Ladinian boundary (Middle Triassic) from Bissendorf (NW Germany) and their contribution to the anatomy, palaeoecology, and palaeobiogeography of the Germanic Basin reptiles

Palaeogeography, Palaeoclimatology, Palaeoecology 273 (2009) 1–16

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The vertebrates of the Anisian/Ladinian boundary (Middle Triassic) from Bissendorf (NW Germany) and their contribution to the anatomy, palaeoecology, and palaeobiogeography of the Germanic Basin reptiles Cajus Diedrich University of Osnabrück, Institute of Culture and Geosciences, Seminarstr. 19, D-49069 Osnabrück, Germany

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Article history: Received 8 July 2008 Received in revised form 29 October 2008 Accepted 31 October 2008 Keywords: Bone bed Northern Germany Vertebrates Taphocoenosis Anisian/Ladinian boundary (Middle Triassic) Palaeoenvironment Palaeoecology Reptile skeleton reconstructions Palaeobiogeography Central Europe

a b s t r a c t Systematically excavated bones are described from Bissendorf (Osnabrücker Bergland, north-western Germany). The bone bed in the compressus zone of the Ceratitenschichten (Meißner Fm, Upper Muschelkalk, Anisian/Ladinian boundary, Middle Triassic) was dated by ceratites. Sedimentologically, it is a bioclastic rudstone built mainly from Coenothyris vulgaris brachiopods, which were heavily compressed into a 3 mm thin layer. Parts of the bone bed and the following 15 cm of autochthonous mud were partially eroded synsedimentary by the compressus storm event. The material of the not-rich bone bed in the Germanic Upper Muschelkalk consists of isolated teeth or fin spines from five well-known shark species: Hybodus longiconus Agassiz, 1843, Acrodus lateralis Agassiz, 1837, Acrodus gaillardoti Agassiz, 1837, Palaeobates angustissimus Agassiz, 1838 and Polyacrodus polycyphus Agassiz, 1837. Teeth and scales from the teleosteans Gyrolepis sp, Dollopterus sp., Colobodus maximus, Quenstedt, 1835, C. frequens, Dames [Dames, W., 1888. Die Ganoiden des Deutschen Muschelkalkes. Palaeontologische Abhandlungen 4, 133–180] and Saurichthys sp. have been proved. Found were mostly vertebra centra and ribs, but also teeth and some other postcranial bones from the small pachypleurosaurs Anarosaurus sp. as well as mostly Neusticosaurus sp. These originated from adult and juvenile animals which indicates the primary habitat and populations of this region. Large marine nothosaur reptiles found include Nothosaurus cf. mirabilis Münster, 1834, and N. giganteus Münster, 1834. Proof of two placodonts is given thanks to Placodus gigas Agassiz, 1833 and Cyamodus sp. Finally, a tooth from the terrestrial lepidosaur Tanystrophaeus longibardicus (Bassani, 1866) is the northerly most sample found. The recorded fauna is well-known with complete skeletons of the described species from the northern Tethys (Mte. San Giorgio, Switzerland). The reptile skeletons are presented here in reconstruction. The bone bed composition in Bissendorf shows differences in the younger and more terrestrial mixed as well as the age difference in bone beds of northern (enodis/posseckeri zone) and southern Germany (dorsoplanus zone). At Bissendorf, only nearly complete marine vertebrates occur within the maximum high stand. High marine ichthyosaurs seem to be absent, indicating a shallow marine position in the western Germanic Basin. © 2008 Elsevier B.V. All rights reserved.

1. Introduction Whereas in southern Germany Middle Triassic Ladinian bone beds are well-known from the Muschelkalk/Keuper boundary (Reif, 1971, 1982), such bone-rich horizons have only begun to be recently studied at the Lamerden in Hessia (Diedrich, 2003) locality. Now the north western most bone-bed (which is much younger than the previously known ones mentioned above) is described with its vertebrate macrofauna. Single scales and teeth or small bone remains were already mentioned in younger levels (“Grenzbonebeds”) in the studied section of the Sundermeyer quarry in Bissendorf (Topographical map 3714 Osnabrück, 52°13′54.48″N; and 8°8′57.52″E, Fig. 1). Those bone beds are in the uppermost section (Duchrow and Groetzner, 1984) and are similar to the

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boundary bone beds, which have been found practically all over Germany (Hagdorn and Reif, 1988; Hagdorn, 1990). The first sauropterygian reptile skeleton remains were found and described in the Osnabrücker Bergland in the Lower Muschelkalk in a much younger strata (Diedrich, 1996). During systematic prospecting and stratigraphic work on the “Muschelkalk reptile tracks” of Germany in 2002, a track bed (muGB Member) was found at the bottom of the quarry in polygonal cracked biolaminates (Diedrich, in press, 2008). Therefore the section was recently studied in detail in its biostratigraphy and palaeoenvironment, including the layers around the bone bed (Diedrich, in press). 2. Materials and methods The excavation style of the four week campaign was adjusted to the geological situation. Luckily an up to 25 cm thick limestone bed

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Fig. 1. Outcropping Upper Muschelkalk (Anisian/Ladinian) limestone in the Osnabrücker Bergland and mapped excavation area of the compressus bone bed (frame, see Fig. 4).

(compressus tempestite) covered the bone bed perfectly, which meant that a back hoe could quickly remove all overlying layers. The massive bed was then removed by hand. At the base of the bed, bones and teeth were sometimes attached because in many areas this layer eroded deeply through the underlying 10 cm thin claystone into the bone bed layer. The channels often were additionally pressed tectonically onto the bone bed; therefore larger bones such as ribs often have strong microtectonic clefts, at which point they broke into pieces. After removing the limestone, the claystone was taken away and softground fauna was isolated, including well-preserved C. compressus ceratites. The 3 mm thin bone bed layer was left and the surface was segmented into squares for the documentation. The bone bed was finally excavated systematically on a large surface of 200 m2; however 15 × 3 m (45 m2) was mapped in detail in its larger vertebrate faunal content. The bone bed itself varied in thickness. One to three millimetre thin brachiopod dominated the shell layer. The more massive layers were smashed into small pieces to get to as much vertebrate remains as possible. As a result of the high density of small material, such as teeth and scales, only 1 m2 was mapped to count the material for the statistical analyses. The larger reptile bones of sauropterygians and other reptiles were mapped on the entire excavation surface as a result of their rarer presence. Some bone bed slabs, on which several teeth are embedded, were taken. Finally 50 kg of the bone bed were sampled for future sieving studies. The bone and invertebrate material from the excavations and collected ceratites from the stratigraphic prospecting work were prepared by the company Palaeologic and are deposited in the Museum am Schöler Berg für Natur und Umwelt Osnabrück (= MSBO) under the running collection numbers for the locality Bissendorf: Pal 327—1–583.

