Department of Anatomical Sciences, Stony Brook University, Health Sciences Center T-8 040, Stony Brook, NY 11794-8081, USA.
J Hum Evol. 2013 Feb;64(2):109-29. doi: 10.1016/j.jhevol.2012.10.003. Epub 2013 Jan 4.
The carpals from the Homo floresiensis type specimen (LB1) lack features that compose the shared, derived complex of the radial side of the wrist in Neandertals and modern humans. This paper comprises a description and three-dimensional morphometric analysis of new carpals from at least one other individual at Liang Bua attributed to H. floresiensis: a right capitate and two hamates. The new capitate is smaller than that of LB1 but is nearly identical in morphology. As with capitates from extant apes, species of Australopithecus, and LB1, the newly described capitate displays a deeply-excavated nonarticular area along its radial aspect, a scaphoid facet that extends into a J-hook articulation on the neck, and a more radially-oriented second metacarpal facet; it also lacks an enlarged palmarly-positioned trapezoid facet. Because there is no accommodation for the derived, palmarly blocky trapezoid that characterizes Homo sapiens and Neandertals, this individual most likely had a plesiomorphically wedge-shaped trapezoid (like LB1). Morphometric analyses confirm the close similarity of the new capitate and that of LB1, and are consistent with previous findings of an overall primitive articular geometry. In general, hamate morphology is more conserved across hominins, and the H. floresiensis specimens fall at the far edge of the range of variation for H. sapiens in a number of metrics. However, the hamate of H. floresiensis is exceptionally small and exhibits a relatively long, stout hamulus lacking the oval-shaped cross-section characteristic of human and Neandertal hamuli (variably present in australopiths). Documentation of a second individual with primitive carpal anatomy from Liang Bua, along with further analysis of trapezoid scaling relative to the capitate in LB1, refutes claims that the wrist of the type specimen represents a modern human with pathology. In total, the carpal anatomy of H. floresiensis supports the hypothesis that the lineage leading to the evolution of this species originated prior to the cladogenetic event that gave rise to modern humans and Neandertals.
来自弗洛里斯人类型标本（LB1）的腕骨缺乏构成尼安德特人和现代人手腕桡侧共同衍生复合体的特征。本文描述并进行了三维形态计量分析，涉及到至少另一个被归类为弗洛里斯人的个体的新腕骨：一个右头状骨和两个钩骨。新的头状骨比 LB1 小，但在形态上几乎相同。与现生类人猿、南方古猿物种和 LB1 的头状骨一样，新描述的头状骨在其桡侧有一个深深凹陷的非关节区，一个延伸到颈部 J 形关节的舟状骨面，以及一个更向桡侧的第二掌骨面；它也没有增大的掌侧梯形面。由于没有适应特征，即人类和尼安德特人的掌侧块状梯形，这个个体很可能有一个原始的楔形梯形（像 LB1）。形态计量分析证实了新头状骨与 LB1 的高度相似性，并且与先前发现的整体原始关节几何形状一致。一般来说，在人类中，钩骨形态更为保守，而弗洛里斯人的标本在许多指标上都处于人类变异范围的远端。然而，弗洛里斯人的钩骨非常小，并且具有相对较长而粗壮的钩突，缺乏人类和尼安德特人钩突的椭圆形横截面（在南方古猿中或多或少存在）。在梁布阿发现第二个具有原始腕骨解剖结构的个体，以及进一步分析 LB1 中相对于头状骨的梯形比例，可以反驳该类型标本的腕骨代表有病理的现代人的说法。总的来说，弗洛里斯人的腕骨解剖结构支持这样的假说，即导致该物种进化的谱系起源于产生现代人类和尼安德特人的分支事件之前。
