Lichtenfels J R, Pilitt P A, Lancaster M B
Biosystematic Parasitology Laboratory, Animal Parasitology Institute, Beltsville, MD 20705.
Vet Parasitol. 1988 Feb;27(1-2):3-12. doi: 10.1016/0304-4017(88)90056-8.
The systematics of the Ostertagiinae is unsettled with no agreement on how many genera and species are present in cattle and sheep. Ten species of Ostertagiinae are commonly parasitic in cattle and sheep. The males can be identified on the basis of differences in morphology of spicules and genital cones but the females of most species cannot be identified. The species-level systematics have been complicated by the proposal that the ten species are polymorphs of only five species. The systematics at genus level has been complicated by the use of numerous genera for the ten species, at present most commonly Ostertagia, Teladorsagia and Marshallagia. This report (1) describes the current knowledge of the systematics and (2) provides diagnoses of the genera recommended for the ten species. The morphology of the ten species was studied to determine whether characteristics could be found to identify females or to further differentiate the males. Characters studied included the system of longitudinal and surface cuticular ridges (synlophe), the internal morphology of the esophagus and the orientation of rays of the copulatory bursa. The study of species morphology resulted in additional support for the polymorphism proposal. All minor species were found to be identical to their major species in characteristics of the synlophe, esophagus and rays of the copulatory bursa. Two recent classifications of the Ostertagiinae both recommended the use of the genus Teladorsagia for the species T. circumcincta and the two minor species that occur with it, T. trifurcata and T. davtiani. Teladorsagia is characterized by a copulatory bursa in which the five lateral rays are arranged 2-2-1 and a ventral swelling of the genital cone (proconus) is absent. One pair of species, Marshallagia marshalli (major species) and Ostertagia occidentalis (minor species) should be included in the genus Marshallagia. This genus has been characterized by an elongated bursa in which the posterior pair of lateral rays are much longer than the ventral pair. The remaining two pairs of species (O. ostertagi and its minor species O. lyrata, and O. leptospicularis and its minor species O. kolchida) and O. bisonis belong in the genus Ostertagia which is characterized by a 2-1-2 arrangement of the five lateral rays of the copulatory bursa and the presence of a proconus.
奥斯特他线虫亚科的分类系统尚未确定，对于牛和羊体内存在多少属和种没有达成共识。奥斯特他线虫亚科的10个物种通常寄生于牛和羊。雄性可以根据交合刺和生殖锥的形态差异来鉴别，但大多数物种的雌性无法鉴别。有人提出这10个物种只是5个物种的多形现象，这使得物种水平的分类变得复杂。由于对这10个物种使用了众多的属（目前最常用的是奥斯特他属、泰勒属和马歇尔属），属水平的分类也变得复杂。本报告（1）描述了当前的分类学知识，（2）提供了推荐用于这10个物种的属的诊断。对这10个物种的形态进行了研究，以确定是否能找到鉴别雌性或进一步区分雄性的特征。研究的特征包括纵向和体表角质嵴系统（联合嵴）、食管的内部形态以及交配囊射线的方向。物种形态学研究为多形现象的提议提供了更多支持。所有的次要物种在联合嵴、食管和交配囊射线的特征上都与其主要物种相同。奥斯特他线虫亚科最近的两个分类都建议将环形泰勒线虫及其伴生的两个次要物种三叉泰勒线虫和达氏泰勒线虫归入泰勒属。泰勒属的特征是交配囊的5条侧射线呈2 - 2 - 1排列，且生殖锥（前锥）没有腹侧肿胀。一对物种，马歇尔马歇尔线虫（主要物种）和西方奥斯特他线虫（次要物种）应归入马歇尔属。该属的特征是交配囊细长，其中后侧的一对侧射线比腹侧的一对长得多。其余两对物种（奥氏奥斯特他线虫及其次要物种琴形奥斯特他线虫，以及细刺奥斯特他线虫及其次要物种科尔希达奥斯特他线虫）和野牛奥斯特他线虫属于奥斯特他属，其特征是交配囊的5条侧射线呈2 - 1 - 2排列且有前锥。
