Helobdella sorojchi, SIDDALL, 2001

SIDDALL, MARK E., 2001, Hirudinea from the Apolobamba in the Bolivian Andes, Including Three New Species of Helobdella (Clitellata: Hirudinea), American Museum Novitates 3341, pp. 1-15 : 9-11

Helobdella sorojchi , new species

Figures 25–35

HOLOTYPE (figs. 25, 30): Free­living under rocks along the shoreline of lakes in Qanchis Qocha ( Siete Lagunas ) at UU99–20 from 4090 to 4100 m, in Madidi National Park , Departmento La Paz, Bolivia, from 14°44'99"S, 69°02'22"W through 4°45'02"S, 69°02'2"W, 25 October 1999, hand collected by M. Siddall (deposited in Colleccion Boliviana de Fauna, La Paz, Bolivia, uncataloged); body length 11.2 mm maximum length in relaxed state, maximal width 3.5 mm, fixed in 10% formalin, stored in 70% ethanol.

PARATYPES: One dissected adult ( AMNH 4236 , Annelida), three adults (deposited in Colleccion Boliviana de Fauna, La Paz, Bolivia, uncataloged), and three additional adults ( AMNH 4237 , Annelida) with and without broods all fixed in 10% formalin from same locality UU99–20 as above, hand collected by M. Siddall on 25 October 1999. Seven adults (deposited in Colleccion Boliviana de Fauna, La Paz, Bolivia, uncataloged), and six additional adults ( AMNH 4238 , Annelida) with and without broods all fixed in 95% ethanol from same locality UU99–20 as above, hand collected by M. Siddall on 25 October 1999. One adult fixed and stored in 95% ethanol held at ‾80°C ( AMNH 100953 , Frozen Tissue Collection) .

FORM (figs. 25–30): Body thin and lanceolate, occasionally broadened from XVI a3 through XX a3 especially in live state; somites I–V uniannulate, VI–XXIV triannulate, XXV biannulate, XXVI and XXVII uniannulate; dorsum convex, without papilla; venter flat to concave, without papillae; anterior sucker oval; mouth pore terminal (figs. 28, 29); annuli from VIII through XV weakly subdivided (fig. 30); caudal sucker circular, concave, directed subterminal to ventrad in relaxed state, approximately two­thirds of width of posterior somites. There is no chitinoid scute and there are no visible glands. Internally this species has an unusually fibrous appearance due to a large amount of connective tissue.

EYES (fig. 27): One pair, punctiform, well separated, at II/III.

COLOR AND PATTERN (figs. 25, 26, 31): Dorsum uniformly brown with fine paramedial and supramarginal longitudinal lines, others with irregular mottled brown chromatophores. Venter much lighter with smooth paramedial pigmentation.

REPRODUCTIVE SYSTEM (figs. 31–33): Male and female gonopores obvious and separated by one annulus, male at XII a1/a2, female at XII a2/a3; six pairs of testisacs at XIII/XIV through XVIII/XIX; sperm ducts and ovaries reach to XVII/XVIII, however ovaries lie dorsal to sperm ducts (fig. 32) as opposed to the ventral position more typical for the family. Atria piriform directed anteriorly, sperm ducts empty into atria dorsally (fig. 33).

ALIMENTARY TRACT (figs. 34, 35): Proboscis in membranous sheath, base at XIII; salivary cells arranged in a small compact mass only in XIII, ductules of the latter are very short; oesophagus simple, not recurved; six gastric chambers with digitiform caeca in midbody somites including large postcecae (diverticula) from XIX through XXV; intestine from XIX/XX with four lobes; anus at XXVI/XXVII.

ETYMOLOGY: The name is Quechua and stems from the fact that these were found at 4100 m (among the highest collection localities for Andean leeches) after the collectors had to crest a 4700 m pass between Tojoloque and Qanchis Qocha, collect the specimens, and return in under seven hours. Sorojchi or soroche means ‘‘altitude sickness’’. The species name should be pronounced soeroe­chay.

REMARKS: Notwithstanding the variability in external pigmentation for this species, the internal anatomy was the same between speckled and striped varieties. In certain respects H. sorojchi resembles H. nununununojensis . Both are relatively long and thin leeches with widened somites from XVI through XX, with a subterminal to ventrally directed caudal sucker, a large terminal mouth pore, and eyes at II/III. Helobdella sorojchi , however is unique among leeches in having the ovaries overlying the sperm ducts. Helobdella species with subdivided annuli but without a nuchal scute or glands include Helobdella cordobensis (see Ringuelet, 1943), Helobdella auricana (see Ringuelet, 1978a), and Helobdella longicollis (see Weber, 1915). Weber’s (1915) figure of H. longicollis , however, shows a highly coiled proboscis and a very long thin neck with a broader cephalic region, not unlike a piscicolid; and its gonopores are on the annuli, not in furrows. Helobdella cordobensis and H. auricana each have diffuse salivary tissue ( Ringuelet, 1943, 1978a) and neither has the ovisacs overlying the descending portions of sperm ducts.

Figures

Figs. 25–35. Helobdella sorojchi, n. sp. 25. Lateral view of the holotype with a finely striped surface. 26. Dorsal surface of a paratype with a more speckled appearance. 27. Cephalic region of an adult exhibiting eyes at margin of II/III. 28. Anterior view of the oral sucker with terminal mouth pore on leading margin. 29. Lateral view of a specimen with proboscis protruding from terminal mouth pore. 30. Dorsal surface of the holotype showing weak subdivisions (arrowheads) of midbody annuli. 31. Ventral surface of an adult with prominent male (m) and female (f) gonopores and paramedial pigmentation pattern. 32. Median reproductive apparatus with the atria (*) removed, ovaries (o) extending to XVII/XVIII, and in which the descending sperm ducts (arrowhead) loop underneath the ovaries along the ventral muscle layer. 33. Dorsoposterior view of male atria. 34. Proboscis (p) and small compact salivary glands (arrowheads). 35. Posterior digestive system with five gastric caeca (g) including large postcaeca (arrowhead) lateral to four pairs of intestinal caeca (i).