Black W C, Piesman J
Department of Microbiology, Colorado State University, Fort Collins 80523.
Proc Natl Acad Sci U S A. 1994 Oct 11;91(21):10034-8. doi: 10.1073/pnas.91.21.10034.
Ticks are parasitiform mites that are obligate hematophagous ectoparasites of amphibians, reptiles, birds, and mammals. A phylogeny for tick families, subfamilies, and genera has been described based on morphological characters, life histories, and host associations. To test the existing phylogeny, we sequenced approximately 460 bp from the 3' end of the mitochondrial 16S rRNA gene (rDNA) in 36 hard- and soft-tick species; a mesostigmatid mite, Dermanyssus gallinae, was used as an outgroup. Phylogenies derived using distance, maximum-parsimony, or maximum-likelihood methods were congruent. The existing phylogeny was largely supported with four exceptions. In hard ticks (Ixodidae), members of Haemaphysalinae were monophyletic with the primitive Amblyomminae and members of Hyalomminae grouped within the Rhipicephalinae. In soft ticks (Argasidae), the derived phylogeny failed to support a monophyletic relationship among members of Ornithodorinae and supported placement of Argasinae as basal to the Ixodidae, suggesting that hard ticks may have originated from an Argas-like ancestor. Because most Argas species are obligate bird octoparasites, this result supports earlier suggestions that hard ticks did not evolve until the late Cretaceous.
蜱是寄生性螨类，是两栖动物、爬行动物、鸟类和哺乳动物的专性吸血外寄生虫。基于形态特征、生活史和宿主关联，已描述了蜱科、亚科和属的系统发育。为了检验现有的系统发育，我们对36种硬蜱和软蜱物种线粒体16S rRNA基因（rDNA）3'端约460 bp进行了测序；以一种中气门螨（鸡皮刺螨）作为外类群。使用距离法、最大简约法或最大似然法得到的系统发育树是一致的。现有的系统发育在很大程度上得到了支持，但有四个例外。在硬蜱（硬蜱科）中，血蜱亚科成员与原始的钝缘蜱亚科成员是单系的，而璃眼蜱亚科成员则归入扇头蜱亚科。在软蜱（argasidae）中，推导的系统发育未能支持钝缘蜱亚科成员之间的单系关系，并支持argasinae位于硬蜱科基部的位置，这表明硬蜱可能起源于类似argas的祖先。由于大多数argas物种是专性鸟类八足寄生虫，这一结果支持了早期的观点，即硬蜱直到白垩纪晚期才进化出来。
