Hirudinea from the Apolobamba in the Bolivian Andes, including three new species of Helobdella (Clitellata, Hirudinea)

15 Pages·2001·2.6 MB·English

by  Siddall, Mark Edward, 1966-

Nowvitate MUSEUM
ovitates
PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY
CENTRAL PARK WEST AT 79TH STREET, NEW YORK, NY 10024
Number 3341, 14 pp., 40 figures June 22, 2001
Hirudinea from the Apolobamba in the Bolivian
Andes, Including Three New Species
of Helobdella (Clitellata: Hirudinea)
MARK E. SIDDALL!
ABSTRACT
Four species of leeches were found in the Apolobamba Range of the Bolivian Andes.
Collections were made from 4100 m down to 2820 m—among the highest collecting localities
ever for leeches. There were three new species in the genus Helobdella including Helobdella
ringueleti, Helobdella nununununojensis, and Helobdella sorojchi, as well as one representa-
tive of Cylicobdella coccinea. One of the new species exhibited an attitude of parental care
unique among glossiphoniids in that the brood was enclosed within two halves of the folded
parent. None of these species is known to be sanguivorous.
INTRODUCTION Since that time, Andean leeches found at
high altitudes have continued to be cylicob-
Some collections of leeches from South
dellids or nonsanguivorous glossiphoniids.
America early in the 20th century were from
The highest among these are Cylicobdella
high altitudes in the Andes. Professor Fuhr-
coccinea at 4100 m near Huaron, Peru (Rin-
mann of the University of Neuchatel fur-
gulet,1960) and at 4100 m from the Mucu-
nished Weber (1913) with specimens found
chies desert near Lake Mucubaji, Venezuela
above 1800 m in Colombia, the highest,
Blanchardiella columbiensis at 3800 m. (Ringulet,1981), Blanchardiella octoculata
Thereafter Weber (1916b) described four at 4150 m near Santa Isabel, Columbia (Rin-
new species of Helobdella from Lagunas Na- gulet,1980a), Helobdella titicacensis (Rin-
ticocha, Lavandera, and Huaron in the vicin- gulet, 1959) in Lake Titicaca, and Maiabdella
ity of Cerro de Pasco in Peru at 5140 m. batracophila (Ringuelet, 1980b).
' Assistant Curator, Division of Invertebrate Zoology, American Museum of Natural History.
Copyright © American Museum of Natural History 2001 ISSN 0003-0082 / Price $2.10
zZ AMERICAN MUSEUM NOVITATES NO. 3341
tas ,
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mall < Piara
Pea lecehe uca a
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Map 1. Satellite image of the Apolobamba region and collection localities (see figs. 1-4) marked
with the joint American Museum Center for Biodiversity and Conservation/Coleccion Boliviana de
Fauna 1999 expedition routes (dashed lines).
In his doctoral thesis Weber (1915) won- lections were conducted at elevations be-
dered, “‘Qui sait si les régions montagneuses tween 3500 m and 4700 m in two adjacent
de l’Equateur, du Pérou ou de la Bolivie, ex- valleys (Tojoloque and Qanchis Qocha)
plorées scientifiquement, ne nous fourniront above the tree line. From 29 October 1999
pas d’intéressants espéces ...?’? Remark- through 4 November 1999 collections were
ably, though several species were described made between 2800 m (at the junction of
from Andean Peru the next year (Weber, Valle Qanchis Qocha and Valle Pelechuco in
19l6a, 1916b), Bolivia has remained unex- a dense cloud forest) and 3900 m (Pusu Pun-
plored. The only accounts of Bolivian leech- ku).
