Department of Anatomy and Physiology, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, 0110, South Africa.
Anat Rec (Hoboken). 2017 Sep;300(9):1705-1715. doi: 10.1002/ar.23594. Epub 2017 May 2.
A specialized region of the bill tip characterized by a complex arrangement of mechanoreceptors and referred to as a bill tip organ, has been identified in numerous avians. A bill tip organ was initially inferred in kiwi species by the presence of numerous, bony pits in the rostrum of the bill, and later confirmed histologically. This study enumerates and compares the number and distribution of pits present in the bill tip in the ostrich and emu. The heads from 10 ostrich and 5 emu were prepared for osteological examination. The pattern and total number of pits was similar between the two species. However, the ostrich had significantly more pits in the regions underlying the Culmen and Gonys, whereas the emu displayed significantly more pits in the dorsal part of the mandibular rostrum. The relatively even distribution of pits in the inner and outer surfaces of both the mandibular and maxillary rostra suggest that the bill tip of the ostrich and emu are equally sensitive externally and intra-orally, as opposed to probing birds, where the major concentration of pits is located on the outer surfaces of the bill tips. The presence of pits in the bill tips of extant paleaognaths may be of relevance in interpreting the pits in the rostra of extinct therapod dinosaurs. The presence of bony pits in a region which is also well supplied with sensory nerves is highly suggestive of a bill tip organ in the ostrich and emu and which needs to be confirmed histologically. Anat Rec, 300:1705-1715, 2017. © 2017 Wiley Periodicals, Inc.
喙尖的一个特化区域，其特点是机械感受器的复杂排列，并被称为喙尖器官，在许多鸟类中都有发现。喙尖器官最初是通过喙的前部存在许多骨陷窝而推断存在于几维鸟中，后来通过组织学得到证实。本研究列举并比较了鸵鸟和鸸鹋喙尖的陷窝数量和分布。对 10 只鸵鸟和 5 只鸸鹋的头部进行了骨骼检查。这两个物种的喙尖陷窝的形态和总数相似。然而，鸵鸟在 Culmen 和 Gonys 下的区域有明显更多的陷窝，而鸸鹋在下颌喙的背侧部分有明显更多的陷窝。内外表面的陷窝在内外表面的相对均匀分布表明，鸵鸟和鸸鹋的喙尖在外部和内部同样敏感，而不是像探测鸟那样，其主要的陷窝集中在喙尖的外表面。现存古颌鸟类喙尖的陷窝的存在可能与解释灭绝的兽脚亚目恐龙的喙部的陷窝有关。在一个有丰富感觉神经供应的区域存在骨陷窝，强烈提示鸵鸟和鸸鹋存在喙尖器官，这需要通过组织学来证实。解剖学记录，300：1705-1715，2017。©2017 威利父子公司。
