holotype of Amphictis miUoquensis in his list of fossil specimens assigned to Amphictis. He therefore included this species, though not explicitly, in the genus Amphictis. Our comparison of the morphology of known remains ofAmphictis milloquensis with the emended diagnoses of Plesictis and Amphictis provided by Wolsan (1993) plainly supports the inclusion of this species in the genus
Amphictis. Additional records of Amphictis miUoquensis involve two other Late Oligocene localities in the Aquitaine Basin : Dieupentale, attributed to the reference level MP 29 by Duranthon (1991), and Th6zels (MP 30, Schmidt-Kittler, ed. 1987). For Th~zels, the species was only mentioned but undescribed by de Bonis & Guinot (1987). The material from Dieupentale includes three isolated teeth : M1 (PDV Dp 245 ; length = 8.6 mm, width = 4.5 mm) and M2 (PDV Dp 247 ; length = 5.8 mm, width = 3.7 mm) described by Crouzel et al. (1977 : figs 2!-24), and an undescribed, partial left p4. This p4 (PDV Dp 256) lacks its protocone and parastyle wings and anterior roots, and has a dentine facet at the paracone tip, well worn shearing surface of the paracone, metacone, and
Description (Fig. 4, Tab. 4) - The M2 has two roots of which the anterior root is considerably smaller than the posterior one. The trigonid is larger than the talonid. The latter is somewhat deflected buccad, giving the buccal margin of the tooth a smoothly concave outline when viewed from above. Wear has polished the surface of the crown, making the tips of the cusps and the ridges round and blunt. There is no trace of a cingulum. The dominant cusps of the crown are the protoconid, metaconid, and hypoconid. The protoconid is positioned buccal and slightly anterior to the metaconid and exactly anterior to the hypoconid. The metaconid and hypoconid appear to be little smaller than the protoconid when viewed from the occlusal surface. Although wear has significantly contributed to the heights of the cusps, affecting particularly the protoconid and hypoconid on which the dentine is exposed, occlusally, it can be inferred that the metaconid was also originally the highest cusp of the crown and that the protoconid was higher than the hypoconid. The protoconid and metaconid each have three ridges that pass down their slopes anteriorly, medially, and posteriorly, whereas the hypoconid has only two, anteriorly and posteriorly. The place where the medial ridges of the protoconid and metaconid meet each other is rounded by wear, but was apparently notched originally. The anterior ridges of the protoconid and metaconid
766
5.0
I
•
La Miltoque + Pech du Fraysse • Pech Desse
e
4, 4-44-4-
EE4. 0.
+ 4-
044-
4,
4.
44-
3.04~
+
4-+ • 4• 44-
5'.0
eb
Length, mm
7.'0
Figure 5 - Relationship between the length and width of M2 in A m p h i c t i s a m b i g u a . Data for Pech Desse and Pech du Fraysse from Cirot (1992). Relations entre la longueur et la largeur des M2 d ' A m p h i c t l s a m b l g u a . Les dimensions des M 2 de Pech Desse et Pech du Fraysse sont de Cirot (1992).
A comparison of the M2 from La Milloque with the holotype of Amphictis ambigua (MNHN Qu 9243) and the corresponding teeth of this species from Pech Desse and Pech du Fraysse (housed in FSP and described by Cirot 1992) revealed no significant differences in morphology. The relatively large dimensions of this tooth, however, placing it at the upper limit of the known range of size variation for the species (Fig. 5), suggest a larger average size in members of the La Milloque population as compared with t h a t for the Pech du Fraysse population and, in particular, t h a t for the population of Pech Desse. Because the faunal assemblage of La Milloque is stratigraphically younger t h a n t h a t from Pech du Fraysse (Schmidt-Kittler, ed. 1987), and the latter fauna is younger t h a n t h a t of Pech Desse (MSdden 1993), the data presented in Fig. 5 provide supporting evidence for a progressive trend towards size increase through time in Amphictis ambigua, postulated by Cirot (1992).
