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OCCASIONAL PAPERS jyj^ \ 4 ^993

of the

MUSEUM OF NATURAL HISTORY
The University of Kansas
Lawrence, Kansas

number 150, pages 1-7 30 june 1992

Eleutherodactylus bearsei New Species
(Anura: Leptodactylidae)
from Northeastern Peru

William E. Duellman1

ABSTRACT Eleutherodactylus bearsei, belonging to the Eleutherodactylus
unistrigatus group, is named from the Rio Huallaga Drainage in the upper Amazon
Basin near the base of the Andes in the Departamento San Martin. Peru.
Eleutherodactylus bearsei is most similar to E. diadematus and E. platydactylus,
allopatric species in the Amazon Basin and Andean slopes of the Andes in central and
southern Peru, respectively.

RESUMEN Eleutherodactylus bearsei, perteneciente al grupo Eleutherodactylus
unistrigatus, se describe del drenaje del Rio Huallaga en la parte superior de la cuenca
amazonica cerca de la base de los Andes en el Departamento de San Martin, Peru.
Eleutherodactylus bearsei es mas similar a E. diadematus y E. platydactylus, especies
alopatricas en la cuenca amazonica y las vertientes de los Andes en las partes central
y meridional del Peru, respectivamente.

Key words: Leptodactylidae, Eleutherodactylus bearsei new species, Amazonian Pern.

Included in the collections of anuran amphibians made by a field party
from The University of Kansas in the Departamento San Martin in northeast-
ern Peru in 1989 were several new species. Some of these have been
described — Ischnocnema saxatilis (Duellman, 1990), an Eleutherodactylus
(Duellman, 1992), and eight species of centrolenids (Duellman and Schulte,
1992). To these may be added another species of Eleutherodactylus. In the
following description, the terminology, method of measurements, and num-
bered characters in the diagnosis follow Lynch and Duellman (1980); snout-

'Curator of Herpetology, Museum of Natural History, and Professor, Department
of Systematics and Ecology, The University of Kansas, Lawrence, Kansas 66045,
USA.

© Museum of Natural History, The University of Kansas. Lawrence. ISSN 009 1-7958

2 UNIV. KANSAS MUS. NAT. HIST. OCC. PAP. No. 150

vent length is abbreviated SVL. The Museum of Natural History, The
University of Kansas is abbreviated KU.

I take pleasure in naming this distinctive new species for Professor Robert
C. Bearse, Associate Vice Chancellor for Research, Graduate Studies, and
Public Service, The University of Kansas; his enlightened and imaginative
administrative actions have continuously enhanced the programs of the
Museum of Natural History.

Eleutherodactylus bearsei new species

Holotype. — KU 2 12268, a gravid female, from the CataratasAhuashiyacu
(06°30'S, 76°20'W, 730 m), 14 km (by road) northeast of Tarapoto, Provincia
San Martin, Departamento San Martin, Peru, obtained on 8 February 1 989 by
William E. Duellman.

Paratypes. — KU 212269-71 and 212273, three adult males and one
gravid female, collected with the holotype.

Referred specimens. — KU 212272, a subadult female, and 212274 and
2 1 73 14-15, juveniles, from the type locality; KU 2 1 2275-76, juveniles, from
30 km (by road) southwest of Zapatero (ca. 10 km NE of San Jose de Sisa),
500 m, Provincia Lamas, Departamento San Martin, Peru.

