A New Genus and Five New Species of Kalyptorhynchia (Platyhelminthes: Rhabdocoela) Discovered in Northern Japan Author Takeda, Naoya Marine Biological Research Institute of Japan, Yutaka-cho 4 - 3 - 16, Shinagawa, Tokyo 142 - 0042, Japan E-mail: bobamo 0 @ gmail. com & Corresponding author bobamo0@gmail.com Author Kajihara, Hiroshi Faculty of Science, Hokkaido University, Sapporo, Hokkaido 060 - 0810, Japan text Species Diversity 2018 2018-05-25 23 1 1 11 http://dx.doi.org/10.12782/specdiv.23.1 journal article 4217 10.12782/specdiv.23.1 f1ac74c9-df4b-4402-a43b-e06abb6e8164 2189-7301 4583800 A9B333A2-FD81-476A-A805-D280C2194964 Proschizorhynchella shibazakii sp. nov. ( Figs 10–14 ; Table 1 ) Material examined. Holotype : ICHUM 4275 , adult, whole mount, 43°12′33″N , 140°51′31″E , Oshoro , Hokkaido , Japan , intertidal sand, 13 June 2011 . Paratypes : ICHUM 4276–4278, three adults, whole mounts, same data as holotype ; ICHUM 4279, 4280, two adults, serial sagittal sections, same data as holotype ; ICHUM 4281, 4282, two adults, serial transverse sections, same data as holotype ; ICHUM 4283, one adult, whole mount, type locality, 21 May 2012 ; ICHUM 4861, egg, whole mount, laid by animals collected on 1 July 2013 . Description. Living animal body approximately 2.6 mm long and 0.5 mm wide ( Figs 10 , 11A ). Four pairs of bristles located at slender anterior tip of body ( Figs 10 , 11C ). Proboscis 350 µm long, 120 µm wide; pair of proboscis glands 140 µm long, 80 µm wide ( Fig. 10 ). Pair of black eyes situated anterior to brain ( Figs 10 , 11C ). Gut anteroposteriorly elongated. Two testes 300–330 µm in diameter ( Figs 10 , 11C ). Pair of yolk glands 1 mm long, 180 µm wide ( Figs 10 , 11A ). Pharynx 480 µm long, 330 µm wide ( Figs 10 , 11A ). Two adhesive girdles present; anterior one located at level of posterior end of pharynx, posterior one near caudal end; each girdle comprised of six adhesive papillae arranged in regular intervals ( Figs 10 , 11B ). Pair of seminal vesicles, each 620 µm long, 60 µm wide, located posterior to pharynx ( Fig. 10 ). Male copulatory organ tubular in shape, 240 µm long, 30 µm wide, with ejaculatory duct surrounded by circular muscles and further surrounded by longitudinal muscles ( Figs 10 , 12A, B , 13 ); copulatory organ tapering toward its tip, equipped with stylet and situated in male genital canal. Stylet cone shaped, 29–31 µm long ( 31 µm in holotype ), 7 µm wide, comprised of thin sclerotic sheet rolled up three times ( Fig. 12C, D ). Male genital canal opens to anterodorsal part of common atrium of the latter ( Fig. 13 ). Uterus 90 µm long, 30 µm wide, anterior to common atrium ( Figs 10 , 13 ). Each yolk gland connected to each side of common atrium ( Figs 10 , 13 ). Common genital pore opening on ventral side of body between two adhesive girdles ( Figs 10 , 13 ). Ovary 110 µm long, 70 µm wide, anteriorly connected to posterodorsal portion of common atrium via a common oviduct ( Figs 10 , 13 ). Bursa oval in dorsal view, 250 µm long, 150 µm wide; bursal tissue divided into two (smaller anterior and larger posterior) parts by constriction; spermatids observed in posterior bursal tissue in all specimens observed; anterior bursal tissue leading forward to connect to common oviduct near ovary via narrow sperm duct ( Figs 10 , 13 ). Egg oval, 260 µm long, 200 µm wide, covered in brown shell with colorless axis ( Fig. 14 ). Fig. 10. Proschizorhynchella shibazakii sp. nov. Schematic representation of the body to show the organization of various organs. A. Dorsal view; B. Ventral view. Abbreviations: ap, adhesive papilla; b, bursa; br, brain; bri, bristle; c, male copulatory organ; ca, common atrium; cp, common genital pore; e, eye; iv, internal vagina; m, mouth; g, gut; o, ovary; p, proboscis; pg, proboscis gland sac; ph, pharynx; st, stylet; sv, seminal vesicle; t, testis; u, uterus; y, yolk gland. Etymology. The specific name is a noun in the genitive case, derived from the name Mr. Kouji Shibazaki, a caretaker of Oshoro Marine Station, Hokkaido University. Fig. 11. Proschizorhynchella shibazakii sp. nov. A. Entire animal in an elongated state, ICHUM 4283 (paratype); B. Same animal in a contracted state, ICHUM 4283 (paratype); C. Photomicrograph showing the anterior part of a specimen (no voucher remains). Abbreviations: ap, adhesive papilla; bri, bristle; e, eye; g, gut; p, proboscis; ph, pharynx; t, testis; y, yolk gland. Fig. 13. Proschizorhynchella shibazakii sp. nov. Schematic diagram of genital organs in lateral view. Abbreviations: b, bursa; c, male copulatory organ; ca, common atrium; cm, circular muscle; co, common oviduct; cp, common genital pore; ed, ejaculatory duct; iv, internal vagina; lm, longitudinal muscle; mc, male genital canal; o, ovary; sd, sperm duct; st, stylet; u, uterus; y, yolk gland. Fig. 12. Proschizorhynchella shibazakii sp. nov. A. Male copulatory organ, ICHUM 4275 (holotype); B. Transverse section of male copulatory organ, ICHUM 4282 (paratype); C. Stylet, ICHUM 4276 (paratype); D. Stylet, schematic diagram of transverse section through the region indicated by the arrowheads in C. Abbreviations: cm, circular muscle; ed, ejaculatory duct; lm, longitudinal muscle; st, stylet. Remarks. Proschizorhynchella shibazakii can be distinguished from all congeners based on the characteristics listed in Table 1 except P. papillata . These two species, however, can be distinguished based on the shape of the male copulatory organ. The differences in morphological characteristics between P. shibazakii sp. nov. and P. papillata are ( i ) the number of the apical sensory bristles, which is eight in P. shibazakii and four in P. papillata ; ( ii ) the male copulatory organ, which is narrow and tubular in P. shibazakii , and bulb shaped in P. papillata ; ( iii ) the internal part of the circular muscles, which is thin in P. shibazakii but thick in P. papillata ; ( iv ) the border cells which are present in P. shibazakii but absent in P. papillata ; and ( v ) the length of the stylet, which is 29–31 µm ( 31 µm in holotype ) in P. shibazakii and 55–57 µm in P. papillata . Proschizorhynchella shibazakii cannot be distinguished from P. caudociliata based on the characteristics listed in Table 1 ; however, they differ in the structure of the copulatory stylet (see Remarks for P. caudociliata ).