De leÓn Rodrigo Ponce, Volonterio Odile
Sección Zoología de Invertebrados, Facultad de Ciencias, Universidad de la República, Iguá 4225, Montevideo 11400, Uruguay..
Zootaxa. 2018 Feb 8;4378(3):323-336. doi: 10.11646/zootaxa.4378.3.2.
Three species of Temnocephala have been reported on Aegla from Uruguay: Temnocephala axenos, Temnocephala mertoni and Temnocephala talicei. As part of a systematic review of the Uruguayan species of Temnocephala, a fourth species was found on Aegla platensis and Aegla uruguayana. This species, new for the genus, has the following diagnostic characters: Large temnocephalan; slightly curved penial stylet (225 µm in length) with a symmetrical introvert (27 long by 18 µm in diameter) that has at least 44 spine-like projections, each bearing 7 rows of internal spines; a seminal vesicle that opens sub-polarly into the contractile vesicle; a muscular vagina with a strong asymmetrical sphincter; preequatorial nephridiopores close to the internal borders of the elongate-oval excretory syncytia; a large pharynx with anterior and posterior sphincters of about the same diameter and a narrow pharyngeal lumen with nearly uniform width. To contemplate the characters of the pharynx, an amendment of the genus Temnocephala is given. The new species resembles Temnocephala cyanoglandula, which also has a very long, slightly curved penial stylet, but differs from it by having a shorter penial stylet, a lower number of rows of spines in the introvert, a larger, different type of pharynx, a smaller contractile vesicle and a larger sucker. The new species is carnivorous and feeds on whole preys, which are mainly annelids (Stratiodrilus) and other species of Temnocephala. The new species was found to be hyperparasitised by plerocercoid and nematode larvae, but hyperparasites were not found in the other sympatric species of Temnocephala. Based on the findings presented here, it is clear that detailed histological descriptions of the pharynx should be contemplated as part of the normal work in taxonomy of temnocephalans.
据报道，在乌拉圭的溪蟹（Aegla）上发现了三种头吻虫属（Temnocephala）物种：异形头吻虫（Temnocephala axenos）、默氏头吻虫（Temnocephala mertoni）和塔利塞头吻虫（Temnocephala talicei）。作为对乌拉圭头吻虫属物种进行系统综述的一部分，在普拉滕斯溪蟹（Aegla platensis）和乌拉圭溪蟹（Aegla uruguayana）上发现了第四个物种。这个对该属来说是新的物种具有以下诊断特征：大型头吻虫；阴茎针略微弯曲（长225微米），具有对称的内翻部分（长27微米，直径18微米），该内翻部分至少有44个棘状突起，每个突起带有7排内部棘；精囊亚极地开口于收缩泡；肌肉质阴道具有强大的不对称括约肌；赤道前肾孔靠近细长椭圆形排泄合胞体的内边界；大咽，前后括约肌直径大致相同，咽腔狭窄，宽度几乎均匀。为了考虑咽的特征，对头吻虫属进行了修订。新物种类似于蓝腺头吻虫（Temnocephala cyanoglandula），后者也有非常长且略微弯曲的阴茎针，但与之不同的是，新物种的阴茎针较短，内翻部分的棘排数较少，咽更大且类型不同，收缩泡较小，吸盘较大。新物种是肉食性的，以整个猎物为食，主要是环节动物（Stratiodrilus）和其他头吻虫属物种。发现新物种被裂头蚴和线虫幼虫高度寄生，但在其他同域分布的头吻虫属物种中未发现高度寄生虫。基于此处呈现的研究结果，很明显，咽的详细组织学描述应被视为头吻虫分类学正常工作的一部分。