es to date are Ringuelet’s (1953) identifica-
tion of four specimens mailed from Cocha-
MATERIALS AND METHODS
bamba (2570 m) and Siddall’s (2001) brief
collections at Laguna Volcan (1100 m). Leeches were collected in Valle Tojoloque
On 17 October 1999 a team of researchers (fig. 1), Qanchis Qocha (fig. 2), Pusu Punku
from the American Museum of Natural His- (fig. 3), and Piara (fig. 4) all in the vicinity
tory, the Collecci6n Boliviana de Fauna, and of the boundary between the Ulla Ulla Na-
the Museo de Historia Natural Noel-Kempff tional Fauna and Biosphere Reserve and
Mercado, sponsored by the Center for Bio- Madidi National Park, Departmento La Paz,
diversity and Conservation of the American Bolivia near the Peruvian border. This re-
Museum of Natural History, embarked on gion, near the villages of Pelechuco and
faunistic survey expeditions in the high An- Quearra, is part of the Apolobamba range of
dean portion of Bolivia (map 1). From 19 the Cordillera Occidental o Real and consists
October 1999 through 26 October 1999, col- of a parallel series of steep valleys each of
2001 SIDDALL: LEECHES OF APOLOBAMBA, BOLIVIA 3
Figs. 1-4. Collection localities in the Apolobamba range. 1. Valle Tojoloque (looking west) with
locality UU99—6 (lower arrow) and UU99-11 (upper arrow) at 3750 m and 3860 m, respectively. 2.
Qanchis Qocha or Siete Lagunas (looking southeast) and collection sites (arrows) for UU99—20 at 4050
northeast down the steep walled Rio Pelechuco Valley toward Piara at 2820 m (arrow).
which is roughly perpendicular to the Rio RESULTS
Pelechuco flowing northeast toward the Tui-
Aquatic leeches were encountered only at
chi, the Beni, and eventually the Amazon.
the highest altitudes examined where the ter-
Leeches were collected by examining the
rain was of a sufficiently shallow grade to
underside of submerged or semisubmerged
rocks, and by dip-netting of sediment in any permit the collection of daily precipitation
into pools or lakes. Deeper in the Rio Pele-
freshwater pools or streams encountered.
Leeches were relaxed with the gradual ad- chuco Valley (i.e., at Piara) aquatic leeches
were absent in the swiftly flowing rivers and
dition of 50% ethanol and fixed either in
95% ethanol or in 10% formalin. Examina- cataracts, though one terrestrial leech was
tion of external morphology and dissections found. At the higher elevations, the land-
were accomplished with a Nikon SMZ-U ste- scape was dominated by terrain that is reg-
reo microscope with a SPOT-RT digital cam- ularly burned to clear ground-dwelling bro-
era. Specimens prepared for histology were meliads from pasture land. Here, each laguna
dehydrated through ethanol, cleared with was fed strictly by rain or snow-melt. In To-
Hemo-D, and infiltrated with Paraplast Plus joloque it was clear that the two lagunitas
in a Tissue Tek II tissue processor. Longitu- containing leeches had neither inlet nor out-
dinal sections (5 4m) were stained with Hae- let for water flow and presumably maintain
matoxylin and Eosin/Phloxine and examined their levels by the daily clouds and rains that
with an Olympus BX50 compound micro- sweep up from the east. Water in the lakes
scope at low power. of Qanchis Qocha and in the bofedales of
- AMERICAN MUSEUM NOVITATES NO. 3341
upper Pusu Punku readily flowed out of these imately same width as posterior somites;
valleys and into the Rio Pelechuco below. middorsal nuchal glands (fig. 7) at VIII al/
The vicinity of Piara (a series of ruins that a2 with tawny-brown secretion, chitinoid
once was a village on the Incan road between scute absent or at least not pronounced, nu-
Pelechuco and Apolo) is primarily dense chal glands not obvious in juveniles.
cloud forest in steep valleys dominated by Eyes (figs. 7, 8): One pair, punctiform,
bamboo, legumes and associated bromeliads well separated, in III.
where it has not been burned and cleared for COLOR AND PATTERN (figs. 5-10): Anterior
subsistence farming or grazing of cattle. All margin of oral sucker (J, II) unpigmented;
of the leeches found at higher elevations dorsum gray to light brown with randomly
(3750 m through 4100 m) can be placed in arranged chromatophores; three pairs of fine
three new species of Helobdella. supramarginal lines (fig. 8) dorsally from
VIII through XXIV or XXV, most obvious
ORDER RHYNCHOBDELLIDA in juveniles; venter lighter than dorsum in
BLANCHARD, 1894 postgenital somites; three pairs of fine infra-
FAMILY GLOSSIPHONIIDAE VAILLANT, 1890 marginal lines (figs. 6, 10) from VIII through
XXIV or XXV corresponding to those seen
Helobdella ringueleti, new species
dorsally. Caudal sucker evenly pigmented.