Diagnosis. — A member of the Eleutherodactylus unistrigatus group, as
defined by Lynch (1976), characterized by: (1) skin of dorsum shagreened
(scattered low tubercles in males), lacking folds; skin on venter areolate; (2)
tympanum distinct, vertically ovoid, its diameter about one-third diameter of
eye; (3) snout acutely rounded in dorsal view, bluntly rounded in profile;
canthus rostralis sharp; (4) upper eyelid broader than interorbital distance, not
bearing tubercles; cranial crests absent; (5) vomerine dentigerous processes
prominent, transverse; (6) males with vocal slits and subgular vocal sac;
nuptial excrescense absent; (7) first finger shorter than second; discs truncate,
largest on Fingers II— IV; (8) fingers bearing lateral keels; (9) ulnar tubercles
diffuse; (10) low tubercles on tarsus; tubercles absent on heel; (11) two
metatarsal tubercles; inner elliptical, 8-10 times size of outer tubercle; (12)
toes unwebbed, bearing narrow lateral keels and toepads nearly as large as
those on outer fingers; ( 13) dorsum brown with darker brown marks on back
and transverse bars on limbs; posterior surfaces of thighs and flanks uniform
brown; dark brown labial bars; venter brown with cream flecks; (14) adults
moderate-sized; three males 22.7-25.5 mm SVL, two females 38.0 and 38.8
mm SVL.

Eleutherodactylus bearsei most closely resembles E. platydactylus from
the Amazonian slopes of the Andes in central and southern Peru, E. diadematus
in the upper Amazon Basin, and a new species from Panguana in Amazonian
Peru being described by Hedges and Schliiter. Eleutherodactylus platydactylus
differs from E. bearsei by having larger, conical tubercles on the dorsum,

A NEW ELEUTHERODACTYLUS FROM PERU 3

distinct scapular ridges, tubercles on the heels, and the venter pigmented only
on the throat. Eleutherodactylus diadematus and the new species from
Panguana differ by having cream flanks with distinct diagonal dark marks and
a cream venter with brown mottling. Furthermore, the new species from
Panguana is smaller (males 18.2-23.6 mm; females 33.5-35.3 mm) and has
an elongate distal tarsal tubercle (absent in E. bearsei).

Description. — Three adult males, two adult females. Head about as wide
as body, about as long as wide; head width 35.2^-0. 1% (x = 38.2) of S VL in
males, 39.4-42.3% (x =40.9) in females; head length 37.0-39.6% (x = 38.5)
of S VL in males, 39.9^4 1 .6 ( x = 40.8 ) in females; snout moderately short, not
protruding beyond margin of lip, round in dorsal view, bluntly rounded in
profile; eye-nostril distance slightly less than length of eye in males, about
equal in females; eye-nostril distance 28.7-30.9% (x = 29. 1 ) of head length
in males, 27.7-30.4% (x = 29.1) in females; eye large, prominent, its length
34.0-38.3% (x = 35.8) of head length in males, 27.2-29.0% (x = 28.1 Tin
females; upper eyelid lacking tubercles, broader than interorbital distance, its
width 108.2-116.0% (x = 111.0) of interorbital distance in males, 123.5-
128.1% (x = 125.8) in females. Top of head flat; cranial crests absent; canthus
rostralis shallowly sigmoid, sharp; loreal region concave; lip slightly flared
anterior to orbit; internarial area depressed; nostril ovoid, slightly protruding
laterally at point above anterior margin of lower jaw. Supratympanic fold
diffuse, curving posteroventrally from posterior comer of orbit, obscuring
posterodorsal part of low tympanic annulus; tympanum vertically ovoid,
separated from eye by distance much greater than diameter of tympanum,
which is 30.3-35.3% (x = 32.3%) of diameter of eye in males, 31.1-37.2%)
(x = 34.2) in females. Choanae ovoid, widely separated, not obscured by
palatal shelf of maxillary arch; vomerine dentigerous processes prominent,
transverse, posteromedial to choanae, widely separated medially, each bear-
ing three or four ( x = 3.2 ) teeth in males, four or five (x =4.3) teeth in females.
Tongue cordiform, distinctly notched posteriorly, free behind for about one
third of its length; vocal slit elongate, extending from midlateral base of
tongue toward angle of jaws; vocal sac single, median, subgular.

Skin on dorsum shagreened with scattered low tubercles in males; dermal
folds absent; flanks smooth; a few prominent tubercles posteroventral to
tympanum; five or six low tubercles on ventrolateral surface of forearm; three
or four tubercles on both inner and outer surface of tarsus; tubercles absent on
heel; skin on belly weakly areolate, that on posteroventral surfaces of thighs
granular; other ventral surfaces smooth; discoidal fold evident only posteri-
orly. Cloacal opening unmodified, directed posteroventrally at upper level of
thighs.

