Southeastern Cooperative Fish Parasite and Disease Laboratory, School of Fisheries, Aquaculture, and Aquatic Sciences, College of Agriculture, Auburn University, 559 Devall Drive, Auburn, Al, 36849, USA.
Unit for Environmental Sciences and Development, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa.
Parasitol Res. 2024 Sep 19;123(9):326. doi: 10.1007/s00436-024-08339-2.
We examined several American alligators, Alligator mississippiensis (Daudin, 1802) (Crocodilia: Alligatoridae) from Louisiana, Alabama, and South Carolina in August 2022. The intestine of one alligator from Alabama was infected by Dracovermis occidentalis Brooks and Overstreet, 1978 (Platyhelminthes: Digenea: Liolopidae Odhner, 1912), a seldom collected and incompletely described trematode that lacks a representative nucleotide sequence. Liolopidae comprises 5 genera and 15 species: Liolope spp. infect giant salamanders; Helicotrema spp. infect turtles and lizards; Harmotrema spp. infect snakes; Paraharmotrema spp. infect turtles; and Dracovermis spp. infect crocodilians. Based on our study of the newly collected specimens and the holotype of D. occidentalis, we redescribe D. occidentalis, correct errors in its original description, and provide an updated phylogeny for Liolopidae that, for the first time, includes Dracovermis Brooks and Overstreet, 1978. Our specimens were identified as D. occidentalis by having testes in the posterior 1/3 of the body, a pretesticular cirrus sac, a spined and eversible cirrus, a bipartite seminal vesicle, and a post-acetabular vitellarium. A phylogenetic analysis of the D1-D3 domains of the nuclear large subunit ribosomal DNA (28S) recovered Liolopidae as monophyletic; however, low taxon sampling in the group precludes hypothesis-testing about liolopid-vertebrate cophyly. This is the first collection for morphological study of the type species for Dracovermis since the genus was proposed 46 years ago, the first record of a liolopid from Alabama, and the first phylogenetic analysis that includes Dracovermis.
我们于 2022 年 8 月检查了来自路易斯安那州、阿拉巴马州和南卡罗来纳州的几只美洲短吻鳄，即密西西比短吻鳄（Alligator mississippiensis）（鳄形目：鳄科）。来自阿拉巴马州的一只短吻鳄的肠道感染了西方旋尾线虫（Dracovermis occidentalis），这是一种少见且描述不完整的吸虫，缺乏代表性的核苷酸序列。旋尾科（Liolopidae）由 5 个属和 15 个种组成：Liolope 属感染巨型蝾螈；Helicotrema 属感染龟和蜥蜴；Harmotrema 属感染蛇；Paraharmotrema 属感染龟；Dracovermis 属感染鳄类。基于我们对新收集标本和西方旋尾线虫模式标本的研究，我们重新描述了西方旋尾线虫，纠正了其原始描述中的错误，并提供了旋尾科的更新系统发育，这是首次将 Dracovermis Brooks 和 Overstreet，1978 包括在内。我们的标本被鉴定为西方旋尾线虫，因为它们具有位于身体后 1/3 的睾丸、一个位于睾丸前的环子宫囊、一个有刺可伸缩的环子宫、一个两部分的精囊和一个位于后髋臼的卵黄腺。核大亚基核糖体 DNA（28S）的 D1-D3 结构域的系统发育分析表明旋尾科是单系的；然而，该组的低分类群采样排除了关于旋尾科与脊椎动物共生的假说检验。这是自 46 年前提出 Dracovermis 属以来对该属模式种进行形态学研究的首次收集，是阿拉巴马州旋尾科的首次记录，也是首次包括 Dracovermis 的系统发育分析。
