Adaptations in the nasal passages for sand burrowing in the saurian genus Uma
Adaptations in the nasal passages for sand burrowing in the saurian genus Uma
复制标题
DOI：
10.1086/281097
复制
发表时间：
1943-01-01
影响因子：
2.9
通讯作者：
Stebbins, RC
中科院分区：
文献类型：
--
作者：
Stebbins, RC
鬣蜥属乌玛的成员拥有环状的U形鼻道，在结构和功能上阻止了沙粒在地下呼吸过程中的吸入。沙粒的排除和消除涉及以下因素：(1)沙粒在吸气时被吸引到外部鼻孔时相互干扰。有一种趋势是形成一个由相互交错的碎片组成的格栅，阻碍其他疏松颗粒。(2)当乌玛被埋葬时，前庭与水平线成一定角度。在到达主鼻腔之前，沙粒必须在重力的作用下被拉上引流管。(3)附着在前庭壁上的沙粒倾向于阻碍游离粒的运动。(4)在亚表层呼吸条件下，外鼻孔的瓣膜将鼻孔缩小为一个狭窄的新月形狭缝，限制了颗粒的吸入。(5)假设鼻管直径减小，伴随着毗邻外鼻孔的前庭底部的瓣膜作用，可能会堵塞沙粒。(6)渐进式吸气配合爆炸性呼气辅助，以避免沙粒在鼻管内积聚。嗅觉通道的配置突出了呼气的爆炸性效果。(7)到达主腔的少量沙粒在纤毛作用下进入口腔的粘液膜中输送，最终进入消化道。乌玛属在鼻结构方面并不是独一无二的。蜥蜴科的其他一些属也被发现具有与该属非常相似的鼻型。Callisaurus、Phrynosoma、Uta、Scelopus就是这样的属。根据田间和实验室的观察，这些群体中出现了土壤淹水的趋势。蜥蜴科其他非穴居属的鼻型与类蜥蜴的鼻型有很大不同。毫无疑问，蜥蜴科内鼻部环状结构的出现对乌玛属几乎完全嗜沙习性的形成具有相当重要的作用。
Members of the iguanid genus Uma possess looped, U-shaped nasal passages which in structure and functioning prevent the inspiration of sand particles during subsurface respiration. The following factors are involved in the exclusion and elimination of sand particles: (1) The sand particles interfere with one another as they are drawn toward the external naris during inspiration. There is a tendency toward the formation of a grill of interlocking fragments which obstruct other loose grains. (2) When Uma lies buried the vestibule is situated at an angle to the horizontal. The sand particles must be drawn up the approach tube against the pull of gravity before reaching the principal nasal cavity. (3) Sand grains which adhere to the walls of the vestibule tend to impede the movement of free grains. (4) Under conditions of subsurface respiration the valve at the external naris reduces the nasal aperture to a narrow crescentic slit, limiting the inspiration of particles. (5) The postulated reduction in the diameter of the nasal tubes concomitant with the valvular action of the floor of the vestibule adjacent to the external naris, may tend to obstruct sand particles. (6) Gradual inspiration coupled with explosive expiration aids in avoiding the accumulation of sand in the nasal tubes. The configuration of the olfactory channels accentuates the explosive effect of expiration. (7) The small number of sand grains reaching the principal cavity are conveyed in a mucous film moved by ciliary action into the mouth, ultimately passing into the digestive tract. The genus Uma is not unique with respect to nasal structure. A number of other genera of the Iguanidae were found to possess a nasal configuration closely similar to that occurring in this genus. Callisaurus, Phrynosoma, Uta, Sceloporus are such genera. A tendency toward soil submergence occurs among these groups as based on field and laboratory observation. Other nonburrowing genera of the Iguanidae exhibited a nasal configuration quite different from the Uma-like types. The occurrence of the looped nasal structure within the Iguanidae doubtless was of considerable importance in the development of the almost completely psammophilous habit of the genus Uma.