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Stegosaurian Dinosaurs from the Bathonian(Middle Jurassic) of England, the earliest record of the family Stegosauridae
STEGOSAURIAN DINOSAURS FROM THE BATHONIAN ( MIDDLE JURASSIC ) OF ENGLAND, THE EARLIEST RECORD OF THE FAMILY STEGOSA URIDAE
by PETER M. GALTON * & H. PHILIP POWELL **
ABSTRACT
RESUME
The earliest records of stegosaurian dinosaurs of the family Stegosauridae are a few isolated bones from the Bathonian (Middle Jurassic) of southern England. A massive femur of a juvenile individual from the Lower Cornbrash (top of Upper Bathonian) of Oxfordshire is tentatively referred to the genus Lexovisaurus HOFFSTETTER as L . . 9 vetustus (HUENE). Four other bones from the Lower Bathonian are tentatively referred to this taxon • two incomplete vertebrae from the Sharp's Hill Formation of Oxfordshire and two large and massive dermal plates from the underlying Chipping Norton Formation (basal Bathonian) of Gloucestershire.
Les plus anciennes traces de dinosaures st6gosauriens de la famille des Stegosauridae sont constitu6es de quelques os isol6s appartenant au Bathonien (Jurassique moyen) de l'Angleterre du sud. Un f6mur massif d'un jeune individu provenant du Cornbrash inf6rieur (fin du Bathonien sup6rieur) de l'Oxfordshire est ~ttitre d'essai rapport6 au genre Lexovisaurus HOFFSTETTER comme L. ? vetustus (HUENE). Quatre os suppl6mentaires du Bathonien inf6rieur sont attribu6s, provisoirement, h la m~me esp6ce : deux vert~bres incompl~tes de la Formation de Sharp's Hill dans l'Oxfordshire, et deux plaques dermales, grandes et massives de la Formation sous-jacente de Chipping Norton (d6but du Bathonien) dans le Gloucestershire.
KEY-WORDS : ORNITHISCHIA (STEGOSA URIA), MIDDLE JURASSIC (BATHONIAN), ANATOMY-SKELETON, ENGLAND. SOTS-CLIPS : ORNITHISCHIA (STEGOSA URIA), JURASSIQUE MOYEN (BATHONIEN), ANATOMIE DU SQUELETTE, ANGLETERRE.
* Department of Biology, University of Bridgeport, Bridgeport, Ct. 06601, USA. ** Geological Collections, University Museum, Oxford OX1 3PR, England.
Geobios, n ° 16, fasc. 2
p. 219-229, 1 fig., 3 tabl., 1 pl.
Lyon, avril 1983
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CONTENTS
I - - Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . .
220
IV - - Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . .
225
Upper Bathonian . . . . . . . . . . . . . . . . . . . . . . .
220
v-
226
III - - Lower Bathonian . . . . . . . . . . . . . . . . . . . . . . .
224
II
-
-
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I -- INTRODUCTION Jurassic stegosaurs or plated dinosaurs of the family Stegosauridae are well known from rocks of Kimmeridgian to Portlandian age (Upper Jurassic, 145-135 my ; Van Hinte, 1976) of western North America, western Europe, East Africa and China (Hoffstetter, 1957 ; Steel, 1969) (tabl. 1). Middle Jurassic stegosaurs are represented by three articulated specimens of Lexovisaurus durobrivensis (HULKE) plus several isolated bones (Hoffstetter, 1957 ; Steel, 1969) that all came from the Middle Callovian (about 155 my ; Van Hinte, 1976) of England (tabl. 2 ; Hulke, 1887 ; Nopcsa, 1911a ; Galton, 1980) and France (Galton & alii, 1980). However, only a few earlier records of stegosaurs have been reported, and these all came from the underlying Bathonian (lower Middle Jurassic, 165-158.5 my ; Van Hinte, 1976) of England (tabl. 3 ; Hoffstetter, 1957 ; Steel, 1969). A femur from the Upper Bathonian of Oxfordshire was described as Omosaurus (Dacentrurus) vetustus HUENE, 1910 (also in Huene, 1956, fig. 584) ; S.H. Reynolds (1937, 1939) referred two large dermal plates from the Lower Bathonian of Gloucestershire to the North American genus
II - - U P P E R HORIZON AND LOCALITY
The holotype of Omosaurus vetustus HUENE, 1910 is a right femur (OUM J. 14000 : figs. 1 A-F ; pl. 1, figs. 16-21) that bears the label <>. This locality is the series of quarries, about 9.6 km north of Oxford, in the west bank of the River Cherwell, which extend about 0.8 km southwards downstream from Enslow Bridge itself (Grid reference SP 42 477 177). A specimen of the bivalve Meleagrinella echinata on the femur (fig. 1B) indicates that the bone was obtained from the Cornbrash Formation, probably the Lower
Stegosaurus ; and P.M. Galton (1980) illustrated a stegosaurian dorsal vertebra from the Middle Bathonian of Oxfordshire. Scelidosaurus OWEN, 1861 of the family Scelidosauridae from the Lower Jurassic of Dorsetshire has long been regarded as a primitive stegosaur, but this is probably incorrect (see Thulborn, 1977; also Galton, 1975, 1980; Romer, 1968). The purpose of this paper is to review the stegosaurian specimens from the Bathonian of England that represent the earliest records of the family Stegosauridae discovered to date from anywhere. The specimens are discussed in descending stratigraphical order starting with the most recent (see tabl. 3). Cited institutions are abbreviated as follows: BMNH, British Museum (Natural History), London ; MGSP, Museum of Geological Survey of Portugal, Lisbon ; OUM, Oxford University Museum ; SDM, Stroud and District Museum, Stroud, Gloucestershire ; SMC, Sedgwick Museum, Cambridge Univers i t y ; U S N M , United States National Museum of Natural History, Washington, D.C.
BATHONIAN Cornbrash ( Clydoniceras discus Subzone of Clydoniceras discus Zone, upper Upper Bathonian, Cope & alii, 1980, fig. 6b. B12) because the Upper Cornbrash (Lower Callovian, Cope & alii, 1980, fig. 8.C6) is thin and patchy in this area. The eroded nature of the bone, and the fact that bones are virtually unknown in the Cornbrash Formation but do occur in the lagoonal facies of the Forest Marble Formation, suggest that it was derived from the underlying Forest Marble Formation (tabl. 3). The top of the Forest Marble Formation (Clydoniceras hollandi Subzone of Discus Zone, Cope & alii, 1980, fig. 6b.B12) has much evidence of land-
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Order ORNITHISCHIA SEELEY, 1888 Suborder S t e g o s a u r i a MARSH, 1877 Family STEGOSAURIDAE MARSH, 1880
Dacentrurus armatus (OWEN) from Lower Kimmeridgian of England, France and Portugal. D. ? vetustus (SEELEY) from Middle Oxfordian of England. Kentrosaurus aethiopicus HENNIG from Upper Kimmeridglan of Tanzania, East Africa. Lexovisaurus durobrivensis (HULKE) from Middle Callovian (Middle Jurassic) of England and France. L. ? vetustus (HUENE) from Bathonian (Middle Jurassic) of England. Stegosaurus spp. from Upper Kimmeridgian or Lower Portlandian of western USA, North America. Tuojiangosaurus multispinus DONG & alii 1977 from the Kimmeridgian of Szechuan, China. Suborder A n k y l o s a u r i a OSBORN, 1923 Family NODOSAURIDAE MARSH, 1890
Sarcolestes leedsi LYDEKKER from Middle Callovian of England. Suborder ineertae sedis Family SCELIDOSAURIDAE HUXLEY, 1869
Scelidosaurus harrisonii OWEN from the Lias (Lower Jurassic) of England.
Tabl. 1 - - Classificaton of taxa cited with stratigraphic and geographic localization (see also tabl. 2, 3). Classification des taxons cites et leur Iocalisation stratigraphique et g6ographique (voir aussi tabl. 2, 3).
Stage Cretaceous
STEGOSAURIDAE
Neocomian Portlandian
Upper Jurassic
Kimmeridgian
Oxfordian
Craterosaurus pottonensis U M L
t U L
Dacentrurus armatus
1 UM
Dacentrurus ? phillipsi
L
Callovian Middle Bathonian Jurassic Bajocian
{-u
M L
Lexovisaurus durobrivensis
t UML
Lexovisaurus ? vetustus vertebrae, armor
1u
L
Aalenian
Tabl. 2 - - Stratigraphic distribution of the family Stegosauridae in England. L - Lower ; M - Middle ; U - Upper ; for Neocomian stegosaurs see P.M. Galton (1981b) ; for the Bathonian see taN. 3. Distribution stratigraphique de la famille de s
Stegosauridae en Angleterre.
L - Inf~rieur ; M - Moyen ; U - Sup~rieur ; pour Craterosaurus voir P.M. Galton (1981b) ; pour le Bathonien voir tabl. 3.
- - 222 - derived material, such as clay-filled channels with charophytes. The femur could have been washed into the area at this time and subsequently reworked as the Cornbrash sea advanced and deepened. Consequently, the femur is probably from near the top of the Upper Bathonian (Discus Zone, 158-156 my, Van Hinte, 1976).
DESCRIPTION AND COMPARISONS
The right femur (figs. 1A-F ; pl. 1, figs. 16-21) is complete, but the ends are a little eroded. Medially the head merges gradually with the shaft (figs. 1A, B ; pl. 1, figs. 17, 18) as in smaller femora of Dacentrurus (Galton, 1981a, 1983)Kentrosaurus (Galton, 1982a) and Stegosaurus (Galton, 1982b). In larger femora of these genera (Zbyszewski, 1946 ; Galton, 1982a, 1983 ; Ostrom & Mclntosh, 1966) and Lexovisaurus (Galton, 1983), the head is more clearly delimited from the shaft and prominent ossified cords are present for the attachment of muscles. The proximal part of the shaft near the head is covered by a series of grooves (figs. 1A, C, D ; pl. 1, figs. 16, 18, 19), and the cleft between the trochanters extended down about 45 mm from the adjacent lateral edge of the greater trochanter (figs. 1A, C ; pl. 1, figs. 16, 17, 19). The trochanters are separate in femora from smaller individuals of the stegosaurs mentioned above but fused in larger individuals of the same genera. Much of the shaft of the bone is obscured by plaster surface (fig. 1A-D), but the total length is correct because there was bone in contact with bone at every part of the length when it was repaired by the junior author a few years ago. Distally, the medial condyle is larger than the broken lateral condyle (fig. 1F ; pl. 1, fig. 21) and, as E. Hennig (1924) noted, the same is true for all other stegosaurs including Stegosaurus (Ostrom & Mclntosh, 1966, pl. 46, 47) despite the statement by C.W. Gilmore (1914 ; p. 82) to the contrary. The principal measurements of the femur (in mm) are : maximum length, 708 ; maximum proximal width, 201 ; maximum anteroposterior width of head, 93 ; maximum distal width, 192.