3. Geology and environment The geology and stratigraphy, with its new environmental interpretation, were recently described. It includes the bone bed and adjacent layers (Diedrich, in press), which is also briefly given here. In Bissendorf the carbonates series of the Upper Muschelkalk comprises the 65 m thick carbonate series of the Middle/Upper Muschelkalk boundary (“Gelbe Basisschichten”, = moGB Member) up to the Muschelkalk/Keuper boundary (Fig. 2). It is the most north western and most complete Upper Muschelkalk section in northern Germany. This section was studied and correlated to the more eastern ones in the Weserbergland by Duchrow and Groetzner (1984) with a first biozonation subdivision by ceratites. This was recently completed and changed in some boundaries by Diedrich (in press). The latter description also adds a vertebrate track bed and a new environmental and bathymetrical interpretation (Fig. 2).The base of the Upper Muschelkalk consists of 6.5 m thick moGB member where vertebrate track bed 21 (see definition in Diedrich, 2008) was found in mud cracked biolaminates. Such biolaminates are very common throughout the Muschelkalk, especially Lower to Middle and basal Upper Muschelkalk of the Osnabrücker Bergland (Diedrich, 2006) and the entire central and southern Germanic Basin (Diedrich, 2001, 2002a,b, 2005, 2008). The Gelbe Basisschichten layer is overlain by the 7 m thick HauptTrochitenkalk (mo1 HT). As a result of flatter conditions, the hard bioclastic limestone contains here in this region only a few remains of the crinoid Encrinus liliiformis, instead of much more ooids. All ooliths are massive crystalline limestone which are a decimetre thick, and have an about 1 m deep sub-tidal origin (Duchrow and Groetzner, 1984). The

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Fig. 2. Stratigraphy, environment and position of the compressus bone bed in the quarry of Bissendorf, NW-Germany at the boundary of the Anisian/Ladinian (Middle Triassic). New ceratite finds allow a precise dating of the bone bed.

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Fig. 3. Surface below the compressus bone bed, which had been removed from the cleaned surface in this stage. Visible are the deeply eroded horse iron like scour troughs and parallel channels into the bone bed resulting from the overlaying compressus storm bed (tempestite).

Fig. 4. Facies model for the compressus bone bed, overlaying sediments and final partial erosion by the compressus tempestite.

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only crinoid rich bed can be found in the Ceratitenschichten of the upper robustus Biozone, whose marker bed is distributed in the region of the Osnabrücker Bergland and Teutoburger Wald (Duchrow and Groetzner, 1984). The Tonplatten (mo2 TP) of the Ceratitenschichten are built from dolomites and more or less thick limestone layers, which mostly contain few marine macrofossils. As a result of new ceratite finds in the lower part of the section (Ältere Tonplatten, Meißner Fm, moM1, Diedrich, in press); the “Ceratitenschichten” between the “Trochitenkalk” and the “Terebratelkalk” (mo 2a-mo 2f, about 15 m thick), the here-described bone bed can be dated into the compressus Biozone (Upper Muschelkalk). At the top of the Älteren Tonplatten just below the massive Terebratelkalk (mo2f member), the here-described only up to 3 mm thin bone bed is extended and falls, according to Hagdorn et al. (1991) and Bachmann et al. (1999) into the maximum flooding of the Anisian/Ladinian boundary. It is built dominantly from brachiopods of Coenothyris vulgaris (Schlotheim) and more rare, the bivalve Hoernesia socialis. Above the bone bed a generally 2 to 5 cm thick grey marl may partly be missing when reworked by the above compressus tempestite. In this soft ground, channels were easily eroded. This is typically found in the Upper Muschelkalk Tonplatten facies (cf. Aigner and Futterer, 1978). The marlstone contained an autochthonous fauna with infaunistic bivalves of Myophoria vulgaris, and also the Ceratites C. compressus. Finally, allochthonous elements are terebratulids (cf. Diedrich, in press). Those sediments are overlain by the mentioned tempestite, a 5–30 cm thick shell, and massive terebratulid rich limestone. At the base, roughly 20 cm connecting channels, narrow and partially parallel to each other, runs over the surface (Fig. 3). Also typical is that horse irons scour troughs developed; almost 3 m long. These erosive structures and the carbonate horizon (compressus-storm shell bed, Fig. 4) were pressed onto the underlying plastic reacting marls, and finally partially onto the bone bed. The bioclasts of the shell bed are mainly Coenothyris, Myophoria, Gervillia and a few ceratites (C. compressus). The storm shell is for Upper Muschelkalk sequences (cf Aigner and Bachmann, 1991), typically graded with smaller particles towards the top. On the top, a shell plaster with mainly single valves of Myophoria has developed. Between the compressus storm shell bed and the Terebratelkalk some decimetre thick Tonplatten are sedimented, in which again storm channels are sometimes present. Bivalves such as Hoernesia socialis (Schlotheim), Myophoria vulgaris (Schlotheim), and less Entolium discites (Schlotheim) dominate. Already in these layers other cephalopods C. evolutus date into younger levels. The Terebratelkalk (mo2 TK) is intercalated into the Ceratitenschichten and a typical 5 to 8 m thick limestone member of the Osnabrücker Bergland and Teutoburger Wald region. These carbonate and shell rich shallow water carbonates contain mainly the brachiopod C. vulgaris but also ooids. The Dolomitische Grenz-Schichten (mo2 DG) follow with about an 8 m layer of Tonplatten in the lower section (mo 2g). C. postspinosus was found here. The more dolomite limestone of the 8 m thick mo 2h is contained in the Rochusberg bed. In the upper part of this eight-nine meter thick series of the mo2i dolomites, marls and also dark claystones can be found. The lack of cephalopods in that uppermost section doesn't make for a clear boundary between the Bremerberg bed and the Keuper. 4. Taphonomy The large amount of fish teeth, especially selachian teeth, did not allow for the mapping of every tooth over the entire excavation area. Therefore 1 m2 was mapped for statistical analyses; this seems to be well representative of the complete excavated area. The reptiles were mapped in 45 m2 (Fig. 5). As shown here, there is less than one reptile find per square that is larger than 3 mm. Therefore the bone bed is not rich, but in this excavated area at least Fig. 5. Bone mapping of 45 m2 for reptile remain statistics in the compressus bone bed in Bissendorf. The overlaying compressus storm event eroded deep channels in the bone bed (explanations to No. see Taphonomy).