Figures 5—15
REPRODUCTIVE SYSTEM (figs. 10—15): Male
HOLOTYPE (figs. 5—7, 9, 10): Free-living and female gonopores separated by one an-
from pond above cataract (fig. 1) in Valle nulus (fig. 10), male at XII al/a2, female at
Tojologque at 3860 m, in Madidi National XII a2/a3; six pairs of testisacs (fig. 15) at
Park, Departmento La Paz, Bolivia, XIUW/XIV through XVII/XIX; sperm ducts
14°44'30"S, 69°01'26"W, 21 October 1999, highly convoluted in XIV and XV (fig. 11),
station number UU99-11, hand collected by atria piriform directed laterally (figs. 11, 12),
M. Siddall; (deposited in Colleccion Bolivi- sperm ducts empty into atria anterioventrally
ana de Fauna, La Paz, Bolivia, uncataloged); with preatrial cornua (fig. 12); ovisacs short,
body length 33.8 mm, maximal width 5.7 in XII only, and folded (fig. 13).
mm, fixed in 10% formalin, stored in 70% ALIMENTARY TRACT (figs. 14, 15): Probos-
ethanol. cis in membranous sheath and very long,
PARATYPES (figs. 8, 11—15): One dissected base at XIV/XV and coiled when retracted
adult and 3 juveniles taken from venter of (fig. 14); salivary cells arranged diffusely in
the dissected adult both fixed in 95% ethanol parenchyma, ductules of the latter forming a
from same locality UU99—11 as above, hand bundle inserting into the base of the probos-
collected by M. Siddall on 23 October 1999, cis; oesophagus simple, not recurved; no gas-
(AMNH 4230, Annelida, and AMNH 4231, tric chambers or digitiform caeca in midbody
Annelida). One juvenile also fixed and stored somites, only postcaeca (diverticula) from
in 95% ethanol held at —80°C (AMNH XIX through XXIV (fig. 15); intestine from
100948, Frozen Tissue Collection). XIX/XX with four lobes; anus at XXVI/
Form (figs. 5-10): Body robust and lan- XXVII.
ceolate, broadest in posterior half; somites I EtTyMo_Locy: Named for Raul Ringuelet of
through VI a2 demarcated in some adults the Museo de La Plata, Argentina, who con-
(fig. 7); somites I-IV uniannulate, V_ bian- tributed impressively to our knowledge of
nulate, VI-XXV triannulate, XX VI biannu- South American leeches from 1936 through
late, and XXVII uniannulate but broad; all 1986, in particular describing or redescribing
annuli from VII al through XX VII subdivid- approximately half of the known species of
ed dorsally (fig. 9) though less regularly ven- Helobdella. The species name should be pro-
trally; dorsum convex, without papillae; ven- nounced rin-geh-let-eye.
ter flat to slightly convex, never concave, REMARKS: There are seven species of He-
without papillae; anterior sucker triangular to lobdella in South America possessing the
ovoid (fig. 6); mouth pore large subterminal, “‘chitinoid’’ plaque at VII al/a2: Helobdella
not central; caudal sucker circular, concave, scutifera (see Blanchard, 1900), Helobdella
directed subterminal in relaxed state, approx- simplex (see Moore, 1911), Helobdella festai
2001 SIDDALL: LEECHES OF APOLOBAMBA, BOLIVIA 3S
(see Dequal, 1916), Helobdella godeti (see venter inside membranous ‘“‘cocoon’’, fixed
Weber, 1916b), Helobdella adiastola (see in 10% formalin, stored in 70% ethanol.
Ringuelet, 1972), Helobdella xenoica (see PARATYPES: One dissected adult (AMNH
Ringuelet, 1975), and Helobdella bolivianita 4232, Annelida), eight adults (deposited in
(see Siddall, 2001). Helobdella ringueleti Colleccion Boliviana de Fauna, La Paz, Bo-
does not exhibit a plaque like the foregoing, livia, uncataloged), and eight additional
but it does have the nuchal glandular region adults (AMNH 4233, Annelida) with and
on VIII al which is more obvious in adults. without broods all fixed in 10% formalin
This is not unlike plaqueless glands reported from the same locality UU99—40 as above,
for Helobdella diploides, Helobdella dupli- hand collected by M. Siddall on 3 November
cata, and Helobdella lineata. From the latter 1999. Eleven adults (deposited in Colleccion
two, both reported originally from Patagonia Boliviana de Fauna, La Paz, Bolivia, uncat-
aloged), and eleven additional adults
(Moore, 1911), H. ringueleti is easily distin-
guished in that H. duplicata has pronounced (AMNH 4234, Annelida) with and without
metameric banding on al of midbody so- broods, all fixed in 95% ethanol from the
mites and H. lineata has a single middorsal same locality UU99—40 as above, hand col-
lected by M. Siddall on 3 November 1999.
