Walker Eric A, Townsend Victor R
Department of Biology, Virginia Wesleyan College, 1584 Wesleyan Drive, Norfolk, Virginia, 23502.
J Morphol. 2014 Dec;275(12):1376-85. doi: 10.1002/jmor.20310. Epub 2014 Jul 23.
The external morphology of the penis is an important source of systematic characters in phylogenetic studies of harvestmen. Modern taxonomic studies generally include micrographs generated by scanning electron microscopy (SEM) to illustrate penis morphology. In contrast, the external morphology of the ovipositor has largely been ignored for harvestmen belonging to the suborder Laniatores. Comparative studies of ovipositor microanatomy using SEM are especially lacking for species belonging to the superfamily Gonyleptoidea. In an effort to determine if the ovipositor could be a useful source of informative characters for these harvestmen, we investigated interspecific variation in the external morphology of the ovipositor for 14 species from the family Cosmetidae. Our SEM-based study revealed that the external surface of the distal tips of the ovipositors of most species was generally divided into four symmetrical lobes, although we observed a bilobed condition in Erginulus clavotibialis and Erginulus subserialis. The distal surfaces were also generally smooth, with the exception of the ovipositor of Erginulus weyerensis, which featured small surface setae. In addition, we observed considerable interspecific variation in the morphology of the peripheral setae on the distal tip, especially with respect to relative size, morphology of the shaft, and number, symmetry, and shapes of the distal tips. The functional significance, if any, of variation in the structure of the peripheral setae is unclear. Additional behavioral studies of copulation and oviposition are needed to determine the functional relationships between reproductive morphology and behavior. The morphological variation that we observed suggests that future taxonomic studies of cosmetid harvestmen, and potentially other gonyleptoidean taxa, would benefit from the inclusion of descriptions of ovipositor morphology.
在盲蛛系统发育研究中，阴茎的外部形态是系统特征的重要来源。现代分类学研究通常包括扫描电子显微镜（SEM）生成的显微照片来说明阴茎形态。相比之下，对于隶属于鞭蛛亚目的盲蛛，产卵器的外部形态在很大程度上被忽视了。对于鞭蛛总科的物种，尤其缺乏使用SEM对产卵器微观解剖结构进行的比较研究。为了确定产卵器是否能为这些盲蛛提供有用的信息特征来源，我们研究了美蛛科14个物种产卵器外部形态的种间差异。我们基于SEM的研究表明，大多数物种产卵器远端的外表面通常分为四个对称叶，不过我们在棒胫窄腹蛛和亚序窄腹蛛中观察到双叶情况。远端表面通常也很光滑，除了韦氏窄腹蛛的产卵器，其表面有小刚毛。此外，我们观察到远端末梢周围刚毛形态存在相当大的种间差异，特别是在相对大小、柄的形态以及远端末梢的数量、对称性和形状方面。周围刚毛结构变化的功能意义（如果有的话）尚不清楚。需要进行更多关于交配和产卵的行为研究，以确定生殖形态与行为之间的功能关系。我们观察到的形态变异表明，未来对美蛛科盲蛛以及可能其他鞭蛛总科类群的分类学研究，将受益于纳入产卵器形态的描述。
