Morphogenesis of the turtle shell: the development of a novel structure in tetrapod evolution

被引:184
作者
Gilbert, SF
Loredo, GA
Brukman, A
Burke, AC
机构
[1] Swarthmore Coll, Dept Biol, Martin Res Labs, Swarthmore, PA 19081 USA
[2] Thomas Jefferson Univ, Orthoped Res Lab, Philadelphia, PA 19107 USA
[3] Wesleyan Univ, Dept Biol, Middletown, CT 06457 USA
关键词
D O I
10.1046/j.1525-142x.2001.003002047.x
中图分类号
Q [生物科学];
学科分类号
07 ; 0710 ; 09 ;
摘要
The turtle shell is an evolutionary novelty that is synapomorphic for chelonians. The carapace is initiated by the entrapment of the ribs by the carapacial ridge (CR), a lateral bulge of the dorsal ectoderm and dermal mesoderm. The mechanisms by which the CR is initiated, the ribs entrapped and the dorsal dermis ossified, remains unknown. Similarly, the formation of the plastron remains unexplained. Here, we present a series of anatomical investigations into plastron and carapace formation in the red-eared slider, Trachemys scripta, and the snapping turtle, Chelydra serpentina. We document the entrapment of the ribs by the CR and the formation of the plastron and carapacial bones by intramembranous ossification. We note the formation of the ossification centers around each rib, which suggest that the rib is organizing dermal ossification by secreting paracrine factors. The nuchal ossification center is complex and appears to involve multiple bone-forming regions. Individual ossification centers at the periphery of the carapace form the peripheral and pygial bones. The intramembranous ossification of the plastron proceeds from nine distinct ossification centers, and there appear to be interactions between the spicules of apposing centers as they draw near each other.
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页码:47 / 58
页数:12
相关论文
共 66 条
[1]   Epidermal differentiation during carapace and plastron formation in the embryonic turtle Emydura macquarii [J].
Alibardi, L ;
Thompson, MB .
JOURNAL OF ANATOMY, 1999, 194 :531-545
[2]   Morphogenesis of shell and scutes in the turtle Emydura macquarii [J].
Alibardi, L ;
Thompson, MB .
AUSTRALIAN JOURNAL OF ZOOLOGY, 1999, 47 (03) :245-260
[3]  
[Anonymous], Z WISS ZOOL
[4]  
[Anonymous], 1999, EVOLUTIONARY DEV BIO
[5]  
BOONSTRA LD, 1933, ANN S AFRICA MUS, V31, P79
[6]  
Burke A.C., 1989, Progress in Zoology, V35, P206
[7]  
BURKE AC, 1991, AM ZOOL, V31, P616
[9]  
BURKE AC, 1989, THESIS HARVARD U CAM
[10]  
Carroll RL., 1988, VERTEBRATE PALEONTOL