The genus Dacentrurus LUCAS, 1902 (type species Omosaurus armatus O W E N , 1875) is represented by an incomplete skeleton from the K immeridgian (Upper Jurassic) of England plus referred material from the Kimmeridgian of France (Nopcsa, 1911b) and Portugal (Lapparent & Zbyszewski, 1957). R. Hoffstetter (1957) made Omosaurus durobrivensis HULKE, 1887 from the Middle Callovian (Middle Jurassic) of Fletton near Peterborough, England, the type species of the new genus Lexovisaurus H O F F S T E T T E R , 1957. He also referred to Lexovisaurus durobrivensis (HULKE) a second slightly smaller specimen (holotype of Stegosauruspriscus NOPCSA, 1911a) from the same locality plus a partial skeleton from the Middle Callovian of Argences, Normandy, France (see Galton & alii, 1980). The femur of a juvenile individual of Dacentrurus from Portugal (Galton, 1982c, maximum length 557 mm) is slender and about the same proportions as femora of juvenile individuals of Dacentrurus ? phillipsi (Galton, 1983, Upper Jurassic of Yorkshire, maximum length 635 mm), Kentrosaurus (Galton, 1982a, maximum length 460 mm) and Stegosaurus (Galton, 1982b, maximum length 520 mm). The femur of Omosaurus vetustus (figs. 1A-F ; pl. 1, figs. 16-21) is more massive than these femora, and this is particularly true of the ends but unfortunately a femur of a juvenile individual of Lexovisaurus durobrivensis is not available for comparison. Because of the juvenile features exhibited by the femur o f Omosaurus vetustus HUENE (gentle medial curve between head and shaft in anterior view, cleft between lesser and greater trochanters, lack of prominent ossified cords for muscle attachment), and the lack of comparable sized stegosaurian femora from the Callovian, we consider it inadvisable to erect a new genus for the Bathonian femur. Omosaurus vetustus HUENE, 1910 is tentatively referred to the Middle Jurassic genus Lexovisaurus HOFFSTETTER, 1957 as Lexovisaurus ? vetustus (HUENE). The other stegosaurian specimens described in this paper from the Bathonian are tentatively referred to this taxon.
Dinosaure st6gosaurien Lexovisaurus ? vetustus (HuENE) du Bathonien (Jurassique moyen) d'Angleterre. A-F - F 6 m u r droit, O U M J. 14000, x 1/8, h o l o t y p e d e Omosaurus vetustus Hu~N~ d u B a t h o n i e n sup6rieur pros d ' O x f o r d . A - vue ant6rieure ; B r u e post6rieure ; C - vue lat6rale ; D - vue m6diale ; E - vue p r o x i m a l e ; F - vue distale. G-L - D e u x p l a q u e s dermales, S D M 44.41 (G-I) et B M N H R.5938 (J-L) x 0,15 de la F o r m a t i o n de C h i p p i n g N o r t o n ( B a t h o n i e n inf~rieur) p r o v e n a n t de L o n g b o r o u g h , d a n s le Gloucestershire. Vue lat6rale o u m~diale (G, K), Vue ant6rieure o u post~rieure (H, J), et vue ventrale (I, L). Les ~chelles repr6sentent 10 cm. Les h a c h u r e s repr6sentent des surfaces bris6es. Les zones blanches repr6sentent les parties en plfitre. a - r a i n u r e i n t e r c o n d y l i e n n e ant6rieure ; f - f o r a m e n (la fl6che i n d i q u e u n trou) ; g - g r a n d t r o c h a n t e r ; h - t&e ; i - c o n d y l e interne ; 1 - petit trochanter ; m - e m p l a c e m e n t d u bivalve Meleagrinella echinata (W. SMITH) ; O - condyle externe.
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Zones( a)
Subzones(a)
Clydoniceras discus Upper Bathonian
~
C. discus C. hollandi
l
Oppelia yeovilensis Morphoceras macrens Parkinsonia convergens
Lower Cornhrash F o r e s t M a r b l e F.
Oppelia aspidoides Procerites hodsoni Morrisiceras morrisi Tulites subcontractus Procerites progracilis Asphinctites tenuiplicatus
Middle Bathonian Lower Bathonian
Zigzagiceras zigzag
Formation
Material
F.
S h a r p ' s Hill F.
Chipping Norton
Femur(b)
Vertebrae(c)
F.
Armor(d)
Tabl. 3 - - Stratigraphic distribution of ste~osaurian dinosaurs from the Bathonian of En21and. ( a ) . after C o p e & alii(1980) ; (b~'_ O U M J.14000 : figs 1A-F ; pl. 1, figs. 16-21 ;~(c)_ O U M J.29770, J. 29827 : pl. 1, figs. 1-9 ; ( d ) . B M N H R.5938, S D M 44.41 : figs. 1G-L ; pl. 1, figs. 10-13.
Distribution stratigraphique des St61~osauriens du Bathonien de l'Angleterre. (a) _ d'apr~s C o p e & alii (1980) ; (b-) . O U M J.14000 : figs. 1A-F ; pl. 1, figs. 16-21 ; (c) _ O U M J.29770, J.29827 : pl. 1, figs. 1-9 ; (d) _ B M N H R.5938, S D M 44.41 : figs. 1G-L ; pl. 1, figs. 10-13.
'A
B
C
D
Ii! {il E
~
L
Fig. 1 A - L - -
Stegosaurian dinosaur Lexovisaurus ? vetustus (HuENE) from the Bathonian (Middle Jurassic) of England. A - F - right f e m u r O U M J. 14000, x 1/8, holotype of Omosaurus vetustus HUENE f r o m the U p p e r B a t h o n i a n near O x f o r d in A anterior ; B - posterior ; C - lateral ; D - medial ; E - proximal and F - distal views. G-L - two dermal plates, S D M 44.41 (G-I) a n d B M N H R.5938 (J-L) x 0.15 f r o m the Chipping N o r t o n F o r m a t i o n (Lower B a t h o n i a n ) o f L o n g b o r o u g h , Gloucestershire in lateral or medial (G,K), anterior or posterior (H,J) a n d ventral views (I,L). Scale lines represent 10 cm, cross-hatching represents b r o k e n bone, plain areas are plaster. a - anterior intercondylar groove ; f - f o r a m e n (route s h o w n by arrow) ; g - greater t r o c h a n t e r ; h - head ; i - inner condyle ; 1 lesser trochanter ; m - site of a t t a c h m e n t o f bivalve mollusc Meleagrinella echinata (W. SMITH) ; O - outer condyle.
- - 224 - -
I I I - - LOWER BATHONIAN HORIZONS AND LOCALITIES
The dorsal vertebra (OUM J.29770, pl. 1, figs. 6-9) was collected from near the base of the Sharp's Hill Member (Bed 18, Perna bed) of the Sharp's Hill Formation at the type section at Sharp's Hill Quarry, 3.2 km NW of Hook Norton church (SP 338 358) (Arkell, 1947 ; Torrens, 1968) and a cervical centrum (OUM J.29827 ; pl. 1, figs. 1-5) was found in bed 14-15 at the same locality. The Sharp's Hill Member is partly in the Proceritesprogracilis Zone, the lowermost zone of the Middle Bathonian, and partly in the Asphinctites tenuiplicatus Zone, the topmost zone of the Lower Bathonian (see Cope & alii, 1980, fig. 6a.B12 ; Torrens, 1968). Beds 18 and 14-15 are all in the Lower Sharp's Hill Beds of W.J. Arkell (1947 : 63) so these vertebrae came from the top of the Lower Bathonian (Tenuiplicatus Zone, tabl. 3 ; 163 my ; Van Hinte, 1976). S.H. Reynolds (1937, 1939) described several dinosaur bones, including two dermal plates (BMNH R.5938, SDM 44.41, figs. IG-L, pl. l, figs. 10-13) referred to Stegosaurus, from the cream-colored limestone of New Park Quarry, Longborough (SP 175 282), about 3 km NW of Stow-on-the-Wold, Gloucestershire. The H o o k Norton Member of the Chipping Norton Formation (Sellwood & McKerrow, 1974) at New Park Quarry has yielded ammonites of the Parkinsonia convergens Subzone (Torrens, 1969), the lowest subzone of the Zigzag&eras zigzag Zone (tabl. 3), so it is lowermost Bathonian (Torrens, 1969 ; Cope & alii, 1980, fig. 6a.B12). DESCRIPTION AND COMPARISONS
The dorsal vertebra (pl. 1, figs. 6-9) is clearly that of a stegosaur as is shown by the proportionally small size of the centrum in anterior and posterior views (pl. 1, figs. 6, 8) and the solid columnar-like form of the neutral arch that bears the pre- and postzygapophyses well above the dorsal margin of the neural canal (pl. 1, figs. 6, 8). The anterior inclination of the columnar-like part (pl. 1, figs. 7, 9) indicates that this is an anterior dorsal vertebra. The articular surfaces of the prezygapophyses are continuous ventromedially (pl. 1, fig. 6), as in all stegosaurs, but this is not the case for the postzygapophyses (pl. 1, fig. 8) that are separated by a notch that is more prominently developed in an anterior dorsal vertebra of Dacentrurus (Owen, 1875, pl. 13, fig. 1). A similar but less prominent notch separates
the postzygapophyses of dorsal vertebrae from the anterior half of the dorsal series of Lexovisaurus (BMNH R.3167) ; this notch is absent from more posterior dorsals so the postzygapophyses are wedgeshaped in posterior view with continuous articular surfaces as in all other stegosaurian dorsal vertebrae. The neural canal is small (pl. 1, figs. 6, 8) as in the dorsal vertebrae of all stegosaurs except Kentrosaurus (Hennig, 1924 ; Galton, 1982a). The ends of the centrum are gently concave (pl. 1, figs. 6, 8) and are slightly crushed transversely. The length of the centrum is greater than the width as in Lexovisaurus (BMNH R.3167) and most other stegosaurs rather than the reverse as in Dacentrurus (BMNH 46013). The maximum height of the vertebra as preserved is 214 mm ; the height to base of articular surface of prezygapophyses is 165 mm, and the measurements of the centrum in mm are : maximum length, 95 ; maximum widths anteriorly and posteriorly, 46, 48 ; maximum heights (to floor of neural canal) anteriorly and posteriorly, 63, 69. Apart from being proportionally less massive in ventral view (pl. 1, fig. 5), the cervical centrum (pl. 1, figs. 1-5) is similar to those of Stegosaurus (Ostrom & McIntosh, 1966) and Dacentrurus (Nopcsa, 1911b) and, judging from the wide neural canal (pl. 1, figs. 1, 3, 4) and the high position of the parapophysis (pl. 1, fig. 2) that is almost level with the adjacent part of the neural arch, it probably came from a vertebra in the posterior third of the neck (ie. cervicals 7 to 10). Both ends of the centrum are equally concave (pl. 1, figs. 1-3) and C.W. Gilmore (1914) notes that in Stegosaurus this occurs in centra posterior to the eighth. The lateral and ventral parts of the end surfaces (pl. 1, figs. 1, 3) are separated by a distinct step (pl. 1, fig. 2) from the rest of the articular surface that has a deep central depression (pl. 1, figs. 1, 3). The more peripheral part of both end surfaces show traces of a pattern of concentric circles (pl. 1, figs. 1, 3) that is also shown by cervical centra of Stegosaurus (Ostrom & McIntosh, 1966) and Dacentrurus (MGSP, cervical centra misidentified as caudal centra by Lapparent & Zbyszewski, 1957, pl. 28, fig. 101, pl. 29, fig. 110). Ventrally, the ends are rugose (pl. 1, fig. 5). The measurements of this centrum in mm are : maximum lengths dorsally and ventrally, 81, 94 ; maximum widths anteriorly and posteriorly, 89, 78 ; maximum heights (to floor of neural canal) anteriorly and posteriorly, 71, 71. The two dermal plates referred to Stegosaurus by S.H. Reynolds (1937, 1939) have maximum widths and heights in mm of 315, 260 (figs. 1, G-I ; pl. 1, figs. 14, 15) and 307, 337 (figs. 1, J-L ; pl. 1, figs. 10-13). The