row of obvious papillae (Moore, 1911). Dif-
One sectioned sexually mature, fixed in 10%
ferences between H. ringueleti and H. diplo-
formalin, all mounted on 30 glass slides
ides from Paraguay are more subtle and the
(AMNH 4235.1 through 4235.30, Annelida).
two are probably closely related. Both spe-
Eggs from one adult fixed and stored in 95%
cies have a simple ovoid nuchal gland region
ethanol held at—80°C (AMNH 100952, Fro-
on VIII al, folded ovaries, the convoluted
zen Tissue Collection).
sperm ducts in XIII through XIV, and both
Additional material includes one specimen
have subdivided annuli from VII to the pos-
from locality UU99—-6 3750 m 14°44'33"S,
terior somites (Ringuelet, 1948). However,
69°01'10”W below cataracts in Valle Tojo-
Helobdella diploides is a very small species
loque (fig. 1) hand collected by M. Siddall
without any obvious external pigmentation
on 21 October 1999 fixed in 10% formalin
pattern like the supramarginal and inframar-
(deposited in Colleccion Boliviana de Fauna,
ginal lines seen in H. ringueleti. Moreover,
La Paz, Bolivia, uncataloged), and another
Helobdella diploides lacks the very large
from this same locality (UU99-—6) fixed and
proboscis of H. ringueleti and has six pairs
stored in 95% ethanol held at —80°C
of gastric caeca unlike the unbranched tube
(AMNH 100950, Frozen Tissue Collection).
in H. ringueleti. Absence of gastric caeca is
Form (figs. 16-20): Body thin and lance-
more a characteristic of H. elongata, H. mi-
olate, distinctly broadened from XVI a3
chaelseni, H. ampullariae, and H. similis through XX a3 (figs. 16-18) especially in
placed collectively in the genus Gloiobdella
live state; somites I-V uniannulate, VI-
by Ringuelet (1978b; see also Sawyer, 1986).
XXIV triannulate, XXV_ biannulate, XX VI
and XXVII uniannulate; dorsum convex,
Helobdella nununununojensis, new species without papillae; all annuli have pronounced
Figures 16—24 deep furrows to the extent that the lateral
margins have a sawtooth appearance (figs.
HOoLoryPke (figs. 16, 17): Free-living under 18, 19); venter flat to concave, without pa-
rocks in bofedales and slow moving streams pillae, and, depending on reproductive status,
with a distinct groove (fig. 19) along the
(UU99—40, fig. 3), in Ulla Ulla National midline from XXIII through XXIV; anterior
Fauna and Biosphere Reserve, Departmento sucker oval; mouth pore terminal, not cen-
La Paz, Bolivia, 14°47'09"S, 69°02'46’W, 3 tral; caudal sucker circular, deeply concave,
November 1999, hand collected by M. Sid- directed subterminal to ventrad in relaxed
dall; (deposited in Colleccion Boliviana de state (fig. 17), approximately half of the
Fauna, La Paz, Bolivia, uncataloged); body width of posterior somites. There is no chi-
length 14.5 mm, maximal width 3.1 mm, tinoid scute and there are no visible glands,
with approximately 20 juveniles attached to however, some specimens fixed in ethanol
AMERICAN MUSEUM NOVITATES NO. 3341
2001 SIDDALL: LEECHES OF APOLOBAMBA, BOLIVIA 7
exhibited a swelling on VHI al (fig. 20). His- 24) in that adults with eggs in various stages
tological sectioning revealed a muscularized of development would invariably be folded
pad in the middorsal region of VIII al but in half so as to enclose their young. More-
no glandular tissue whatsoever. over, this specialized brooding behavior is
EYES (fig. 20): One pair, punctiform, well accompanied by a distinct broadening from
separated, at II/II. XVI a3 through XX a3 where the eggs are
COLOR AND PATTERN (figs. 16—20): Dor- held in a pocket on the venter (fig. 17). In
sum with irregular longitudinal arrays of adults that had eggs (as opposed to hatched
gray to brown chromatophores but no defi- juveniles) attached, there was a distinct
nite lines or bands. Venter much lighter with trough in the ventral midline (fig. 19) run-
