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Tanystropheus



Dear all,

I would notify that is out a new monograph on Tanystropheus:

Nosotti, Stefania, 2007, Tanystropheus longobardicus (Reptilia, Protorosauria): re-interpretations of the anatomy based on new specimens from the Middle Triassic of Besano (Lombardy, Northern Italy). Memorie della Società Italiana di Scienze Naturali e del Museo Civico di Storia Naturale di Milano, Vol. XXXV - Fascicolo III, pp. 1-88.

Abstract (long): After more than one century since the first report of Tanystropheus longobardicus from the middle triassic of Besano, new specimens from the same outcrops are described. These specimens include two articulated skeletons and an isolated pes, all from small-sized individuals, and fragmentary remains of larger individuals, i.e. a skull with some associated cervical vertebrae, an isolated dorsal vertebra and isolated cervical ribs.
This new material confirms the presence of T. longobardicus in the Besano Formation, which previously yielded few evidence. Moreover, it includes remarkably complete and well preserved specimens which provided the opportunity of a new interpretation of the anatomy of Tanystropheus, formerly described on the basis of a rich sample from the Swiss Grenzbitumenzone.
The description presented here applies to small-sized individuals of Tanystropheus, traditionally interpreted as the juveniles of T. longobardicus. However, the point is raised that they might represent the adults of a different species, demonstrating the presence of two taxa among the Swiss and Italian material referred to T. longobardicus. The holotype, and the single know specimens, of the small-sized Tanystropheus meridensis from the Meride Limestone is also considered and re-interpretated, leading to the conclusion that the species is probably a junior synonym of T. longobardicus.
Comparisions of the specimens of Tanystropheus from the Besano Formation with those from the equivalent Grenzbitumenzone helped to find the problematic elements of the classical reconstruction.
A new reconstruction of the skull of Tanystropheus is presented based on a three-dimensional clay model, with a re-interpretation of the pre-orbital region, the skull roof, and the lower jaw. The reconstruction of the temporal region of the skull is shown to be highly problematical. Finally, the new specimens confirm the presence of a sclerotic ring in Tanystropheus.
In the postcranial skeleton, the more important new information concern the morphology of the appendicular skeleton, which is remarkably well preserved in the new specimens. In particular, preservation of complete and perfectly articulated manus and pedes for the first time yield unequivocal evidence on their morphology.
The anatomy of the appendicular skeleton, in particular that of the hindlimb, is discussed in the context of locomotion mode. An overall view of previous studies on the mode of life of Tanystropheus is presented and discussed. According to these results, Tanystropheus should be regarded as a marine protorosaur, with close terrestrial ancestors, living in shallow waters. The feeding strategy of Tanystropheus is discussed, on the assumption that it likely was a slow, axial or paraxial swimmer with a stiff neck.
In conclusion, the new information obtained from the specimens described here is evaluated in the context of the recent cladistic analyses of protorosaurian relationships, highlighting the bearing of systematic anatomical work of the original materials on the description and coding of phylogenetically informative characters.


The volume can be ordered at the following address:

info@scienzenaturali.org

Marco

MARCO AUDITORE
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