A new species of Tritetrabdella (Hirudinida: Hirudiniformes: Haemadipsidae) from northern Indochina Author Nakano, Takafumi Author Jeratthitikul, Ekgachai Author Nguyen, Tao Thien Author Panha, Somsak text Raffles Bulletin of Zoology 2016 2016-05-20 64 105 116 journal article 10.5281/zenodo.5354972 2345-7600 5354972 3B918034-7C31-4D51-81AA-E1C06142C38F Tritetrabdella longiducta , new species ( Figs. 2–5 ) Material examined. Holotype : hermaphrodite ( CUMZ 5100 ), dissected, Doi Phuka , Tambon Phu Kha , Nan Province , Thailand (19.201306°, 101.082250°; elevation 1286 m ), coll. Fig. 2. Tritetrabdella longiducta , new species , holotype (CUMZ 5100). A, dorsal view; B, ventral view. Scale bar = 3 mm. Fig. 3. Tritetrabdella longiducta , new species , holotype (CUMZ 5100). A, dorsal view of somites I–VII; B, lateral view of somites I–VII; C, ventral view of somites I–VII; D, dorsal view of somites XXII–XXVII and caudal sucker; E, lateral view of somites XXI–XXVII and caudal sucker; F, ventral view of somites XXI, XXII and caudal sucker. Abbreviations: fr, friction ray; np, nephridiopore; phl, prehensile lobe; ra, respiratory auricle. Scale bars = 1 mm. E. Jeratthitikul, 13 October 2013 . Paratype : hermaphrodite ( VNMN 04733 ), dissected, Ta Co , Sop Cop District , Son La Province , Vietnam (20.96°, 103.6°; elevation 720–920 m ), coll. T . T . Nguyen , 15 September 2014 . Diagnosis. Caudal sucker circular, with 57 friction rays. Somite VII triannulate, somites VIII–XXII quadrannulate, somite XXV uniannulate. Somites XXV–XXVII forming respiratory auricles. Male gonopore in somite XI b5/b6, female gonopore slightly anterior to middle of somite XII b5, gonopores separated by 3 + 1/2 annuli. Jaws trignathous, each jaw without salivary papillae. Paired epididymides in somite XIII b6 to somite XIV a2, occupying more than one full somite; from each epididymal mass, thick sperm ducts reaching to each ejaculatory bulb. Ejaculatory bulbs ellipsoidal, in somite XI b6 to somite XIII a1. Common oviduct length nearly equal with length of vaginal duct. Vaginal sac slightly folded, reaching to somite XIV a1/a2–b5. Description of holotype . Body firm, muscular, with constant width posteriorly, BL 19.7 mm , BW 3.7 mm ( Fig. 2 ). Caudal sucker ventral, elliptical, CL 4.3 mm , CW 2.57 mm ; prehensile lobe undeveloped, not sharply hooked; with 57 friction rays ( Figs. 2B , 3F ). Somite I completely merged with prostomium ( Fig. 3A ). Somite II uniannulate, comprising two paramedian ocular plates with one interocular plate and margins ( Fig. 3A ). Somite III uniannulate, comprising two ocular plates and two interocular plates with median small plates and margins ( Fig. 3A ). Somite IV uniannulate, comprising two ocular plates and four interocular plates with median small plate and margins ( Fig. 3A ). Somite V biannulate, (a1 + a2)> a3, (a1 + a2) comprising two ocular plates and six interocular plates ( Fig. 3A, B ). Somite VI dorsally triannulate/ventrally biannulate, a1 = a2 = a3/(a1 + a2)> a3. Somite V to somite VI (a1 + a2) unite altogether, forming posterior margin of oral sucker ( Fig. 3A–C ). Somite VII triannulate, a1 = a2 = a3 ( Fig. 3A–C ). Somites VIII–XXII quadrannulate, a1 = a2 = b5 = b6 ( Figs. 3D–F , 4A ). Somite XXIII triannulate, a1 = a2 = a3 ( Fig. 3D, E ). Somite XXIV biannulate, (a1 + a2) = a3 ( Fig. 3D, E ). Somites XXV–XXVII uniannulate; ambilateral margins of each of somites XXV–XXVII forming three lobes of one pair of trilobate respiratory auricles, median lobe of somite XXVI smaller than other two lobes ( Fig. 3D, E ). Anus at posterior margin of somite XXVII. Male gonopore in somite XI b5/b6 ( Fig. 4A ). Female gonopore slightly anterior to middle of somite XII b5 ( Fig. 4A ). Gonopores separated by 3 + 1/2 annuli. Anterior ganglionic mass in somite VII a1 and somite VIII a1. Ganglion VII in somite VIII a1 and a2. Ganglion VIII in b5 and b6. Ganglion IX in b5. Ganglia X and XI of each somite, in a2 and b5 ( Fig. 4B ). Ganglion XII in b5. Ganglia XIII–XV of each somite, in a2 and b5 ( Fig. 4B ). Ganglia XVI–XVIII of each somite, in a2 ( Fig. 4B ). Ganglia XIX and XX of each somite, in a2 and b5 ( Fig. 4B ). Ganglion XXI in somite XX b6 and somite XXI a1 ( Fig. 4B ). Ganglion XXII in somite XXI a2 and b5 ( Fig. 4B ). Ganglion XXIII in somite XXII a2 and b5 ( Fig. 4B ). Ganglion XXIV in somite XXIII a1 ( Fig. 4B ). Ganglion XXV in somite XXIII a2 ( Fig. 4B ). Ganglion XXVI in somite XXIII a2 and a3 ( Fig. 4B ). Posterior ganglionic mass in somite XXIII a3 to somite XXV ( Fig. 4B ). Eyes 5 pairs, in parabolic arc; first pair on somite II, second pair on somite III, third pair on somite IV, fourth pair on somite V (a1 + a2), and fifth pair on somite VI a2 ( Fig. 3A, B ). Sensillae developed, one row on every annulus. Furrow pit undetectable. Nephridiopores in 13 pairs, one each situated laterally at posterior margin of a1 of each somite in somites XI–XXIII ( Fig. 3E ). Nephridiopores anterior to somite XI undetectable. Nephridiopores of somite XXIV under respiratory auricles. Each jaw without salivary papillae; monostichodont, number of teeth of each jaw uncounted. Pharynx reaching to somite VIII/somite IX. Crop reaching to somite XIX b6–somite XX a2, bearing 10 pairs of crop caeca: first pair in somite X b6 and somite XI a1; second pair in somite XI b5 and b6; third pair in somite XII a2–b6; fourth pair in somite XIII a2–b6; fifth pair in somite XIV a1–b5; sixth pair in somite XV a2–b6; seventh pair in somite XVI a1 and a2; eighth pair in somite XVII a1–b5; ninth pair in somite XVIII a2 and b5; and 10th pair being post-crop caeca, right post-crop caecum in somite XIX a1 to somite XXIV (a1 + a2), left post-crop caecum in somite XIX a1 to somite XXII b6. Intestine reaching to somite XXIII a1–somite XXIV (a1 + a2). Rectum simple, tubular. Testisacs nine pairs with an additional sac on left side: first pair, right testisac in somite XIII b6 and somite XIV a1, left testisac in somite XIV a1; second pair, right sac in somite XIV b6 and somite XV a1, left sac in somite XV a1 and a2; third pair in somite XV b5 to somite XVI a1; fourth pair in somite XVI b5 and b6; fifth pair, right sac in somite XVII b5 to somite XVIII a1, left sac in somite XVII a2–b6; sixth pair, right sac in somite XVIII b5 to somite XIX a1, left sac in somite XVIII b5 and b6; seventh pair in somite XIX a2–b6; eighth pair, right sac in somite XX b5 to somite XXI a1, left sac in somite XX a2–b6; ninth pair, right sac in somite XXI a1–b5, left sac in somite XX b6 to somite XXI a2; and an additional testisac on left side in somite XXI b6 to somite XXII a2 ( Fig. 4B ). Paired epididymides developed; right epididymis in somite XIII b6 to somite XV a1; and left epididymis in somite XIV a1 to somite XV a2; from each epididymal mass, thick sperm ducts reaching to each ejaculatory bulb ( Fig. 4B–D ). Ejaculatory bulbs developed, ellipsoidal; right bulb in somite XI b6 to somite XII b5; and left bulb in somite XI b6 to somite XII a2 ( Fig. 4B–D ). Ejaculatory ducts narrow, running inward toward male atrium in somite XI b5; left ejaculatory duct crossing ventrally beneath nerve cord ( Fig. 4C, D ). Male atrium globular in somite XI b5 and b6 ( Fig. 4B–D ). Paired ovisacs globular, in somite XII b5 to somite XIII a1 ( Fig. 4B, E, F ). Oviducts short; left oviduct crossing ventrally beneath nerve cord; both oviducts converging into common oviduct in somite XII b6 ( Fig. 4E, F ). Common oviduct descending to female vaginal sac in somite XII b6 to somite XIII a1/a2 ( Fig. 4E, F ). Vaginal sac slightly folded, reaching to somite XIV a1/a2 ( Fig. 4B, E, F ). Vaginal duct from somite XIII a2 to somite XII b5, directly descending to female gonopore ( Fig. 4E, F ). Fig. 4. Tritetrabdella longiducta , new species , holotype (CUMZ 5100). A, ventral view of somites XI and XII; B, dorsal view of reproductive system including ventral nervous system; C, dorsal view of male median reproductive system including positions of ganglia XI–XV; D, left lateral view of schematic drawing of male median reproductive system; E, dorsal view of female reproductive system including positions of ganglia XII–XIV; F, left lateral view of schematic drawing of female reproductive system. Abbreviations: at, atrium; cod, common oviduct; eb, ejaculatory bulb; ed, ejaculatory duct; ep, epididymis; fg, female gonopore; mg, male gonopore; od, oviduct; ov, ovisac; ts, testisac; vd, vaginal duct; vs, vaginal sac. Scale bars = 0.5 mm [A, E]; 1 mm [B, C]. Variation. BL 8.5 mm , BW 2.7 mm , CL 2.8 mm , CW 2.6 mm . Somite III uniannulate, comprising two ocular plates and three interocular plates with median small plates and margins. Somite IV uninnaulte, comprising two ocular plates and five interocular plates with margins. Somite V biannulate, (a1 + a2) = a3, (a1 + a2) comprising two ocular plates and eight interocular plates. Nephridiopores in somites IX and X detected. Male gonopore in somite XI b5/b6. Female gonopore in anterior margin of somite XII b5. Gonopores separated by 3 annuli at least. Paired epididymides; right epididymis in somite XIV b5 to somite XVI a1; and left epididymis in somite XIV b6 to somite XVI a2. Ejaculatory bulbs; right bulb in somite XII a2–b5; and left bulb in somite XII a2 to somite XIII a1. Paired ovisacs; right ovisac in somite XII b5 to somite XIII a1; left ovisac somite XII b5 and b6. Oviducts; right oviduct crossing ventrally beneath nerve cord. Common oviduct descending to female vaginal sac in somite XII b6 to somite XIII b6. Vaginal sac slightly folded, reaching to somite XIV b5. Vaginal duct from somite XIII b6 to somite XII b5. Fig. 5. Tritetrabdella longiducta , new species , holotype (CUMZ 5100). Dorsal view of a live animal. Colouration. In life, dorsal surface yellowish clay with three brown longitudinal stripes with blackish borders; median stripe wider than lateral stripes, with irregular asymmetrical loops expanding toward lateral stripes ( Fig. 5 ); ventral surface paler than dorsal surface. Color faded in preservative, but longitudinal stripes with blackish borders on dorsal surface remain. Distribution. Known only from the type locality and Ta Co, Son La Province in northern Vietnam ( Fig. 1 ). The elevations of the localities were more than 700 m above sea level. The individual from Doi Phuka was found on soil around a decayed banana tree containing very high moisture. Natural history. The hosts are not known because the specimens examined were collected free-living, but are presumed to include amphibians ( Lai & Chen, 2010 ). The Vietnamese individual was collected when it was climbing the third author; therefore, mammals may also be hosts of T . longiducta . Etymology. The specific name is a compound adjective derived from the Latin words, longus (long), and ductus (duct), referring to the fact that the common oviduct of this species nearly equals the length of its vaginal duct, a diagnostic character of the species.