- - 225 - ventral surface of one plate is gently concave transversely and smooth (fig. IL ; pl. 1, fig. I I) but that of the other is deeply excavated (figs. 1H, I ; maximum depth of groove about 80 mm) with two large foramina opening into the deep indentation (figs. 1G, I ; pl. 1, fig. 14, 15). These plates differ from the large dermal plates of Lexovisaurus (pl. 1, figs. 22-24 ; parts of three plates with BMNH R3167) and Stegosaurus (Gilmore, 1914, pl. 12-14 ; Ostrom & McIntosh, 1966, pl. 60-65 ; Farlow & alii, 1976) in a few respects. Apart from the base, the large dermal plates of these stegosaurs are surprisingly thin and sheet-like with a maximum thickness of about 1 cm and a progressive taper towards the very fine edges (pl. 1, fig. 23). Both Bathonian plates are thick (figs. 1H, J) and very massive. Much of the lateral surface of the plates of Stegosaurus are covered with a prominent series of <
like the horn cores of homed vertebrates, are probably vascular channels ~>(Farlow & alii, 1976 ; p. 1124), but these grooves are not present in Lexovisaurus (pl. 1, fig. 22). Z.-M. Dong & alii (1977, fig. 5, pl. 2, fig. 2 ; maximum width 18 cm) illustrates a more massive nonvascularized plate for Tuojiangosaurus from the Upper Jurassic of China. The Bathonian plates are unlike any dermal plates of ankylosaurs, that are definitely known from the Middle Jurassic (Callovian, Sarcolestes, see Galton, 1980), and of Scelidosaurus (Owen, 1863) from the Lower Jurassic of England that may be either an ornithopod (Thulborn, 1977) or an ankylosaur (Romer, 1968). Consequently, these two plates (figs. 1G-L ; pl. 1, figs. 10-15) are provisionally regarded as stegosaurian and are tentatively referred to Lexovisaurus ? vetustus.
IV - - C O N C L U S I O N S T~ae holotype femur (figs. 1A-F ; pl. 1, figs. 16-21) of Omosaurus vetustus HUENE, 1910 came from near Oxford, probably from the Lower Cornbrash Formation although it may have been derived from the underlying Forest Marble Formation. Either way, it came from the Discus Zone or uppermost Upper Bathonian (tabl. 3). This femur exhibits certain juvenile features such as the gentle curve between the head and shaft in anterior view, the persistance of a cleft between the lesser and greater trochanters, and the lack of prominent longitudinal ossified cords proximally and on the shaft. The femur is proportionally massive when compared to those of other stegosaurs from England viz. Dacentrurus armatus (OWEN) from the Kimmeridgian and D. ?phillipsi (SEELEY) from the Oxfordian (both Upper Jurassic, tabl. 2) plus Lexovisaurus durobrivensis (HULKE) from the Callovian (Middle Jurassic, tabl. 2) (see Galton, 1983, pl. 1). This femur may represent a new genus of stegosaurid, but we consider it inadvisable to erect a new name because it is probably from a juvenile individual, the absence of diagnostic characters, and the lack of comparable sized femora of Lexovisaurus durobrivensis (HULKE) for
comparison. Omosaurus vetustus HUENE, 1910 is tentatively referred to the Middle Jurassic genus Lexovisaurus HOFFSTETTER, 1957 as L. ? vetustus (HUENE). The centrum of a neck vertebra (pl. 1, figs. 1-5) and an anterior dorsal vertebra (pl. 1, figs. 6-9) from the Sharp's Hill Member of the Sharp's Hill Formation (Tenuiplicatus Zone, uppermost Lower Bathonian) of Oxfordshire are stegosaurid, generically indeterminate, and are tentatively referred to Lexovisaurus ? vetustus. The length of the centmm of the dorsal vertebra is greater than the width rather than the reverse as in Dacentrurus. Two large dermal plates from the Hook Norton Member of the Hook Norton Formation (Zigzag Zone, Convergens Subzone, lowermost Lower Bathonian) of Gloucestershire are remarkably massive when compared to the complete series of plates of Stegosaurus and the few known for Lexovisaurus. These Bathonian plates are provisionally regarded as stegosaurid and are tentatively referred to Lexovisaurus ? vetustus
(HUENE).
Acknowledgements We thank the following people for all their help while studying the specimens cited above in their respective institutions : A.G. Charig, A.C. Milner, C.A. Walker (BMNH) ; G. Zbyszewski (MGSP) ; L.F.J. Walrond (SDM) ; C.L.
Forbes (SMC) ; and N. Hotton III, R. Purdy (USNM). We thank David Oliver of 46 Pitts Rd., Headington, Oxfordshire for donating the cervical centrum (pl. 1, figs. 1-5 ; OUM J.29827) that he collected from the Sharp's Hill Quarry,
m 226 m
Michael Benton (OUM) for translations of the German papers cited ; and C. Gu6rin of University Claude-Bernard, Lyon 1, for his comments on this paper. Figure 1 was drawn by Joan Nicoletti, the photographs were printed by Laurel
Freed and Andrew Collins (all of the University of Bridgeport), and the MS was typed by Natalie S. Galton-Rawls. This research was supported by USA NSF Grant Number DEB 77-24048 to the senior author.
REFERENCES ARKELL W.J. (1947) - The geology of Oxford. Clarendon Press edit., 267 p., figs. , 6 pls. COPE J.C.W., DUFF K.L., PARSONS C.F., TORRENS H.S., WlMBLEDON W.A. & WRIGHT J.K. (1980) - A correlation of Jurassic rocks in the British Isles. Part two • Middle and Upper Jurassic. Geol. Soc. Spec. Rept. ,~London, n ° 15, p. 1-109, 13 figs: DONG Z.-M., LI X.-M., ZHOU S.-W. & CHANG Y.-H. (1977) - On the dinosaurian remain from Zigong (Tzekung), Zsechuan Province. Fertebrata Palasiatica, Peking, vol. 15, p. 307-312, 6 figs., 3 pls. FARLOW J.O., THOMPSON C.V. & ROSNER D.E. (1976) Plates of the dinosaur Stegosaurus ." forced convection heat loss fins. Science, Washington, vol. 192, p. 11231125, 1 fig. GALTON P.M. (1975) - English hypsilophodontid dinosaurs (Reptilia : Ornithischia). Palaeontology, London, vol. 18, p. 741-752, 5 figs. GALTON P.M. (1980) - Armored dinosaurs (Ornithischia : Ankylosauria) from the Middle and Upper Jurassic of England. Geobios, Lyon, vol. 13, p. 825-837, 1 fig., 1 pl. GALTON P.M., BRUN R. & RIOULT M. (1980) - Skeleton of the stegosaurian dinosaur Lexovisaurus from the lower part of Middle Callovian (Middle Jurassic) of Argences (Calvados), Normandy. Bull. Soc. gdol. Normandie et AmisduMus~um duHavre, vol. 67(4), p. 39-60, 5 figs., 1 pl. GALTON P.M. (1981a) - A juvenile stegosaurian dinosaur, ~ Astrodon pusillus ~, from the Upper Jurassic of Portugal, with comments on Upper Jurassic and Lower Cretaceous biogeography. J. Fert. Paleont., Norman, vol. 1, p. 245-256, 3 figs. GALTON P.M. (1981b) - Craterosaurus pottonensis SEELEY, a stegosaurian dinosaur from the Lower Cretaceous of England, and a review of Cretaceous stegosaurs. Neues Jb. GeoL Palaeont. Abh., Stuttgart, vol. 161, p. 28-46, 5 figs. GALTON P.M. (1982a) - The postcranial anatomy of stegosaurian dinosaur Kentrosaurus from the Upper Jurassic
of Tanzania, East Africa. GeoL Palaeont., Marburg, vol. 15, p. 139-160, 2 figs., 6 pls. GALTON P.M. (1982b) - Juveniles of the stegosaurian dinosaur Stegosaurus from the Upper Jurassic of North America. J. Vert. Paleont., Norman, vol. 2, p. 47-62, 8 figs. GALTON P.M. (1983) - A juvenile stegosaurian dinosaur, Omosaurus phillipsi SEELEY, from the Oxfordian (Upper Jurassic) of England. Geobios, Lyon, vol. 16/1, p. 95-101, 1 pl. GILMORE C.W. (1914) - Osteology of the armored Dinosauria in the United States National Museum, with special reference to the genus Stegosaurus. Bull. U.S. natn. Mus., Washington, vol. 89, p. 1-136, 73 figs., 37 pls. HENNIG E. (1924) - Kentrurosaurus aethiopicus : die Stegosaurier - Funde vom Tendaguru, Deutsch-Ostafrika. Palaeontographica, Stuttgart, Suppl. 7, E.R. 1, T.2, p. 101-274, 92 figs., 8 pls. HOFFSTETTER R. (1957) - Quelques observations sur les St6gosaurin6s. Bull. Mus. nat. Hist. natur., Pads, (2), vol. 29, p. 537-547. HUENE F. von (1910) - Ueber den altesten Rest von Omosaurus (Dacentrurus) im englischen Dogger. Neues Jb. Miner., GeoL Paltiont., Stuttgart, vol. 1910, p. 75-78, 1 fig., 1 pl. HUENE F. von (1956) - Pal~iontologie und Phylogenie der niederen Tetrapoden. Fischer edit., Jena, 716 p., 690 figs. HULKE J.W. (1887) - Note on some dinosaurian remains in the collection of A. Leeds, Esq., of Eyebury, Northamptonshire. Q. Jl. Geol. Soc., London, vol. 43, p. 695-702, 2 figs. LAPPARENT A.F. de & ZBYSZEWSKI G. (1957) - Les dinosauriens du Portugal. M~m. Serv. g~oL Port., Lisbonne, (N.S.), vol. 2, p. 1-63, 13 figs., 36 pls. LUCAS F.A. (1902) - The generic name Omosaurus. Science, Washington, vol. 16, p. 435.
