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.[3]
^Schumacher, B. A., 2007, A new polycotylid plesiosaur (Reptilia; Sauropterygia) from the Greenhorn Limestone (Upper Cretaceous; lower upper Cenomanian), Black Hills, South Dakota: In: The Geology and Paleontology of the Late Cretaceous marine deposits of the Dakotas, edited by Martin, J. E., and Parris, D. C., The Geological Society of America, Special Paper 427, p. 133-146.
^Ketchum, H. F. & Benson, R. B. J. (2010). "Global interrelationships of Plesiosauria (Reptilia, Sauropterygia) and the pivotal role of taxon sampling in determining the outcome of phylogenetic analyses". Biological Reviews. 85 (2): 361–392.
doi:
10.1111/j.1469-185X.2009.00107.x.
PMID20002391.
S2CID12193439.
^Hilary F. Ketchum; Roger B. J. Benson (2011). "A new pliosaurid (Sauropterygia, Plesiosauria) from the Oxford Clay Formation (Middle Jurassic, Callovian) of England: evidence for a gracile, longirostrine grade of Early-Middle Jurassic pliosaurids". Special Papers in Palaeontology. 86: 109–129.