A Phylogenetic Study of Late Growth Events in a Mammalian Evolutionary Radiation-The Cranial Sutures of Terrestrial Artiodactyl Mammals
A Phylogenetic Study of Late Growth Events in a Mammalian Evolutionary Radiation-The Cranial Sutures of Terrestrial Artiodactyl Mammals
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DOI：
10.1007/s10914-011-9176-8
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发表时间：
2012-03-01
影响因子：
1.9
通讯作者：
Sanchez-Villagra, Marcelo R.
中科院分区：
文献类型：
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作者：
Baermann, Eva V.;Sanchez-Villagra, Marcelo R.
我们记录了 480 个头骨中 29 条外颅缝融合的相对时间，这些头骨属于陆生偶蹄目所有主要分支的 35 个现存物种和 4 个化石物种。使用缝线融合事件和 Parsimov 的事件配对图谱在系统发育背景下研究了所得数据。作为系统发育框架，我们从之前发表的几项分析中生成了复合系统发育。六齿兽中每个物种的总体缝线闭合范围从 5 条到全部 29 条缝线不等。所有现存的非反刍动物（牛科动物、骆驼科动物和河马科动物）所研究缝合线的融合率超过 50%（大多数超过 75%），而几乎所有反刍动物中，只有不到 50% 的缝合线完全融合。系统发育回归发现缝线闭合与体重之间存在显着相关性。在所有物种中，我们观察到枕骨大孔周围的缝合线（外枕骨-上枕骨，外枕骨-基枕骨）的早期融合，这在其他哺乳动物中也是一致的方案。将每个通常公认的头骨模块中缝合线数量的变化数量进行缩放，揭示了颅顶、颧骨-蝶骨区域、眼眶和前口鼻区域中相对相同数量的变化。仅基骨在缝线融合变化的绝对量和相对量方面显示出小得多的数量。一些物种表现出独特的缝线融合模式，例如佩卡里腭部许多缝线的早期融合或匕首巨兽的前上颌骨缝线的融合，可能与摄食模式有关。通过消除缝合线来强化颅骨的策略可以解释具有大颅附肢的反刍动物物种中缝合线融合增加的模式。
We recorded the relative timing of fusion of 29 ectocranial sutures in 480 skulls belonging to 35 extant and four fossil species from all major clades of terrestrial artiodactyls. The resulting data were studied in a phylogenetic context, using mapping of event-pairing of suture fusion events and Parsimov. As phylogenetic framework we generated a compound phylogeny from several previously published analyses. Overall suture closure per species ranged from five to all 29 sutures in Hexaprotodon. All living non-ruminants (suids, camelids, and hippopotamids) fuse more than 50% of the studied sutures (most over 75%), whereas in almost all ruminants less than 50% of the sutures fuse completely. Phylogenetic regression found a significant correlation between suture closure and body mass. In all species we observed an early fusion of the sutures surrounding the foramen magnum (Exoccipital-Supraoccipital, Exoccipital-Basioccipital), a consistent scheme also among other mammals. Scaling the number of changes to the number of sutures in each of the usually recognized skull modules reveals relatively equal numbers of changes in the cranial vault, the zygomatic-sphenoid region, the orbit, and the anterior oral-nasal region. Only the basicranium shows a much smaller number in terms of absolute and relative amount of suture fusion change. Some species show a unique pattern of suture fusion, such as the early fusion of many sutures in the palatal region in Pecari or that of premaxillary sutures in dagger Cainotherium, perhaps related to feeding mode. A strategy to strengthen the skull by obliterating the sutures could explain the pattern of increased sutural fusion in ruminant species with large cranial appendages.