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There are several other explanations such as dwarfism, and other genetic diseases that stunt human growth without odd physical features. Not that I'm saying that it's impossible for an ancestor to survive, but I find it highly unlikely. Imagining the possibility though is intriguing...

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Three complete carpals—a trapezoid, scaphoid, and capitate—all of which are from a left wrist, were recovered along with the cranium, mandible, and additional postcranial material of LB1 in Spit No. 59 of Sector VII during the September 2003 excavation (fig. S1 and table S3) (1, 2, 18). Each is well preserved and shows no signs of pathology or abnormal development. As shown in Figs. 1 to 3, these three articulating bones display none of the shared, derived features of modern human and Neandertal carpals (13). Instead, they show the general symplesiomorphic pattern exhibited by all extant African apes, as well as fossil hominins that preserve comparable wrist morphology and date before 1.7 Ma (13, 19–22). Like other nonhuman primates, LB1's trapezoid is (i) wedge-shaped; (ii) the ulnar side of its second metacarpal articulation is oriented more sagittally (Fig. 1, top and bottom rows); (iii) its scaphoid articular surface is more triangular in shape (Fig. 1, middle row); and (iv) it lacks the expanded palmar nonarticular area (Fig. 1, top row) and the more palmarly placed capitate articulation observed in modern humans and Neandertals (Fig. 1, bottom row). We quantified these shape differences using three-dimensional (3D) methods measuring the relative areas and angles of carpal articular surfaces (13, 14, 18, 23). Multivariate statistical analysis of these data distinguishes modern humans and Neandertals from the great apes, Papio, and LB1 (Fig. 1). Primarily, the trapezoids of modern humans and Neandertals are distinct in their shape and articular configuration as a consequence of the large expansion of palmar nonarticular area, which tends to square off the entire palmar half of the bone (Fig. 1, top row) (13).The scaphoid and capitate of LB1 both exhibit the shapes and articular configurations that occur concomitantly with the primitive hominid trapezoid condition (13, 18), and multivariate analyses of these carpals provide similar results (Figs. 2 and 3). For example, LB1's capitate lacks the enlarged palmarly placed articular surface for the trapezoid observed in modern humans and Neandertals (9, 13) and, instead, shows the waisted neck characteristic of extant great apes and Australopithecus (Fig. 3, middle row) (20). Similarly, the articular surface for the trapezium on LB1's scaphoid does not extend out onto the scaphoid tubercle as it does in modern humans and Neandertals (Fig. 2, middle row) (13). However, LB1's scaphoid includes a fused centrale, as does the OH7 scaphoid from Olduvai Gorge (Fig. 2) (21, 24). Congenital fusion of these two carpal elements is a synapomorphy of Gorilla, Pan, and Homo (25), and the fossil evidence from LB1 and OH7 further indicates that fusion is the most likely primitive condition for all hominins.

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The consistent carpal shape differences between human and nonhuman primates are the result of differences in the cavitation of the carpal mesenchyme during embryonic development (18, 26). In modern humans, the trapezoid, capitate, and trapezium arise in the mesenchyme in essentially their adult form by the 11th week of development, long before the processes of chondrification and ossification are complete, and the remaining carpal elements achieve their distinctive shapes shortly thereafter (26). Because of the timing of carpal formation, dysostoses (i.e., errors in cell patterning) or disruptions (i.e., through exposure to toxic substances or infection) may result in malformation of the initial carpal shape (27, 28). However, the transient characteristics of such disturbances most often produce localized skeletal shape abnormalities (e.g., individual bones are affected) that are not typically associated with skeletal dwarfism (27, 28). In contrast, dysplasias usually involve systemic errors in ossification and growth, frequently resulting in dwarfism (27, 28). The genes that result in dysplasias, however, do not normally become expressed until after normal shape formation of the carpal mesenchyme (27). Although skeletal dysplasias may include carpal and digit abnormalities related to ossification errors, as well as various forms of microcephaly (27), none are known to result in abnormal carpal morphology that closely mimics a plesiomorphic state. Our diverse modern human sample includes a pituitary dwarf (USNM 314306) and a pituitary giant (USNM 227508) (tables S1 and S2). Both show normal modern human carpal shapes and articular configurations despite their abnormal sizes, demonstrating that LB1'swrist morphology is not the result of allometric scaling, errors in metabolism, or a skeletal growth disorder.Our analyses support hypotheses that LB1 is descended from a hominin ancestor that migrated out of Africa before the evolution of the shared, derived wrist morphology that is characteristic of modern humans, Neandertals, and their last common ancestor. The association of LB1 with direct evidence of stone flaking technology comparable to that found at Oldowan or other Lower Paleolithic sites throughout the Old World (29) provides additional support for the hypothesis that the earliest hominins to use and make stone tools retained primitive hominin wrist morphology (13, 21, 30, 31). The structurally modified wrist of modern humans and Neandertals probably evolved sometime between 1.8 and 0.8 Ma (13). These structural modifications form a morphological complex that may represent an adaptation for better distribution of forces radio-ulnarly across the wrist to facilitate the full commitment to tool-related manipulative behaviors that arose in the hominin lineage leading to modern humans and Neandertals (13).The wrist morphology of LB1 may ultimately help falsify or support specific hypotheses regarding the phylogenetic position of H. floresiensis (1, 5, 7). Unfortunately, no carpals are attributed to Homo erectus sensu lato, which is otherwise well represented in the fossil record between 1.8 and 0.8 Ma, with the exception of a partial lunate from Zhoukoudian (32). However, if hominin carpals that date within this period of time are discovered, their primitive or derived morphology will allow a firmer assessment of their phylogenetic relationship to other Pleistocene hominin species, such as modern H. sapiens and H. floresiensis.I apologize for the lack of figures accompanying this paper.

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Makes you wonder!

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