Helobdella ringueleti, 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 : 4

Helobdella ringueleti , new species

Figures 5–15

HOLOTYPE (figs. 5–7, 9, 10): Free­living from pond above cataract (fig. 1) in Valle Tojoloque at 3860 m, in Madidi National Park , Departmento La Paz, Bolivia, 14°44'30"S, 69°01'26"W, 21 October 1999, station number UU99–11, hand collected by M. Siddall; (deposited in Colleccion Boliviana de Fauna, La Paz, Bolivia, uncataloged); body length 33.8 mm, maximal width 5.7 mm, fixed in 10% formalin, stored in 70% ethanol.

PARATYPES (figs. 8, 11–15): One dissected adult and 3 juveniles taken from venter of the dissected adult both fixed in 95% ethanol from same locality UU99–11 as above, hand collected by M. Siddall on 23 October 1999, ( AMNH 4230 , Annelida, and AMNH 4231 , Annelida). One juvenile also fixed and stored in 95% ethanol held at ‾80°C ( AMNH 100948 , Frozen Tissue Collection) .

FORM (figs. 5–10): Body robust and lanceolate, broadest in posterior half; somites I through VI a2 demarcated in some adults (fig. 7); somites I–IV uniannulate, V biannulate, VI–XXV triannulate, XXVI biannulate, and XXVII uniannulate but broad; all annuli from VII a1 through XXVII subdivided dorsally (fig. 9) though less regularly ventrally; dorsum convex, without papillae; venter flat to slightly convex, never concave, without papillae; anterior sucker triangular to ovoid (fig. 6); mouth pore large subterminal, not central; caudal sucker circular, concave, directed subterminal in relaxed state, approximately same width as posterior somites; middorsal nuchal glands (fig. 7) at VIII a1/ a2 with tawny­brown secretion, chitinoid scute absent or at least not pronounced, nuchal glands not obvious in juveniles.

EYES (figs. 7, 8): One pair, punctiform, well separated, in III.

COLOR AND PATTERN (figs. 5–10): Anterior margin of oral sucker (I, II) unpigmented; dorsum gray to light brown with randomly arranged chromatophores; three pairs of fine supramarginal lines (fig. 8) dorsally from VIII through XXIV or XXV, most obvious in juveniles; venter lighter than dorsum in postgenital somites; three pairs of fine inframarginal lines (figs. 6, 10) from VIII through XXIV or XXV corresponding to those seen dorsally. Caudal sucker evenly pigmented.

REPRODUCTIVE SYSTEM (figs. 10–15): Male and female gonopores separated by one annulus (fig. 10), male at XII a1/a2, female at XII a2/a3; six pairs of testisacs (fig. 15) at XIII/XIV through XVIII/XIX; sperm ducts highly convoluted in XIV and XV (fig. 11), atria piriform directed laterally (figs. 11, 12), sperm ducts empty into atria anterioventrally with preatrial cornua (fig. 12); ovisacs short, in XII only, and folded (fig. 13).

ALIMENTARY TRACT (figs. 14, 15): Proboscis in membranous sheath and very long, base at XIV/XV and coiled when retracted (fig. 14); salivary cells arranged diffusely in parenchyma, ductules of the latter forming a bundle inserting into the base of the proboscis; oesophagus simple, not recurved; no gastric chambers or digitiform caeca in midbody somites, only postcaeca (diverticula) from XIX through XXIV (fig. 15); intestine from XIX/XX with four lobes; anus at XXVI/ XXVII.

ETYMOLOGY: Named for Raul Ringuelet of the Museo de La Plata, Argentina, who contributed impressively to our knowledge of South American leeches from 1936 through 1986, in particular describing or redescribing approximately half of the known species of Helobdella . The species name should be pronounced rin­geh­let­eye.

REMARKS: There are seven species of Helobdella in South America possessing the ‘‘chitinoid’’ plaque at VIII a1/a2: Helobdella scutifera (see Blanchard, 1900), Helobdella simplex (see Moore, 1911), Helobdella festai (see Dequal, 1916), Helobdella godeti (see Weber, 1916b), Helobdella adiastola (see Ringuelet, 1972), Helobdella xenoica (see Ringuelet, 1975), and Helobdella bolivianita (see Siddall, 2001). Helobdella ringueleti does not exhibit a plaque like the foregoing, but it does have the nuchal glandular region on VIII a1 which is more obvious in adults. This is not unlike plaqueless glands reported for Helobdella diploides , Helobdella duplicata , and Helobdella lineata . From the latter two, both reported originally from Patagonia ( Moore, 1911), H. ringueleti is easily distinguished in that H. duplicata has pronounced metameric banding on a1 of midbody somites and H. lineata has a single middorsal row of obvious papillae ( Moore, 1911). Differences between H. ringueleti and H. diploides from Paraguay are more subtle and the two are probably closely related. Both species have a simple ovoid nuchal gland region on VIII a1, folded ovaries, the convoluted sperm ducts in XIII through XIV, and both have subdivided annuli from VII to the posterior somites ( Ringuelet, 1948). However, Helobdella diploides is a very small species without any obvious external pigmentation pattern like the supramarginal and inframarginal lines seen in H. ringueleti . Moreover, Helobdella diploides lacks the very large proboscis of H. ringueleti and has six pairs of gastric caeca unlike the unbranched tube in H. ringueleti . Absence of gastric caeca is more a characteristic of H. elongata , H. michaelseni , H. ampullariae , and H. similis placed collectively in the genus Gloiobdella by Ringuelet (1978b; see also Sawyer, 1986).

Figures

Figs. 5–15. Helobdella ringueleti, n. sp. 5. Dorsal surface of the holotype. 6. Ventral surface of the holotype. 7. Cephalic region of the holotype showing constriction at VI a2/a3 (arrowheads) and nuchal gland at VII a1 (arrow). 8. Anterior dorsal surface of a juvenile found attached to an adult. 9. Dorsum of the holotype exhibiting subdivision of midbody annuli (arrowheads). 10. Clitellar region of the holotype with male (m) and female (f) gonopores separated by one annulus. 11. Male median reproductive apparatus with laterally deployed atria (a) and sperm ducts arranged in XIII and XIV. 12. Male median reproductive apparatus dissected away from the adult and viewed from anterior to the male gonopore (m) illustrating the preatrial cornua (arrowheads) of the sperm ducts. 13. Folded ovary (o) and thinner oviducts (arrowheads) in XIII. 14. Anterior digestive system showing the long coiled proboscis (p), salivary ductules (arrowheads), and gastric tube lacking caeca (g). 15. Posterior digestive system with unbranched gastric tube (g) and two postcaeca (white arrowheads); black arrowheads = testisacs.