- - 227 - -
NOPCSA F. (1911a) - Notes on British dinosaurs. Part IV. Stegosaurus priscus sp. nov. Geol. Mag., London, (5), vol. 8, p. 109-115, 145-153, 9 figs.
ROMER A.S. (1968) - Notes and comments on vertebrate paleontology. Chicago University Press edit., 304 p.
NOPCSA F. (1911b) - Omosaurus lennieri un nouveau dinosaurien du Cap de la H~ve. Bull. Soc. g~ol. de Normandie, Le Havre, vol. 30, p. 23-42, 5 pls.
SELLWOOD B.W. & MCKERROW W.S. (1974) - Depositional environments in the lower part of the Great Oolite Group of Oxfordshire and North Gloucestershire. Proc. Geol. Assn., London, vol. 85, p. 189-210, 4 figs.
OSTROM J.H. & MCINTOSH J.S. (1966) - Marsh's dinosaurs. The collection from Como Bluff. Yale University Press edit., 402 p., 13 figs., 155 pls.
STEEL R. (1969) - Handbuch der Pal~oherpetology. Part 15, Ornithischia. Fischer edit., Portland, 84 p., 24 figs.
OWEN R. (1861) - A monograph of a fossil dinosaur (Scelidosaurus harrisonii OWEN) of the Lower Lias. Part I. Palaeontogr. Soc. (Monogr.), London, vol. 13, p. 1-13, 6 pls. OWEN R. (1863) - A monograph of a fossil dinosaur (Scelidosaurus harrisonii OWEN) of the Lower Lias. Part II. Palaeontogr. Soc. (Monogr.), London, vol. 14, p. 1-26, 10 pls. OWEN R. (1875) - Monograph of the fossil dinosaur (Omosaurus armatus OWEN) of the Kimmeridge Clay. Palaeontogr. Soc. (Monogr.), London, vol. 29, p. 45-93, 17 pls. REYNOLDS S.H. (1937) - Fossil reptiles of Gloucestershire. Proc. Cott. Nat. FieM Club, Gloucester, vol. 26, p. 5165, 4 figs. REYNOLDS S.H. (1939) - On a collection of reptilian bones from the Oolite of Stow-on-the-Wold, Gloucestershire. GeoL Mag., London, vol. 76, p. 193-214, 15 figs.
THULBORN R.A. (1977) - Relationships of the Lower Jurassic dinosaur Scelidosaurus harrisonii. J. Paleont., Tulsa, vol. 51, p. 725-739, 6 figs. TORRENS H.S. (1968) - The Great Oolite Series. In P.C. Sylvester-Bradley & T.D. Ford (edit.). The geology of the East Midlands. Leicester Univ. Press edit., p. 227-289, 2 figs. TORRENS H.S. (1969) - The stratigraphical distribution of Bathonian ammonites in Central England. Geol. Mag., London, vol. 106, p. 63-76. VAN HINTE J.E. (1976) - A Jurassic time scale. Bull. Am. Assoc. Petrol. Geol., vol. 60, p. 489-497, 4 figs. ZBYSZEWSKI G. (1946) - Les ossements d'Omosaurus d6couverts pros de Baleal (Peniche). Comm. Serv. g~ol. Port., Lisbonne, vol. 28, p. 135-144, 10 pls.
Manuscrit d6finitif re9u le 23.11.1982
PLATE 1
Stegosaurian dinosaur Lexovisaurus ? vetustus (HUENE) from the Bathonian (Middle Jurassic) of England. Dinosaure st6gosaurien Lexovisaurus ? vetustus ( H U E N E ) du B a t h o n i e n (Jurassique moyen) d'Angleterre.
Fig. 1 - 5 - -
C e n t r u m o f posterior cervical vertebra, O U M J.29827 f r o m S h a r p ' s Hill F o r m a t i o n (Lower B a t h o n i a n ) o f S h a r p ' s Hill Quarry, Oxfordshire in 1 - anterior ; 2 - left lateral ; 3 - posterior ; 4 - dorsal a n d 5 - ventral views, x 1/3. C e n t r u m d ' u n e vertbbre cervicale post6rieure, O U M J.29827 p r o v e n a n t de la carri~re de S h a r p ' s Hill dans l'Oxfordshire (x 1/3). 1 - Vue ant6rieure ; 2 - Vue lat6rale gauche ; 3 - Vue post6rieure ; 4 - Vue dorsale ; 5 Vue ventrale.
Fig. 6 - 9 - -
A n t e r i o r dorsal vertebra, O U M J.29770 f r o m S h a r p ' s Hill F o r m a t i o n o f S h a r p ' s Hill Q u a r r y in 6 -anterior ; 7 - left lateral ; 8 - posterior a n d 9 - right lateral views, x 1/3. Vert6bre dorsale ant6rieure, O U M J.29770 p r o v e n a n t de la carri6re de S h a r p ' s Hill (x 1/3). 6 - Vue ant6rieure ; 7 -Vue lat6rale gauche ; 8 - Vue post6rieure ; 9 - Vue lat6rale droite.
Fig. 1 0 - 1 5 -
Two dermal plates, B M N H R5938 (10-13) a n d S D M 44.41 (14, 15) f r o m Chipping N o r t o n F o r m a t i o n (Lower B a t h o n i a n ) o f L o n g b o r o u g h , Gloucestershire in lateral or medial (10, 12, 14, 15), ventral (11) a n d anterior or posterior (13) views, x 1/6. Deux plaques dermales, B M N H R5938 (10-13) et S D M 44.41 (14, 15) de la C h i p p i n g N o r t o n F o r m a t i o n ( B a t h o n i e n inf6rieur) p r o v e n a n t de L o n g b o r o u g h dans le Gloucestershire (x 1/6). Fig. 10, 12, 14, 15 - Vues lat6rales o u m6diales ; 11 - Vue ventrale ; 13 - Vue ant6fieure ou post6rieure.
Fig. 16 - 21 - -
Right f e m u r O U M , J.14000, holotype o f Omosaurus vetustus H U E N E f r o m the U p p e r B a t h o n i a n near Oxford in 16- lateral ; 17- anterior ; 18- posterior ; 19- medial ; 2 0 - proximal a n d 2 1 - distal views (see fig. 1A-F), x 1/7. F6mur droit, O U M J.14000, holotype de Omosaurus vetustus H U E N E , du B a t h o n i e n sup6rieur pr6s d ' O x f o r d (x 1/7). 16 - Vue lat6rale ; 17 - Vue a n t 6 d e u r e ; 18 - Vue post6rieure, 19 - Vue m6diale, 20 - Vue proximale ; 21 - Vue distale (voir les figures dans le texte 1A-F).
Stegosaurian dinosaur Lexovisaurus durobrivensis (HULKE) from the CaHovian (Middle Jurassic) of England. Dinosaure st6gosaurien Lexovisaurus durobrivensis ( H U L K E ) du Callovien (Jurassique moyen) d'Angleterre.
Fig. 22 - 24 --
Right dermal plate S M C J.46874 f r o m the Lower Oxford Clay o f H e t t o n near P e t e r b o r o u g h in 22 -medial ; 23 - posterior a n d 24 - proximal views, x 1/6. P l a q u e dermale droite, S M C J.46874 p r o v e n a n t de la partie inf6rieure de <~ l ' O x f o r d Clay >>de H e t t o n pros de P e t e r b 0 r o u g h . 22 - Vue m6diale ; 23 - Vue post6rieure ; 24 - Vue proximale.
Scale lines represent 5 cm (fig. 1-9) a n d 10 cm (fig. 10-24). c - neural canal ; f - f o r a m e n (route indicated by arrow) ; n - base of neural spine ; o - postzygapophysis ; p - parapophysis ; r - prezygapophysis ; s - suture between c e n t r u m a n d neural arch ; t base o f transverse process. Les 6chelles repr6sentent 5 c m (fig. 1-9) et 10 cm (fig. 10-24). c - canal neural ; f - f o r a m e n (la fl6che indique u n trou) ; n - base de n e u r a p o p h y s e ; o - zygapophyse post6rieure ; p - p a r a p o p h y s e ; r - zygapophyse ant6rieure ; s - suture entre le c e n t r u m et l'arc neural ; t - base de l ' a p o p h y s e transversale.
