Department of Anthropology, National Museum of Nature and Science, 4-1-1 Amakubo, Tsukuba-shi, Ibaraki Prefecture Japan.
J Hum Evol. 2011 Dec;61(6):644-82. doi: 10.1016/j.jhevol.2011.08.008. Epub 2011 Oct 28.
This paper describes in detail the external morphology of LB1/1, the nearly complete and only known cranium of Homo floresiensis. Comparisons were made with a large sample of early groups of the genus Homo to assess primitive, derived, and unique craniofacial traits of LB1 and discuss its evolution. Principal cranial shape differences between H. floresiensis and Homo sapiens are also explored metrically. The LB1 specimen exhibits a marked reductive trend in its facial skeleton, which is comparable to the H. sapiens condition and is probably associated with reduced masticatory stresses. However, LB1 is craniometrically different from H. sapiens showing an extremely small overall cranial size, and the combination of a primitive low and anteriorly narrow vault shape, a relatively prognathic face, a rounded oval foramen that is greatly separated anteriorly from the carotid canal/jugular foramen, and a unique, tall orbital shape. Whereas the neurocranium of LB1 is as small as that of some Homo habilis specimens, it exhibits laterally expanded parietals, a weak suprameatal crest, a moderately flexed occipital, a marked facial reduction, and many other derived features that characterize post-habilis Homo. Other craniofacial characteristics of LB1 include, for example, a relatively narrow frontal squama with flattened right and left sides, a marked frontal keel, posteriorly divergent temporal lines, a posteriorly flexed anteromedial corner of the mandibular fossa, a bulbous lateral end of the supraorbital torus, and a forward protruding maxillary body with a distinct infraorbital sulcus. LB1 is most similar to early Javanese Homo erectus from Sangiran and Trinil in these and other aspects. We conclude that the craniofacial morphology of LB1 is consistent with the hypothesis that H. floresiensis evolved from early Javanese H. erectus with dramatic island dwarfism. However, further field discoveries of early hominin skeletal remains from Flores and detailed analyses of the finds are needed to understand the evolutionary history of this endemic hominin species.
本文详细描述了 LB1/1 的外部形态，LB1/1 是已知的弗洛勒斯人近乎完整的且唯一的颅骨。我们将其与大量早期人类属种进行了比较，以评估 LB1 的原始、衍生和独特的颅面特征，并讨论其进化情况。我们还从度量学的角度探讨了 LB1 与智人之间的主要颅骨形状差异。LB1 标本的面颅骨表现出明显的简化趋势，与智人状况相当，可能与咀嚼压力的降低有关。然而，LB1 在颅测量上与智人不同，表现为整体颅骨尺寸极小，同时具有原始的低矮且狭窄的颅顶形状、相对前突的面型、圆形的卵圆孔，其在前方与颈动脉管/颈静脉孔相距甚远，以及独特的高眶型。尽管 LB1 的神经颅骨与一些能人标本一样小，但它具有侧向扩展的顶骨、较弱的顶乳突嵴、适度弯曲的枕骨、明显的面部缩小以及许多其他特征，这些特征表明其属于能人之后的人类。LB1 的其他颅面特征包括，例如相对狭窄的额鳞，左右两侧扁平，明显的额嵴，向后发散的颞线，下颌窝前内角向后弯曲，眶上嵴的外侧末端呈球状，以及向前突出的上颌体，具有明显的眶下沟。在这些方面和其他方面，LB1 与来自 Sangiran 和 Trinil 的早期爪哇直立人最为相似。我们得出结论，LB1 的颅面形态与弗洛勒斯人从早期爪哇直立人进化而来，且具有显著岛屿侏儒化的假说一致。然而，需要在弗洛勒斯岛进一步发现早期人类骨骼遗骸，并对这些发现进行详细分析，以了解这一特有人类物种的进化历史。
