Prodiplocynodon

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Prodiplocynodon
Temporal range:
Ma
↓
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauromorpha
Clade: Archosauriformes
Order: Crocodilia
Superfamily: Crocodyloidea
Genus: †Prodiplocynodon
Mook, 1941
Type species
†Prodiplocynodon langi
Mook, 1941

Prodiplocynodon is an extinct

crocodylian. It is one of the only crocodyloids known from the Cretaceous and existed during the Maastrichtian stage.[1] The only species of Prodiplocynodon is the type species P. langi from the Lance Formation of Wyoming, known only from a single holotype skull lacking the lower jaw.[2]

The skull was collected by the

Niobrara County. It was described by Charles C. Mook of the American Museum of Natural History in 1941.[2] The generic name means "before Diplocynodon" because Mook saw close similarities between the holotype skull and that of the alligatoroid Diplocynodon from the Eocene of Europe
.

Description

Most of the cranial sutures that outline individual bones of the skull are not visible in the holotype, and are often obscured by cracks. However, the overall shape of Prodiplocynodon is similar to that of basal alligatoroids.[1] Many of the features seen in Prodiplocynodon are common among eusuchians. The skull is short and triangular, being around 50 centimetres (20 in) in length. The orbits, or eye sockets, are quite large and subtriangular. The teeth are short and somewhat sharp, and in comparison to modern crocodiles show little variation. The orbits face directly upwards, but this may have been the result of slight compression in the holotype skull. The external nasal aperture, the opening for the nostrils, is very large. There is a constriction at the point of contact between the premaxilla and maxilla which would have been an area of reception for a large mandibular tooth. In Prodiplocynodon, the constriction is not deep, being intermediate between that of Alligator and Crocodylus.[2]

Classification

Mook suggested that Prodiplocynodon may be ancestral to

crocodylids because it possessed features of both families. However, Mook also noted that some of the features observed in Prodiplocynodon that are also found in modern crocodylians may be the result of evolutionary convergence,[2] and thus Prodiplocynodon was also proposed to be an alligatorine.[3][4]

Phylogeny

Prodiplocynodon was not included in a

derived crocodylines, and is lost in some ingroups of Alligatorinae.[5]

Successive phylogenetic studies have placed Prodiplocynodon as a basal member of Crocodyloidea along with Asiatosuchus,[6][7][8] as shown in the cladogram below:

Crocodyloidea  *Note: Tomistominae, which includes the extant
False Gharial, is sometimes considered to be a gavialoid lineage on the basis of genetic evidence.[9][10]


A 2018

stratigraphic (fossil age) data established the inter-relationships within Crocodilia,[11] which was expanded upon in 2021 by Hekkala et al. using paleogenomics by extracting DNA from the extinct Voay.[12]

The below cladogram shows the results of the latest studies, which placed Prodiplocynodon outside of Crocodyloidea, as more basal than Longirostres (the combined group of crocodiles and gavialids).[11]

Crocodylia

Alligatoroidea

Prodiplocynodon†

Asiatosuchus†

"Crocodylus" affinis
†

"Crocodylus" depressifrons
†

References

  1. ^
    doi:10.1146/annurev.earth.31.100901.141308
    .
  2. ^ a b c d Mook, C. C. (1941). "A new crocodilian from the Lance Formation" (PDF). American Museum Novitates (1128): 1–5.
  3. ^ Steel, R. (1973). "Crocodilia". Handbuch der Paläoherpetologie. Stuttgart and Portland: Gustav Fischer Verlag. pp. 116pp.
  4. ISBN 9780716718222
    .
  5. ^ Wu, X.-C.; Brinkman, D. B.; Russell, A. P. (1996). "A new alligator from the Upper Cretaceous of Canada and the relationships of early eusuchians" (PDF). Palaeontology. 39 (2): 351–375. Archived from the original (PDF) on 2011-09-28.
  6. S2CID 85824292
    .
  7. ^ Brochu, C. A.; Gingerich, P. D. (2000). "New tomistomine crocodylian from the middle Eocene (Bartonian) of Wadi Hitan, Fayum Province, Egypt" (PDF). Contributions from the Museum of Paleontology: The University of Michigan. 30: 251–268.
  8. S2CID 86497272
    .
  9. doi:10.1093/icb/29.3.831
    .
  10. S2CID 131176447
    .
  11. ^
    PMID 30051855
    .
  12. PMID 33907305
    .

External links
Retrieved from "https://en.wikipedia.org/w/index.php?title=Prodiplocynodon&oldid=1134967231"