Biology:Polycotylidae

Short description: Extinct family of reptiles

Polycotylids Temporal range: Early - Late Cretaceous, 103–66 Ma PreЄ Є O S D C P T J K Pg N
Martinectes in the Rocky Mountain Dinosaur Resource Center
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Superorder:	†Sauropterygia
Order:	†Plesiosauria
Clade:	†Leptocleidia
Family:	†Polycotylidae Williston, 1909
Genera
†Edgarosaurus †Georgiasaurus †Manemergus †Piratosaurus? †Rarosaurus †Occultonectia †Plesiopleurodon †Sulcusuchus †Palmulasaurinae †Pahasapasaurus †Palmulasaurus †Polycotylinae †Eopolycotylus †Mauriciosaurus †Polycotylus †Scalamagnus †Serpentisuchops †Thililua? †Trinacromerum †Dolichorhynchia †Dolichorhynchops †Martinectes †Unktaheela

Polycotylidae is a family of plesiosaurs from the Cretaceous, a sister group to Leptocleididae. Polycotylids first appeared during the Albian stage of the Early Cretaceous, before becoming abundant and widespread during the early Late Cretaceous. Several species survived into the final stage of the Cretaceous, the Maastrichtian.

With their short necks and large elongated heads, they resemble the pliosaurs, but closer phylogenetic studies indicate that they share many common features with the Leptocleididae and Elasmosauridae. They have been found worldwide, with specimens reported from New Zealand, Australia , Japan , Morocco, the United States of America , Canada , Eastern Europe, and South America.

Phylogeny

Trinacromerum bentonianum from the Late Cretaceous of Kansas

Cladogram after Albright, Gillette and Titus (2007).

Plesiosauria	Plesiosaurus     Tricleidus    Polycotylidae    Edgarosaurus       Thililua      Palmulainae    UMUT MV 19965 (from Japan)     Pahasapasaurus (=AMM 98.1.1)     Palmulasaurus      Polycotylinae    Dolichorhynchops       Trinacromerum       Eopolycotylus     Polycotylus

Cladogram after Ketchum and Benson (2010).

Plesiosauroidea	Cryptoclididae    Leptocleidia    Leptocleididae    Polycotylidae    Plesiopleurodon       Edgarosaurus       QM F18041       Eopolycotylus       Trinacromerum       Dolichorhynchops herschelensis       Dolichorhynchops     Manemergus     Palmulasaurus

Below is a cladogram of polycotylid relationships from Ketchum & Benson, 2011.

Plesiosauroidea	Cryptoclididae    Leptocleidia    Leptocleididae    Polycotylidae    Edgarosaurus         Plesiopleurodon     QM F18041           Eopolycotylus     Polycotylus     Thililua         Trinacromerum       Manemergus       Dolichorhynchops herschelensis       Dolichorhynchops     Palmulasaurus

External links

• Palæos: The Vertebrates, Lepidosauromorpha: Cryptocleidoidea: Tricleidia

Wikidata ☰ Q135400 entry