| Zoogeography is a subject animal life, distribution and its interaction with geographical environment sciences, it's an interdisciplinary science between Geography and Zoology. As an important branch of Biogeography, the first task on this study is to make clear the distribution pattern of animals, and further explore pattern behind the geographical origin. This study using phenotypic data, combining with the existing geological and climate data to explain the causes of differentiation of geological history. Phenotype analysis is an important method in Zoogeography, it has always taken seriously by many scientists. The Sexual dimorphism(SD) refers to be significant respectively on some phenotype characteristics between sexes, these characteristics including shape, color, or other body organs. The Geographic variation(GV) refers to be significant respectively on some phenotype characteristics in geography groups. SD and GV studies help to understand animals how to response the environmental change by difference geographic populations or difference sexes. Another valuable work was focus on ancient climate and geography.Protobothrops mucrosquamatus(Cantor, 1839) is affiliated with the Viperidae, Crotalinae. This species is distributed in the southwest and southeast of China, Laos, northern Bangladesh, Vietnam, north Myanmar and northeast India; the range mainly belongs to Oriental Realm of central area and southern area that covers different climate and vegetation types. In recent years, several congers were described such that P. dabieshanensis Huang et al,2012 and P. maolanensis Yang et al,2011, these two species were similar with P. mucrosquamatus on morphology. Past research on P. mucrosquamatus was mainly focused on genealogy, and no record about SD or GV.A total of 142 P. mucrosquamatus specimens were examined in this study, and 29 external characteristics were recored. We used SPSS, GIS to analysis data and ANOVA, ANCOVA, Regression analysis, Principal component analysis to analysis SD and GV on P. mucrosquamatus. We explained the geography or biological reasons for SD and GV, and we preliminarily discussed biogeography for this species. The main results were as follows:A series of characteristics showed to be SD on P. mucrosquamatus including VS, SC, TL, DIAE, SC10-8, SC8-6, WHEAD and LHEAD. Male P. mucrosquamatus has bigger DIAE and logger TL than female; Female has bigger head size than male; Male has less VS and more SC than female, as well as the more posterior of SC8to6 and SC6to4 than female.P. mucrosquamatus mainland population does not exist obvious differentiation; Male P. mucrosquamatus showed to be significantly different between mainland population and Hainan Island population.These differentiation were morphologically continuous and can't be used to be the basis for taxonomy.The reason of SD and GV may be the result of natural selection and sexual selection, sexual selection may leaded to male snakes has bigger DIAE and more VS; Nature selection may leaded to female has bigger head size and less VS; The isolation effect of Qiongzhou strait was the main reason for population differentiation between mainland and Hainan Island.The distribution pattern of P. mucrosquamatus was the result of many factor's joint effect. In nature conditions, one last chance to landing Hainan Island is in the middle of the Holocene, one last chance to landing Taiwan Island is the late Pleistocene(Dali ice age). The influence of human activity also may promote genetic swapping between mainland and Hainan Island population. It's difficult to discuss the relationship between north Myanmar population and north Vietnam population due to no specimens included here. |
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