Orobdella dolichopharynx Nakano, 2011, sp. nov.
Creators: name: Nakano, Takafumi
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Annelida
Clitellata
Arhynchobdellida
Gastrostomobdellidae
Orobdella
Orobdella dolichopharynx

description: Orobdella dolichopharynx sp. nov.
(Figs. 5–7)
Orobdella ijimai: Oka (1910a): 19 (in part); Oka (1910b): 178 (in part).
Diagnosis. In life, dorsal surface yellowish green, ventral surface whitish yellow. Somite VII quadrannulate. Somite VIII quinquannulate. Somites IX–XXV complete sexannulate. Somite XXVI quinquannulate. Pharynx reaching to XVI. Gastropore absent. Gastroporal duct narrow, tubular, not joining with crop. Male gonopore in XI c11/c12 or at anterior of XI c12, close to c11/c12. Female gonopore in XIII b1/b2 or at anterior of XIII b2, close to b1/b2. Gonopores separated by eight annuli. Pre-atrial loop present, extending to ganglion XI. Atrial cornua absent.
Materials examined. Holotype. KUZ Z120, mature specimen of 106.7 mm length, dissected, collected from under fallen leaves along a road at Mt. Yuwandake (alt. 448 m, 28°17´11˝N, 129°18´56˝E), Uken, Amamioshima Island, Kagoshima Pref., Japan, by Takafumi Nakano on April 30, 2010. Paratypes (a total of nine specimens collected from Amamioshima Island in 2009–2010). Six specimens collected from the type locality by Takafumi Nakano: KUZ Z115 (alt. 520 m, 28°17´27˝N, 129°18´58˝E), dissected, on March 6, 2009; KUZ Z116 (alt. 536 m, 28°17´29˝N, 129°19´00˝E), dissected, on March 12, 2009; KUZ Z117 (alt. 440 m, 28°17´06˝N, 129°18´55˝ E), on August 28, 2009; KUZ Z118 (alt. 606 m, 28°17´42˝N, 129°19´06˝E), dissected, on April 27, 2010; KUZ Z119 (alt. 434 m, 28°17´08˝N, 129°18´55˝E), dissected, and KUZ Z121 (alt. 448 m, 28°17´11˝N, 129°18´56˝E), dissected, on April 30, 2010. Three specimens collected from Kinsakubaru, by Masahiro Nishi on July 26, 2010: KUZ Z122, dissected, KUZ Z123 and KUZ Z124.
Etymology. The specific name is a compound noun in apposition derived from the Greek words transliterated into Latin, dolicho (long), and pharynx (pharynx), referring that the pharynx of this new species is reaching to somite XVI (those of the other known Orobdella species in Japanese islands north of the Ryukyu Archipelago are reaching to somite XIV).
Description of holotype. Body firm, muscular, BL 106.7 mm, BW 6.6 mm (Fig. 5). Caudal sucker ventral, oval, its diameter slightly smaller than maximum body width (Fig. 6 D). In life, dorsal surface yellowish green, ventral surface whitish yellow, dorsal surface darker than ventral surface. Color faded in preservative, without any dark lines.
Somite I completely merged with prostomium (Fig. 6 A). Somite II uniannulate, not separated from I (Fig. 5 A). Somite III uniannulate (Fig. 6 A). Somite IV biannulate (Fig. 6 A). Somite V biannulate, a3 forming posterior margin of oral sucker (Fig. 6 A, B). Somites VI triannulate (Fig. 6 A, B). Somite VII complete quadrannulate, a1 = a2> b5 = b6 (Fig. 6 A, B). Somite VIII complete quinquannulate, a1> a2 = b5> c11 = c12 (Fig. 6 A, B). Somite IX complete sexannulate, b1 <b2 = a2 = b5> c11 = c12. Somites X–XXV complete sexannulate, b1 = b2 = a2 = b5 = c11 = c12 (Fig. 6 C–E, H), X a2 the first annulus of the clitellum, XIII b5 the last annulus of the clitellum. Somite XXVI quinquannulate, b1 = b2 = a2 <b5> b6, b6 the last complete annulus on the venter (Fig. 6 C, D). Somite XXVII incomplete biannulate (Fig. 6 C). Anus behind XXVII (Fig. 6 C). Post-anal annulus absent (Fig. 6 C).
