leeches of laguna volcn, bolivia, including a new species of helobdella

P U B L I S H E D B Y T H E A M E R I C A N M U S E U M O F N AT U R A L H I S T O RY

CENTRAL PARK WEST AT 79TH STREET, NEW YORK, NY 10024

Number 3313, 11 pp., 7 figures January 30, 2001

Leeches of Laguna Volcan, Bolivia, Includinga New Species of Helobdella

(Clitellata: Hirudinea)

MARK E. SIDDALL1

ABSTRACT

Three species of leeches were found in Laguna Volcan in Departmento de Santa Cruz,Bolivia. None are known to be sanguivorous. Two of the species found, Semiscolex similisand Helobdella triserialis, are known to be broadly distributed in South America. A newspecies, Helobdella bolivianita, is described. Diagnostic characters for this species include anuchal scute on somite VIII and the possession both of compact salivary glands and of diffuseparenchymal salivary tissue.

INTRODUCTION

The hirudifauna of Bolivia remains essen-tially unstudied. Ringuelet (1953) wrote theonly existing account of leeches in Boliviabased on four specimens mailed to him byProf. Harry Marcus of the University of Co-chabamba, Bolivia. Three of the four speci-mens were identified to species (Helobdelladuplicata, Helobdella obscura, and Semis-colex similis). Later Helobdella titicacensis,originally described from Peru (Ringuelet,1959), and other leeches were listed amongfaunistic samples taken from Lake Titicaca

1 Assistant Curator, Division of Invertebrate Zoology, American Museum of Natural History.

(Dejoux, 1992), but exclusively from theLago Grande on the Peruvian side.

From September through November of1999, the Center for Biodiversity and Con-servation of the American Museum of NaturalHistory conducted faunistic surveys in thehigh Andean portion of Bolivia in collabora-tion with Colleccion Boliviana de Fauna, LaPaz, and another small excursion for aquaticinvertebrates in the lowland under the auspic-es of the Museo de Historia Natural Noel-Kempff Mercado. This study details findingsfrom the latter and constitutes only the secondaccount of leeches in Bolivia.

2 NO. 3313AMERICAN MUSEUM NOVITATES

Fig. 1. Laguna Volcan, Departmento Santa Cruz, Bolivia.

MATERIALS AND METHODS

Leeches were collected in Laguna Volcan(fig. 1), Departmento de Santa Cruz, Bolivia(188079170S, 638389880W) on November 14,1999. Laguna Volcan is situated in red sand-stone foothills of the Bolivian Andes (1100m) and is part of the Rio Grande drainage.Despite its name, it is not a caldera lake andis not in a geologically active area. Leechesfound attached to submerged stems of aquat-ic plants, and on the underside of submergedbranches along the shoreline of the lake wererelaxed with the gradual addition of 50% eth-anol and fixed either in 95% ethanol or in10% formalin.

Examination of external morphology anddissections were accomplished with a NikonSMZ-U stereo microscope with a SPOT-RTdigital camera. Specimens prepared for his-tology were dehydrated through ethanol,cleared with Hemo-D, and infiltrated withParaplast Plus in a Tissue Tek II tissue pro-cessor. Longitudinal sections (5 mm) werestained with Haematoxylin and Eosin/Phlox-ine and examined with an Olympus BX50compound microscope at low power.

ORDER ARHYNCHOBDELLIDABLANCHARD, 1894

SUBORDER HIRUDINIFORMESCABALLERO, 1952

FAMILY HIRUDINIDAEWHITMAN, 1886

SUBFAMILY SEMISCOLESCINAE(SCRIBAN AND AUTRUM, 1934)

Semiscolex similis (Weyenbergh, 1879)Figure 2

MATERIAL EXAMINED: Free-living from La-guna Volcan, Departmento de Santa Cruz,Bolivia, 188079170S, 638389880W, 14 No-vember 1999, hand collected by M. Siddalland C. Specht; determination by M. Siddall.One specimen fixed in 10% formalin, storedin 70% ethanol (AMNH 4220, Annelida);one specimen fixed in 10% formalin, storedin 70% ethanol (Museo de Historia NaturalNoel-Kempff Mercado, Santa Cruz, Bolivia,uncataloged); one specimen fixed and storedin 95% ethanol (AMNH 4221, Annelida);one specimen fixed and stored in 95% etha-nol (Museo de Historia Natural Noel-KempffMercado, Santa Cruz, Bolivia, uncataloged);one specimen fixed and stored in 95% etha-

2001 3SIDDALL: LEECHES OF LAGUNA VOLCAN, BOLIVIA

Fig. 2. Semiscolex similis. (A) Anterior somites with eyes dorsally in II, III, IV, V and VII. (B)Genital region with six annuli (arrows) ventrally between male and female gonopores. (C) Posteriorsomites showing four annuli, three annuli, and one annulus respectively for somites XXV, XXVI, andXXVII.

nol held at 2808C (AMNH 100016, FrozenTissue Collection). The separation of maleand female gonopores by six annuli, presenceof five pairs of eyes (on II, III, IV, V, andVII), somites XXV quadrianulate, XXVI tri-anulate, and XXVII uniannulate, all are con-sistent with descriptions for this species(Weyenbergh, 1879; Cordero, 1937a, 1937b;Ringuelet, 1944a, 1944b).

