[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

re: Yonghesuchus, was Shuvosaurus



D. Marjanovic wrote:

*Turfanosuchus* alone may not be able to tell you much.


Wu Xiaochun, Liu Jun & Li Jinling: The anatomy of the first
archosauriform (Diapsida) from the terrestrial Upper Triassic of China,
Vertebrata
PalAsiatica 39(4), 252 -- 264 + Pl. I (?December? 2001)

Abstract: "*Yonghesuchus sangbiensis*, a new genus and species of the
Archosauriformes, is erected on the basis of its peculiar cranial
features. This taxon represents the first record of tetrapods from the
Late Triassic terrestrial deposits of China. Its discovery is
significant not
only to our study on the phylogeny of the Archosauriformes but also to
our understanding of the evolution of the Triassic terrestrial
vertebrate
faunae in China. The presence of pterygoid teeth may exclude the new
form from the [crown group] Archosauria [...certainly it does!], and the

apomorphic position of the foramen for the internal carotid artery
indicates that the new form appears to be phylogenetically closer to the

Archosauria than are *Turfanosuchus* and the Proterochampsidae.
Comparisons with these taxa suggest that the *Y. sangbiensis*-bearing
Tongchuan Formation is probably of early Late Triassic age."

Material: 2 halfway complete skulls + 1 partial neck.


As reconstructed, the nasal and the prefrontal meet, and the lacrimal
does not participate in the dorsal side of the skull. Worse yet, the
prefrontal meets the maxilla and separates the orbit from the antorbital
fenestra. I wonder how much we can trust the reconstruction...

p. 263: "From the above discussion, *Euparkeria*, *Turfanosuchus
dabanensis* (if the intercentrum was present between the post-axial
vertebrae), the Proterochampsidae, and *Yonghesuchus* appear to be
successively closer in relationship to the Archosauria. This pattern of
relationships among these early archosauriforms seems to match their
geological occurrences: [...]"


>>>>>>>

Once again here is the problem of one or two characters trying to
"upset" a suite from head to toe (or whatever is present). The presence
of pterygoid teeth reoccurs in Turfanosuchus. I don't know why. These
things, like all characters, come and go. The broader perspective
reveals this.

The Proterochampsidae lies outside of whatever is left of the
Archosauriformes. You'll find they nest in a continuum from Youngina -
Choristodera - Proterochampsidae - Doswellia  - Parasuchia. So the rest
of the logic fails.

Send a jpeg of Yonghesuchus. I wasn't able to find it on the web.
Considering the above problems with cladistics,  it sounds ancillary to
the present discussion.

David Peters