A new elasmosaurid specimen from the upper Maastrichtian of Antarctica: new evidence of a monophyletic group of Weddellian elasmosaurids

O'GORMAN, J.P.; CORIA, R.

Congreso; 11 Congreso de la Asociacion Palentológica Argentina; 2016

A new elasmosaurid specimen (MLP 15-I-7-48, MLP = Museo de La Plata; Buenos AiresProvince), from the upper Maastrichtian Sandwich Bluff Member of the López de BertodanoFormation gives new information about the Weddellian elasmosaurids. The MLP 15-I-7-48, a well preserved anterior limb, shares with Vegasaurus molyi O´Gorman et al., 2015 from the lower Maastrichtian of Antarctica, a concave anterior margin of the humeral shaft, and a well defined depression on the anterior margin of the ventral surface of the humeral shaft.Additionally MLP 15-I-7-48 share with Vegasaurus molyi, Kawanectes lafquenianumO´Gorman, 2016; Morenosaurus stocki Welles, 1943, Kaiwhekea katiki Cruickshank andFordyce, 2002 and Aristonectes quiriquinensis Otero et al., 2014, the posterior expansion ofthe humerus. A phylogenetic analysis recovered the MLP 15-I-7-48 as a sister group of theupper Campanian-lower Maastrichtian Vegasaurus molyi within a new clade: Kawanecteslafquenianum ((Vegasaurus molyi; MLP 15-I-7-48) (Morenosaurus stocki (Aristonectine))).This result is consistent with previous results and indicates the presence of a majorWeddellian clade of elasmosaurids. Additionally MLP 15-I-7-48 is recovered as a sister group of V. molyi, showing a close relationship between the upper and lower Maastrichtianelasmosaurids from Antarctica