PI. 1
Geobios n ° 16, fasc. 2
P . M . Galton & H . P . Powell
4
2
2~
20
21
24
by PETER M. GALTON * & H. PHILIP POWELL **
ABSTRACT
RESUME
The earliest records of stegosaurian dinosaurs of the family Stegosauridae are a few isolated bones from the Bathonian (Middle Jurassic) of southern England. A massive femur of a juvenile individual from the Lower Cornbrash (top of Upper Bathonian) of Oxfordshire is tentatively referred to the genus Lexovisaurus HOFFSTETTER as L . . 9 vetustus (HUENE). Four other bones from the Lower Bathonian are tentatively referred to this taxon • two incomplete vertebrae from the Sharp's Hill Formation of Oxfordshire and two large and massive dermal plates from the underlying Chipping Norton Formation (basal Bathonian) of Gloucestershire.
Les plus anciennes traces de dinosaures st6gosauriens de la famille des Stegosauridae sont constitu6es de quelques os isol6s appartenant au Bathonien (Jurassique moyen) de l'Angleterre du sud. Un f6mur massif d'un jeune individu provenant du Cornbrash inf6rieur (fin du Bathonien sup6rieur) de l'Oxfordshire est ~ttitre d'essai rapport6 au genre Lexovisaurus HOFFSTETTER comme L. ? vetustus (HUENE). Quatre os suppl6mentaires du Bathonien inf6rieur sont attribu6s, provisoirement, h la m~me esp6ce : deux vert~bres incompl~tes de la Formation de Sharp's Hill dans l'Oxfordshire, et deux plaques dermales, grandes et massives de la Formation sous-jacente de Chipping Norton (d6but du Bathonien) dans le Gloucestershire.
KEY-WORDS : ORNITHISCHIA (STEGOSA URIA), MIDDLE JURASSIC (BATHONIAN), ANATOMY-SKELETON, ENGLAND. SOTS-CLIPS : ORNITHISCHIA (STEGOSA URIA), JURASSIQUE MOYEN (BATHONIEN), ANATOMIE DU SQUELETTE, ANGLETERRE.
* Department of Biology, University of Bridgeport, Bridgeport, Ct. 06601, USA. ** Geological Collections, University Museum, Oxford OX1 3PR, England.
Geobios, n ° 16, fasc. 2
p. 219-229, 1 fig., 3 tabl., 1 pl.
Lyon, avril 1983
- - 220 - -
CONTENTS
I - - Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . .
220
IV - - Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . .
225
Upper Bathonian . . . . . . . . . . . . . . . . . . . . . . .
220
v-
226
III - - Lower Bathonian . . . . . . . . . . . . . . . . . . . . . . .
224
II
-
-
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I -- INTRODUCTION Jurassic stegosaurs or plated dinosaurs of the family Stegosauridae are well known from rocks of Kimmeridgian to Portlandian age (Upper Jurassic, 145-135 my ; Van Hinte, 1976) of western North America, western Europe, East Africa and China (Hoffstetter, 1957 ; Steel, 1969) (tabl. 1). Middle Jurassic stegosaurs are represented by three articulated specimens of Lexovisaurus durobrivensis (HULKE) plus several isolated bones (Hoffstetter, 1957 ; Steel, 1969) that all came from the Middle Callovian (about 155 my ; Van Hinte, 1976) of England (tabl. 2 ; Hulke, 1887 ; Nopcsa, 1911a ; Galton, 1980) and France (Galton & alii, 1980). However, only a few earlier records of stegosaurs have been reported, and these all came from the underlying Bathonian (lower Middle Jurassic, 165-158.5 my ; Van Hinte, 1976) of England (tabl. 3 ; Hoffstetter, 1957 ; Steel, 1969). A femur from the Upper Bathonian of Oxfordshire was described as Omosaurus (Dacentrurus) vetustus HUENE, 1910 (also in Huene, 1956, fig. 584) ; S.H. Reynolds (1937, 1939) referred two large dermal plates from the Lower Bathonian of Gloucestershire to the North American genus
II - - U P P E R HORIZON AND LOCALITY
The holotype of Omosaurus vetustus HUENE, 1910 is a right femur (OUM J. 14000 : figs. 1 A-F ; pl. 1, figs. 16-21) that bears the label <
Stegosaurus ; and P.M. Galton (1980) illustrated a stegosaurian dorsal vertebra from the Middle Bathonian of Oxfordshire. Scelidosaurus OWEN, 1861 of the family Scelidosauridae from the Lower Jurassic of Dorsetshire has long been regarded as a primitive stegosaur, but this is probably incorrect (see Thulborn, 1977; also Galton, 1975, 1980; Romer, 1968). The purpose of this paper is to review the stegosaurian specimens from the Bathonian of England that represent the earliest records of the family Stegosauridae discovered to date from anywhere. The specimens are discussed in descending stratigraphical order starting with the most recent (see tabl. 3). Cited institutions are abbreviated as follows: BMNH, British Museum (Natural History), London ; MGSP, Museum of Geological Survey of Portugal, Lisbon ; OUM, Oxford University Museum ; SDM, Stroud and District Museum, Stroud, Gloucestershire ; SMC, Sedgwick Museum, Cambridge Univers i t y ; U S N M , United States National Museum of Natural History, Washington, D.C.
BATHONIAN Cornbrash ( Clydoniceras discus Subzone of Clydoniceras discus Zone, upper Upper Bathonian, Cope & alii, 1980, fig. 6b. B12) because the Upper Cornbrash (Lower Callovian, Cope & alii, 1980, fig. 8.C6) is thin and patchy in this area. The eroded nature of the bone, and the fact that bones are virtually unknown in the Cornbrash Formation but do occur in the lagoonal facies of the Forest Marble Formation, suggest that it was derived from the underlying Forest Marble Formation (tabl. 3). The top of the Forest Marble Formation (Clydoniceras hollandi Subzone of Discus Zone, Cope & alii, 1980, fig. 6b.B12) has much evidence of land-
- - 221 - -
Order ORNITHISCHIA SEELEY, 1888 Suborder S t e g o s a u r i a MARSH, 1877 Family STEGOSAURIDAE MARSH, 1880
Dacentrurus armatus (OWEN) from Lower Kimmeridgian of England, France and Portugal. D. ? vetustus (SEELEY) from Middle Oxfordian of England. Kentrosaurus aethiopicus HENNIG from Upper Kimmeridglan of Tanzania, East Africa. Lexovisaurus durobrivensis (HULKE) from Middle Callovian (Middle Jurassic) of England and France. L. ? vetustus (HUENE) from Bathonian (Middle Jurassic) of England. Stegosaurus spp. from Upper Kimmeridgian or Lower Portlandian of western USA, North America. Tuojiangosaurus multispinus DONG & alii 1977 from the Kimmeridgian of Szechuan, China. Suborder A n k y l o s a u r i a OSBORN, 1923 Family NODOSAURIDAE MARSH, 1890
Sarcolestes leedsi LYDEKKER from Middle Callovian of England. Suborder ineertae sedis Family SCELIDOSAURIDAE HUXLEY, 1869
Scelidosaurus harrisonii OWEN from the Lias (Lower Jurassic) of England.
Tabl. 1 - - Classificaton of taxa cited with stratigraphic and geographic localization (see also tabl. 2, 3). Classification des taxons cites et leur Iocalisation stratigraphique et g6ographique (voir aussi tabl. 2, 3).
Stage Cretaceous
STEGOSAURIDAE
Neocomian Portlandian
Upper Jurassic
Kimmeridgian
Oxfordian
Craterosaurus pottonensis U M L
t U L
Dacentrurus armatus
1 UM
Dacentrurus ? phillipsi
L
Callovian Middle Bathonian Jurassic Bajocian
{-u
M L
Lexovisaurus durobrivensis
t UML
Lexovisaurus ? vetustus vertebrae, armor
1u
L
Aalenian
Tabl. 2 - - Stratigraphic distribution of the family Stegosauridae in England. L - Lower ; M - Middle ; U - Upper ; for Neocomian stegosaurs see P.M. Galton (1981b) ; for the Bathonian see taN. 3. Distribution stratigraphique de la famille de s
Stegosauridae en Angleterre.
L - Inf~rieur ; M - Moyen ; U - Sup~rieur ; pour Craterosaurus voir P.M. Galton (1981b) ; pour le Bathonien voir tabl. 3.
- - 222 - derived material, such as clay-filled channels with charophytes. The femur could have been washed into the area at this time and subsequently reworked as the Cornbrash sea advanced and deepened. Consequently, the femur is probably from near the top of the Upper Bathonian (Discus Zone, 158-156 my, Van Hinte, 1976).
DESCRIPTION AND COMPARISONS
The right femur (figs. 1A-F ; pl. 1, figs. 16-21) is complete, but the ends are a little eroded. Medially the head merges gradually with the shaft (figs. 1A, B ; pl. 1, figs. 17, 18) as in smaller femora of Dacentrurus (Galton, 1981a, 1983)Kentrosaurus (Galton, 1982a) and Stegosaurus (Galton, 1982b). In larger femora of these genera (Zbyszewski, 1946 ; Galton, 1982a, 1983 ; Ostrom & Mclntosh, 1966) and Lexovisaurus (Galton, 1983), the head is more clearly delimited from the shaft and prominent ossified cords are present for the attachment of muscles. The proximal part of the shaft near the head is covered by a series of grooves (figs. 1A, C, D ; pl. 1, figs. 16, 18, 19), and the cleft between the trochanters extended down about 45 mm from the adjacent lateral edge of the greater trochanter (figs. 1A, C ; pl. 1, figs. 16, 17, 19). The trochanters are separate in femora from smaller individuals of the stegosaurs mentioned above but fused in larger individuals of the same genera. Much of the shaft of the bone is obscured by plaster surface (fig. 1A-D), but the total length is correct because there was bone in contact with bone at every part of the length when it was repaired by the junior author a few years ago. Distally, the medial condyle is larger than the broken lateral condyle (fig. 1F ; pl. 1, fig. 21) and, as E. Hennig (1924) noted, the same is true for all other stegosaurs including Stegosaurus (Ostrom & Mclntosh, 1966, pl. 46, 47) despite the statement by C.W. Gilmore (1914 ; p. 82) to the contrary. The principal measurements of the femur (in mm) are : maximum length, 708 ; maximum proximal width, 201 ; maximum anteroposterior width of head, 93 ; maximum distal width, 192.
