九种沙蜥的核型——兼论中国沙蜥属核型演化

KARYOTYPES OF NINE SPECIES IN THE GENUSPHRYNOCEPHALUS, WITH DISCUSSION OF KARYOTYPICEVOLUTION OF CHINESE PHRYNOCEPHALUS

报道了沙蜥属９种２１个不同居群的核型及银分带核型。荒漠沙蜥、草原沙蜥和斑点沙蜥２ｎ＝４６＝２２Ｉ＋２４ｍ，ＮＦ＝４６。叶城沙蜥２ｎ＝４６＝２ｓＩ＋２０Ｉ＋２４ｍ，ＮＦ＝４６。南疆沙蜥、泽当沙蜥、青海沙蜥和红原沙蜥２ｎ＝４８＝２４Ｉ＋２４ｍ，ＮＦ＝４８。青海沙蜥具有异型性染色体。大耳沙蜥２ｎ＝４８＝２Ｖ＋８ｓＶ＋１２ｓＩ＋２６ｍ，ＮＦ＝５８。９种中，ＮＯＲ均位于微小染色体对上。与本属已知核型比较，确认我国沙蜥属核型均来自共同的核型祖先，可分为３个核型类群：（１）２ｎ＝４６，１１对大染色体类群；（２）２ｎ＝４８，１２对大染色体类群；（３）大耳沙蜥。前两个类群核型与生态地理分布紧密相关。讨论了我国沙蜥属物种核型演化趋势，并结合地史资料探讨了本属核型演化与第三纪以来古地史变迁的关系。

Theodore J. Papenfuss ,,Robert J. Macey (Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA) The karyotypes and silver staining bands of 9 species with 21 different populations in the genus Phrynocephalus were investigated. Pprzewalskii, Pfrontalis and Pguttatus showed the same karyotype formula as 2n=46=22I+24m with NF=46. Paxillaris showed 2n=46=2sI+20I+24m with NF=46. Both Pforsythi and Pzetangensis showed 2n=48=24I+24m with NF=48, so did Phongyuanensis and Pvlangalii. But advanced stages of differentiation of sex chromosomes were found in P.vlangalii. Pmystaceus showed 2n=48=2V+8sV+12sI+26m with NF=58. The NORs were all located on the microchromosome pairs in 9 species.Comparing with others in the same genus,it was confirmed that the karyotypes of Phrynocephalus were originated from the same mutual ancestor. The karyotypes of Chinese Phrynocephalus species can be divided into three groups: (1)The first group showed 2n=46 , all with 11 large and 12 small pairs of chromosomes , and most of them are acrocentric type. Their karyotypes resembled each other. (2)The second group showed 2n=48 , all with 12 large and 12 small pairs of chromosomes, and most of them are acrocentric type. (3)P.mystaceus was different from the former two groups because it had 11 large and 13 small pairs of chromosomes, and most of them were of bi-armed type. The trend of karyotypic differentiation of Chinese Phrynocepalus species was discussed. The first group and the second group were closely associated with their ecogeographical distributions. The group with 2n=46 were all lower altitude populations whereas the group with 2n=48, except P.mystaceus, were all higher altitude populations. The relationship between the routes of karyotypic differentiation and the change of ancient geography and weather from the Tertiary in Cenozoic Era were discussed with the materials of geological history. The pattern of distributions and dispersal routes of differentiation of Chinese Phrynocephalus species was given.