Hanselman Katherine M, Gobiraj Ramajeyam, Jensen Kirsten
J Parasitol. 2025 Sep 10;111(5):582-605. doi: 10.1645/24-92.
The genus Flapocephalus Deshmukh, 1979, is a little-known group of lecanicephalidean cestodes parasitizing cowtail rays (genus Pastinachus Rüppell) mainly in the Indo-Pacific region. Since the erection of the genus, with Flapocephalus trygonis Deshmukh, 1979, as the type species, and the description of a second species, Flapocephalus saurashtri Shinde and Deshmukh, 1979, both from Pastinachus sephen (Fabricius) from India, reports of this genus have been restricted mainly to brief mentions or discussion of its validity and taxonomic placement. More recently, phylogenetic analyses based on molecular sequence data that included specimens of Flapocephalus have supported Flapocephalus as a distinct genus allied with the Polypocephalidae Meggitt, 1924. Limited by the amount of detail provided in the original descriptions, the unavailability of type material, and the lack of a detailed generic diagnosis, we aimed to fully characterize the genus based on newly collected specimens. A total of 38 specimens of Pastinachus, representing 3 of the 5 described species and 1 undescribed species, from throughout the Indo-Pacific region were examined for specimens of Flapocephalus. Worms were prepared for examination with light and scanning electron microscopy and as histological sections. A subset of specimens was included in a phylogenetic analysis based on data for a portion of the 28S rDNA gene. Overall, these specimens were found to include the type species, 4 new species that are described herein (Flapocephalus monostylorchis Hanselman and Jensen n. sp., Flapocephalus capitonis Hanselman and Jensen n. sp., Flapocephalus rudkinorum Hanselman and Jensen n. sp., and Flapocephalus infundibulapex Hanselman and Jensen n. sp.), and 4 putative new species. Flapocephalus trygonis is redescribed from specimens from Pastinachus ater (Macleay) from Sri Lanka, and a neotype is designated. The newly described species are distinct genetically and can be distinguished morphologically from the existing species and one another based on a combination of total length, the shape of the apical organ, and the arrangement of testes and vitelline follicles. A revised diagnosis of the genus and a key to the described species are presented, as is a hypothesis of the interrelationships resulting from a maximum likelihood analysis including 4 of the 5 described species and the 4 putative new species. The presence of 4 glandular, sac-like structures surrounded by scolex proper, with channels that open to the outside at the base of the apical organ, is reported in lecanicephalidean tapeworms for the first time.
弗拉波头虫属（Deshmukh，1979年）是一组鲜为人知的勒卡尼头科绦虫，主要寄生于印度洋-太平洋地区的牛尾魟（Pastinachus Rüppell属）。自该属建立以来，以1979年的三角弗拉波头虫（Flapocephalus trygonis Deshmukh）为模式种，并描述了第二个物种，即1979年来自印度的斯蒂芬牛尾魟（Pastinachus sephen (Fabricius)）的萨拉斯赫特拉弗拉波头虫（Flapocephalus saurashtri Shinde和Deshmukh），该属的报告主要限于简短提及或对其有效性和分类地位的讨论。最近，基于分子序列数据的系统发育分析（其中包括弗拉波头虫属的标本）支持弗拉波头虫属是与1924年的多线头虫科（Polypocephalidae Meggitt）相关的一个独特属。由于原始描述中提供的细节有限、模式标本不可用以及缺乏详细的属诊断，我们旨在根据新收集的标本对该属进行全面描述。对来自印度洋-太平洋地区的38个牛尾魟标本（代表已描述的5个物种中的3个以及1个未描述的物种）进行检查，以寻找弗拉波头虫属的标本。将虫体制成标本，用于光学显微镜和扫描电子显微镜检查以及组织切片。一部分标本被纳入基于28S rDNA基因部分数据的系统发育分析。总体而言，这些标本包括模式种、本文描述的4个新物种（单茎弗拉波头虫（Flapocephalus monostylorchis Hanselman和Jensen新种）、卡皮托弗拉波头虫（Flapocephalus capitonis Hanselman和Jensen新种）、鲁德金弗拉波头虫（Flapocephalus rudkinorum Hanselman和Jensen新种）以及漏斗尖弗拉波头虫（Flapocephalus infundibulapex Hanselman和Jensen新种））和4个假定的新物种。从斯里兰卡的黑牛尾魟（Pastinachus ater (Macleay)）标本中重新描述了三角弗拉波头虫，并指定了一个新模标本。新描述的物种在基因上是不同的，并且可以根据全长、顶端器官的形状以及睾丸和卵黄滤泡的排列组合，在形态上与现有物种以及彼此区分开来。给出了该属的修订诊断和已描述物种的检索表，以及包括已描述的5个物种中的4个和4个假定新物种的最大似然分析所产生的相互关系假说。首次报道在勒卡尼头科绦虫中存在4个被固有头节包围的腺状囊状结构，其通道在顶端器官基部通向外部。
