Abstract：
During an ecological study with a near-endangered anuran in Brazil, the Schmidt\'s Spinythumb frog, Crossodactylus schmidti Gallardo, 1961, we were given a chance to analyze the gastrointestinal tract of a few individuals for parasites. In this paper, we describe a new species of an allocreadiid trematode of the genus Creptotrema Travassos, Artigas & Pereira, 1928, which possesses a unique trait among allocreadiids (i.e., a bivalve shell-like muscular structure at the opening of the ventral sucker); the new species represents the fourth species of allocreadiid trematode parasitizing amphibians. Besides, the new species is distinguished from other congeners by the combination of characters such as the body size, ventral sucker size, cirrus-sac size, and by having small eggs. DNA sequences through the 28S rDNA and COI mtDNA further corroborated the distinction of the new species. Phylogenetic analyses placed the newly generated sequences in a monophyletic clade together with all other sequenced species of Creptotrema. Genetic divergences between the new species and other Creptotrema spp. varied from 2.0 to 4.2% for 28S rDNA, and 15.1 to 16.8% for COI mtDNA, providing robust validation for the recognition of the new species. Even though allocreadiids are mainly parasites of freshwater fishes, our results confirm anurans as hosts of trematodes of this family. Additionally, we propose the reallocation of Auriculostoma ocloya Liquin, Gilardoni, Cremonte, Saravia, Cristóbal & Davies, 2022 to the genus Creptotrema. This study increases the known diversity of allocreadiids and contributes to our understanding of their evolutionary relationships, host-parasite relationships, and biogeographic history.
摘要：
在对巴西濒临灭绝的anuran进行的生态研究中，施密特的拇指蛙,CrossodactylusSchmidtiGallardo,1961年，我们有机会分析一些人的胃肠道中的寄生虫。在本文中,我们描述了CreptotremaTravassos属的同种异体吸虫的新物种，Artigas&Pereira,1928年，在同种异体动物中具有独特的性状(即，腹侧吸盘开口处的双壳类壳状肌肉结构）；新物种代表了寄生两栖动物的第四种同种异体吸虫。此外,新物种与其他同类物种的区别在于其体型等特征的组合，腹侧吸盘大小，卷云囊大小,还有小鸡蛋.通过28SrDNA和COImtDNA的DNA序列进一步证实了新物种的区别。系统发育分析将新生成的序列与所有其他测序的Creptotrema物种一起置于单系进化枝中。新物种与其他Creptotrema种之间的遗传差异。28SrDNA的变化范围从2.0％到4.2％，和15.1至16.8%的COImtDNA，为新物种的识别提供了强有力的验证。尽管异类类动物主要是淡水鱼的寄生虫，我们的结果证实无尾藻是这个家族的吸虫的宿主。此外,我们建议重新分配阳伞，Gilardoni,Cremonte,Saravia,克里斯托巴尔和戴维斯，2022年到Creptotrema属。这项研究增加了已知的异类类动物的多样性，并有助于我们理解它们的进化关系，宿主-寄生虫关系，和生物地理历史。
