Polycotylidae indet

O’Gorman, José Patricio & Otero, Rodrigo A., 2023, Revision of the short-necked Cretaceous plesiosaurians from New Zealand, Comptes Rendus Palevol 22 (6), pp. 77-90 : 78

Polycotylidae indet .

( Fig. 2 A-D)

Pliosauridae gen. et sp. indet. – Wiffen & Moisley 1986: 243.

MATERIAL. — NPC CD 459 , anterior cervical vertebra .

LOCALITY AND HORIZON. — Mangahouanga Stream , a northern tributary of Te Hoe River , inland Hawke’s Bay, North Island, New Zealand. Maungataniwha Sandstone Member of the Tahora Formation, upper Campanian-lower Maastrichtian ( Vajda & Raine 2010; Fig. 1).

REMARKS

NPC CD 459 possesses amphicelous articular facets, a large neural canal (near the half of the centrum breadth), high neural pedicels and pre- and postzygapophyses as broad as the centrum, which are traits commonly found among cervical vertebrae of polycotylids ( Sato & Storrs 2000; Salgado et al. 2007; Sato et al. 2018). NPC CD 459 was initially described by Wiffen & Moisley (1986), being then referred as an indeterminate pliosaurid. At that moment, polycotylids were considered as part of the clade Pliosauroidea Welles 1943. This systematic placement of Polycotylidae was not questioned until O’Keefe (2001) recognized closer affinities to cryptoclidids and “cimoliasaurids” for this clade, based on large-scale phylogenetic analyses. A growing body of evidence currently recognizes the Polycotylidae as the sister taxon of Leptocleididae Benson & Druckenmiller, 2014 and part of the larger clade Leptocleidia. In addition, the Pliosauridae as currently understood were extinct by the Campanian-Maastrichtian ( Druckenmiller & Russell 2008; Benson & Druckenmiller 2014).