A New Species Of Rainfrog, Eleutherodactylus Phasma (Anura: Leptodactylidae), From Montane Costa Rica

5 Pages·1996·1.7 MB·

by  K R Lips

PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
109(4):744-748. 1996
A new species of rainfrog, Eleutherodactylus phasma
(Anura: Leptodactylidae), from Montane Costa Rica
Karen R. Lips and Jay M. Savage
(KRL & JMS) Department ofBiology, University of Miami, P.O. Box 249118,
Coral Gables, Florida 33124, U.S.A. (current address of KRL Department of Biology,
St. Lawrence University, Canton, New York 13617, U.S.A.)
—
Abstract. Eleutherodactylusphasma (Leptodactylidae), a new rainfrog from
the Cordillera de Talamanca, Costa Rica is described. The new form belongs to
the Eleutherodactylusfitzingeri group, and can be distinguished from the other
members ofthis group from Lower Central Americaby the combination ofbasal
toe webbing,—no heel tubercle, and its distinctivegray-whiteghost-likecoloration.
Resumen. Se describe una nueva especie, Eleutherodactylus phasma, de la
Cordillera de Talamanca al sureste de Costa Rica. Esta nueva forma puede ser
distinguida de las otras por las membranas interdigitales en lo base de los dedos,
la ausencia de un tuberculo del talon, y la coloracion inusual de bianco y gris.
In March 1992 the first author collected housed at the University of Miami, to be
an unusually colored frog of the genus deposited in the LACM) an adult female
Eleutherodactylus in the southern Cordil- from Costa Rica: Puntarenas Province,
lera de Talamanca of Costa Rica. Aside Canton Coto Brus, Zona Protectora Las
from the black eyes and a scattering of Tablas, Finca Jaguar, 8°55'N, 82°44'W on
black markings on the head and hindlimbs, the Rio Coton; ca. 20 km NNE of La Lu-
the dorsal and ventral surfaces were a uni- cha, 1850 m elevation; taken 1 March 1992
form ghost-like gray-white. by Karen R. L—ips.
Initially we thought this specimen might Etymology. The species name is de-
be apartial albino ofone ofthe several spe- rived from the Greek phasma meaning an
cies of the genus from the same region. apparition or spirit, in reference to the
However, further study indicated that this ghost-like app—earance of this white frog.
frog differed from all congeners in signifi- Diagnosis. The new species is a mem-
cant morphological features. berofthe Eleutherodactylusfitzingeriseries
Subsequent fieldwork in the same area in and fitzingeri species group as defined by
1993 and 1994 failed to uncover additional Savage (1987). Within the. fitzingeri group
examples of this form which we now be- it shares with a number of taxa {Eleuthero-
lieve represents a distinctive taxon. Conse- dactylus cuaquero, E. emcelae, E. monni-
quently, we describe this specimen below chorum, and E. rayo) the features of basal
in order that it may be included in the sec- toe webbing and emarginate disk covers on
ond author's handbook on the herpetofauna some digits. The webs between toes III-IV
of Costa Rica. Because ofits ghost-like ap- extend at most only slightly distal to the
pearance, this specimen is to be called: proximal subarticular tubercles in these
forms. In most other members ofthefitzin-
Eleutherodactylus phasma, new species geri group from Lower Central America
— Fig. 1 (Eleutherodactylus andi, E. crassidigitus,
Holotype. CRE 5331 (Costa Rican Ex- E.fitzingeri, E. longirostris, and E. ranifor-
peditions, the private collection of JMS mis) the toe webs are moderate to extensive
VOLUME 109, NUMBER4 745
Fig. 1. Holotype ofEleutherodactylusphasma (CRE 5331) in life.
and minimally encompass the proximal su- comparison, lacks a tarsal fold and has a
barticular tubercles on all toes. The new finely tuberculate dorsum and black eye
form differs from E. emcelae, E. monnicho- mask.
rum, and E. rayo most obviously in lacking The only other form with which the new
a definite large heel tubercle. species might be confused is E. cuaquero
Eleutherodactylus phasma also differs ofthe Cordillera de Tilaran ofnorthwestern
from E. talamancae, a lowland species of Costa Rica (Savage 1980). Eleutherodac-
thefitzingeri group having basal toe webs, tylus phasma differs from that species
in the predominantly gray-white dorsum, (characters for E. cuaquero in parentheses)
flanks, limb surfaces, and venter. In E. tal- in having smaller disks on fingers III-IV,
amancae, the upper surfaces are tan to dark their width being less than the length ofthe
brown with some darker markings, the pos- inner metatarsal tubercle (greater in E. cua-
terior thigh is uniform, pale yellowish- quero), and in having a uniform gray-white
brown to reddish and suffused with red in ventral and posterior thigh surface (venter
life, as is the groin region. Eleutherodac- bright yellow, suffused with pink posteri-