ORDER RHYNCHOBDELLIDABLANCHARD, 1894

FAMILY GLOSSIPHONIIDAE VAILLANT, 1890

Helobdella triserialis (Blanchard, 1849)Figure 3

MATERIAL EXAMINED: Free-living from La-guna Volcan, Departmento de Santa Cruz,Bolivia, 188079170S, 638389880W, 14 No-vember 1999, hand collected by M. Siddalland C. Specht; determination by M. Siddall;four specimens fixed in 10% formalin, storedin 70% ethanol (AMNH 4222, Annelida);five specimens fixed in 10% formalin, storedin 70% ethanol (Museo de Historia NaturalNoel-Kempff Mercado, Santa Cruz, Bolivia,uncataloged); five specimens fixed and storedin 95% ethanol (AMNH 4223, Annelida);five specimens fixed and stored in 95% eth-anol (Museo de Historia Natural Noel-

Kempff Mercado, Santa Cruz, Bolivia, un-cataloged); one specimen fixed and stored in95% ethanol held at 2808C (AMNH 100020,Frozen Tissue Collection). The annulation,absence of nuchal glands and presence ofthree rows of black tipped papillae are con-sistent with descriptions of this highly vari-able pan-American species (Blanchard, 1849;Blanchard,1896; Weber, 1915; Cordero,1937a, 1937b; Ringuelet, 1943, 1944a,1944b; Klemm, 1982).

Helobdella bolivianita, new speciesFigures 4–7

HOLOTYPE (fig. 4): Free-living from La-guna Volcan, Departmento de Santa Cruz,Bolivia, 188079170S, 638389880W, 14 No-vember 1999, hand collected M. Siddall andC. Specht; (deposited in Museo de HistoriaNatural Noel-Kempff Mercado, Santa Cruz,Bolivia, uncataloged); body length 15.4 mm,maximal width 2.6 mm, fixed in 10% for-malin, stored in 70% ethanol.

PARATYPES: Free-living from Laguna Vol-can, Departmento de Santa Cruz, Bolivia,188079170S, 638389880 W, 14 November1999, hand collected M. Siddall and C.Specht. Six mature specimens and 10 im-mature fixed in 10% formalin, stored in 70%


Fig. 3. Helobdella triserialis exhibiting ste-reotypical three longitudinal rows of black-tippedpapillae.

ethanol (AMNH 4224, Annelida); one ma-ture cleared in Hemo-D (AMNH 4225, An-nelida); one dissected sexually mature, fixedin 10% formalin, stored in 70% ethanol(AMNH 4226, Annelida); one sectioned sex-ually mature, fixed in 10% formalin, mount-ed on 22 glass slides (AMNH 4227.1 through4227.22, Annelida); seven sexually mature

and 11 immature specimens fixed in 10%formalin, stored in 70% ethanol (Museo deHistoria Natural Noel-Kempff Mercado, San-ta Cruz, Bolivia, uncataloged); one sexuallymature fixed and stored in 95% ethanol heldat 2808C (AMNH 100009, Frozen TissueCollection); six mature specimens and six ju-veniles fixed and stored in 95% ethanol(AMNH 4228); seven mature specimens andsix juveniles fixed and stored in 95% ethanol(Museo de Historia Natural Noel-KempffMercado, Santa Cruz, Bolivia, uncataloged).

ETYMOLOGY: Name refers to the combinedviolet and yellow appearance of this leech inthe living state, which resembles a compositemineral, Bolivianite (or ametrine), a combi-nation of amethyst and citrine unique to east-ern Bolivia.

DIAGNOSIS: This species is distinguishedfrom other scutiferous species of the genusby having paired salivary glands at the baseof the proboscis as well as diffuse salivarytissue in the parenchyma, subdivided annuli,six pairs of gastric caeca including divertic-ula, and six pairs of testisacs.

FORM (fig. 4): Body lanceolate, broadest inposterior half; somites I through IV formingsomewhat broadened head region; dorsumconvex, with inconspicuous papillae in some;venter flat to slightly concave, without pa-pillae; anterior sucker oval; mouth pore sub-terminal; caudal sucker circular, concave, di-rected ventrad, diameter smaller than widthof posterior somites; middorsal nuchal glandsand scute in VIIIa1/a2.

