Schultzsuchus

Add links
Source: Wikipedia, the free encyclopedia.

Schultzsuchus
Temporal range: Triassic, Ladinian–Carnian
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauria
Clade: Pseudosuchia
Clade: †Poposauroidea
Genus: †Schultzsuchus
Desojo & Rauhut, 2024
Species:
†S. loricatus
Binomial name
†Schultzsuchus loricatus
Desojo & Rauhut, 2024
Synonyms
  • von Huene
    , 1938

Schultzsuchus is an extinct genus of

pseudosuchian from the Triassic Santa Maria Formation of Brazil. Initially described as a species of Prestosuchus,[1][2] a 2024 study found the taxon to differ in multiple aspects of its anatomy, enough to warrant it being placed in a distinct genus. Unlike Prestosuchus, which is a more derived member of Loricata, Schultzsuchus appears to have been a basal member of the clade Poposauroidea
.

History and naming

The remains of what is now called Schultzsuchus were first described under the name Prestosuchus loricatus by German paleontologist Friedrich von Huene in 1938,[1] who had recovered the fossils of this pseudosuchian from the Cynodontier Sanga of the Santa Maria Supersequence in 1928/29 and regarded the animal as having been congeneric with Prestosuchus chiniquensis, also named by him.

While

calcaneum to this taxon, but he himself was uncertain of this assessment.[2]

The validity of P. loricatus eventually came into question, with several authors regarding this a possibility. Krebs (1976) and Barberena (1978) regarded the species to have probably been synonymous with P. chiniquensis,

nomina nuda. A thorough examination of the type material of Prestosuchus loricatus was eventually published by Desojo and Rauhut in 2024, who agreed with Kischlat (2023) in so far that the material did represent a taxon distinct from Prestosuchus,[5] which they dubbed Schultzsuchus.[6]

Schultzsuchus was named in honor of Cesar Schultz, who was noted for his contributions to the understanding of the vertebrate fauna of the Santa Maria Supersequence.[6]

Description

Schultzsuchus is only known from limited material thought to have belonged to a single individiual, though this is sometimes called into question. Among the material are the tip of a tooth, the

osteoderms have also been described for this taxon.[6]

The only known skull remains of Schultzsuchus consist of a single tooth crown. The element is conical in shape and stout, but with laterally compressed sides and carinae that feature partially abraded serrations (ziphodont). The tooth is recurved, causing the mesial carina to be convex in shape, while the carina facing towards the back of the jaw is straight. The only carina well-enough preserved to show the amount of serrations is the mesial carina, which has about 10 denticles across 5 mm (0.20 in), which is only slightly lower than the amount seen in Heptasuchus. There has been some doubt on the assignment of the tooth to Schultzsuchus given the fact that it's an isolated element not directly associated with any other material while also having been found with the fossils of a synapsid. However, the shape does suggest that it belonged to what was likely a paracrocodylomorph or some other predatory archosaur.[6]

A notable feature that distinguishes Schultzsuchus from Prestosuchus is the fact that the cervical vertebrae preserve

Postosuchus alisonae. Similarly, an epipophysis is also present on the second neck vertebra, the axis, which is even less common and stated to be present in Revueltosaurus, Longosuchus, Xilousuchus and possibly Effigia.[6]

The neural spine of the neck vertebrae also represents a markedly different anatomy from Prestosuchus and most other basal loricatans. In those forms the neural spine tends to be short from the front to the back and tall, keeping a relatively consistent rectangular profile and being notably thickened. Schultzsuchus meanwhile has neural spines is visibly longer anteroposteriorly and shaped like a fan, owing to the spinous process expanding towards the top most edge of the bone. Even more so than the presence of epipophysis, this element could suggest affinities with poposauroids, as Desojo and Rauhut note that the only other pseudosuchians with such neural spines are Xilousuchus, Qianosuchus, Arizonasaurus and Mandasuchus, all of which appeared as poposauroids in their 2024 publication on Schultzsuchus.[6]

The elongated neural arches might indicate that Schultzsuchus had elongated neck vertebrae, a notion that might find additional support in the presence of just such a vertebra from the type locality. While this bone was originally assigned to a

saurischian, its anatomy is similar to that of a poposauroid, with some taxa within this group even having elongated necks. Though Desojo and Rauhut do not concretely assign the vertebrae to Schultzsuchus, further study could change that.[6]

The

synapomorphy of the clade by Desojo and Rauhut.[6]

The

calcaneum, the heel bone, of Schultzsuchus has a tuber that is much higher than it is broad, which is the exact opposite of Prestosuchus, in which the tuber is broader than it is high. Both did possess a pit in the underside of the tuber, but it is noted as being much shallower in Schultzsuchus.[6]

Phylogeny

Several

sister taxon of Qianosuchus and all more derived poposauroids (consisting of Poposauridae, Shuvosauridae, Lotosaurus and Ctenosauriscidae). This is primarily based on two anatomical characters shared with poposauroids (both relating to the neck vertebrae) and the absence of traits seen in the derived members of the clade. The only analysis that fail to recover these results are those with higher weighing strengths, which instead place Schultzsuchus as being placed in a more derived position than Saurosuchus towards the crown of Pseudosuchia.[6]

References

  1. ^ a b von Huene, F. (1938). Die fossilen Reptilien des südamerikanischen Gondwanalandes. Ergebnisse der Sauriergrabungen in Südbrasilien 1928/29. Neues Jahrbuch für Mineralogie, Geologie Und Paläontologie, 1938(3), 142–151.
  2. ^ a b von Huene, F. (1942). Die fossilen Reptilien des südamerikanischen Gondwanalandes. C.H. Beck'sche Verlagsbuchhandlung.
  3. ^ Barberena, M. C. (1978). A huge thecodont skull from the Triassic of Brazil. Pesquisas, Institute de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, 9, 62–75.
  4. ^ Krebs, B. (1976). Pseudosuchia. In O. Kuhn (Ed.), Handbuch der Paläoherpetologie. Teil 13: Thecodontia (pp. 40–98). Gustav-Fischer-Verlag, München.
  5. ISSN 1519-7530
    .
  6. ^
    PMID 38344898
    .
Retrieved from "https://en.wikipedia.org/w/index.php?title=Schultzsuchus&oldid=1215161901"