Alexandronectes zealandiensis gen. et sp nov., a new aristonectineplesiosaur from the lower maa strichtian of New Zealand

A fragmentary plesiosaur skull from lower Maastrichtian levels of the Conway Formation, New Zealand, is redescribed. Originally regarded as pertaining to two separate individuals, we argue that they represent a single individual belonging to a new aristonectine elasmosaurid, Alexandronectes zealandi...

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Bibliographic Details
Published in:Journal of Vertebrate Paleontology
Main Authors: Otero, Rodrigo A., O'Gorman, Jose P., Hiller, Norton, O'Keefe, F. Robin, Fordyce, R. Ewan
Format: Article in Journal/Newspaper
Language:English
Published: Taylor & Francis 2016
Subjects:
Online Access:https://doi.org/10.1080/02724634.2015.1054494
https://repositorio.uchile.cl/handle/2250/141908
Description
Summary:A fragmentary plesiosaur skull from lower Maastrichtian levels of the Conway Formation, New Zealand, is redescribed. Originally regarded as pertaining to two separate individuals, we argue that they represent a single individual belonging to a new aristonectine elasmosaurid, Alexandronectes zealandiensis gen. et sp. nov. This new taxon has common morphologies with other aristonectines such as expansion of the pterygoids extending posteriorly beyond the occipital condyle (as observed in Ar. quiriquinensis and probably in Kaiwhekea katiki) and the presence of an A'-shaped squamosal arch in dorsal view. Otherwise, it is distinguished from these latter species by having different paraoccipital processes, a different mandibular glenoid, and an adult skull comparatively smaller than K. katiki and Aristonectes spp. The new taxon is a morphologically intermediate form between the dorsoventrally high skull of K. katiki and the mediolaterally expanded skulls of Aristonectes spp. The studied specimen is the second genus and species and the third report of an aristonectine recovered from lower Maastrichtian beds of New Zealand, emphasizing the diversity of this group in New Zealand and also indicating that aristonectines could include smaller species than those already known. Antarctic Ring Project (Anillos de Ciencia Antartica, Conicyt-Chile) ACT-105 Domeyko II grant-Red Paleontologica U-Chile of the Universidad de Chile UR-C12/1 PIP 0433 PICT 2012-0748 PICTO 2010-0093 UNLP N 677 UNLP N607