Forearms moderately robust; fingers moderately short, slender, bearing
naiTow lateral keels and truncate discs, much wider on Fingers II— IV than on
Finger I; relative lengths of fingers I < II < IV < III; subarticular tubercles

4 UNIV. KANSAS MUS. NAT. HIST. OCC. PAP. No. 150

subconical; few large supernumerary tubercles on proximal segments; pal-
mar tubercle large, bifid; thenar tubercle large, broadly ovoid, slightly
elevated (Fig. 1 ); males lacking nuptial excrescences. Hind limbs moderately
robust; heels barely overlapping when hind limbs flexed at right angles to axis
of body; tibia length 53.7-59.5% ( x = 56.4) of SVL in males, 49.7-50.5% (x
= 50. 1 ) in females; foot length 43.2-48.9% ( X = 46.6) of SVL in males, 46.3-
46.9% (x =46.6) in females. Inner tarsal fold absent; inner metatarsal tubercle
elliptical, eight to ten times size of subconical outer metatarsal tubercle; toes
long, slender, bearing narrow lateral keels and truncate discs; those on Toes
III— IV nearly as large as those on outer fingers; toes unwebbed; relative
lengths of toes I < II < III < V < IV; subarticular tubercles round; supernumer-
ary tubercles diffuse, present only on proximal segments (Fig. 1 ).

Color in preservative: Dorsum of head, body, and limbs dull brown with
indistinct darker brown markings consisting of narrow interorbital bar, W-
shaped mark in scapular region, and one or two small middorsal blotches

Fig. 1. Hand and foot of Eleutherodactylus bearsei, KU 212273. Scale = 5 mm.

A NEW ELEUTHERODACTYLUS FROM PERU

posteriorly on body; two males and one subadult female with square tan spot
anterior to interorbital bar and large, square tan spot posterior to sacrum.
Dorsal surfaces of limbs with transverse dark brown bars — one on upper arm,
one or two on forearm, four each on thigh and shank, three on tarsus; digits
also barred; posterior surfaces of thighs brown. Flanks brown with small,
diffuse cream spots ventrally; one brown bar on lip just posterior to level of
nostril; three diagonal brown bars below orbit. Venter brown with cream
flecks in larger individuals, cream with brown reticulations in smaller
individuals, and cream with brown flecks in small juveniles.

Color in life: Dorsum dull brown with faint, darker brown markings;
posterior surfaces of thighs dark gray; venter dark gray with bluish white
flecks; iris dull grayish bronze with brown flecks and horizontal brown bars;
some individuals with pale creamy orange spot on head and another on
dorsum posterior to sacrum (Fig. 2).

Measurements (in mm; 3 males followed 2 females with means in
parentheses): SVL 22.7-25.5 (24.0), 38.0-38.8 (38.4); tibia length 12.2-14.3
(13.5), 19.2-19.3 (19.3); foot length 9.8-12.2 ( 1 1.2), 17.6-18.2 (17.9); head
width 8.0-10.4 (9.2), 15.3-16.1 (15.7); head length 8.6-9.7 (9.2), 15.5-15.8
(15.7); interorbital distance 2.3-2.5 (2.4). 3.2-3.4 (3.3); eyelid width 2.5-2.9
(2.7), 4.1^.2 (4.2); eye-nostril distance 2.6-3.0 (2.8), 4.3-4.8 (4.6); eye
diameter 3.2-3.4 (3.3), 4.3-4.5 (4.4); tympanum diameter 1 .0-1 .2 (1.1), 1.4-
1.6(1.5).

Distribution and ecology. — Eleutherodactylus bearsei is known from
two streams at elevations of 500 and 730 m on ridges extending from the
Andes into the Amazon Basin in Departamento San Martin in northeastern
Peru. These ridges support lower montane humid forest (Tosi, 1960). Adults
were found at night on mossy boulders at the edges of streams in deep ravines;
juveniles were on low herbs or ferns near the streams. No calls were
associated with this species.