The genus Dacentrurus LUCAS, 1902 (type species Omosaurus armatus O W E N , 1875) is represented by an incomplete skeleton from the K immeridgian (Upper Jurassic) of England plus referred material from the Kimmeridgian of France (Nopcsa, 1911b) and Portugal (Lapparent & Zbyszewski, 1957). R. Hoffstetter (1957) made Omosaurus durobrivensis HULKE, 1887 from the Middle Callovian (Middle Jurassic) of Fletton near Peterborough, England, the type species of the new genus Lexovisaurus H O F F S T E T T E R , 1957. He also referred to Lexovisaurus durobrivensis (HULKE) a second slightly smaller specimen (holotype of Stegosauruspriscus NOPCSA, 1911a) from the same locality plus a partial skeleton from the Middle Callovian of Argences, Normandy, France (see Galton & alii, 1980). The femur of a juvenile individual of Dacentrurus from Portugal (Galton, 1982c, maximum length 557 mm) is slender and about the same proportions as femora of juvenile individuals of Dacentrurus ? phillipsi (Galton, 1983, Upper Jurassic of Yorkshire, maximum length 635 mm), Kentrosaurus (Galton, 1982a, maximum length 460 mm) and Stegosaurus (Galton, 1982b, maximum length 520 mm). The femur of Omosaurus vetustus (figs. 1A-F ; pl. 1, figs. 16-21) is more massive than these femora, and this is particularly true of the ends but unfortunately a femur of a juvenile individual of Lexovisaurus durobrivensis is not available for comparison. Because of the juvenile features exhibited by the femur o f Omosaurus vetustus HUENE (gentle medial curve between head and shaft in anterior view, cleft between lesser and greater trochanters, lack of prominent ossified cords for muscle attachment), and the lack of comparable sized stegosaurian femora from the Callovian, we consider it inadvisable to erect a new genus for the Bathonian femur. Omosaurus vetustus HUENE, 1910 is tentatively referred to the Middle Jurassic genus Lexovisaurus HOFFSTETTER, 1957 as Lexovisaurus ? vetustus (HUENE). The other stegosaurian specimens described in this paper from the Bathonian are tentatively referred to this taxon.
Dinosaure st6gosaurien Lexovisaurus ? vetustus (HuENE) du Bathonien (Jurassique moyen) d'Angleterre. A-F - F 6 m u r droit, O U M J. 14000, x 1/8, h o l o t y p e d e Omosaurus vetustus Hu~N~ d u B a t h o n i e n sup6rieur pros d ' O x f o r d . A - vue ant6rieure ; B r u e post6rieure ; C - vue lat6rale ; D - vue m6diale ; E - vue p r o x i m a l e ; F - vue distale. G-L - D e u x p l a q u e s dermales, S D M 44.41 (G-I) et B M N H R.5938 (J-L) x 0,15 de la F o r m a t i o n de C h i p p i n g N o r t o n ( B a t h o n i e n inf~rieur) p r o v e n a n t de L o n g b o r o u g h , d a n s le Gloucestershire. Vue lat6rale o u m~diale (G, K), Vue ant6rieure o u post~rieure (H, J), et vue ventrale (I, L). Les ~chelles repr6sentent 10 cm. Les h a c h u r e s repr6sentent des surfaces bris6es. Les zones blanches repr6sentent les parties en plfitre. a - r a i n u r e i n t e r c o n d y l i e n n e ant6rieure ; f - f o r a m e n (la fl6che i n d i q u e u n trou) ; g - g r a n d t r o c h a n t e r ; h - t&e ; i - c o n d y l e interne ; 1 - petit trochanter ; m - e m p l a c e m e n t d u bivalve Meleagrinella echinata (W. SMITH) ; O - condyle externe.
- - 223 - -
Zones( a)
Subzones(a)
Clydoniceras discus Upper Bathonian
~
C. discus C. hollandi
l
Oppelia yeovilensis Morphoceras macrens Parkinsonia convergens
Lower Cornhrash F o r e s t M a r b l e F.
Oppelia aspidoides Procerites hodsoni Morrisiceras morrisi Tulites subcontractus Procerites progracilis Asphinctites tenuiplicatus
Middle Bathonian Lower Bathonian
Zigzagiceras zigzag
Formation
Material
F.
S h a r p ' s Hill F.
Chipping Norton
Femur(b)
Vertebrae(c)
F.
Armor(d)
Tabl. 3 - - Stratigraphic distribution of ste~osaurian dinosaurs from the Bathonian of En21and. ( a ) . after C o p e & alii(1980) ; (b~'_ O U M J.14000 : figs 1A-F ; pl. 1, figs. 16-21 ;~(c)_ O U M J.29770, J. 29827 : pl. 1, figs. 1-9 ; ( d ) . B M N H R.5938, S D M 44.41 : figs. 1G-L ; pl. 1, figs. 10-13.
Distribution stratigraphique des St61~osauriens du Bathonien de l'Angleterre. (a) _ d'apr~s C o p e & alii (1980) ; (b-) . O U M J.14000 : figs. 1A-F ; pl. 1, figs. 16-21 ; (c) _ O U M J.29770, J.29827 : pl. 1, figs. 1-9 ; (d) _ B M N H R.5938, S D M 44.41 : figs. 1G-L ; pl. 1, figs. 10-13.
'A
B
C
D
Ii! {il E
~
L
Fig. 1 A - L - -
Stegosaurian dinosaur Lexovisaurus ? vetustus (HuENE) from the Bathonian (Middle Jurassic) of England. A - F - right f e m u r O U M J. 14000, x 1/8, holotype of Omosaurus vetustus HUENE f r o m the U p p e r B a t h o n i a n near O x f o r d in A anterior ; B - posterior ; C - lateral ; D - medial ; E - proximal and F - distal views. G-L - two dermal plates, S D M 44.41 (G-I) a n d B M N H R.5938 (J-L) x 0.15 f r o m the Chipping N o r t o n F o r m a t i o n (Lower B a t h o n i a n ) o f L o n g b o r o u g h , Gloucestershire in lateral or medial (G,K), anterior or posterior (H,J) a n d ventral views (I,L). Scale lines represent 10 cm, cross-hatching represents b r o k e n bone, plain areas are plaster. a - anterior intercondylar groove ; f - f o r a m e n (route s h o w n by arrow) ; g - greater t r o c h a n t e r ; h - head ; i - inner condyle ; 1 lesser trochanter ; m - site of a t t a c h m e n t o f bivalve mollusc Meleagrinella echinata (W. SMITH) ; O - outer condyle.
- - 224 - -
I I I - - LOWER BATHONIAN HORIZONS AND LOCALITIES
The dorsal vertebra (OUM J.29770, pl. 1, figs. 6-9) was collected from near the base of the Sharp's Hill Member (Bed 18, Perna bed) of the Sharp's Hill Formation at the type section at Sharp's Hill Quarry, 3.2 km NW of Hook Norton church (SP 338 358) (Arkell, 1947 ; Torrens, 1968) and a cervical centrum (OUM J.29827 ; pl. 1, figs. 1-5) was found in bed 14-15 at the same locality. The Sharp's Hill Member is partly in the Proceritesprogracilis Zone, the lowermost zone of the Middle Bathonian, and partly in the Asphinctites tenuiplicatus Zone, the topmost zone of the Lower Bathonian (see Cope & alii, 1980, fig. 6a.B12 ; Torrens, 1968). Beds 18 and 14-15 are all in the Lower Sharp's Hill Beds of W.J. Arkell (1947 : 63) so these vertebrae came from the top of the Lower Bathonian (Tenuiplicatus Zone, tabl. 3 ; 163 my ; Van Hinte, 1976). S.H. Reynolds (1937, 1939) described several dinosaur bones, including two dermal plates (BMNH R.5938, SDM 44.41, figs. IG-L, pl. l, figs. 10-13) referred to Stegosaurus, from the cream-colored limestone of New Park Quarry, Longborough (SP 175 282), about 3 km NW of Stow-on-the-Wold, Gloucestershire. The H o o k Norton Member of the Chipping Norton Formation (Sellwood & McKerrow, 1974) at New Park Quarry has yielded ammonites of the Parkinsonia convergens Subzone (Torrens, 1969), the lowest subzone of the Zigzag&eras zigzag Zone (tabl. 3), so it is lowermost Bathonian (Torrens, 1969 ; Cope & alii, 1980, fig. 6a.B12). DESCRIPTION AND COMPARISONS
The dorsal vertebra (pl. 1, figs. 6-9) is clearly that of a stegosaur as is shown by the proportionally small size of the centrum in anterior and posterior views (pl. 1, figs. 6, 8) and the solid columnar-like form of the neutral arch that bears the pre- and postzygapophyses well above the dorsal margin of the neural canal (pl. 1, figs. 6, 8). The anterior inclination of the columnar-like part (pl. 1, figs. 7, 9) indicates that this is an anterior dorsal vertebra. The articular surfaces of the prezygapophyses are continuous ventromedially (pl. 1, fig. 6), as in all stegosaurs, but this is not the case for the postzygapophyses (pl. 1, fig. 8) that are separated by a notch that is more prominently developed in an anterior dorsal vertebra of Dacentrurus (Owen, 1875, pl. 13, fig. 1). A similar but less prominent notch separates
the postzygapophyses of dorsal vertebrae from the anterior half of the dorsal series of Lexovisaurus (BMNH R.3167) ; this notch is absent from more posterior dorsals so the postzygapophyses are wedgeshaped in posterior view with continuous articular surfaces as in all other stegosaurian dorsal vertebrae. The neural canal is small (pl. 1, figs. 6, 8) as in the dorsal vertebrae of all stegosaurs except Kentrosaurus (Hennig, 1924 ; Galton, 1982a). The ends of the centrum are gently concave (pl. 1, figs. 6, 8) and are slightly crushed transversely. The length of the centrum is greater than the width as in Lexovisaurus (BMNH R.3167) and most other stegosaurs rather than the reverse as in Dacentrurus (BMNH 46013). The maximum height of the vertebra as preserved is 214 mm ; the height to base of articular surface of prezygapophyses is 165 mm, and the measurements of the centrum in mm are : maximum length, 95 ; maximum widths anteriorly and posteriorly, 46, 48 ; maximum heights (to floor of neural canal) anteriorly and posteriorly, 63, 69. Apart from being proportionally less massive in ventral view (pl. 1, fig. 5), the cervical centrum (pl. 1, figs. 1-5) is similar to those of Stegosaurus (Ostrom & McIntosh, 1966) and Dacentrurus (Nopcsa, 1911b) and, judging from the wide neural canal (pl. 1, figs. 1, 3, 4) and the high position of the parapophysis (pl. 1, fig. 2) that is almost level with the adjacent part of the neural arch, it probably came from a vertebra in the posterior third of the neck (ie. cervicals 7 to 10). Both ends of the centrum are equally concave (pl. 1, figs. 1-3) and C.W. Gilmore (1914) notes that in Stegosaurus this occurs in centra posterior to the eighth. The lateral and ventral parts of the end surfaces (pl. 1, figs. 1, 3) are separated by a distinct step (pl. 1, fig. 2) from the rest of the articular surface that has a deep central depression (pl. 1, figs. 1, 3). The more peripheral part of both end surfaces show traces of a pattern of concentric circles (pl. 1, figs. 1, 3) that is also shown by cervical centra of Stegosaurus (Ostrom & McIntosh, 1966) and Dacentrurus (MGSP, cervical centra misidentified as caudal centra by Lapparent & Zbyszewski, 1957, pl. 28, fig. 101, pl. 29, fig. 110). Ventrally, the ends are rugose (pl. 1, fig. 5). The measurements of this centrum in mm are : maximum lengths dorsally and ventrally, 81, 94 ; maximum widths anteriorly and posteriorly, 89, 78 ; maximum heights (to floor of neural canal) anteriorly and posteriorly, 71, 71. The two dermal plates referred to Stegosaurus by S.H. Reynolds (1937, 1939) have maximum widths and heights in mm of 315, 260 (figs. 1, G-I ; pl. 1, figs. 14, 15) and 307, 337 (figs. 1, J-L ; pl. 1, figs. 10-13). The