irregularly arranged chromatophores on ei- ning directly from the female gonopore to
ther side of the midline. XVI. This groove also was visible histolog-
REPRODUCTIVE SYSTEM (figs.19, 21): Male ically. It is tempting to think of it as a bowl-
and female gonopores separated by one an- ing lane for eggs being passed back to the
nulus, male at XII al/a2, female at XII a2/ brooding somites. The possession of the very
a3; six pairs of testisacs at XIII/XIV through pronounced sawtooth-like annuli is charac-
XVIUI/XIX; sperm ducts reach to XIX, atria teristic of Helobdella godeti and Helobdella
piriform, directed anterolaterally, sperm columbiensis, both of which might be ex-
ducts empty into atria dorsally; ovisacs pected to occur in the area in as much as the
straight and long, reaching to XVII. former was discovered at 5140 m in Peru and
ALIMENTARY TRACT (figs. 22, 23): Probos- the latter at 2400 m in Colombia (Weber,
cis in membranous sheath, base at XIII; sal- 1913, 1915, 1916a, 1916b). Helobdella col-
ivary cells arranged in a compact mass only umbiensis apparently resembles Helobdella
in XXIII, ductules of the latter forming a triserialis in having very distinct lines on its
bundle inserting into base of proboscis; oe- dorsum. In addition, H. columbiensis has a
sophagus simple, not recurved; no gastric long tapering “‘neck’’ between the clitellum
chambers or digitiform caeca in midbody so- and the cephalic somites and the oral sucker
mites; postcecae (diverticula) in XIX only is reportedly exceedingly small (Weber,
(fig. 23); intestine from XIX/XX with four 1913, 1915). Helobdella godeti, which also
lobes; anus at XX VI/XXVILI. , has short postcaeca, nonetheless has the full
ETYMOoLocy: Reflects the type locality Nu- Six pairs of gastric caeca and a distinct chi-
tinoid scute on VII al, a2. The lack of gastric
Place of Very Bare Breasts”, from Nufu caeca and the presence of short postcaeca in
meaning nipple), a bowl at the top of Valle XIX or XIX to XX is more a characteristic
Pusu Punku. The species name, thus, should of H. elongata, H. michaelseni, H. ampul-
be pronounced nyue-nyue-nyue-nyue-nyoe- lariae, and H. similis placed collectively in
hen-sis. the genus Gloiobdella by Ringuelet (1978b;
REMARKS: This species was found exhib- see also Sawyer, 1986). Much like H. nunu-
iting a wholly unique brooding behavior (fig. nununojensis, Helobdella michaelseni and H.
<
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 al (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 ho-
lotype 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 (0) 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.
8 AMERICAN MUSEUM NOVITATES NO. 3341
Figs. 16-24. Helobdella nununununojensis, n. sp. 16. Dorsal surface of the holotype. 17. Ventral
surface of the holotype with attached brood of hatchlings. 18. Venter showing the broadened brood
pouch from XVI through XX. 19. Venter showing the male (m) and female (f) gonopores as well as
2001 SIDDALL: LEECHES OF APOLOBAMBA, BOLIVIA 9
obscura have no caeca whatsoever, including without broods all fixed in 10% formalin
no postcaeca (Blanchard, 1900; Weber, 1915; from same locality UU99—20 as above, hand
Ringuelet, 1944b), whereas H. ampullariae collected by M. Siddall on 25 October 1999.
and H. similis do have postcaeca in XIX only Seven adults (deposited in Colleccion Boli-
(Ringuelet, 1942a, 1942b, 1945). These spe- viana de Fauna, La Paz, Bolivia, uncata-
cies, like H. elongata in North America, are loged), and six additional adults (AMNH
completely colorless even when viewed live 4238, Annelida) with and without broods all
(Ringuelet, 1942a, 1942b, 1944a, 1944b, fixed in 95% ethanol from same locality
1945). Moreover, both have their eyes situ- UU99-20 as above, hand collected by M.
