Crocodylus palaeindicus

Crocodylus palaeindicus is an extinct species of crocodile from southern Asia. C. palaeindicus lived from the Miocene to the Pliocene. It may be an ancestor of the living Mugger crocodile.

Crocodylus palaeindicus
Temporal range: Late MiocenePliocene, 11.6–2.6 Ma[1]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauromorpha
Clade: Archosauriformes
Order: Crocodilia
Family: Crocodylidae
Genus: Crocodylus
Species:
C. palaeindicus
Binomial name
Crocodylus palaeindicus
Falconer, 1859
Synonyms

History

edit

C. palaeindicus was first named by Scottish paleontologist Hugh Falconer in 1859. Falconer found fossils of the species in the Siwalik Hills of India along with the remains of many other animals like turtles, ostriches, camels, saber-toothed cats, mastodons.[2] Richard Lydekker later named another crocodile from the Siwalik Hills which he called C. sivalensis. Although the two crocodiles are very similar, C. sivalensis was distinguished from C. palaeindicus because the margin of its skull was less convex. C. sivalensis has recently been synonymized with C. palaeindicus, as the slight differences in shape are thought to be from natural variation or from fossilization.[3] In later years, fossils were also found from Pakistan and Myanmar.

Classification

edit
 
The Mugger crocodile, a close relative and possible descendant of Crocodylus palaeindicus

Historically, C. palaeindicus was considered a direct ancestor of the Mugger crocodile C. palustris. The two species are similar in appearance, and some fossils of C. palaeindicus were at first mistaken for C. palustris.[3] Most modern phylogenetic analyses of crocodiles place C. palaeindicus in a basal position among members of the genus Crocodylus. Below is a cladogram modified from Brochu et al. (2010) showing the relation of C. palaeindicus with other crocodiles:[4]

Crocodylidae

A 2018 tip dating study by Lee & Yates simultaneously using morphological, molecular (DNA sequencing), and stratigraphic (fossil age) data established the inter-relationships within Crocodylidae.[5] In 2021, Hekkala et al. were able to use paleogenomics, extracting DNA from the extinct Voay, to better establish the relationships within Crocodylidae, including the subfamilies Crocodylinae and Osteolaeminae.[6]

The below cladogram shows the results of the latest study:

Crocodylidae
Osteolaeminae

Brochuchus

Rimasuchus

Osteolaemus osborni Osborn’s dwarf crocodile

Osteolaemus tetraspis Dwarf crocodile

Crocodylinae

Voay

Crocodylus

Crocodylus palaeindicus

Crocodylus Tirari Desert

Asia+Australia

Crocodylus johnstoni Freshwater crocodile  

Crocodylus novaeguineae New Guinea crocodile

Crocodylus mindorensis Philippine crocodile

Crocodylus porosus Saltwater crocodile  

Crocodylus siamensis Siamese crocodile  

Crocodylus palustris Mugger crocodile  

Africa+New World

Crocodylus suchus West African crocodile

Crocodylus niloticus Nile crocodile  

New World

Crocodylus moreletii Morelet's crocodile

Crocodylus rhombifer Cuban crocodile  

Crocodylus intermedius Orinoco crocodile

Crocodylus acutus American crocodile  

(crown group)

References

edit
  1. ^ Rio, Jonathan P.; Mannion, Philip D. (6 September 2021). "Phylogenetic analysis of a new morphological dataset elucidates the evolutionary history of Crocodylia and resolves the long-standing gharial problem". PeerJ. 9: e12094. doi:10.7717/peerj.12094. PMC 8428266. PMID 34567843.
  2. ^ Lydekker, R. (1885). Catalogue of the remains of Siwalik Vertebrata contained in the Geological Department of the Indian Museum, Calcutta. Vol. 1. Superintendent of Government Printing, India.
  3. ^ a b Brochu, C. A. (2000). "Phylogenetic relationships and divergence timing of Crocodylus based on morphology and the fossil record". Copeia. 2000 (3): 657–673. doi:10.1643/0045-8511(2000)000[0657:pradto]2.0.co;2.
  4. ^ Brochu, C. A.; Njau, J.; Blumenschine, R. J.; Densmore, L. D. (2010). "A new horned crocodile from the Plio-Pleistocene hominid sites at Olduvai Gorge, Tanzania". PLoS ONE. 5 (2): e9333. Bibcode:2010PLoSO...5.9333B. doi:10.1371/journal.pone.0009333. PMC 2827537. PMID 20195356.
  5. ^ Michael S. Y. Lee; Adam M. Yates (27 June 2018). "Tip-dating and homoplasy: reconciling the shallow molecular divergences of modern gharials with their long fossil". Proceedings of the Royal Society B. 285 (1881). doi:10.1098/rspb.2018.1071. PMC 6030529. PMID 30051855.
  6. ^ Hekkala, E.; Gatesy, J.; Narechania, A.; Meredith, R.; Russello, M.; Aardema, M. L.; Jensen, E.; Montanari, S.; Brochu, C.; Norell, M.; Amato, G. (2021-04-27). "Paleogenomics illuminates the evolutionary history of the extinct Holocene "horned" crocodile of Madagascar, Voay robustus". Communications Biology. 4 (1): 505. doi:10.1038/s42003-021-02017-0. ISSN 2399-3642. PMC 8079395. PMID 33907305.