- - 225 - ventral surface of one plate is gently concave transversely and smooth (fig. IL ; pl. 1, fig. I I) but that of the other is deeply excavated (figs. 1H, I ; maximum depth of groove about 80 mm) with two large foramina opening into the deep indentation (figs. 1G, I ; pl. 1, fig. 14, 15). These plates differ from the large dermal plates of Lexovisaurus (pl. 1, figs. 22-24 ; parts of three plates with BMNH R3167) and Stegosaurus (Gilmore, 1914, pl. 12-14 ; Ostrom & McIntosh, 1966, pl. 60-65 ; Farlow & alii, 1976) in a few respects. Apart from the base, the large dermal plates of these stegosaurs are surprisingly thin and sheet-like with a maximum thickness of about 1 cm and a progressive taper towards the very fine edges (pl. 1, fig. 23). Both Bathonian plates are thick (figs. 1H, J) and very massive. Much of the lateral surface of the plates of Stegosaurus are covered with a prominent series of <
like the horn cores of homed vertebrates, are probably vascular channels ~>(Farlow & alii, 1976 ; p. 1124), but these grooves are not present in Lexovisaurus (pl. 1, fig. 22). Z.-M. Dong & alii (1977, fig. 5, pl. 2, fig. 2 ; maximum width 18 cm) illustrates a more massive nonvascularized plate for Tuojiangosaurus from the Upper Jurassic of China. The Bathonian plates are unlike any dermal plates of ankylosaurs, that are definitely known from the Middle Jurassic (Callovian, Sarcolestes, see Galton, 1980), and of Scelidosaurus (Owen, 1863) from the Lower Jurassic of England that may be either an ornithopod (Thulborn, 1977) or an ankylosaur (Romer, 1968). Consequently, these two plates (figs. 1G-L ; pl. 1, figs. 10-15) are provisionally regarded as stegosaurian and are tentatively referred to Lexovisaurus ? vetustus.
IV - - C O N C L U S I O N S T~ae holotype femur (figs. 1A-F ; pl. 1, figs. 16-21) of Omosaurus vetustus HUENE, 1910 came from near Oxford, probably from the Lower Cornbrash Formation although it may have been derived from the underlying Forest Marble Formation. Either way, it came from the Discus Zone or uppermost Upper Bathonian (tabl. 3). This femur exhibits certain juvenile features such as the gentle curve between the head and shaft in anterior view, the persistance of a cleft between the lesser and greater trochanters, and the lack of prominent longitudinal ossified cords proximally and on the shaft. The femur is proportionally massive when compared to those of other stegosaurs from England viz. Dacentrurus armatus (OWEN) from the Kimmeridgian and D. ?phillipsi (SEELEY) from the Oxfordian (both Upper Jurassic, tabl. 2) plus Lexovisaurus durobrivensis (HULKE) from the Callovian (Middle Jurassic, tabl. 2) (see Galton, 1983, pl. 1). This femur may represent a new genus of stegosaurid, but we consider it inadvisable to erect a new name because it is probably from a juvenile individual, the absence of diagnostic characters, and the lack of comparable sized femora of Lexovisaurus durobrivensis (HULKE) for
comparison. Omosaurus vetustus HUENE, 1910 is tentatively referred to the Middle Jurassic genus Lexovisaurus HOFFSTETTER, 1957 as L. ? vetustus (HUENE). The centrum of a neck vertebra (pl. 1, figs. 1-5) and an anterior dorsal vertebra (pl. 1, figs. 6-9) from the Sharp's Hill Member of the Sharp's Hill Formation (Tenuiplicatus Zone, uppermost Lower Bathonian) of Oxfordshire are stegosaurid, generically indeterminate, and are tentatively referred to Lexovisaurus ? vetustus. The length of the centmm of the dorsal vertebra is greater than the width rather than the reverse as in Dacentrurus. Two large dermal plates from the Hook Norton Member of the Hook Norton Formation (Zigzag Zone, Convergens Subzone, lowermost Lower Bathonian) of Gloucestershire are remarkably massive when compared to the complete series of plates of Stegosaurus and the few known for Lexovisaurus. These Bathonian plates are provisionally regarded as stegosaurid and are tentatively referred to Lexovisaurus ? vetustus
(HUENE).
Acknowledgements We thank the following people for all their help while studying the specimens cited above in their respective institutions : A.G. Charig, A.C. Milner, C.A. Walker (BMNH) ; G. Zbyszewski (MGSP) ; L.F.J. Walrond (SDM) ; C.L.
Forbes (SMC) ; and N. Hotton III, R. Purdy (USNM). We thank David Oliver of 46 Pitts Rd., Headington, Oxfordshire for donating the cervical centrum (pl. 1, figs. 1-5 ; OUM J.29827) that he collected from the Sharp's Hill Quarry,
m 226 m
Michael Benton (OUM) for translations of the German papers cited ; and C. Gu6rin of University Claude-Bernard, Lyon 1, for his comments on this paper. Figure 1 was drawn by Joan Nicoletti, the photographs were printed by Laurel
Freed and Andrew Collins (all of the University of Bridgeport), and the MS was typed by Natalie S. Galton-Rawls. This research was supported by USA NSF Grant Number DEB 77-24048 to the senior author.
REFERENCES ARKELL W.J. (1947) - The geology of Oxford. Clarendon Press edit., 267 p., figs. , 6 pls. COPE J.C.W., DUFF K.L., PARSONS C.F., TORRENS H.S., WlMBLEDON W.A. & WRIGHT J.K. (1980) - A correlation of Jurassic rocks in the British Isles. Part two • Middle and Upper Jurassic. Geol. Soc. Spec. Rept. ,~London, n ° 15, p. 1-109, 13 figs: DONG Z.-M., LI X.-M., ZHOU S.-W. & CHANG Y.-H. (1977) - On the dinosaurian remain from Zigong (Tzekung), Zsechuan Province. Fertebrata Palasiatica, Peking, vol. 15, p. 307-312, 6 figs., 3 pls. FARLOW J.O., THOMPSON C.V. & ROSNER D.E. (1976) Plates of the dinosaur Stegosaurus ." forced convection heat loss fins. Science, Washington, vol. 192, p. 11231125, 1 fig. GALTON P.M. (1975) - English hypsilophodontid dinosaurs (Reptilia : Ornithischia). Palaeontology, London, vol. 18, p. 741-752, 5 figs. GALTON P.M. (1980) - Armored dinosaurs (Ornithischia : Ankylosauria) from the Middle and Upper Jurassic of England. Geobios, Lyon, vol. 13, p. 825-837, 1 fig., 1 pl. GALTON P.M., BRUN R. & RIOULT M. (1980) - Skeleton of the stegosaurian dinosaur Lexovisaurus from the lower part of Middle Callovian (Middle Jurassic) of Argences (Calvados), Normandy. Bull. Soc. gdol. Normandie et AmisduMus~um duHavre, vol. 67(4), p. 39-60, 5 figs., 1 pl. GALTON P.M. (1981a) - A juvenile stegosaurian dinosaur, ~ Astrodon pusillus ~, from the Upper Jurassic of Portugal, with comments on Upper Jurassic and Lower Cretaceous biogeography. J. Fert. Paleont., Norman, vol. 1, p. 245-256, 3 figs. GALTON P.M. (1981b) - Craterosaurus pottonensis SEELEY, a stegosaurian dinosaur from the Lower Cretaceous of England, and a review of Cretaceous stegosaurs. Neues Jb. GeoL Palaeont. Abh., Stuttgart, vol. 161, p. 28-46, 5 figs. GALTON P.M. (1982a) - The postcranial anatomy of stegosaurian dinosaur Kentrosaurus from the Upper Jurassic
of Tanzania, East Africa. GeoL Palaeont., Marburg, vol. 15, p. 139-160, 2 figs., 6 pls. GALTON P.M. (1982b) - Juveniles of the stegosaurian dinosaur Stegosaurus from the Upper Jurassic of North America. J. Vert. Paleont., Norman, vol. 2, p. 47-62, 8 figs. GALTON P.M. (1983) - A juvenile stegosaurian dinosaur, Omosaurus phillipsi SEELEY, from the Oxfordian (Upper Jurassic) of England. Geobios, Lyon, vol. 16/1, p. 95-101, 1 pl. GILMORE C.W. (1914) - Osteology of the armored Dinosauria in the United States National Museum, with special reference to the genus Stegosaurus. Bull. U.S. natn. Mus., Washington, vol. 89, p. 1-136, 73 figs., 37 pls. HENNIG E. (1924) - Kentrurosaurus aethiopicus : die Stegosaurier - Funde vom Tendaguru, Deutsch-Ostafrika. Palaeontographica, Stuttgart, Suppl. 7, E.R. 1, T.2, p. 101-274, 92 figs., 8 pls. HOFFSTETTER R. (1957) - Quelques observations sur les St6gosaurin6s. Bull. Mus. nat. Hist. natur., Pads, (2), vol. 29, p. 537-547. HUENE F. von (1910) - Ueber den altesten Rest von Omosaurus (Dacentrurus) im englischen Dogger. Neues Jb. Miner., GeoL Paltiont., Stuttgart, vol. 1910, p. 75-78, 1 fig., 1 pl. HUENE F. von (1956) - Pal~iontologie und Phylogenie der niederen Tetrapoden. Fischer edit., Jena, 716 p., 690 figs. HULKE J.W. (1887) - Note on some dinosaurian remains in the collection of A. Leeds, Esq., of Eyebury, Northamptonshire. Q. Jl. Geol. Soc., London, vol. 43, p. 695-702, 2 figs. LAPPARENT A.F. de & ZBYSZEWSKI G. (1957) - Les dinosauriens du Portugal. M~m. Serv. g~oL Port., Lisbonne, (N.S.), vol. 2, p. 1-63, 13 figs., 36 pls. LUCAS F.A. (1902) - The generic name Omosaurus. Science, Washington, vol. 16, p. 435.