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eight reptile genera can be proven. The main remains are the three to six mm small vertebra centra (No. 1, 2, 4, 9–11, 15, 21, 23, 25–28) of the pachypleurosaur Neusticosaurus. From this a possible radius and only one neural arch half (No. 22) was found, plus one rib (No. 18). Only one vertebra centrum of the pachypleurosaurid Anarosaurus was recognized (No. 7). Nothosaurus bones were identified through one coracoid (No. 20), one ileum (No. 29), two vertebra centra (No. 13, 17) and two costae (No. 8,14). One gastralia fragment is unclear in the identification (No.19). From the placodont Placodus a maxillary or mandible tooth (No. 5) and two ribs (No. 12, 16) can be identified. The most important find is a tooth from the terrestrial large lepidosaur Tanystrophaeus (No. 30). The bones, which are often not elongated pieces do not have any use for current interpretations and are scattered completely irregularly across the surface. The problem of later erosion by channels of the compressus storm event overprinted the real amount of finds in each square. Bones are somewhat to considerably fragmented, but generally they are not well-rounded and therefore haven't been transported too far or too long. A sorting took place, which found vertebra centra are the dominating and most robust bone types. Long bones especially are nearly absent; but a few pelvic and pectoral bones were found. 5. Systematics Of the total surface amount of 150 m2 excavated, proof of five selachian species, five osteichthyes species, seven to eight marine reptiles and one terrestrial lepidosaur was found. The material consists of isolated bone material. Five hundred thirty-eight bones could be determined, about 50 of the reptiles are not even of the bone type or genus level to identify, about 100 bones and teeth are impossible to identify. Whereas teeth can easily be determined in most cases, as well as selachians' fin spines and even some fish scales; postcranial bones from the reptiles are in many cases still problematic even in the genus identification. Class Chondrichthyes Huxley, 1880 Subclass Elasmobranchii Bonaparte, 1838 Cohort Euselachii Hay, 1902 Suprafamily Hybodontoidea Zangerl, 1981 Family Hybodontidae Owen, 1846 Genus Hybodus Agassiz, 1837 Hybodus longiconus Agassiz, 1843 Fig. 6.1–3 Material: 103 teeth from all jaw positions, one more or less complete fin spine and fin spine fragments (Coll.-No. Pal 327—1–104). Discussion: The hybodontid shark teeth are heterodont (Cappetta, 1987) and were described therefore under several specie names in history (c.f. Schmidt, 1928). As described for material from the enodis/ posseckeri bone bed in Lamerden, Central Germany (Diedrich, 2003), here teeth of different jaw positions are figured. Their amount of lateral accessory cusps rise from the anterior to the posterior position. All teeth have strong enamel striations on both sides, lingual and labial. The root base is flat and angled. Small symphyseal teeth also have nearly no lateral cusps. The largest teeth are the 6–17 mm in height anterior ones which have no lateral cusps (= H. longiconus). Lateral teeth with one and up to four lateral cusps were published as H. plicatilis Agassiz, 1843 or H. multiplicatus Jaekel, 1889 and H. multiconus Jaekel, 1889 (cf. Agassiz, 1833–1843; Jaekel, 1889; Schmidt, 1928). The last posterior teeth are nearly without a cusp and are quite flat. Family Acrodontidae Casier, 1959 Genus Acrodus Agassiz, 1837 Acrodus gaillardoti Agassiz, 1837 Fig. 6.6–9 Material: 24 teeth from different anterior to posterior positions and different old animals (Coll.-No. Pal 327—105–128, and 139). Discussion: The largest Acrodus species teeth reached up to 24 m in length. The heterodont teeth are much shorter and a little oval in their

outline in the anterior position (Cappetta, 1987). In the lateral they are more elongated. The surface is covered by a complex and irregular crest structure. Very often the teeth are lost and dropped ones, and preserved by the rootless enamel with strongly used surfaces (Fig. 6.9). These large teeth are from the fourth most common shark in the German Upper Muschelkalk bone beds (Seilacher, 1943, 1991; Hagdorn and Reif, 1988; Hagdorn, 1990; Diedrich, 2003). Acrodus lateralis Agassiz, 1837 Fig. 6.4–6 Material: 144 teeth from different jaw positions (Coll.-No. Pal 327— 129–138, and 140–275). Discussion: The acrodontid shark dentition is heterodont (Cappetta, 1987) whose flat oval shaped teeth are no larger than 12 mm. A median crest runs over the enamel and from this there are several crests running to the tooth's edge. The anterior teeth are much shorter but wider compared to the more elongated lateral ones. A series of tooth outlines from different jaw positions was figured for the material of Lamerden (Diedrich, 2003). This is the most common shark tooth in the Germanic Muschelkalk and its bone beds (cf. Agassiz, 1833–1843; Seilacher, 1943, 1991; Hagdorn and Reif, 1988; Hagdorn, 1990; Schultze and Kriwet, 1999; Diedrich, 2003). Family Polyacrodontidae Glückmann, 1964 Genus Palaeobates Meyer, 1849 Palaeobates angustissimus (Agassiz, 1838) Fig. 6.10–12 Material: 125 teeth from all jaw positions and one fin spine (Coll.No. Pal 327—275–401). Discussion: These ray-like selachians are the most common and are heterodont however the anterior teeth are much shorter with a small tip on the centre of the enamel (Cappetta, 1987). The more lateral they are, the more elongated they are, with a rectangular outline. Typical only for this species (to distinguish them from the other ones found in the Upper Muschelkalk) are the grooves on the surface. These teeth reach maximum sizes of 8 mm in length. Some teeth still have the roots, others don't. Many teeth are heavily used. Teeth from this shark are the second most abundant in the Upper Muschelkalk bone beds all over Germany (cf. Seilacher, 1943, 1991; Hagdorn and Reif, 1988; Hagdorn, 1990; Diedrich, 2003). Genus Polyacrodus Jaekel, 1889 Polyacrodus polycyphus (Agassiz, 1837) Fig. 6.13 Material: Five teeth from anterior to lateral positions (Coll.-No. Pal 327—402–406). Discussion: This is the rarest tooth in Bissendorf. Per 2 m2 only one tooth is represented. These sharks also have a heterodont dentition (Cappetta, 1987). The amount of lateral cusps arises to the posterior teeth. Also those become wider, whereas the roots become flatter. The cusps are in a pin shape, of which the central one is the highest. This species is fairly rare in other Upper Muschelkalk bone beds in Germany and France (Jaekel, 1889; Seilacher, 1943, 1991; Hagdorn and Reif, 1988; Hagdorn, 1990; Schultze & Kriwet, 1999; Schoch & Wild, 1999; Diedrich, 2003). Class Osteichthyes Huxley, 1880 Subclass Actinopterygii Klein, 1885 Family Palaeoniscidae Vogt, 1852 Genus Gyrolepis Agassiz, 1833 Gyrolepis sp. Fig. 6.14 Material: 12 single scales (Coll.-No. Pal 327—407–418). Discussion: Such scales were described long ago from many Muschelkalk localities in Germany (e.g. Dames, 1888; Stolley, 1920; Schmidt, 1928) and are figured more recently from northern German bone beds of the enodis/poseckeri zone of Lamerden (Diedrich, 2003). From the Upper Muschelkalk of Lüdge and Vahlbruch (Weserbergland), even articulated fish skeletons of G. cf. albertii Münster have been described in carbonate concretions (Plesker, 1995). Articulated