EYES (fig. 4): One pair, punctiform to tri-angular, at junction of III and IV.

ANNULATION (fig. 4): Somites I and II un-iannulate; III and IV biannulate; V throughXXIV triannulate each annulus subdivided;XXV and XXVI biannulate and subdivided,XVII uniannulate but no distinction fromcaudal sucker middorsally.

COLOR AND PATTERN (fig. 4): When alive,anterior one-third of body appearing violetblending to yellow posteriad; chromato-phores arranged in approximately 30 faintlongitudinal arrays dorsally, and approxi-mately 20 faint longitudinal arrays ventrally;dorsally one pair of solid paramedial linesfrom IV to XXIII or XXIV, becoming inter-mittent more posteriorly, a second pair oflines, fainter and more lateral from VII


Fig. 4. Holotype of Helobdella bolivianita (A) dorsal view, (B) ventral view, (C) anterior somiteswith middorsal nuchal scute on VIII, and (D) midbody somites showing typical dorsal pigmentation.


Fig. 5. Diagram of internal anatomy of Helobdella bolivianita illustrating the relative position andshape of the proboscis (pr), salivary cells (sc), testisacs (ts), gastric caeca (gc), intestinal caeca (ic), andanus (an).


Fig. 6. Median reproductive anatomy of He-lobdella bolivianita relative to somatic ganglia XIthrough XVI. Abbreviations: at, atrium; sd, spermduct; ov, ovary.

through XXIII, supramarginal lines fainter;ventrally two pairs of paramedial lines, theinnermost being stronger. Anterior margin oforal sucker (I, II) considerably less pigment-ed than midbody somites.

REPRODUCTIVE SYSTEM (figs. 5, 6): Maleand female gonopores separated by one an-nulus, male at XII a1/a2, female at XII a2/a3; six pairs of testisacs visible histologicallyat XIII/XIV through XVIII/XIX; sperm ductsexit parenchyma in XIII, extend posteriad toXVI, and fold back to XV or XIV such thatif unfolded would reach XVI before return-ing anteriad, sperm ducts empty into atria an-terioventrally without preatrial loops; atriapiriform approximately at 458 to midline;ovisacs robust but simple, extending to XV.

ALIMENTARY TRACT (figs. 5, 7): Proboscisslightly thicker at base than tip, in membra-nous sheath, base of proboscis at XII in re-laxed state; salivary cells arranged both as apair of glandular masses at base of proboscisand diffusely in parenchyma, ductules of thelatter forming a bundle inserting into the for-mer, oesophagus simple, not recurved; gas-tric chambers with digitiform caeca, six in-cluding postcaeca (diverticula), first five inXIV through XVII, postcaeca from XIXthrough XXIII or XXIV; intestine from XIX/XX, four lobes but not pronouncedly caecate;anus at XXVI/XXVII.

REMARKS: No other scutiferous species ofleech is known to possess both compact sal-ivary glands and diffuse salivary tissue. Thepresence of a nuchal scute on VIII is a clearsynapomorphy (Light and Siddall, 1999) fora subset of species in the genus Helobdella,indicating that H. bolivianita is allied withthe type species of the genus, Helobdellastagnalis (L.). In South America there are 11known scutiferous species, most of whichcan be readily distinguished from H. boli-vianita. Although Adaetobdella xenoica(Ringuelet, 1975) Sawyer, 1986, has compactsalivary glands, six pairs of testisacs and ascute on VIII, it has seven crop chambers, apreatrial loop for each sperm duct, and noposterior crop diverticula and does not ex-hibit subdivided annuli (Ringuelet, 1975,1978b). The most broadly distributed speciesof scutiferous leech in South America is He-lobdella scutifera Blanchard, 1900, knownfrom as far south as Tierra del Fuego


