新恐龙描述
阿根廷发现首个早白垩世确认的梁龙科恐龙记录，也是南美洲的首个梁龙科恐龙——宽尾 末梁龙 Leinkupal laticauda
梁龙科（Diplodocids）恐龙目前被认为是最具代表性的蜥脚类恐龙。这群恐龙属于分支庞大的梁龙超科（Diplodocoidea）蜥脚类，化石分布包括在非洲，欧洲，北美洲和南美洲的侏罗纪和白垩纪地层。
然而，梁龙科恐龙在白垩纪尚未有确认的化石记录或在除了非洲的南部大陆。
在本文，作者描述一新的蜥脚类恐龙——宽尾 末梁龙Leikupal laticauda，化石来自阿根廷内乌肯省早白垩世早期Bajada Colorada组，是首次确认的白垩纪梁龙科恐龙孑遗属。
系统发育分析不但支持新属属于梁龙科恐龙而且也是梁龙亚科（Diplodocinae）成员，并和非洲梁龙科拖尼龙（Tornieria）的关系接近，这使作者认为梁龙超科起源于中侏罗世或更早的时期。
末梁龙是南美洲首个梁龙科恐龙也是这个分支在全球地层上最晚期的化石记录。
虽然末梁龙的标本零碎但其化石来自早白垩世的地层表明普遍认为在侏罗纪/白垩纪边界灭绝的梁龙科恐龙至少一部分在南美洲早白垩世幸存下来。
南美洲早白垩世梁龙科蜥脚类恐龙孑遗属
Leinkupal laticauda
宽尾 末梁龙（新属、新种）
A Diplodocid Sauropod Survivor from the Early Cretaceous of South America
PabloA. Gallina, Sebastián Apesteguía, Alejandro Haluza, Juan I. Canale
Abstract
Diplodocids are by far themost emblematic sauropod dinosaurs. They are part of Diplodocoidea, a vastclade whose other members are well-known from Jurassic and Cretaceous strata inAfrica, Europe, North and South America. However, Diplodocids were nevercertainly recognized from the Cretaceous or in any other southern land mass besidesAfrica. Here we report a new sauropod, Leikupal laticauda gen. et sp. nov.,from the early Lower Cretaceous (Bajada Colorada Formation) of NeuquénProvince, Patagonia, Argentina. This taxon differs from any other sauropod bythe presence of anterior caudal transverse process extremely developed withlateroventral expansions reinforced by robust dorsal and ventral bars, veryrobust centroprezygapophyseal lamina in anterior caudal vertebra and pairedpneumatic fossae on the postzygapophyses in anterior-most caudal vertebra. Thephylogenetic analyses support its position not only within Diplodocidae butalso as a member of Diplodocinae, clustering together with the African formTornieria, pushing the origin of Diplodocoidea to the Middle Jurassic or even earlier.The new discovery represents the first record of a diplodocid for South Americaand the stratigraphically youngest record of this clade anywhere.