CONCLUSION are continued with a low crest t h a t broadly arches along the anterior border of the crown and is produced into four weakly differentiated, low elevations. The posterior ridge of the protoconid is separated from the anterior hypoconid ridge by a distinct depression, now rounded by wear but plausibly notched originally. The posterior ridge of the metaconid is continuous with a low crest t h a t runs postero-buccad along the slightly convex lingual border of the talonid. This low crest constitutes a tiny elevation t h a t culminates posteriorly and presumably represent the entoconid. Between this elevation and the posterior ridge of the hypoconid, at the posterior end of the crown, there is a small cuspule corresponding in its position to the hypoconulid. This cusplet is barely visible at the state of wear of the crown but it is well indicated by a tiny, ovoid dentine facet. The trigonid and talonid basins are shallow ; the latter is almost twice as extensive as the former. The basin of the trigonid is situated nearly centrally, whereas t h a t on the talonid appears to be little shifted linguad in occlusal view. - This species was erected by Gervais (1872) based on a partial mandible from Concots (Phosphorites du Quercy) in south-western France. The exact age of the fossil is unknown. However, the recent excavations in the Quercy area, involving the Late Oligocene localities Pech Desse and Pech du Fraysse (MP 28, Schmidt-Kittler, ed. 1987), have yielded an abundant material of Amphictis ambigua (de Bonis 1976 ; Cirot 1992 ; Cirot & de Bonis 1993). Discussion
1. The populations of Amphictis milloquensis from La Milloque and Dieupentale did not differ significantly. 2. The characteristic trait in evolution of Amphictis ambigua was a progressive size increase. Acknowledgments - We thank M. Brunet (Poitiers) and D. Vidalenc (Saint Gaudens) for the contribution of amphictid remains from a new collection of La Milloque and from Dieupentale, respectively. The drawings of the fossils are by S. Riffault (Poitiers). This study was supported by the State Committee for Scientific Research grant 6 P204 051 05 (Poland) and the Swiss National Science Foundation.
REFERENCES Bo~s L. de 1976 - D~couverte d'un crane d'Amphictis (Mammalia, Carnivora) dans l'Oligoc~ne sup~rieur des Phosphorites du Quercy (Lot). Comptes Rendus hebdomadaires des Sgances de l'Acadgmie des Sciences (Paris), Sgrie D, 283 : 327-330. BONIS L. de & GUINOTY. 1987 - Le gisement de Vertebras de Th~zels (Lot) et la limite Oligo-Mioc~ne dans les formations continentales du bassin d'Aquitaine. Mi~nchner Geowissenschaftliche Abhandlungen, Reihe A, 10 : 49-57. BOWDICHT.E. 1821 - An analysis of the natural classifications of Mammalia, for the use of students and travellers. J. Smith, Paris : 115 p. BRUNET M. 1979 - Les grands Mammi~res chefs de file de l~immigration Oligoc~ne et le p robl~rne de la limite Eoc~ne-Oligoc~ne en Europe. Editions de la Fondation Singer-Polignac, Paris : 281 p.
767 CIROT E. 1992 - t~tude phylog6n6tique de quelques g e n r e s d'Arctoidea de l'Oligoc6ne eurasiatique. C o m p a r a i s o n des donn6es morphologiques et mol6culaires. 2 vols. Th6se, Universit6 de Poitiers, 496 : 1-152. CIROT E. • BONIS L. de 1993 - Le cr~ne d'Amphictis ambiguus (Carnivora, M a m m a l i a ) : son i m p o r t a n c e pour la compr6hension de la phylog6nie des Must6loides. Comptes Rendus de l'Acaddmie des Sciences (Paris), Sdrie H, 316 : 1327-1333. CROUZEL F., GINSBURG L. & VIDALENC D. 1977 - Les C a r n i v o r e s fissip6des du S t a m p i e n t e r m i n a l de D i e u p e n t a l e (Tarn-et-Garonne). Bulletin de la Socidtd d'Histoire naturelle de Toulouse, 112 (1976) : 207-229. DURANTHON F. 1991 - Biozonation des molasses contin e n t a l e s oligo-mioc6nes de la r6gion toulousaine p a r l'6tude des mammif'eres. A p p o r t s ~ la connaissance d u b a s s i n d ' A q u i t a i n e (France). Comptes Ren-
dus de l'Acaddmie des Sciences (Paris), Sdrie II, 313: 965-970. FLOWER W.H. 1869 - On the v a l u e of t h e c h a r a c t e r s of t h e b a s e of the c r a n i u m in t h e classification of t h e o r d e r Carnivora, a n d on t h e s y s t e m a t i c position of Bassaris a n d o t h e r d i s p u t e d forms. Proceedings of
the Scientific Meetings of the Zoological Society of London, 1869 : 4-37. GERVAIS P. 1872 - S u r les MammiFeres dont les ossem e n t s a c c o m p a g n e n t les d6pSts de chaux phosphat6e des d 6 p a r t e m e n t s de T a r n - e t - G a r o n n e et du Lot. Journal de Zoologie (Paris), 1 : 261-268. HELBING H. 1928 - C a r n i v o r e n des oberen Stampien.
