Calsoyasuchus

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Calsoyasuchus
Temporal range:
Ma
↓
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauria
Clade: Pseudosuchia
Clade: Crocodylomorpha
Clade: Crocodyliformes
Family: †Goniopholididae
Genus: †Calsoyasuchus
Tykoski et al., 2002
Type species
†Calsoyasuchus valliceps
Tykoski et al., 2002

Calsoyasuchus (meaning "[Dr. Kyril] Calsoyas'

derived for such an early crocodile relative. This genus was described in 2002 by Ronald Tykoski and colleagues; the specific name means "valley head" and refers to a deep groove along the midline of the nasal bones and frontal bones.[2] It has often been interpreted as the earliest diverging member of Goniopholididae
, but other studies have recovered it in various other positions.

Description

The

braincase. Sutures between the skull bones are mostly fused. As preserved, it is about 38.0 centimeters (15.0 in) long, making its owner a moderately sized animal.[2]

The skull was long, low, and curved so that both extremities were higher than the middle. The

CT scanning, which revealed internal cavities and air passages, and showed that it had a double-walled secondary palate similar to that of true crocodylians, and similar pneumatic cavities as well.[2]

Phylogeny

Tykoski and colleagues performed a

Upper Jurassic Morrison Formation. Calsoyasuchus pushes back the earliest occurrence of goniopholids from the Late Jurassic into the Early Jurassic, and not only helps to bridge a temporal gap between groups of crocodyliforms, but also a morphological gap. It also implies that some groups of crocodyliforms have long undiscovered histories.[2]

In 2011, Calsoyasuchus was recovered as the basalmost goniopholidid and the sister taxon to all other goniopholidids.[3]

Neosuchia

Its placement as a goniopholid is not uncontested. A cladistic analysis of Crocodylomorpha published by Wilberg et al. (2019) in their discussion of crocodylomorph paleobiology recovers Calsoyasuchus as a close relative of the basal mesoeucrocodyliform Hsisosuchus.[4] A 2022 analysis found it to be the sister group of Thalattosuchia.[5]

Paleoecology

During the

sauropodomorph, and ornithischian dinosaurs, and early relatives of mammals (tritylodontids and morganucodontids).[2]

References

  1. ^ Mesoeucrocodylia is the clade that includes all the living crocodilians and their closest extinct relatives.
  2. ^
    S2CID 85969174
    .
  3. doi:10.1111/j.1096-3642.2011.00709.x
    .
  4. ^ Eric W. Wilberg, Alan H. Turner, Christopher A. Brochu. Evolutionary structure and timing of major habitat shifts in Crocodylomorpha. Scientific Reports, 2019; 9 (1) DOI: 10.1038/s41598-018-36795-1
  5. PMID 35699105
    .

External links

  • Digimorph page featuring various views and movies of the CT scans of the skull
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