Queiroz Murilo S, Alves Philippe V, López-Hernández Danimar, Anjos Luciano A, Pinto Hudson A
Instituto de Biociências de Botucatu, Universidade Estadual Paulista, Postal Code 18618-970, Botucatu, SP, Brazil.
Departmento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, P.O. Box 486, Postal Code 31270-901, Belo Horizonte, MG, Brazil.
Parasitology. 2021 Jun;148(7):798-808. doi: 10.1017/S0031182021000330. Epub 2021 Feb 17.
Amphistome species belonging to the genus Catadiscus are poorly studied intestinal trematodes found primarily in Neotropical anurans. Herein, developmental stages of an amphistome species found during herpetological and malacological surveys in a temporary marsh pond from Brazil were subjected to morphological (light and scanning electron microscopy) and molecular analyses. Adult parasites recovered from anurans were identified as Catadiscus marinholutzi. Amphistome cercariae found in the planorbid snails Drepanotrema depressissimum and Drepanotrema lucidum from the same waterbody were used for experimental and molecular studies. Immature parasites, morphologically compatible with members of Catadiscus, were experimentally obtained in laboratory-reared tadpoles. Sequencing of a partial region of 28S rDNA gene of both adult and cercariae revealed 100% similarity between these developmental stages, confirming their conspecificity. Phylogenetic analyses were attempted for the first time to reveal the position of a species of Catadiscus in the superfamily Paramphistomoidea. Catadiscus marinholutzi falls in a virtual polytomy together with other paramphistomoids, which leaves its phylogenetic relationships within the group unclear. Moreover, the high genetic divergence to Diplodiscus spp. (10.06–10.84%) cast doubts on the placement of Catadiscus within Diplodiscidae. Hence the species composition of the Diplodiscidae should be re-evaluated in further studies using a broader spectrum of related taxa.
属于卡塔盘属（Catadiscus）的双口吸虫种类是研究较少的肠道吸虫，主要发现于新热带区的无尾两栖类动物体内。在此，对在巴西一个临时沼泽池塘进行的爬虫学和贝类学调查中发现的一种双口吸虫的发育阶段进行了形态学（光学显微镜和扫描电子显微镜）及分子分析。从无尾两栖类动物体内采集到的成年寄生虫被鉴定为马林霍卢茨卡塔盘吸虫（Catadiscus marinholutzi）。在同一水体的扁卷螺属（Drepanotrema）的凹陷扁卷螺（Drepanotrema depressissimum）和透明扁卷螺（Drepanotrema lucidum）中发现的双口吸虫尾蚴用于实验和分子研究。在实验室饲养的蝌蚪中通过实验获得了形态上与卡塔盘属成员相符的未成熟寄生虫。对成年寄生虫和尾蚴的28S rDNA基因部分区域进行测序，结果显示这些发育阶段之间有100%的相似性，证实了它们属于同一种。首次尝试进行系统发育分析以揭示卡塔盘属一个物种在双口吸虫超科（Paramphistomoidea）中的位置。马林霍卢茨卡塔盘吸虫与其他双口吸虫类一起处于一个虚拟的多分支状态，这使得它在该类群中的系统发育关系尚不清楚。此外，与双盘属（Diplodiscus）物种的高遗传差异（10.06 - 10.84%）让人对卡塔盘属在双盘科（Diplodiscidae）中的分类位置产生怀疑。因此，在进一步研究中应使用更广泛的相关分类单元重新评估双盘科的物种组成。