Abhandlungen der Schweizerischen Palaeontologischen Gesellschaft, 47 (4) : 1-83. KRETZOI M. 1945 - B e m e r k u n g e n fiber das Raubtiersystem. Annales Historico-Naturales Musei Nationalis Hungarici, 38 : 59-83. MODDEN C. 1993 - Revision d e r A r c h a e o m y i n i Schlosser (Rodentia, M a m m a l i a ) des europfiischen Oberoligoz~n. Schweizerische Paliiontologische Abhandlungen, 115 : 1-83. POMEL A. 1846 - M6moire pour servir h la g6ologie pa16ontologique des t e r r a i n s t e r t i a i r e s du d6partem e n t de l'Allier. Bulletin de la Socidtd gdologique de France, Sdrie 2, 3 (1845-1846) : 353-373.
POMEL A. 1853 - Catalogue des vert6br6s fossiles (suite.). Annales Scientifiques, Littdraires et IndustrieUes de l'Auvergne, 26 : 81-229. RICHARD M. 1948 - Contribution ~ l'6tude du B a s s i n d'Aquitaine. Les g i s e m e n t s de Mammif'eres tertiaires. Mdmoires de la Socidtd gdologique de France, Nouvelle Sgrie, 24 (52) : 1-380. SCHLOSSER M. 1887 Die Affen, Lemuren, Chiropteren, Insectivoren, M a r s u p i a l i e r , Creodonten u n d Carnivoren des europ~iischen Terti~irs u n d deren Beziehungen zu i h r e n l e b e n d e n u n d fossilen aussereuropfiischen V e r w a n d t e n . Beitr~ige zur
Paldontologie Osterreich-Ungarns und des Orients, 6 : 1-224. SCHMIDT-KITTLER N. (ed.) 1987 - E u r o p e a n reference levels a n d correlation tables. Mi~nchner Geowissenschaftliche Abhandlungen, Reihe A, 10 : 13-31. TEDFORD R.H. 1976 - Relationship of p i r m i p e d s to other carnivores (Mammalia). Systematic Zoology, 2 5 : 363-374. WINGE H. 1895 - J o r d f u n d n e og n u l e v e n d e Rovdyr (Carnivora) fra Lagoa S a n t a , Minas Geraes, Brasilien. Med U d s i g t over Rovdyrenes i n d b y r d e s Staegtskab. In LOTKEN C.F. (ed.) : E Museo Lundii.
En Samling af Afhandlinger om de i det indre Brasiliens Kalkstenshuler af Professor Dr. Peter Vilhelm Lund udgravede og i den Lundske palaeontologiske Afdeling af Kjbenhavns Universitets zoologiske Museum opbevarede Dyre- og Menneskeknogler, Bind 2 (2, 4). H. H a g e r u p s Boghandel, Copenh a g e n : 1-130. WOLSAN M. 1993 - Phylogeny a n d classification of early E u r o p e a n M u s t e l i d a ( M a m m a l i a : Carnivora). Acta Theriologica, 38 : 345-384. E. CIROT
Facult6 des Sciences Laboratoire de G6obiologie, Biochronologie et Pal6ontologie Humaine 40, avenue du Recteur Pineau F-86022 Poitiers Cedex M. WOLSAN Instytut Paleobiologii, Polska Akademia Nauk Aleja Zwirki i Wigury 93 02-089 Warszawa, Poland