Plioplatecarpinae

Plioplatecarpinae Temporal range: Late Cretaceous 94–66  Ma PreꞒ Ꞓ O S D C P T J K Pg N
Skeleton cast of Platecarpus tympaniticus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Clade:	†Mosasauria
Superfamily:	†Mosasauroidea
Family:	†Mosasauridae
Clade:	†Russellosaurina
Subfamily:	†Plioplatecarpinae Dollo, 1884;[1] Williston, 1897[2]
Genera
Angolasaurus Ectenosaurus Sarabosaurus Plioplatecarpini Latoplatecarpus Platecarpus Plesioplatecarpus Plioplatecarpus Selmasaurini[3] Gavialimimus Goronyosaurus Khinjaria Selmasaurus

Plioplatecarpinae is a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "plioplatecarpines" and have been recovered from all continents,^[4] though the occurrences in Australia remain questionable. The subfamily includes the genera Latoplatecarpus, Platecarpus, Plioplatecarpus and Plesioplatecarpus.

Plioplatecarpines were small to medium-sized mosasaurs that were comparatively fast and agile compared to mosasaurs of other subfamilies. The first plioplatecarpines appear in the Turonian and are among the oldest of mosasaurs, and the clade persists throughout the Maastrichtian, a period of approximately 24 million years. The subfamily was seemingly heavily affected during a poorly understood middle-Campanian mosasaur extinction event^[5] and its genera appear to have faced competition from mosasaurine mosasaurs during the Maastrichtian, leading to a decline in numbers and in diversity.^[6]

The etymology of this group derives from the genus Plioplatecarpus (Greek pleion = "more" + Greek plate = "oar" + Greek karpos = "wrist, carpus").

Description

In general, plioplatecarpines were short-skulled, short-bodied forms and were among the strongest swimming mosasaurs ^[

. The plioplatecarpines were medium-sized mosasaurs ranging from around 2.5 to 7.5 meters in length.

Russell (1967, pp. 148

centra

. Appendicular elements lack smoothly finished articular surfaces."

Phylogeny

Russell^[7] included two tribes, the Plioplatecarpini and Prognathodontini, the latter of which has been reassigned by Bell^[8] to the Mosasaurinae.

Polcyn and Bell (2005, p. 322^[9]) have erected a more inclusive clade, the parafamily Russellosaurina, which includes the "subfamilies Tylosaurinae and Plioplatecarpini and their sister-clade containing the genera Tethysaurus, Russellosaurus, and Yaguarasaurus."

The cladogram below follows Simões et al. (2017)^[10]

Plioplatecarpinae	Angolasaurus bocagei Selmasaurus johnsoni Ectenosaurus clidastoides Plesioplatecarpus planifrons Latoplatecarpus willistoni Platecarpus tympaniticus Plioplatecarpus

In their 2024 description of the Moroccan plioplatecarpine

sister taxon to Plioplatecarpini.^[3] A similar clade was recovered by Strong et al. (2020) in their description of Gavialimimus.^[11] The results of the analyses of Longrich et al. are shown in the cladogram

below:

Tethysaurus Plioplatecarpinae Russellosaurus Yaguarasaurus columbianus Carlile Formation plioplatecarpine Yaguarasaurus regiomontanus spp. Angolasaurus Plioplatecarpini Plesioplatecarpus Platecarpus Latoplatecarpus willistoni Plioplatecarpus nichollsae Plioplatecarpus brachycephalus Plioplatecarpus corphaeus Plioplatecarpus primaevus Plioplatecarpus peckensis Plioplatecarpus houzeaui Plioplatecarpus marshi Selmasaurini Selmasaurus johnsoni Selmasaurus russelli Gavialimimus Goronyosaurus Khinjaria

Species and taxonomy

Plioplatecarpinae

• Angolasaurus
  • A. bocagei
• Ectenosaurus
  • E. clidastoides
  • E. tlemonectes
  • E. shannoni
• Sarabosaurus
  • S. dahli

• Selmasaurini
  • Gavialimimus
    • G. almaghribensis
  • Goronyosaurus
    • G. nigeriensis
  • Khinjaria
    • K. acuta
  • Selmasaurus
    • S. russelli
    • S. johnsoni

• Plioplatecarpini
  • Latoplatecarpus
    • L. nichollsae
    • L. willistoni
  • Platecarpus
    • P. tympaniticus
  • Plesioplatecarpus
    • P. planifrons
  • Plioplatecarpus
    • P. primaevus
    • P. houzeaui
    • P. marshii
    • P. peckensis

References

1. ^ Dollo L. 1884. Le mosasaure. Revue des Questions Scientifiques XVI:648-653.
2. ^ Williston SW. 1897. Range and distribution of the mosasaurs with remarks on synonymy. Kansas University Quarterly 4 (4): 177-185.
3. ^
   ISSN 0195-6671
   .
4. ^ "Fossilworks: Plioplatecarpinae". fossilworks.org. Retrieved 17 December 2021.
5. ^ "Stratigraphical distribution of Campanian and Maastrichtian mosasaurs in Sweden - Evidence of an intercontinental marine extinction event?". ResearchGate. Retrieved 2017-09-11.
6. doi:10.1016/j.palaeo.2013.05.018
   .
7. ^ ^{a b} Russell DA. 1967. Systematics and morphology of American mosasaurs. Peabody Museum of Natural History, Yale University, Bulletin 23.
8. ^ Bell GL. Jr. 1997. A phylogenetic revision of North American and Adriatic Mosasauroidea. pp. 293-332 In: Callaway JM, Nicholls EL, (eds.), Ancient Marine Reptiles, Academic Press, 501 pp.
9. ^ Polcyn MJ, Bell GL. Jr. 2005. Russellosaurus coheni n. gen., n. sp., a 92 million-year-old mosasaur from Texas (USA), and the definition of the parafamily Russellosaurina. Netherlands Journal of Geosciences 84 (3): 321-333.
10. PMID 28467456
    .
11. ISSN 1477-2019
    .