- - 227 - -
NOPCSA F. (1911a) - Notes on British dinosaurs. Part IV. Stegosaurus priscus sp. nov. Geol. Mag., London, (5), vol. 8, p. 109-115, 145-153, 9 figs.
ROMER A.S. (1968) - Notes and comments on vertebrate paleontology. Chicago University Press edit., 304 p.
NOPCSA F. (1911b) - Omosaurus lennieri un nouveau dinosaurien du Cap de la H~ve. Bull. Soc. g~ol. de Normandie, Le Havre, vol. 30, p. 23-42, 5 pls.
SELLWOOD B.W. & MCKERROW W.S. (1974) - Depositional environments in the lower part of the Great Oolite Group of Oxfordshire and North Gloucestershire. Proc. Geol. Assn., London, vol. 85, p. 189-210, 4 figs.
OSTROM J.H. & MCINTOSH J.S. (1966) - Marsh's dinosaurs. The collection from Como Bluff. Yale University Press edit., 402 p., 13 figs., 155 pls.
STEEL R. (1969) - Handbuch der Pal~oherpetology. Part 15, Ornithischia. Fischer edit., Portland, 84 p., 24 figs.
OWEN R. (1861) - A monograph of a fossil dinosaur (Scelidosaurus harrisonii OWEN) of the Lower Lias. Part I. Palaeontogr. Soc. (Monogr.), London, vol. 13, p. 1-13, 6 pls. OWEN R. (1863) - A monograph of a fossil dinosaur (Scelidosaurus harrisonii OWEN) of the Lower Lias. Part II. Palaeontogr. Soc. (Monogr.), London, vol. 14, p. 1-26, 10 pls. OWEN R. (1875) - Monograph of the fossil dinosaur (Omosaurus armatus OWEN) of the Kimmeridge Clay. Palaeontogr. Soc. (Monogr.), London, vol. 29, p. 45-93, 17 pls. REYNOLDS S.H. (1937) - Fossil reptiles of Gloucestershire. Proc. Cott. Nat. FieM Club, Gloucester, vol. 26, p. 5165, 4 figs. REYNOLDS S.H. (1939) - On a collection of reptilian bones from the Oolite of Stow-on-the-Wold, Gloucestershire. GeoL Mag., London, vol. 76, p. 193-214, 15 figs.
THULBORN R.A. (1977) - Relationships of the Lower Jurassic dinosaur Scelidosaurus harrisonii. J. Paleont., Tulsa, vol. 51, p. 725-739, 6 figs. TORRENS H.S. (1968) - The Great Oolite Series. In P.C. Sylvester-Bradley & T.D. Ford (edit.). The geology of the East Midlands. Leicester Univ. Press edit., p. 227-289, 2 figs. TORRENS H.S. (1969) - The stratigraphical distribution of Bathonian ammonites in Central England. Geol. Mag., London, vol. 106, p. 63-76. VAN HINTE J.E. (1976) - A Jurassic time scale. Bull. Am. Assoc. Petrol. Geol., vol. 60, p. 489-497, 4 figs. ZBYSZEWSKI G. (1946) - Les ossements d'Omosaurus d6couverts pros de Baleal (Peniche). Comm. Serv. g~ol. Port., Lisbonne, vol. 28, p. 135-144, 10 pls.
Manuscrit d6finitif re9u le 23.11.1982
PLATE 1
Stegosaurian dinosaur Lexovisaurus ? vetustus (HUENE) from the Bathonian (Middle Jurassic) of England. Dinosaure st6gosaurien Lexovisaurus ? vetustus ( H U E N E ) du B a t h o n i e n (Jurassique moyen) d'Angleterre.
Fig. 1 - 5 - -
C e n t r u m o f posterior cervical vertebra, O U M J.29827 f r o m S h a r p ' s Hill F o r m a t i o n (Lower B a t h o n i a n ) o f S h a r p ' s Hill Quarry, Oxfordshire in 1 - anterior ; 2 - left lateral ; 3 - posterior ; 4 - dorsal a n d 5 - ventral views, x 1/3. C e n t r u m d ' u n e vertbbre cervicale post6rieure, O U M J.29827 p r o v e n a n t de la carri~re de S h a r p ' s Hill dans l'Oxfordshire (x 1/3). 1 - Vue ant6rieure ; 2 - Vue lat6rale gauche ; 3 - Vue post6rieure ; 4 - Vue dorsale ; 5 Vue ventrale.
Fig. 6 - 9 - -
A n t e r i o r dorsal vertebra, O U M J.29770 f r o m S h a r p ' s Hill F o r m a t i o n o f S h a r p ' s Hill Q u a r r y in 6 -anterior ; 7 - left lateral ; 8 - posterior a n d 9 - right lateral views, x 1/3. Vert6bre dorsale ant6rieure, O U M J.29770 p r o v e n a n t de la carri6re de S h a r p ' s Hill (x 1/3). 6 - Vue ant6rieure ; 7 -Vue lat6rale gauche ; 8 - Vue post6rieure ; 9 - Vue lat6rale droite.
Fig. 1 0 - 1 5 -
Two dermal plates, B M N H R5938 (10-13) a n d S D M 44.41 (14, 15) f r o m Chipping N o r t o n F o r m a t i o n (Lower B a t h o n i a n ) o f L o n g b o r o u g h , Gloucestershire in lateral or medial (10, 12, 14, 15), ventral (11) a n d anterior or posterior (13) views, x 1/6. Deux plaques dermales, B M N H R5938 (10-13) et S D M 44.41 (14, 15) de la C h i p p i n g N o r t o n F o r m a t i o n ( B a t h o n i e n inf6rieur) p r o v e n a n t de L o n g b o r o u g h dans le Gloucestershire (x 1/6). Fig. 10, 12, 14, 15 - Vues lat6rales o u m6diales ; 11 - Vue ventrale ; 13 - Vue ant6fieure ou post6rieure.
Fig. 16 - 21 - -
Right f e m u r O U M , J.14000, holotype o f Omosaurus vetustus H U E N E f r o m the U p p e r B a t h o n i a n near Oxford in 16- lateral ; 17- anterior ; 18- posterior ; 19- medial ; 2 0 - proximal a n d 2 1 - distal views (see fig. 1A-F), x 1/7. F6mur droit, O U M J.14000, holotype de Omosaurus vetustus H U E N E , du B a t h o n i e n sup6rieur pr6s d ' O x f o r d (x 1/7). 16 - Vue lat6rale ; 17 - Vue a n t 6 d e u r e ; 18 - Vue post6rieure, 19 - Vue m6diale, 20 - Vue proximale ; 21 - Vue distale (voir les figures dans le texte 1A-F).
Stegosaurian dinosaur Lexovisaurus durobrivensis (HULKE) from the CaHovian (Middle Jurassic) of England. Dinosaure st6gosaurien Lexovisaurus durobrivensis ( H U L K E ) du Callovien (Jurassique moyen) d'Angleterre.
Fig. 22 - 24 --
Right dermal plate S M C J.46874 f r o m the Lower Oxford Clay o f H e t t o n near P e t e r b o r o u g h in 22 -medial ; 23 - posterior a n d 24 - proximal views, x 1/6. P l a q u e dermale droite, S M C J.46874 p r o v e n a n t de la partie inf6rieure de <~ l ' O x f o r d Clay >>de H e t t o n pros de P e t e r b 0 r o u g h . 22 - Vue m6diale ; 23 - Vue post6rieure ; 24 - Vue proximale.
Scale lines represent 5 cm (fig. 1-9) a n d 10 cm (fig. 10-24). c - neural canal ; f - f o r a m e n (route indicated by arrow) ; n - base of neural spine ; o - postzygapophysis ; p - parapophysis ; r - prezygapophysis ; s - suture between c e n t r u m a n d neural arch ; t base o f transverse process. Les 6chelles repr6sentent 5 c m (fig. 1-9) et 10 cm (fig. 10-24). c - canal neural ; f - f o r a m e n (la fl6che indique u n trou) ; n - base de n e u r a p o p h y s e ; o - zygapophyse post6rieure ; p - p a r a p o p h y s e ; r - zygapophyse ant6rieure ; s - suture entre le c e n t r u m et l'arc neural ; t - base de l ' a p o p h y s e transversale.
PI. 1
Geobios n ° 16, fasc. 2
P . M . Galton & H . P . Powell
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