Remarks. — The type locality is northeast of Tarapoto on the road to
Yurimaguas; it is a rocky gorge into which two streams plunge. The sides of
the gorge are nearly vertical rock walls, and the floor of the gorge is littered
with huge boulders, many of which support thin layers of moss. Small ferns
and herbs grow on some of the boulders, and small trees, ferns, and a variety
of herbs grow in patches of soil on the floor of the gorge. At this locality, three
other species of frogs (Cochranella sp., Eleutherodactylus sp., and Hyla
phyllognatha) were active on boulders at night and three others (Atelopus
pulcher, Colostethus nexipus, and Epipedobates bassleri) were active there
by day. The arboreal Osteocephalus verrucigerus and stream-edge
Leptodactylus wagneri were active at night. The second locality is a wooded,
boulder-strewn ravine with a cascading stream on the road from Cunubuque
(just east of the Moyobamba-Tarapoto Road) to San Jose de Sisa. Ischnocnema
saxatilis and Leptodactylus rhodonotus were found in the ravine at night, and

6 UNIV. KANSAS MLJS. NAT. HIST. OCC. PAP. No. 150

Bufo typhonius and two species of Colostethus were active in the ravine by
day.

Phenotypically, E. bearsei can be grouped with E. diadematus, E.
platycephalus, and an undescribed species from Panguana, all of which occur
in the upper Amazon Basin and on the lower Andean slopes in Peru. The

Fig. 2. Eleutherodactylus bearsei: Top — KU 212268. holotype, female. 38.0
ram SVL. Bottom— KU 212269. paratype, male. 22.7 mm SVL.

A NEW ELEUTHERODACTYLUS FROM PERU 7

similarity of E. bearsei to E. diadematus suggests that E. bearsei may be an
Andean foothill vicariant of the Amazonian E. diadematus. A similar pattern
seems to exist within Ischnocnema with /. quixensis in the Amazon Basin and
/. saxatilis in the foothills (Duellman, 1990).

Acknowledgments: I am grateful to Fernando M. Cuadros V.. Michael E.
Morrison, Rainer Schulte, and John J. Wiens for their assistance in the field.
Erik R. Wild assisted with data gathering, and Amy Lathrop executed the
drawings. S. Blair Hedges graciously provided a specimen of. and data on, the
new species from Panguana, and John D. Lynch critically reviewed the
manuscript. The field work and laboratory research were supported by the
National Science Foundation (Grant BSR 88-05920). Permits were issued by
Ing. Gonzalo Bravo Mejfa Munoz and Jose Purisaca, Direccion General
Forestal y de Fauna, Ministerio de Agricultura, Lima, Peru.

LITERATURE CITED

Duellman, W. E. 1 990. A new species of leptodactylid frog, genus Ischnocnema, from

Peru. Univ. Kansas Mus. Nat. Hist. Occas. Pap. 138:1-7.
Duellman, W. E. 1992. A new species of the Eleutherodactylus conspicillatus group

(Anura: Leptodactylidae) from northeastern Peru. Rev. Espan. Herpetol. In press.
Duellman, W. E., and R. Schulte. 1992. New species of centrolenid frogs from

northern Peru. Univ. Kansas Mus. Nat. Hist. Occas. Pap. In press.
Lynch, J. D. 1976. The species groups of South American frogs of the genus

Eleutherodactylus (Leptodactylidae). Univ. Kansas Mus. Nat. Hist. Occas. Pap.

61:1-24.
Lynch, J. D., and W. E. Duellman. 1980. The Eleutherodactylus of the Amazonian

slopes of the Ecuadorian Andes (Anura: Leptodactylidae). Univ. Kansas Mus. Nat.

Hist. Misc. Publ. 69:1-86.
Tosi, J. A., Jr. 1 960. Zonas de vida natural en el Peru. Bol. Teen. Inst. Interamer. Cienc.

Agric. 5:1-271.

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