PDF(Pubmed)
Abstract：
BACKGROUND: Mammalian skeletons are largely formed before birth. Heterochronic changes in skeletal formation can be investigated by comparing the order of ossification for different elements of the skeleton. Due to the challenge of collecting prenatal specimens in viviparous taxa, opportunistically collected museum specimens provide the best material for studying prenatal skeletal development across many mammalian species. Previous studies have investigated ossification sequence in a range of mammalian species, but little is known about the pattern of bone formation in Carnivora. Carnivorans have diverse ecologies, diets, and biomechanical specializations and are well-suited for investigating questions in evolutionary biology. Currently, developmental data on carnivorans is largely limited to domesticated species. To expand available data on carnivoran skeletal development, we used micro-computed tomography (micro-CT) to non-invasively evaluate the degree of ossification in all prenatal carnivoran specimens housed in the Harvard Museum of Comparative Zoology. By coding the presence or absence of bones in each specimen, we constructed ossification sequences for each species. Parsimov-based genetic inference (PGi) was then used to identify heterochronic shifts between carnivoran lineages and reconstruct the ancestral ossification sequence of Carnivora.
RESULTS: We used micro-CT to study prenatal ossification sequence in six carnivora species: Eumetopias jubatus (Steller sea lion, n = 6), Herpestes javanicus (small Indian mongoose, n = 1), Panthera leo (lion, n = 1), Urocyon cinereoargenteus (gray fox, n = 1), Ursus arctos arctos (Eurasian brown bear, n = 1), and Viverricula indica (small Indian civet, n = 5). Due to the relatively later stage of collection for the available specimens, few heterochronic shifts were identified. Ossification sequences of feliform species showed complete agreement with the domestic cat. In caniforms, the bear and fox ossification sequences largely matched the dog, but numerous heterochronic shifts were identified in the sea lion.
CONCLUSIONS: We use museum specimens to generate cranial and postcranial micro-CT data on six species split between the two major carnivoran clades: Caniformia and Feliformia. Our data suggest that the ossification sequence of domestic dogs and cats are likely good models for terrestrial caniforms and feliforms, respectively, but not pinnipeds.
RESULTS: We used micro-CT to study prenatal ossification sequence in six carnivora species: Eumetopias jubatus (Steller sea lion, n = 6), Herpestes javanicus (small Indian mongoose, n = 1), Panthera leo (lion, n = 1), Urocyon cinereoargenteus (gray fox, n = 1), Ursus arctos arctos (Eurasian brown bear, n = 1), and Viverricula indica (small Indian civet, n = 5). Due to the relatively later stage of collection for the available specimens, few heterochronic shifts were identified. Ossification sequences of feliform species showed complete agreement with the domestic cat. In caniforms, the bear and fox ossification sequences largely matched the dog, but numerous heterochronic shifts were identified in the sea lion.
CONCLUSIONS: We use museum specimens to generate cranial and postcranial micro-CT data on six species split between the two major carnivoran clades: Caniformia and Feliformia. Our data suggest that the ossification sequence of domestic dogs and cats are likely good models for terrestrial caniforms and feliforms, respectively, but not pinnipeds.
摘要：
背景：哺乳动物骨骼在出生前大量形成。可以通过比较骨骼不同元素的骨化顺序来研究骨骼形成的异时变化。由于在胎生类群中收集产前标本的挑战，机会性收集的博物馆标本为研究许多哺乳动物物种的产前骨骼发育提供了最佳材料。以前的研究已经调查了一系列哺乳动物物种的骨化序列，但对食肉中骨形成的模式知之甚少。食肉动物有不同的生态，饮食，和生物力学专业，非常适合研究进化生物学中的问题。目前,食肉动物的发育数据主要限于驯化物种。为了扩大食肉动物骨骼发育的现有数据，我们使用显微计算机断层扫描(micro-CT)非侵入性评估了哈佛比较动物学博物馆所有产前食肉动物标本的骨化程度.通过编码每个样本中是否存在骨骼，我们为每个物种构建了骨化序列。然后使用基于Parsimov的遗传推断（PGi）来识别食肉谱系之间的异慢性变化，并重建食肉的祖先骨化序列。
结果：我们使用微型CT研究了六种食肉动物的产前骨化序列：Eumetopiasjubatus（Steller海狮，n=6),Herpestesjavanicus（小印度猫鼬，n=1),PantheraLeo（狮子，n=1),Urocyoncinereoargenteus(灰色狐狸，n=1),Ursusarctosarctos（欧亚棕熊，n=1),和Viveruceraindica(小印度果子鱼，n=5)。由于现有标本的采集阶段相对较晚，发现了很少的非慢性变化。鳞茎类物种的骨化序列与家猫完全一致。在caniforms中，熊和狐狸的骨化序列在很大程度上与狗相匹配，但是在海狮中发现了许多非慢性变化。
结论：我们使用博物馆标本来生成颅骨和颅后骨的微型CT数据，这些数据分为两种主要的食肉进化枝：犬齿和费利形虫。我们的数据表明，家犬和猫的骨化序列可能是陆生犬形和类动物的良好模型，分别,但不是针脚.
结果：我们使用微型CT研究了六种食肉动物的产前骨化序列：Eumetopiasjubatus（Steller海狮，n=6),Herpestesjavanicus（小印度猫鼬，n=1),PantheraLeo（狮子，n=1),Urocyoncinereoargenteus(灰色狐狸，n=1),Ursusarctosarctos（欧亚棕熊，n=1),和Viveruceraindica(小印度果子鱼，n=5)。由于现有标本的采集阶段相对较晚，发现了很少的非慢性变化。鳞茎类物种的骨化序列与家猫完全一致。在caniforms中，熊和狐狸的骨化序列在很大程度上与狗相匹配，但是在海狮中发现了许多非慢性变化。
结论：我们使用博物馆标本来生成颅骨和颅后骨的微型CT数据，这些数据分为两种主要的食肉进化枝：犬齿和费利形虫。我们的数据表明，家犬和猫的骨化序列可能是陆生犬形和类动物的良好模型，分别,但不是针脚.