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Fig. 6. Selachii and teleostei remains from the compressus bone bed (Anisian/Ladinian boundary) of Bissendorf, NW-Germany. 1. Hybodus longiconus Agassiz, 1843 incomplete fin spine (No. Pal 327—78), lateral. 2. Hybodus longiconus Agassiz, 1843 anterior tooth (No. Pal 327—69), labial. 3. Hybodus longiconus Agassiz, 1843 lateral tooth (No. Pal 327—77), labial. 4. Acrodus lateralis Agassiz, 1837 lateral tooth cusp (No. Pal 327—131), dorsal. 5. Acrodus lateralis Agassiz, 1837 lateral tooth cusp (No. Pal 327—129), dorsal. 6. Acrodus gaillardoti Agassiz, 1837 anterior tooth (No. Pal 327—123), dorsal. 7. Acrodus gaillardoti Agassiz, 1837 lateral tooth cusp (No. Pal 327—139), dorsal. 8. Acrodus gaillardoti Agassiz, 1837 lateral tooth cusp (No. Pal 327—106), dorsal. 9. Acrodus gaillardoti Agassiz, 1837 posterior tooth cusp (No. Pal 327—107), dorsal. 10. Palaeobates angustissimus (Agassiz, 1838) anterior tooth (No. Pal 327—291), dorsal. 11. Palaeobates angustissimus (Agassiz, 1838) lateral tooth cusp (No. Pal 327—306), dorsal. 12. Palaeobates angustissimus (Agassiz, 1838) fin spine (No. Pal 327—311), lateral. 13. Polyacrodus polycyphus (Agassiz 1837) lateral tooth cusp (No. Pal 327—403), a. dorsal, b. labial. 14. Gyrolepis sp. scale (No. Pal 327—407), lateral. 15. Colobodus maximus Quenstedt, 1835 jaw fragment (No. Pal 327—419), dorsal. 16. Colobodus frequens Dames, 1888 jaw fragment (No. Pal 327—424), dorsal. 17. Colobodus sp. scale (No. Pal 327—423), lateral. 18. Dollopterus sp. scale (No. Pal 327—436), lateral. 19. Saurichthys sp. tooth (No. Pal 327—443), lateral. 20. Teleostei indet. scale (No. Pal 327—441), lateral. 21. Coprolite (No. Pal 327—442).

skulls were also figured from the southern German Upper Muschelkalk locality Nussloch (Schultze and Kriwet, 1999). Suborder Orthoganoidei Stolley, 1920 Family Colobontidae Stensio, 1916 Genus Colobodus Agassiz, 1844 Colobodus maximus Quenstedt, 1835 Fig. 6.15 Material: Two jaw fragments, each with two articulated teeth. Other material from two scales might refer to this genus (Coll.-No. Pal 327—419–423).

Discussion: The material from Bissendorf consists only of teeth, which are typical for the genus and the species' size and form. Skeleton remains and single scales of C. maximus were well-figured by Schmidt (1928), or were discussed by Guttormsen (1937). A skull has been described from Alverdissen in northern Germany (Plesker, 1995). A nearly complete specimen was found in Nussloch in southern Germany (Schultze and Kriwet, 1999). This fish was found in the Germanic Basin and northern Tethys (e.g. Schmidt, 1928; Guttormsen, 1937) and proved the faunal similarities of both regions during the Anisian/Ladinian boundary (Upper Muschelkalk).

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Colobodus frequens Dames, 1888 Fig. 6.16 (?17) Material: One jaw fragment with four teeth and eight isolated teeth, possibly scales from this genus belong to this species (Coll.-No. Pal 327—424–431). Discussion: Scales are described from all over the Germanic Basin, even some articulated skeletons are known (Schmidt, 1928). The teeth are maximum 3 mm in width and smaller like C. maximus. Such jaw remains were also figured from the enodis/posseckeri bone bed of Lamerden (Diedrich, 2003). Genus Dollopterus Abel, 1906 Dollopterus sp. Fig. 6.18 Material: Nine small scales are preserved (Coll.-No. Pal 327—432– 440). Discussion: These up to 3 mm wide scales of this small fish have a typical enamel sculpture of branching crests and are similar to the much larger Gyrolepis. Comparable scales and even articulated skeletons of D. brunsvicensis Stolley, 1920 were described from Barntrup (Weserbergland, Plesker, 1995). This again is one of the most common small fish in the Germanic Basin (Schmidt, 1928; Schultze and Kriwet, 1999). Family Saurichthyidae Goodrich, 1909 Gattung Saurichthys Agassiz, 1834 Saurichthys sp. Fig. 6.19 Material: One single tooth (Coll.-No. Pal 327—443). Discussion: The pin shaped teeth differ in two main types (cf. Rieppel, 1985; Diedrich, 2003). The first large one is wide and short and has enamel faults similar in shape to sauropterygian teeth. The second herefigured one has a pointed tip and smooth surface. This predator is very well-known in the Germanic basin Upper Muschelkalk bone beds, where even articulated skulls (Schmidt, 1928; Seilacher, 1943, 1991; Hagdorn and Reif, 1988; Hagdorn, 1990; Schultze and Kriwet, 1999) and skeletons from the northern Tethys (Rieppel, 1985) are known. Subclass Synaptosauria Owen, 1860 Order Sauropterygia Owen, 1860 Suborder Eusauropterygia Tschanz, 1989 Suprafamily Nothosauria Seeley, 1882 Order Pachypleurosauroidea Huene, 1956 Suborder Pachypleurosauria Nopcsa, 1928

Family Pachypleurosauridae Nopcsa, 1928 Genus Anarosaurus Dames, 1890 Anarosaurus sp. Fig. 8.1 Material: Only one thoracic vertebra can be definitely attributed to this genus (Coll.-No. Pal 327—444). Discussion: The thoracic vertebrae of this genus are much longer, rather than wide and therefore differ from the ones of Neusticosaurus. The material was compared to A. heterodontus Rieppel and Lin, 1995 skeleton remains from the basal Lower Muschelkalk (Bithynian) of the Winterswijk locality where reptile fauna was briefly analysed and wellfigured (Oosterink et al., 2003). In the basal Lower Muschelkalk, the skeletons of A. heterodontus Rieppel and Lin, 1995 are known from the Germanic Basin, however in younger layers (mm1 member, lower Illyrian) A. pumilio Dames, 1890 has been described with a skeleton (Dames, 1890; Rieppel, 2000; Diedrich and Trostheide, 2007). In the Upper Muschelkalk this genus is not yet well-known. A skeleton reconstruction of this paraxial swimming reptile A. heterodontus (according to Rieppel and Lin, 1995; Rieppel, 2000; Diedrich and Trostheide, 2007) in dorsal view, as for all sauropterygians, is figured here because of their similar locomotion (Fig. 10A). Genus Neusticosaurus Seeley, 1882 Neusticosaurus sp. Fig. 7.2–11 Material: 45 vertebra centra, one neural arch, one rib, some rib fragments and possibly a fibula (Coll.-No. Pal 327—445–493). Discussion: The main material consists of the most robust vertebra centra. All centra are between 3 and 6 mm in length and width. They differ from Anarosaurus vertebrae centra because of their shorter length. There are larger vertebrae and some nearly half in size from each body region (cervical, thoracic, caudal). It is unclear yet if those might represent the two known middle Upper Muschelkalk (Anisian/ Ladinian boundary) species N. peyeri Sander, 1989 and N. edwardsii (Cornalia, 1854), or if the material only reflects juvenile animals from one species. Possibly the largest vertebra of Fig. 7.2–6 are from the larger species N. edwardsii, whereas the smaller ones are from the small species N. peyeri. The vertebrae centra are not diagnosed enough to get into a species level discussion. Postcranial large bones and cranial material would be needed in the future. Similar vertebrae were figured and described for the evolutus bone bed of Eilversen; the

