Abstract：
Morphological data are used to describe a new nematode species, Heterocheilus floridensis sp. n. (Heterocheilidae) from the digestive tract of the Florida manatee Trichechus manatus latirostris (Harlan) (Trichechidae, Sirenia) from Florida, USA. Examination by light and scanning electron microscopy revealed that the new species differs from the related Heterocheilus tunicatus Diesing, 1839 mainly by having dentigerous ridges on the inner surface of the lips, a median unpaired papilla located anterior to the cloaca, and a considerably larger body size. Sequence data for subunits I and II of mitochondrial cytochrome oxidase gene, 18S small subunit and 28S ribosomal RNA genes were provided for molecular characterisation of the new species. However, the current unavailability of homologous sequence data for congeneric specimens precluded a molecular assessment of the morphological species hypothesis, and ascaridoid phylogenetic hypotheses could not be advanced. Specimens of Heterocheilus sp. collected from the Antillean manatee Trichechus manatus manatus Linnaeus in Puerto Rico, on loan from the US National Museum of Natural History, were morphologically consistent with the new species, so apparently all congeneric nematodes reported from both subspecies of the West Indian manatee Trichechus manatus Linnaeus and previously identified as H. tunicatus belong rather to H. floridensis sp. n. Heterocheilus hagenbecki (Khalil et Vogelsang, 1932) Sprent 1980 is here considered to be a species inquirenda. A key to valid species of Heterocheilus Diesing, 1839 is provided.
摘要：
形态学数据用于描述一种新的线虫物种，弗洛里奇。n。（Heterocheilidae），来自佛罗里达海牛Trichechusmanatuslatirostris（Harlan）的消化道（Trichechidae，Sirenia)来自佛罗里达，美国。通过光学和扫描电子显微镜检查发现，新物种与相关的HeterocheilustunicatusDiesing不同，1839年主要是在嘴唇的内表面上有含牙的脊，位于泄殖腔前的中间不成对的乳头，和相当大的体型。线粒体细胞色素氧化酶基因I和II亚基的序列数据，提供了18S小亚基和28S核糖体RNA基因，用于新物种的分子表征。然而,同源序列数据的当前不可用的同类标本排除了分子评估的形态物种假说，并且无法提出类星虫系统发育假设。Heterocheilussp。从波多黎各的Antillean海牛TrichusmanatusmanatusLinnaeus收集，从美国国家自然历史博物馆借来的，在形态上与新物种一致，因此，显然从西印度海牛TrichechusmanatusLinnaeus的两个亚种报告的所有同属线虫，以前被鉴定为H.tunicatus属于H.floridensissp。n.Heterocheilushagenbecki(KhaliletVogelsang,1932)Sprent1980在这里被认为是一个物种调查。HeterocheilusDiesing有效物种的关键，1839提供。
