Rosser Thomas G, Meaux Aiden, Woodyard Ethan T, Stilwell Justin M, Richardson Bradley M, Robison Logan R S, Hudnall Jill B, McNulty Kaylin, Nguyen Jonah A, Rose Divya, Moore Debra, Peterman Beth, Reichley Stephen R, Lawrence Mark L
Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, 39762, USA.
Mississippi State University Global Center for Aquatic Health and Food Security, Mississippi State University, Mississippi State, MS, 39762, USA.
Syst Parasitol. 2025 Jun 30;102(4):44. doi: 10.1007/s11230-025-10243-x.
Adult flukes of the genus Orchidasma were collected from the intestinal tracts of loggerhead Caretta caretta and Kemp's ridley Lepidochelys kempii sea turtles as part of diagnostic investigations into sea turtle strandings. Two morphologically distinct species were present: one represented the type-species Orchidasma amphiorchis and an undescribed species. Orchidasma amphiorchis is redescribed and Orchidasma orchilobata n. sp. is described based on morphological, molecular and phylogenetic analyses. Oxford Nanopore Technology and Illumina sequencing were used to generate complete mitochondrial genomes and nuclear ribosomal operons for both species. Sanger sequencing from additional hologenophore specimens for both species were used to assess interspecific and intraspecific variability. Single locus phylogenetic analyses of aligned partial 28S rRNA gene sequences and concatenation of mitochondrial genes of the two species and other trematodes were performed to assess the taxonomic affinity of Orchidasma. Analysis of partial 28S rRNA gene sequences placed O. amphiorchis and O. orchilobata n. sp. as members of the Monorchioidea and closest to Skrjabinopsolus nudidorsalis, a member of Deropristidae. This disagreed with previous inclusion of Orchidasma as a member of Telorchiidae within Plagiorchioidea. Whole mitochondrial genome sequencing and phylogenetic analysis resulted in similar topology, suggesting a revision to include Orchidasma as a member of Deropristidae supported by shared morphological characters and nucleotide sequence data with deropristid congeners.
作为海龟搁浅诊断调查的一部分，从蠵龟（Caretta caretta）和肯氏丽龟（Lepidochelys kempii）的肠道中采集了Orchidasma属的成年吸虫。存在两种形态上不同的物种：一种代表模式种Orchidasma amphiorchis，另一种为未描述的物种。本文对Orchidasma amphiorchis进行了重新描述，并基于形态学、分子学和系统发育分析对Orchidasma orchilobata新种进行了描述。利用牛津纳米孔技术和Illumina测序技术生成了这两个物种的完整线粒体基因组和核核糖体操纵子。通过对这两个物种额外的全基因组标本进行桑格测序，评估种间和种内变异性。对两个物种以及其他吸虫的对齐的部分28S rRNA基因序列进行单基因座系统发育分析，并将两个物种的线粒体基因串联起来，以评估Orchidasma的分类学亲缘关系。对部分28S rRNA基因序列的分析将O. amphiorchis和O. orchilobata新种置于单睾总科中，并且最接近Deropristidae科的成员裸背斯克里亚宾吸虫（Skrjabinopsolus nudidorsalis）。这与之前将Orchidasma归入斜睾总科中的泰勒科的分类不同。全线粒体基因组测序和系统发育分析得出了相似的拓扑结构，这表明应将Orchidasma修订为Deropristidae科的成员，这一修订得到了与Deropristidae科同属物种共享的形态特征和核苷酸序列数据的支持。