Fig. 7. Marine sauropterygian pachypleurosaur reptile remains in the compressus bone bed (Anisian/Ladinian boundary) from Bissendorf, NW Germany. 1. Anarosaurus sp. thoracic vertebra centrum from an adult individual (No. Pal 327—444). 2. Neusticosaurus sp. anterior cervical vertebra centrum from a large individual (No. Pal 327—451). 3. Neusticosaurus sp. posterior cervical vertebra centrum from a large individual (No. Pal 327—460). 4. Neusticosaurus sp. middle thoracic vertebra centrum from a large individual (No. Pal 327—469). 5. Neusticosaurus sp. lumbar vertebra centrum from a large individual (No. Pal 327—446). 6. Neusticosaurus sp. middle caudal vertebra centrum from a large individual (No. Pal 327— 455). 7. Neusticosaurus sp. small cervical vertebra (No. Pal 327—464). 8. Neusticosaurus sp. small thoracic vertebra (No. Pal 327—445). 9. Neusticosaurus sp. thoracic rib (No. Pal 327— 454). 10. Neusticosaurus sp. ?fibula (No. Pal 327—457), lateral. 11. Neusticosaurus sp. half neural arch (No. Pal 327—463). Vertebrae: a. dorsal, b. lateral, c. cranial.

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nodosus bone bed of Vahlbruch (Diedrich et al., 2003) and the enodis/ posseckeri bone bed of Lamerden (Diedrich, 2003), all being northern German localities. Other Neusticosaurus species are described from different stratigraphic levels such as one N. pusillus Seeley, 1882 skeleton from the Lower Keuper of southern Germany (Seeley, 1882; Rieppel, 2000). Whereas in the Germanic Basin mostly only isolated bones are known, hundreds of complete skeletons from the black

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shale of Monte San Giorgio were described in all kinds of different age stages (e.g. Peyer, 1944; Sander, 1989, Rieppel, 1995, 2000). We recently learned the pachypleurosaur group is known to give birth under water (Yen-nien Cheng et al., 2004). This seems to explain the absence of tracks in the carbonate tidal flats (Diedrich, 2008). The small pachypleurosaurs were hunted by the larger nothosaurs, which is proved by the stomach contents of large nothosaur skeletons from

Fig. 8. Marine sauropterygian Nothosaurus sp. reptile remains in the compressus bone bed (Anisian/Ladinian boundary) from Bissendorf, NW-Germany. 1. Lateral tooth (No. Pal 327— 505), labial. 2. Anterior fang tooth (No. Pal 327—496), lateral. 3. Right coracoid fragment (No. Pal 327—514), ventral. 4. Neck vertebra centrum (No. Pal 327—495), a. dorsal, b. cranial, c. lateral. 5. Thoracic vertebra centrum (No. Pal 327—504), a. dorsal, b. cranial, c. lateral. 6. Upper tail vertebra centrum (No. Pal 327—513), a. dorsal, b. cranial, c. lateral. 7. Lower tail vertebra centrum (No. Pal 327—494), a. dorsal, b. cranial, c. lateral. 8. Ileum (No. Pal 327—503). lateral. 9. Upper tail costa (No. Pal 327—512), ventral. 10. Thoracic costa fragment (No. Pal 327—498), lateral.

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Monte San Giorgio (Peyer, 1944). The small reptiles must have lived in large, dense populations. This can be proved by the large amount of their vertebrae at the Bissendorf and Lamerden bone beds (Diedrich, 2003), and finally at Monte San Giorgio where complete embryos were figured and several hundred skeletons were excavated in small areas (Sander, 1989). Here a skeleton reconstruction of the paraxial swimming P. peyeri is presented in dorsal view (Fig. 9B) according to anatomical studies by Sander (1989), Rieppel (1995, 2000) or Diedrich and Trostheide (2007). Family Nothosauridae Baur, 1889 Subfamily Nothosaurinae Nopcsa, 1889

Genus Nothosaurus Münster, 1923 Nothosaurus sp. Fig. 8.1–10 Material: 12 teeth from different jaw positions, several vertebra centra from all positions (cervical to caudal), some incomplete thoracic ribs and one caudal rib, one incomplete coracoid (Coll.-No. Pal 327—494). Some additional bone fragments might possibly refer to Nothosaurus, but their identifications are unclear. Discussion: In nearly all cases the material is not usable for species identification and even on the genus level rib fragments are questionable. N. mirabilis Münster, 1834 and N. giganteus Münster, 1834 seem to

Fig. 9. Marine sauropterygian skeleton reconstructions: A. Anarosaurus pumilio from Remkersleben (according to Rieppel and Lin, 1995; Rieppel, 1995, 2000; Diedrich and Trostheide, 2007), B. Neusticosaurus peyeri from Monte San Giorgio (according to Sander, 1989; Rieppel and Lin, 1995; Rieppel, 1995, 2000), C. Nothosaurus mirabilis (after Diedrich and Trostheide, 2007) and D. Nothosaurus giganteus (reconstructions made according to Peyer, 1939; Rieppel, 2000; Diedrich et al., 2003). All from the middle Upper Muschelkalk or Anisian/Ladinain boundary, except Anarosaurus, which is from the uppermost Lower Muschelkalk (Illyrian).

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both be present in the material, but the material is too fragmented to distinguish them clearly. Also vertebra centra can not be separated from both of the largest marine predators in most cases. Neural arches are not represented completely, which doesn't allow for the differentiation of either species, especially on the thoracic vertebrae with low and high dorsal spines (cf. Rieppel, 2000; Diedrich et al., 2003). Both large nothosaurids are presented here with skeleton reconstructions, which are based on one N. giganteus skeleton (Fig. 9D) from Monte San Giorgio (Peyer, 1931b; Rieppel, 2000). There are no N. mirabilis skeletons, only isolated skulls and postcranial bones, but this large nothosaur was very close to the high marine adapted forms from Monte San Giorgio. Here in the Anisian/Ladinian boundary two different ecologically adapted forms have separated in Europe, the one paraxial swimming N. giganteus with a shorter neck and wider skull. This seems to have evolved from a former nothosaur species (N. marchicus, Lower Muschelkalk) which was adapted to flat marine to lagoon-type environments. N. mirabilis, as figured here, hypothetically (Fig. 9C) was already a high marine adapted partly paraxial swimming hunter with elongated neck, elongated skull and hyperphalangy. Such open marine nothoaurs are described from Monte San Giorgio as “Ceresiosaurus” (e.g. Peyer, 1944) which seem to be the only different Nothosaurus species. Order Placodontia Meyer, 1863 Suborder Placodontoidea Nopcsa, 1923 Family Placodontidae Nopcsa, 1923 Genus Placodus Agassiz, 1833–43 Placodus gigas Agassiz, 1833 Fig. 11.2–5 Material: One incomplete tooth and one tooth fragment, some incomplete ribs and possibly gastralia fragments (Coll.-No. Pal 327— 527–531). Discussion: This species is well known in the Germanic Basin and was first described with its typical large and today black fossilized teeth (Agassiz,1833–43; Meyer,1847–1855). A skeleton was found in southern Germany and is reconstructed in the Senckenbergmuseum Frankfurt (Drevermann, 1933). The material here, especially the ribs, was compared directly to this skeleton. The ribs differ from the ones of Nothosaurus by their rounder cross section, in contrast to the more rectangular ones in Nothosaurus. Also the long double headed cervical rib figured here might be referred to Placodus. Two more teeth fragments