Anterior ganglionic mass in VI a2 and a3. Ganglion VII in a2. Ganglia VIII–XXI in a2 of each somite (Fig. 6 H). Ganglia XXII–XXV in b2 and a2 of each somite. Ganglion XXVI in b1 and b2. Posterior ganglionic mass in XXVI a2–b6.
Eyes three pairs, first pair dorsally in II, second and third pairs dorsolaterally on posterior margin of V (a1 + a2) (Fig. 6 A). Nephridiopores 17 pairs, ventrally at posterior margin of a1 at VIII and b2 of each somite, at IX– XXIV (Fig. 6 B, E). Papillae numerous, minute, hardly visible, one row on every annulus.
Pharynx agnathous, euthylaematous, reaching to XVI b2/a2. Crop tubular, acecate, in XVI b2/a2 to XXII a2. Gastropore absent (Fig. 6 E, G). Gastroporal duct narrow, tubular but slightly bulbous at female gonopore, in XIII b1/b2 to XVI b2, not joining with crop (Fig. 6 F). Intestine tubular, acecate, in XXII a2 to XXIV/XXV. Rectum tubular, thin-walled.
Male gonopore at anterior of XI c12, close to annular furrow of c11/c12 (Fig. 6 E). Female gonopore at anterior of XIII b2, close to annular furrow of b1/b2 (Fig. 6 E, G). Gonopores separated by 8 annuli (Fig. 6 E). Testisacs multiple, two or three testisacs on each side in each annulus, in XVII b5 to XXV b5 (Fig. 6 H). Epididymides absent. Ejaculatory bulbs absent (Fig. 6 H). ejaculatory ducts in XI a2 to XVII a2, coiled, widen from each junction with testisacs, narrow gradually toward each junction with atrium, with pre-atrial loop extending to ganglion XI (Fig. 6 H, I). Atrial cornua absent. Atrium rudimentary in XI c11 and c12 (Fig. 6 H, I). Ovisacs one pair, thin-walled, globular, in XIII a2 (Fig. 6 H, J). Oviduct thin-walled, right oviduct crossing ventrally beneath nerve cord, both oviducts converging into common oviduct in XIII b2 (Fig. 6 H, J). Common oviduct thin-walled, very short, directly descending to female gonopore (Fig. 6 H, J).
Variation. Somite VII triannulate (KUZ Z124) or ventrally triannulate (KUZ Z118, Z122). Somite XXVII incomplete biannulate or triannulate. Clitellum from X b5 to XIII a2–XIV b1. Pharynx reaching to XVI b1–c11. Crop reaching to XXII b1–XXIII b1. Gastroporal duct tends to attach ventral sinus (Fig. 7). Intestine reaching to XXIV c11–XXV b1/b2. Male gonopore in XI c11/c12 or at anterior XI c12. Female gonopore in XIII b1/b2 or at anterior of XIII b2. Testisacs in XVIII b1–XVIII b5 to XXV a2–c11.
Distribution and ecology. Known from the mountain region of Amamioshima Island in the Ryukyu Archipelago, Japan (Fig. 1). Leeches were found under rocks or fallen leaves.
Remarks. Orobdella dolichopharynx was considered to be Orobdella ijimai (Oka 1910a; b). However, O. dolichopharynx is easily distinguished from the latter by the number of annuli between the gonopores.
description: Published as part of Nakano, Takafumi, 2011, Redescription of Orobdella ijimai (Hirudinida: Arhynchobdellida: Gastrostomobdellidae), and two new species of Orobdella from the Ryukyu Archipelago, Japan, pp. 1-15 in Zootaxa 2998 on pages 6-10, DOI: 10.5281/zenodo.207870