ated on IV G.e., on the fifth annulus), H. am- Siddall on 25 October 1999. One adult fixed
pullariae has only four pairs of testisacs and stored in 95% ethanol held at —80°C
(Ringuelet, 1945) and the sperm ducts of H. (AMNH 100953, Frozen Tissue Collection).
similis reach only to XV/XVI, and both of ForM (figs. 25—30): Body thin and lance-
these have diffuse salivary tissue. Perhaps olate, occasionally broadened from XVI a3
the most similar known species is Adaetob- through XX a3 especially in live state; so-
della cryptica (see Ringuelet, 1978b) in the mites I-V uniannulate, VI-XXIV triannulate,
genus Ringuelet erected for those species of
XXV biannulate, XXVI and XXVII unian-
Helobdella possessing compact salivary nulate; dorsum convex, without papilla; ven-
glands. Although the cream-colored Adae- ter flat to concave, without papillae; anterior
tobdella cryptica has the short postcaeca, its sucker oval; mouth pore terminal (figs. 28,
ovaries reach only XV and it possesses five 29); annuli from VIII through XV weakly
pairs of testisacs whereas H. nununununojen- subdivided (fig. 30); caudal sucker circular,
sis has the more typical six. concave, directed subterminal to ventrad in
relaxed state, approximately two-thirds of
Helobdella sorojchi, new species width of posterior somites. There is no chi-
Figures 25-35 tinoid scute and there are no visible glands.
HOLoryPkE (figs. 25, 30): Free-living under Internally this species has an unusually fi-
rocks along the shoreline of lakes in Qanchis brous appearance due to a large amount of
Qocha (Siete Lagunas) at UU99-—20 from connective tissue.
4090 to 4100 m, in Madidi National Park, EYES (fig. 27): One pair, punctiform, well
Departmento La Paz, Bolivia, from separated, at II/III.
14°44'99"S, 69°02'22”W through 4°45'02’S, COLOR AND PATTERN (figs. 25, 26, 31):
69°02'2"W , 25 October 1999, hand collected Dorsum uniformly brown with fine parame-
by M. Siddall (deposited in Colleccion Bo- dial and supramarginal longitudinal lines,
liviana de Fauna, La Paz, Bolivia, uncata- others with irregular mottled brown chro-
loged); body length 11.2 mm maximum matophores. Venter much lighter with
length in relaxed state, maximal width 3.5 smooth paramedial pigmentation.
mm, fixed in 10% formalin, stored in 70% REPRODUCTIVE SYSTEM (figs. 31—33): Male
ethanol. and female gonopores obvious and separated
PARATYPES: One dissected adult (AMNH by one annulus, male at XII al/a2, female at
4236, Annelida), three adults (deposited in XII a2/a3; six pairs of testisacs at XIII/XIV
Colleccion Boliviana de Fauna, La Paz, Bo- through X VIII/XIX; sperm ducts and ovaries
livia, uncataloged), and three additional reach to XVII/X VIII, however ovaries lie
adults (AMNH 4237, Annelida) with and dorsal to sperm ducts (fig. 32) as opposed to
<
the central egg-bowling trough (arrowhead) exhibited by adults in the early stages of brooding. 20.
Anterior of an adult demonstrating the aglandular nuchal pad. 21. Median reproductive apparatus with
the tip of an oviduct (0) at XVII and the longer sperm ducts reaching X VIII/XIX. 22. Anterior digestive
system with the proboscis (p) having two glandular salivary masses (arrowheads) at its base in XIII.
23. Posterior digestive system with the short postcaeca (arrowheads) in XIX only and the four pairs of
intestinal caeca (i). 24. Typical brooding attitude of this species.
10 AMERICAN MUSEUM NOVITATES NO. 3341
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 pigmen-
tation pattern. 32. Median reproductive apparatus with the atria (*) removed, ovaries (0) 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).
the ventral position more typical for the fam- cis in membranous sheath, base at XIII; sal-
ily. Atria piriform directed anteriorly, sperm __ ivary cells arranged in a small compact mass
ducts empty into atria dorsally (fig. 33). only in XII, ductules of the latter are very
ALIMENTARY TRACT (figs. 34, 35): Probos- short; oesophagus simple, not recurved; six