Department of Anatomy, Midwestern University, 19555N. 59th Ave., Glendale, AZ 85308, USA.
J Hum Evol. 2011 Jan;60(1):106-16. doi: 10.1016/j.jhevol.2010.09.006. Epub 2010 Nov 12.
Cranial arterial patterns are commonly used for determining phylogenetic patterns in extant taxa and have often been used in studies investigating the relationships among fossil taxa. In primitive eutherians, the stapedial artery provided blood to the meninges, orbits, and certain regions of the face. In many modern mammals, however, blood supply to most of these areas has been taken over by branches of the external carotid, although some groups (e.g., treeshrews, some families of primates) still retain aspects of the ancestral pattern. Here, we show that the relative size of the obturator foramen of the stapes is a reliable indicator of the presence or absence of a "functional" stapedial artery in Euarchonta. We also describe newly discovered stapedes for extinct euarchontans, Ignacius graybullianus, and Plesiadapis tricuspidens, and use the approach described here to show that these taxa likely did not have a functional stapedial artery. The implications of these findings for auditory function and phylogenetic studies are discussed.
颅动脉模式通常用于确定现存分类群的系统发育模式，并且经常用于研究化石分类群之间的关系。在原始真兽类中，镫骨动脉为脑膜、眼眶和面部的某些区域提供血液。然而，在许多现代哺乳动物中，这些区域的大部分血液供应已经被颈外动脉的分支接管，尽管有些类群（例如树鼩、某些灵长类家族）仍然保留了祖先模式的某些方面。在这里，我们表明镫骨的闭孔动脉的相对大小是真兽类中是否存在“功能性”镫骨动脉的可靠指标。我们还描述了已灭绝的真兽类 Ignacius graybullianus 和 Plesiadapis tricuspidens 的新发现的镫骨，并使用这里描述的方法表明这些类群可能没有功能性的镫骨动脉。讨论了这些发现对听觉功能和系统发育研究的影响。