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(Moore, 1911) and as far North as RioGrande do Norte, Brazil (Cordero, 1937a).Blanchard (1900) noted dorsal paramediallines in some individuals of H. scutifera rem-iniscent of Glossiphonia complanata and su-perficially similar to those described here forH. bolivianita. However, H. scutifera has sal-ivary cells diffusely arranged in the paren-chyma, a very long proboscis extending toand folding back anteriorly at XIV, ovariesonly as long as XIV, and sperm ducts thatreach XIX (Blanchard, 1900; Weber, 1915;Ringuelet, 1978a). Helobdella diploides Rin-guelet, 1948, although it lacks any observ-able pigmentation, exhibits subdivided an-nuli from VII through XXV and a scute inVIII similar to H. bolivianita. Otherwise it isunique in having exceedingly short spermducts, recurving anteriorly at XIV, and atriathat are distinctly at right angles to the mid-line (Ringuelet, 1948). Helobdella godetiWeber, 1916, Helobdella simplex Moore,1911, and Helobdella montevidensis Corde-ro, 1937, though scutiferous, do not havesubdivided annuli and each has obvious dor-sal papillation. The most similar species andone that individuals of H. bolivianita maypreviously have been confused with is He-lobdella duplicata Moore, 1911, originallydescribed from Patagonia but now attributedto a broader South American distribution.Helobdella duplicata has subdivided annuli,six pairs of gastric caeca including postcaeca,six pairs of testisacs, a scute in VIII, and acaudal sucker directed strongly ventrad(Moore, 1911). However, numerous featuresdistinguish H. duplicata from H. bolivianita,most notably a lack of compact salivaryglands, a transverse metameric pigmentationon annulus a1 of each somite, globular atriawith anteriodorsal insertion of spermducts,ovaries that reach XVII, and the presence ofpronounced lateral caeca of the intestine(Moore, 1911).

DISCUSSION

Ringuelet’s (1953) note, the only preexist-ing taxonomic account of leeches from Bo-livia, recorded the existence of Helobdelladuplicata, Helobdella obscura and an undes-cribed Helobdella species in samples sentfrom Cochabamba. His description of the

specimen attributed by him to H. duplicatadetails only external morphology and doesnot note the strongly metameric pigment pat-tern otherwise characteristic of this species(Moore, 1911). In later work (Ringuelet,1944b) the characteristics attributed to H. du-plicata, ‘‘Color liso, con los annilos a3 maspigmentados, o liso con 2 estrıas dorso-lon-gitudinales’’ were not completely in accordwith Moore’s (1911) description of H. dupli-cata. Moore (1911) noted two broad andfaint paramedial bands of pigmentation butat six muscle bundles wide they were in nosense distinct longitudinal lines on the dor-sum like those of H. bolivianita. EventuallyRinguelet (1985) appears only to have re-quired subdivided annuli and a scute for in-clusion in H. duplicata, thus obviating theneed for dissection. As such, it is quite pos-sible that the one specimen from Cochabam-ba, Bolivia, was not H. duplicata. Whetheror not it was Helobdella bolivianita cannotbe determined from the information provided(Ringuelet, 1953). The presence in Bolivia ofthe other two species noted here is unre-markable. One individual of Semiscolex sim-ilis also was among the leeches detailed byRinguelet (1953) from Cochabamba, and He-lobdella triserialis is found from Concep-cion, Chile (Weber, 1915) through NorthernMichigan, USA (Klemm, 1982).

The presence both of compact salivaryglands at the base of the proboscis and ofdiffuse parenchymal salivary tissue in Helob-della bolivianita is unprecedented in Hiru-dinea. Two principle clades of leeches exhib-it the derived condition of compact salivaryglands (Light and Siddall, 1999): a mono-phyletic subset of Placobdella species andthe genus Haementeria. Although not includ-ed in current phylogenetic assessments of theGlossiphoniidae (see Light and Siddall,1999), the genus Adaetobdella Ringuelet,1978 comprises species previously in the ge-nus Helobdella but which lack parenchymalsalivary tissue and possess a pair of compactsalivary glands set-off from the base of theproboscis by their bundled salivary ductules(Ringuelet, 1978b). Because the genus Hae-menteria currently is supported as sister tax-on to Helobdella, it may have been reason-able to conclude that the presence of compactsalivary glands is a synapomorphy for the


genera Haementeria and Adaetobdella. How-ever, the existence of both kinds of salivarytissue in the scutiferous H. bolivianita, andonly compact tissue in another scutiferousspecies, Adaetobdella xenoica, puts thosecharacters in conflict. Because the type spe-cies of the genus, Helobdella stagnalis, hasa scute, retaining scutiferous species in thegenus Helobdella would seem to be prudent.

ACKNOWLEDGMENTS

I thank the Center for Biodiversity andConservation of the American Museum ofNatural History for funding and coordinatingthis expedition. The collegiality and gener-osity of Maria-Esther Montano of the Museode Historia Natural Noel-Kempff Mercado,Santa Cruz, Bolivia facilitated collection andexit of specimens. I thank Chelsea Siddall forher expertise as field guide and chauffeur aswell as for her assistance with the collecting.Paula Mikkelsen kindly made available re-sources and knowledge in her histology lab-oratory. I thank Marie Lawrence for her thor-ough histological and curatorial work, aswell as Steve Thurston for skillfully illus-trating the internal anatomy of the new spe-cies.

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leeches of laguna volcn, bolivia, including a new species of helobdella

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