Department of Biological Sciences, Fayetteville State University, Fayetteville, North Carolina, United States of America.
PLoS One. 2012;7(8):e43911. doi: 10.1371/journal.pone.0043911. Epub 2012 Aug 29.
The Yellow Cat Member of the Cedar Mountain Formation (Early Cretaceous, Barremian?) of Utah has yielded a rich dinosaur fauna, including the basal therizinosauroid theropod Falcarius utahensis at its base. Recent excavation uncovered a new possible therizinosauroid taxon from a higher stratigraphic level in the Cedar Mountain Formation than F. utahensis.
METHODOLOGY/PRINCIPAL FINDINGS: Here we describe a fragmentary skeleton of the new theropod and perform a phylogenetic analysis to determine its phylogenetic position. The skeleton includes fragments of vertebrae, a scapula, forelimb and hindlimb bones, and an ischium. It also includes several well-preserved manual unguals. Manual and pedal morphology show that the specimen is distinct from other theropods from the Cedar Mountain Formation and from previously described therizinosauroids. It is here named as the holotype of a new genus and species, Martharaptor greenriverensis. Phylogenetic analysis places M. greenriverensis within Therizinosauroidea as the sister taxon to Alxasaurus + Therizinosauridae, although support for this placement is weak.
CONCLUSIONS/SIGNIFICANCE: The new specimen adds to the known dinosaurian fauna of the Yellow Cat Member of the Cedar Mountain Formation. If the phylogenetic placement is correct, it also adds to the known diversity of Therizinosauroidea.
犹他州雪松山组（早白垩世，巴列姆阶？）的黄猫段产出了丰富的恐龙化石群，其中包括最基础的镰刀龙超科兽脚亚目恐龙法索拉鳄龙。最近的挖掘在雪松山组比法索拉鳄龙更高的地层中发现了一种新的可能的镰刀龙类分类单元。
方法/主要发现：在这里，我们描述了一个新兽脚亚目恐龙的骨骼碎片，并进行了系统发育分析以确定其系统发育位置。骨骼包括脊椎骨、肩胛骨、前肢和后肢骨骼以及坐骨的碎片。它还包括几个保存完好的手爪。手部和足部形态表明，该标本与雪松山组的其他兽脚类恐龙以及以前描述的镰刀龙类恐龙不同。它被命名为一个新属和种的模式标本，Martharaptor greenriverensis。系统发育分析将 M. greenriverensis 置于镰刀龙超科内，是 Alxasaurus + 镰刀龙科的姊妹分类单元，尽管这种位置的支持很弱。
结论/意义：新标本增加了雪松山组黄猫段已知的恐龙动物群。如果系统发育位置正确，它也增加了已知的镰刀龙超科多样性。
