Abstract：
Two new species of lung-dwelling nematodes are described from North American frogs: Rhabdias aurorae n. sp. from Rana aurora and Rhabdias conni n. sp. from Rana clamitans and Rana catesbeiana from Arkansas; the latter species was also found in Oklahoma and Georgia. Rhabdias aurorae n. sp. differs from other Nearctic congeners in the combination of the following characteristics: buccal capsule 22-25 μm wide, elongated tail covered with inflated cuticle, esophagus with prominent dilatation in anterior part and 6 small circumoral lips. Rhabdias conni n. sp. is morphologically closest to Rhabdias ranae Walton, 1929 and Rhabdias joaquinensisIngles, 1936; it differs from them in the shape of lateral pseudolabia, the dimensions of the body, and the egg size. Both new species were found to be significantly different from the Nearctic congeners in the nucleotide sequences of nuclear ribosomal DNA (18S-ITS-28S region), 12S, and CO1 mitochondrial genes. The 2 new species differ from other currently sequenced Nearctic congeners by 1.1-2.7% of nucleotide positions in the nuclear rDNA region, 1.3-3.4% in the 12S gene, and 3.4-9.4% in CO1 gene. Molecular phylogenetic analysis based on nuclear ribosomal DNA sequences placed both new species into the clade consisting of Nearctic and Neotropical Rhabdias spp. The position of Rh. aurorae n. sp. within the clade is uncertain because of a polytomy, but Rh. conni n. sp. is nested within the \"Rh. joaquinensis complex\" related to Rh. ranae and Rhabdias tarichaeKuzmin, Tkach, and Snyder, 2003. The phylogenetic analysis based on nuclear ribosomal DNA sequences has revealed 3 evolutionary host-switching events from anuran to caudatan hosts among Rhabdias spp. that occurred in the Nearctic and Palearctic. The molecular phylogeny also suggests that Rhabdias may have originally evolved in what is now Africa.
摘要：
从北美青蛙中描述了两种新的肺部线虫：Rhabdiasauoraen.sp。来自Ranaaurora和Rhabdiasconnin.sp.来自阿肯色州的Ranaclamitans和Ranacatesbeiana；后者也在俄克拉荷马州和乔治亚州发现。Rhabdiasauroaen.sp.在以下特征的组合中与其他近地同源物不同：颊囊22-25μm宽，细长的尾巴覆盖着膨胀的角质层，食道，前部明显扩张，有6个小的环唇。Rhabdiasconnin.sp.在形态上最接近RhabdiasranaeWalton,1929年和RhabdiasjoaquinensisIngles，1936年；它与它们的不同之处在于侧向假性的形状，身体的尺寸，和鸡蛋的大小。发现这两个新物种在核核糖体DNA的核苷酸序列（18S-ITS-28S区域）中与近核同源物显着不同，12S,和CO1线粒体基因。这2个新物种与其他目前测序的近核同源物的差异为核rDNA区域中核苷酸位置的1.1-2.7％，12S基因中的1.3-3.4％，CO1基因中占3.4-9.4%。基于核核糖体DNA序列的分子系统发育分析将两个新物种都放入了由Nearctic和新热带Rhabdiasspp组成的进化枝中。Rh的位置。极光n.sp.由于多发性切除术，进化枝内部不确定，但是Rh.connin.sp.嵌套在\"Rh中。与Rh有关的华喹复合体。ranae和RhabdiastarichaeKuzmin，Tkach,还有斯奈德,2003.基于核核糖体DNA序列的系统发育分析揭示了Rhabdiasspp中从anuran到caudatan宿主的3种进化宿主转换事件。发生在近地和古地。分子系统发育还表明，Rhabdias可能最初是在现在的非洲进化的。