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might belong to Placodus or to Cyamodus. Placodus seems not to have been a shell crusher as believed in the past (Westphal, 1967, 1988). He is now more often compared to the anatomy of the very convergent developed mammalian dugongs (Diedrich, in review) and is therefore believed to be similar to other placodontids; an algae feeder from the Middle Triassic flat Germanic Basin (Diedrich and Trostheide, 2007). The anatomy is very convergent to modern and fossil sirenia; the pachyostotic gastral ribs especially were an adaptation to increase the body weight for diving and feeding on the sea floor (Diedrich, in review). Suborder Cyamodontoidea Nopcsa, 1923 Superfamily Cyamodontida Nopcsa, 1923 Family Cyamodontidae Nopcsa, 1923 Genus Cyamodus Meyer, 1863 Cyamodus sp. Fig. 11.1 and 6 Material: One osteoderm plate, possibly also one tooth fragment (Coll.-No. Pal 327—532–533), and one anterior tooth (Coll.-No. Pal 327— 526). Discussion: The anterior teeth of Paraplacodus are more slender and longer (cf. Peyer,1931b) like the ones from Placodus (cf. Westphal, 1967, 1988). The short anterior tooth present from Bissendorf is an anterior tooth, which is much shorter like the Paraplacodus ones. After comparing the material with anterior tooth material from the Lower Muschelkalk (Schaumkalk member) of the central German locality Feyburg a.U. it can reported that Paraplacodus was in the Germanic Basin several million years earlier. This is also true for the described skeleton from the Anisian/ Ladinian boundary of Monte San Giorgio (cf. Peyer,1931b, Rieppel, 2000) and at two more localities in the Germanic Basin. Finally a single tooth of that genus was even figured from the much older basal Lower Muschelkalk (Bithynian) from the locality Winterswijk in the Netherlands (Oosteerink et al., 2003). Both Lower Muschelkalk teeth finds are more elongated, like the one from Bissendorf. The direct comparison to the lower jaw dentition of Cyamodus rostratus in the Museum Stuttgart (coll. No. 81668) show similar short first anterior teeth. Whether postcranial rib fragments from Bissendorf might also belong to this genus can not yet be proved. Isolated osteoderm material was described as Psephosaurus (Fraas, 1896) from the Upper Muschelkalk of southern Germany and seems to belong to Cyamodus, for which a skeleton with carapax was described and figured for the species C. hildegardis Peyer, 1931 (Peyer, 1931c). Here a reconstruction of a Cyamodus skeleton is

Fig. 10. Skeleton of the placodontids: A. Paraplacodus broilii from Monte San Giorgio (according to Peyer, 1931b), and B. Placodus gigas from Steinsfurt (according to Drevermann, 1933) and reconstruction of the cyamodontid Cyamodus rostratus (according to Peyer, 1931c; Westphal, 1988). All from the middle Upper Muschelkalk or Anisian/Ladinian boundary.

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presented (Fig. 9C) which shows the carapax in the middle body part consisting of an osteoderm shield. After the C. hildegardis find, the carapace was open on the bottom, very wide and enlarged ribs covered the stomach from the bottom and there was some space in between the ribs. Here C. rostratus Münster, 1839, well known through cranial material and possibly isolated articulated osteoderms, attempted to design a preliminary skeleton reconstruction. Here the aim is to show the presence of such a carapace in Cyamodus which is quite unique for these Middle Triassic marine reptiles. As newly believed for the placodonts (Diedrich and Trostheide, 2007), cyamodonts have similar dentitions to other placodonts, similar body shapes and seem to have been algae feeders (Diedrich, in review), not durophag and shell crushers, as described by Westphal (1967, 1988). Also too many teeth from Cyamodus were found isolated and are barely worn, which would explain soft nutrition, that was squeezed, rather than chewed. Even jelly fish might have been a source of food for the half turtle-shaped Cyamodus. All placodonts are figured similarly here in a lateral view

Fig. 12. Terrestrial lepidosaur Tanystrophaeus longibardicus (Bassani 1886) anterior tooth from the compressus bone bed (Anisian/Ladinian boundary) in the quarry of Bissendorf, NW-Germany. a. labial, b. caudal, c. lingual, d. cranial (MSB No. Pal 327— 534).

Fig. 11. Placodontid and sauropterygian pachypleurosaurid remains from the compressus bone bed (Anisian/Ladinian boundary) of Bissendorf, NW-Germany. 1. Cyamodus sp. anterior tooth (No. Pal 327—526), a. lateral, b. lingual. 2. Placodus gigas incomplete palatinal or lower jaw tooth (No. Pal 327—531), a. dorsal. 3. Placodontid cervical rib (No. Pal 327— 527), lateral. 4. Placodontid thoracic rib (No. Pal 327—529), lateral. 5. Placodontid thoracic rib (No. Pal 327—528), lateral. 6. Cyamodus sp. carapax osteoderm (No. Pal 327—532), a. dorsal, b. lateral.

