指间区纹在灵长类动物中的进化

EVOLTION OF INTERDIGITAL PATTERNS AMONG PRIMATES

各种灵长类动物的指间区纹有很大差异。树到原猴是由原始多垫指间区纹变为各区发育均匀的单垫纹。新大陆猴发展出两侧发达中部退化的类型。旧大陆猴的指间区纹最发达 ,疣猴多为箕纹但各区不均匀 ,猴类为各区均匀的斗纹。类人猿的指间区纹极退化 ,长臂猿丧失了指间区纹。对照各种灵长动物的生活习性 ,发现树栖类型指间各区发育不均匀 ,地栖类型则均匀 ,使用多则指间区纹发达 ,反之则退化。人类因为握持工具而次生出了环指侧花纹。各种灵长动物的各区指间区纹并不同源 。

As the interdigital patterns of primates are different from that of human being, the studies and the comparisons of them will result in the clarification of the course and factors of interdigital patterns evolution. 1\ Origin of Interdigital Patterns\;General opinion about how dermatoglyphy comes into being is that primates need to enhance the frictional force and sense of the palms and soles for tree inhabiting lives. Interdigital pattern is one of the earliest dermatoglyphies. When interdigital patterns have just taken shape, those in different area did not contact each other. There were still large fur areas between dermatoglyphy areas. On palms of Tupaia, there are always 3 to 4 muscle pads, fairly close to each other, opposite to each finger, with simple arch patterns on each pad. Ridge trends are different from one pad to another. During latter primates' development, some of these pads expand, and others get narrowed. Neighboring pads contact each other. Dermatoglyphies are distributed all over the palm. There is a tripartite point left at the demarcation of each three pads. On the pads, appear more complicated patterns. 2\ Evolutionary course of Interdigital Patterns\;Commonly speaking, there is only one biggest pad in each interdigital area of those species higher to Tupaia . Analyzing the ridge trends and the positions of tripartite points, we find that primates have reserved different pads according to Tupaia , which suggests some big categories split up quite more earlier than we think. So the evolutionary pattern of primates is bush like.\;There are mainly 5 evolution branches out of Tupaia . ① Tarsidae . There is only one pad in each interdigital area, and fairly big space between pads. On the pads, there is only simple arch pattern. ② Lemur and Lorisidae , one pad in each area, too, small gap between pads. On the pads, equally develop out primitive pattern, loop or small whorl. ③New World monkey. Side interdigital areas are developed while central areas are retrograde. In Cebidae interdigital area II is a big whorl, and in area IV is a loop. In Hapalidae area I is a big whorl, area IV also loop. Interdigital areas have completely connected. ④Old World monkey. The interdigital patterns of Old World monkey are the most developed. There are loops in different sizes in Colobidae . In Macaca area II, III and IV are all big obvious whorls.⑤Human like ape. Their interdigital patterns are quite retrograde. Gibbons have no interdigital patterns. Chimpanzees occasionally have some little loops. Humankind has developed out of ape. So the original interdigital patterns are also degenerate. But opposite to the third finger, appears a new various pattern.\;3\ Evolution Factors of Interdigital Patterns\;Comparing the categories of primates, we find interdigital areas of tree inhabiting primates developed rather unequally, while ground inhabiting ones are on the contrary. Equality of interdigital patterns is directly proportional to the ground inhabited tendency. It is possibly because palms of whom that is ground\|inhabiting need to touch ground equally, but while living on tree, palms must press the branch from both sides. So interdigital areas of tree inhabiting primates are side developed and central retrograde. Pattern intensity is also directly proportional to the rate of utilization. This is reflected very well in human like apes. Gibbons use fingers to seize hold branches, and seldom use interdigital area (so that to be nimble when seize or release). Then there are no patterns in their interdigital areas. When chimpanzees are walking, they let fingers back to touch ground. Only when they hold something occasionally, they will use interdigital patterns. So their interdigital patterns are very degenenate. Only few individuals have small loop in their interdigital areas.\;Interdigital patterns of humankind, corresponding to those of human like apes, are also very degenerate. They are all inperfectible dominant or recessive small loops.It does not fit the high freq