Oryctos
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Accès privé :
| volume 2, 1999 |
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Michel Martin, Laurent Barbieri & Gilles Cuny, The Madagascan Mesozoic ptychoceratodontids (Dipnoi) : systematic relationships and paleobiogeographical significance. Oryctos 2, 3-16.
The Mesozoic continental deposits of Madagascar have yielded a lot of Dipnoan tooth plates which have been described a long time ago, on the bases of new data they are revised inside. Dipnoan tooth plates yielded by the madagascan continental Upper Triassic are referred to Ptychoceratodus cf. hislopianus and to P. acutus. These species are closely related to P. hislopianus and to P. virapa respectively (continental Late Triassic, India). They possess an obtuse inner angle on the tooth plates which could be an apomorphic character. These species provide evidences for good terrestrial connection between Madagascar and India during the Late Triassic. The Late Cretaceous lungfish cf. Ferganaceratodus madagascariensis is related to a special group of ptychoceratodontids worldly recorded since the Late Triassic (apart from Africa), frequently these ptychoceratodontids do not show a clear apex of the inner angle on the tooth plates. In the Late Cretaceous these latter ptychoceratodontids have no longer paleogeographical significance. During the Mesozoic they are recorded everywhere apart from Africa and several landroutes are possible in order to explain their distribution during the Late Cretaceous.
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Gilles Cuny, François-Xavier Gauffre and Adrian Hunt, First discovery of a cynodont from the Moenkopi Formation (Middle Triassic) of Northeastern Arizona. Oryctos 2, 17-20.
An incomplete tooth crown from the upper part (Holbrook Member) of the Moenkopi Formation (Middle Triassic) of northeastern Arizona is described and attributed to Cynodontia incertae sedis. It is the only record of cynodonts from the Middle Triassic of the southwestern United States.
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Virginia Tidwell, Kenneth Carpenter & Williams Brooks, New sauropod from the Lower Cretaceous of Utah, USA. Oryctos 2, 21-37.
The sauropod record for the Lower Cretaceous is poor in North America and consists mostly of isolated bones. Recently, however, a partial semiarticulated skeleton of a brachiosaurid, Cedarosaurus weiskopfae n.g., n.sp, was recovered from the Yellow Cat Member of the Cedar Mountain Formation, Utah, USA. The humeral length is almost the same as the femur, while the dorsal and caudal vertebrae, and the metacarpal all display characters that identify the specimen as brachiosaurid. The forelimb and caudal vertebrae distinctly set it apart from all currently described genera in that family. A brief review of Early to Middle Cretaceous brachiosaurs sorts through the confusing jumble of taxa that has developed over the years. In North America, most brachiosaurids found in Lower or Middle Cretaceous strata have historically been referred to the genus Pleurocoelus. The review illustrates the need for a reexamination of Pleurocoelus type material, as well as several specimens referred to that genus. Other material previously assigned to Pleurocoelus may yet prove to be the same as Cedarosaurus weiskopfae.
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Valérie Martin, Varavudh Suteethorn & Eric Buffetaut, Description of the type and referred material of Phuwiangosaurus sirindhornae Martin, Buffetaut et Suteethorn, 1994, a sauropod from the Lower Cretaceous of Thailand. Oryctos 2, 39-91.
The type specimen of P. sirindhornae Martin, Buffetaut and Suteethorn, 1994 is an incomplete, partly articulated, skeleton discovered in the Phu Wiang area of northeastern Thailand). Most of the abundant sauropod material from the Sao Khua Formation (Early Cretaceous), collected on the Khorat Plateau, in northeastern Thailand, is referable to this species. Phuwiangosaurus is a middle-sized sauropod, which is clearly different from the Jurassic Chinese sauropods (Euhelopodidae). On the basis of a few jaw elements and teeth, P. sirindhornae may be considered as an early representative of the family Nemegtosauridae.
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Zoltan Csiki, New evidence of armoured titanosaurids in the Late Cretaceous - Magyarosaurus dacus from the Hateg Basin (Romania). Oryctos 2, 93-99.
A peculiar osteoderm discovered in the Late Maastrichtian of the "La Cãrare" locality near Sînpetru village (Hateg Basin, Romania) is described and referred to the titanosaurid sauropod Magyarosaurus dacus. This represents the third report on the presence of osteoderms in European titanosaurids, besides those from South America and Madagascar, showing that possession of a dermal armour had a wide distribution in these Late Cretaceous sauropods.
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Eric Buffetaut, Mantell, Cuvier, Buckland and the identification of Iguanodon : a contribution based on unpublished annotations by Mantell. Oryctos 2, 101-109.
Previously unpublished annotations by Gideon Mantell on a publication sent to Alexandre Brongniart in 1824 document his vacillating conceptions about the fossil vertebrates from Tilgate Forest, just before he finally identified Iguanodon as a giant herbivorous reptile. The influences of Cuvier and Buckland on Mantell’s conceptions are discussed. Cuvier at first misidentified Iguanodon remains as those of mammals, and it took him nearly a year to change his mind. His eventual conversion to Mantell’s original idea of a large herbivorous reptile then played an important part in the final recognition of Iguanodon.
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Christian A. Meyer & Adrian P. Hunt, The first pterosaur from the Late Jurassic of Switzerland: evidence for the largest Jurassic flying animal. Oryctos 2, 111-116.
An enigmatic bone from the Solothurn Turtle Limestone (Late Jurassic; Kimmeridgian) from an old quarry near St. Niklaus (Solothurn, Switzerland) is reexamined. This specimen, previously identified as coelurosaurian fibula by Huene (1926) is now interpreted as the wing phalanx II of a pterodactyloid pterosaur with a wingspan between 3.5m and 5 m. Pterosaurs with wingspans of over 2.5 m had previously not been found in rocks older than Early Cretaceous.
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