because they seem not to have been paraxial swimming reptiles, such as nothosaurs and pachypleurosaurs. They must have been “long-term divers” with slow movements, for which they developed additional bone growth types to enhance their body weights. Class Lepidosauria Haeckel, 1866 Order Squamata Oppel, 1811 Suborder Prolacertilia Huene, 1940 Subclass Thalattosauria Merriam, 1904 Tanystrophaeus Meyer, 1830 Tanystrophaeus longibardicus (Bassani, 1886) Fig. 12 Material: One anterior tooth (Fig. 12) from the compressus bone bed (Anisian/Ladinian boundary) from Bissendorf (Coll.-No. Pal 327—534). Discussion: The tooth is a tall-oval shape in the cross section and has no cutting edges or serrulations. The enamel has an irregular longitudinal groove system, which disappears at the base. The very fine enamel faults are irregularly connected to each other, especially on the upper part of the tooth. They have at the base a more honeycomb-like structure which is described and figured for skeleton remains from T. longibardicus from the Anisian/Ladinian boundary of Monte San Giorgio (cf. Peyer, 1937; Wild, 1973). The tip of the tooth is worn and polished. Using the descriptions of T. longibardicus by Peyer (1931a) and Wild (1973), the tooth is from the anterior upper or lower jaw position and is one of the first teeth, which are the largest ones. T. longibardicus was found at the Anisian/Ladinian boundary with several skeletons (Fig. 13) and is therefore exactly the same age as the material from Bissendorf, which is believed to be from the same species that was distributed around the Germanic Basin and the northern Tethys (cf. Wild, 1973). In earlier periods of the Lower Muschelkalk in the Germanic Basin, a few shorter necked species were described as Tanystrophaeus antiquus Huene, 1931 from Freyburg a. U. (von Huene, 1931; Diedrich and Trostheide, 2007) and Winterswijk (Wild and Oosterink, 1984). The find from Bissendorf is the most northerly one in the Upper Muschelkalk, which makes it interesting because around the Rhenish Massif this terrestrial reptile can not only be proven, but also could only have migrated between this Massif and the Vindelizic Massiv. At this Anisian/ Ladinian boundary the populations from northern Germany and the Alps must have been separated by the Burgundian seaway. Here T. longibardicus is illustrated in its anatomy according to the new result from Diedrich and Trostheide (2007). The animal seems to have left the

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Fig. 13. Skeleton of the long-necked terrestrial lepidosaur Tanystrophaeus longibardicus (reconstructed after Peyer, 1937; Wild, 1973) anatomically modified, especially the extremity positions, according to Diedrich and Trostheide, 2007).

Synaptichnium tracks; therefore it must have walked upright such as the smaller lepidosaur Macrocnemus (Diedrich, 2008). The neck ribs did not allow for a swan-like neck position as classically illustrated (Wild, 1973). Tanystrophaeus seem to have hunted in the inter-tidal flat ponds and channels of tidal flats (Lower Muschelkalk) and on sandy beach zones (Upper Muschelkalk). Most likely this reptile was waiting in front of such channels, and on the beach with its long neck reaching deep over the water's surface to catch fish. 6. Discussion Whereas the bone beds of southern Germany are at the Muschelkalk/ Keuper boundary (Reif, 1971, 1982; Hagdorn and Reif, 1988; Hagdorn, 1990; Seilacher, 1991), and a bone bed in northern Germany is in the enodis/posseckeri ceratite biozone (Diedrich, 2003; Diedrich and Fichter, 2006) a recently discovered and excavated bone bed in north-western Germany at Bissendorf can be dated to be younger and in the compressus biozone (Diedrich, in press). The here-described bone bed of northern Germany is much younger and from the Anisian/Ladinian boundary, dated by the Ceratites (C. compressus) underlying and overlaying the bone bed. This bone bed is therefore isochronous to the famous black shale of Monte San Giorgio (Switzerland/Italy) with their rich vertebrate fauna of many kinds of articulated fish and reptile skeletons (e.g. Guttormsen, 1937; Peyer, 1931a,b, 1939, 1944; Sander, 1989, 1990; Brinkmann, 1994; Bürgin, 1992; Rieppel, 1981, 1982, 1995). This compressus bone bed can be followed in northern Germany along the north eastern margin of the Rhenish Massif, and is present in the Weserbergland and most northern Hessia (Diedrich et al., 2003). Possibly it is similar in age to the bone-rich carbonate sands and bone

beds of Bayreuth. In Hessia and Bavaria the fauna is similar to the material from Bissendorf, but systematic excavations are lacking and a detailed comparison is not yet possible. Material from Pachypleurosaurus sp., Nothosaurus sp. and the same shark and fish species listed for Bissendorf were found e.g. in Eilversen (Weserbergland, coll. Lippisches Landesmuseum Detmold; Diedrich et al., 2003) (Fig. 14). The most important and completely exposed Upper Muschelkalk section of north-western Germany was presented recently by Diedrich (in press) with a complete palaeobathymetrical and ecological interpretation. This included the German and international subdivision for the entire roughly 65 m thick carbonate series. It is here that the typical Muschelkalk vertebrate tracks of Rhynchosauroides and Procolophonichnium on polygonal cracked carbonate biolaminates indicate tidal flat conditions at the beginning of the basal Upper Muschelkalk in this region (Diedrich, in press, 2008). Bone material from the track makers was not found in the nearly completely sub-tidal marine vertebrate fauna of Bissendorf, which points towards, with the environment, a maximum water depth of about 5 m. Bissendorf was mainly under flat sub-tidal conditions and the early terrestrial sedimentation starting in the postspinosus zones prove the close position to the Rhenish Massif main land in general. During the compressus bone bed time, very flat sub-tidal conditions were present even during the maximum high stand. The flat bathymetry is indicated by tempestites and especially scours troughs and channels (Diedrich, in press). The environmental interpretation is important in order to understand reptile taphonomy and the palaeoecology, especially of the marine sauropterygian reptiles, which were usually studied systematically (cf. Rieppel, 2000). The reptile fauna from Bissendorf shows some differences to other Muschelkalk bone beds.

Fig. 14. Faunal composition of 534 bones and teeth from the compressus bone bed in the middle Upper Muschelkalk (Anisian/Ladinian boundary) in Bissendorf. The near absence of terrestrial reptiles or amphibians and high marine ichthyosaurs indicates a shallow marine macro fauna assemblage.

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Whereas in the slightly younger enodis/posseckeri bone bed of Lamerden (Hesse) placodontids are almost absent (cf. Diedrich, 2003), they are relatively more “frequent” in the bone bed of Bissendorf. Pachypleurosaurs are more abundant in the bone bed of Lamerden, but at both sites complete large populations from juveniles to old individuals were proven because of the different vertebrae sizes. At both localities the pachypleurosaurid Anarosaurus is rare, and we have no proof yet of its relative Serpianosaurus being in Bissendorf. More common are the large Nothosaurus remains, typically vertebra centra, and teeth at Lamerden

(Diedrich, 2003) and in Bissendorf. At both localities extremity and pectoral or pelvic bones are rare, also ribs, which seem to reflect a taphonomic sorting of bones. For satisfactory, exact identifications, the latter mentioned bones are useful, but are mostly lacking. The here-presented fragmentary coracoid from Bissendorf fits more to the paraxial and not-high marine adapted Nothosaurus giganteus species (cf. Diedrich et al., 2003), whereas all other material might also belong to this or to the more full marine adapted longnecked and skull-elongated Nothosaurus mirabilis. Both are common

Fig. 15. Reptiles in the Germanic Basin and northern Tethys in the Middle Triassic (Anisian/Ladinian boundary).

