Caira J N, Kuchta R, Desjardins L
Department of Ecology & Evolutionary Biology, 75 N. Eagleville Road, University of Connecticut, Storrs, Connecticut 06269-3043, USA.
J Parasitol. 2010 Dec;96(6):1185-90. doi: 10.1645/GE-2390.1. Epub 2010 Jun 17.
New collections of cestodes from the spiral intestines of catsharks (Carcharhiniformes: Scyliorhinidae) off Taiwan have led to the discovery of a new genus and 2 new species of trypanorhynchs. These taxa are relatively unique among trypanorhynchs in their lack of all elements of the rhyncheal apparatus. The new genus, Nakayacestus n. gen., is considered to belong with Aporhynchus in the Aporhynchidae. In addition to lacking the rhyncheal apparatus, these 2 genera share circum-medullary vitelline follicles, post-ovarian testes, and complex terminal genitalia consisting of accessory, external, and internal seminal vesicles. The 2 genera differ conspicuously in spinithrix configuration; whereas both species of Nakayacestus n. gen. bear scolex spinitriches that are bifid, trifid, or pectinate, species of Aporhynchus either lack scolex spinitriches entirely or possess spathulate spinitriches. The configuration of the bothria of the 2 genera also differ conspicuously. Whereas the bothria of Aporhynchus are sessile and generally do not extend beyond the lateral margins of the cephalic peduncle, those of Nakayacestus bear only a tenuous connection with the scolex proper, being conspicuously free both anteriorly and posteriorly and extending conspicuously beyond the cephalic peduncle. Futhermore, the boundary between the scolex and the strobila of members of the new genus is clearly delineated, whereas this distinction is ill-defined in species of Aporhynchus. Nakayacestus takahashii n. sp., the type of the new genus, was collected from the Broadmouth catshark, Apristurus macrostomus, and differs from Nakayacestus tanyderus n. sp., collected from the Blacktip sawtail catshark, Galeus sauteri, in being shorter, bearing a longer pedunculus scolecis, an ovary that is more posterior in the proglottid, and fewer post-ovarian testes. Furthermore, the 2 new species differ conspicuously from one another in the configuration of their scolex spinitriches.
对台湾附近猫鲨（真鲨目：猫鲨科）螺旋肠内新采集的绦虫进行研究，发现了一个新属和2种新的三崎科绦虫。这些分类单元在三崎科绦虫中相对独特，因为它们缺少吻部器官的所有组成部分。新属中井绦虫属（Nakayacestus n. gen.）被认为与无吻绦虫属同属无吻绦虫科。除了缺少吻部器官外，这两个属还都有围绕髓质的卵黄滤泡、卵巢后的睾丸，以及由附属、外部和内部精囊组成的复杂的末端生殖器。这两个属在棘状突形态上有明显差异；中井绦虫属的两个物种都有双歧、三歧或栉状的头节棘状突，而无吻绦虫属的物种要么完全没有头节棘状突，要么有匙状棘状突。这两个属的吸沟形态也有明显差异。无吻绦虫属的吸沟是固着的，通常不超出头部柄节的侧缘，而中井绦虫属的吸沟与头节本体仅有微弱连接，在前后都明显游离，且明显超出头部柄节。此外，新属成员的头节与节片之间的界限清晰，而在无吻绦虫属的物种中这种区别不明显。新属的模式种高桥中井绦虫（Nakayacestus takahashii n. sp.）采自宽口猫鲨（Apristurus macrostomus），与采自黑鳍锯尾猫鲨（Galeus sauteri）的长须中井绦虫（Nakayacestus tanyderus n. sp.）不同，前者较短，头节柄较长，节片中卵巢位置更靠后，卵巢后的睾丸较少。此外，这两个新物种在头节棘状突形态上也有明显差异。