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at many sites in the Germanic Basin in the entire middle Upper Muschelkalk (Meyer, 1847–1855; Rieppel and Wild, 1996; Rieppel and Hagdorn, 1997; Diedrich et al., 2003). The material from Bissendorf is from the most north-western one and comprises the largest recently identified collection. Generally the Bissendorf bone bed represents a slightly deeper water condition or nearly “full shallow marine” bone bed association on the north-eastern flat ramp of the Rhenish Massif. This is compared to the not as deep sub-tidal and more “terrestrial influenced shallow marine” environmental position of the younger enodis/posseckeri bone bed at the eastern margin of the Rhenish Massif in northern Hesse at Lamerden (cf. Diedrich, 2003). The enodis/posseckeri bone bed is mainly built out of a bivalve Hoernesia shell bed. In Bissendorf the occurrence of Placodus in the Coenothyris brachiopod shell bed possibly indicate the main habitat and stratigraphical range of the placodontid reptile. As recently discussed (Diedrich and Trostheide, 2007), Placodus was probably not a “shell cracking” reptile as suggested (Westphal, 1967, 1988), but more likely a macro algae feeder that lived in sand bar areas. In such areas macro algae could grow in shallow subtidal environments with water depths of up to a few meters. The Coenothyris floatstones of Bissendorf represent such bar conditions. Most likely Placodus, Paraplacodus and Cyamodus were feeding here in such flat water bioclastic sand bar environments for algae and lived in this Germanic Basin margin region with larger populations being confirmed for the first time this far north in the Germanic Basin. Tapystrophaeus longibardicus in contrast was a terrestrial adapted animal, and its anatomy and palaeoecology was recently slightly revised, too (Diedrich and Trostheide, 2007). These animals must have been coastal adapted lepidosaur reptiles with very elongated necks which they could not lift up, as figured in classical illustrations (Wild, 1973). The older interpretations of Peyer (1931a,b,c) were closer to this reconstruction, but the leg and feet positions were largely corrected following new footprint interpretations (Diedrich and Trostheide, 2007). This bizarre long-necked lizard like reptile must have hunted on the beach areas, but the elongated neck also allowed the reptile to hunt deeper into tidal ponds, channels or the beach shore zone in general. As proven for the Bissendorf fauna, the reptiles during the Anisian/ Ladinian boundary were also more distributed over the Germanic Basin and the Northern Tethys. The separation of too many different Tethyan and Germanic basin species in former times was more the product of different scientists in different countries. The same seems to be more and more true for the tracks being left by different terrestrial, but not aquatic, reptiles (Diedrich, 2008). These beach adapted reptiles were partly washed, with their carcasses, from the beach zone into the lagoons or basin, especially Monte San Giorgio. Terrestrial reptiles found there were identified as Middle Triassic track makers of the coastal zones (Diedrich, 2008). Many terrestrial and marine reptile genera for sure and even species in the Anisian/ Ladinian boundary were distributed all over the Germanic Basin and Tethys (Fig. 15), possibly even globally. Acknowledgements For the excavation permissions I thank the Sundermeyer family, who runs the quarry. They sponsored the back hoe works. The quarry is the property of the city of Osnabrück, which supported the necessary permits. The excavations were partly undertaken with the support of K. Benn, H. Escher, J. Haunert, J. Gores and others. The financial support of the rescue excavation was made through the Geopark Terra.Vita by the Landschaftsverband Osnabrück, where I have to especially thank Mr. H. Escher. Mrs A. Leipner of the Museum für Natur und Umwelt am Schölerberg Osnabrück I thank for the field work support and the acquisition of research funding. Additionally I thank Prof. Dr. R. Springhorn for the comparison of bone material from the Upper Muschelkalk of the Weserbergland, which was inventoried

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in 2000 by the author for the Lippischen Landesmuseum Detmold. Dr. J. Fichter gave access to the material from northern Hessia, which was excavated by the author during 2003–2005. Dr. N. Hauschke allowed the comparison to Lower Muschelkalk reptile material from the Freyburg a.U. locality in the collections of the University Halle/Saale. The spell-check was performed by J. Ynsua. References Agassiz, L., 1833–1843. Recherches sur les Poissons fossiles. Neuchâtel et Soleure. 3 + 8, +390 + 32 pp. Aigner, T., Futterer, E., 1978. Fossil-Lagerstätten Nr.44: Kolk-Töpfe und -Rinnen (pot and gutter casts) im Muschelkalk - Anzeiger für Wattenmeer? Neues Jahrbuch Geologie und Paläontologie Abhandlungen 156, 285–304. Aigner, T., Bachmann, G.H., 1991. Sequence stratigraphy of the German Muschelkalk. In: Hagdorn, H., Seilacher, A. (Eds.), Muschelkalk. Schöntaler Symposium. Goldschneck-Verlag, Stuttgart, pp. 15–18. Bachmann, G.H., Beutler, G., Hagdorn, H., Hauschke, N., 1999. Stratigraphie der Germanischen Trias. In: Hauschke, N., Wilde, V. (Eds.), Trias. Eine ganz andere Welt. Mitteleuropa im frühen Erdmittelalter. Pfeil-Verlag, München, pp. 81–104. Brinkmann, W., 1994. Paläontologisches Museum der Universität Zürich. Führer durch die Ausstellung. Zürich. 108 pp. Bürgin, T., 1992. Basal ray-finned fishes (Osteichthyes; Actinopterygii) from the Middle Triassic of Monte San Giorgio (Canton Tessin, Switzerland). Systematic palaeontology with notes on functional morphology and palaeoecology. Schweizerische Paläontologische Abhandlungen 114, 3–164. Cappetta, H., 1987. Chondrichthyes II.Mesozoic and Cenozoic elasmobranchii. Handbook of Paleoichthyology, Volume 3B. Gustav-Fischer-Verlag, Stuttgart-New York. 193 pp. Cornalia, E., 1854. Notizie zoologiche sul Pachypleura edwardsii Cor. Nuovo sauro acrodonte degli strati triasici di Lombardia. Giornale del' J.R. Instituto Lombardo di Scienze letter ed Arti Nuova Serie 6, 1–46. Dames, W., 1888. Die Ganoiden des Deutschen Muschelkalkes. Palaeontologische Abhandlungen 4, 133–180. Dames, W., 1890. Anarosaurus pumilo nov. gen. nov. spe. Zeitschrift der Deutschen Geologischen Gesellschaft 42, 74–85. Diedrich, C., 1996. Paranothosaurus teutonicus n. sp. aus dem Unteren Muschelkalk (Terebratel-Zone) von Borgholzhausen (NW-Deutschland) und seine Bedeutung für die Phylogenie und Taphonomie der Nothosauriden des germanischen Beckens. Terra Nostra 96 (6), 36. Diedrich, C., 2001. Feinstratigraphische Untersuchungen der Wirbeltierfährtenhorizonte des Unteren Muschelkalkes am Westerberg in Osnabrück (NW-Deutschland). Osnabrücker Naturwissenschaftliche Mitteilungen 27, 21–38. Diedrich, C., 2002a. Die Ausgrabungsergebnisse der Wirbeltierfährtenfundstelle aus der Oolith-Zone (Bithyn, Unterer Muschelkalk) von Borgholzhausen (Teutoburger Wald, NW-Deutschland). Paläontologische Zeitschrift 76 (1), 35–56. Diedrich, C., 2002b. 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