tylusphasma differs from E. talamancae in orly and posterior thigh with yellow-white
that it has a weak tarsal fold, the skin of lines and spots on dark brown ground col-
the dorsum smooth, and it lacks a dark eye or). Eleutherodactylus melanostictus, a
mask. Eleutherodactylus talamancae by member of thefitzingeri group that is sym-
746 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
Fig. 2. Diagram ofA) hand and B) foot ofholotype, showing characteristics ofwebbing, tubercle, anddisk
shape. Bar indicates A) 3 mm and B) 5 mm.
patric with E. phasma, is easily distin- upper eyelid smooth. Tympanum distinct,
guished from it by lacking any trace of toe elliptical, vertical diameter slightly more
webbing and having a distinctheel tubercle, than Vi length of orbit; bordered above and
granulate venter and the posterior thigh sur- posteriorly by a distinct glandular ridge.
face marked with vertical bars and scarlet Dorsum, flanks and upper limb surfaces
interspaces. — smooth. Finger I longer than II when ad-
General characteristics. Head relative- pressed together; relative finger lengths III
ly narrow, slightly longer than broad; snout > IV > I > II (Fig. 2a). Disk on finger I
subovoid in dorsal outline; snoutprofile ob- rounded, slightly wider than finger. Disk on
tuse. Canthus rostralis sharp. Loreal region finger II slightly expanded and truncate.
obtuse, upper lip not flared in cross section. Disks on fingers III and IV expanded, that
Choanae ovoid, slightly smaller than vo- of III truncate, emarginate, almost twice as
merine tooth patches; posterior but internal wide as finger, width equals that of tym-
to choanae, widely separated on midline. panum; disk pads broadened and truncate.
Surface of head smooth, without pustules; Subarticular tubercles under fingers round
VOLUME 109, NUMBER4 747
in outline, globular in profile, and slightly real length 14.8 (30.8); vertical tympanum
projecting; no supernumerary tubercles; diameter 3.7 (7.6); hind limb length 89.9
thenar tubercle large, elongate; palmar tu- (187.7); tibia 31.—7 (66.3).
bercle very large, cordate; no obvious ac- Distribution. Known only from the
cessory palmar tubercles. No distinct heel type locality in the Lower Montane Rain-
tubercle or calcar. Toe disks smaller than forest (Holdridge 1982) in the Cordillera de
finger disks, disk on III larger than disks on Talamanca of Costa Rica near the Panama
m
other toes, equal to disk on finger II; disks border at 18—50 elevation.
on toes II-IV truncate, palmate and only Remarks. The type specimen was col-
slightly expanded on toes I and V. Relative lected from the rocky banks ofthe Rio Co-
toe lengths IV > III > V > II > I; toe III ton during arainy afternoon in the early wet
much longer than toe V (Fig. 2b). Slight season. This site is within a transect that
basal toe webbing between toes I-IV; toe was monitored at intervals of 1-4 d over a
webbing formula 12 -2^4112 -3V4III3 period of 24 months from July 1991-June
-4V4YV4V4 -2%V. Subarticular tubercles un- 1994. No other specimens were ever seen.
der toes round, slightly projecting, globular The addition ofE. phasma brings the to-
in profile. No supernumerary norplantartu- tal number of Eleutherodactylus species at
bercles; inner metatarsal tubercle well-de- this site to seven: E. crassidigitus, E. cruen-
veloped, elongate; outer metatarsal tubercle tus, E. hylaeformis, E. melanostictus, E.
moderate and low; weak inner tarsal fold phasma, E. podiciferus, E. punctariolus.
present. No inguinal gland; venter smooth.
—
Coloration. Dorsal ground color dirty
Discussion
white to faint gray-brown. Scattered small
brown punctuations contribute to gray- On the basis of external morphology
brown tint of dorsum. Scattering of 15-20 Eleutherodactylus phasma clearly belongs
small black spots forming dark blotches to the fitzingeri species group (Savage
posterior and medial to eyes. Upper lips 1987), agreeing with most other members
pale gray-brown to black, color becoming of this stock in habitus and in having a
more distinct along edges of canthus and smooth venter, inner tarsal fold, and some
nasal area. Black line extending from just toe webbing. This assignment is further
anterior to eyes, along edge ofupper eyelid confirmed by an examination of the jaw
and posterior to eye; upper \ oftympanum muscles. As noted by Lynch (1986) and
colored similarly, with eye line continued Savage (1987), ihQ fitzingeri group is part
posterior to tympanum, but interrupted dor- ofthe Middle American clade or "subgenus
sally. Two black spots on posteriortibiaand Craugaster", characterized by having only
knee of left leg. Right knee slightly suf- an extemus superficialis mandibular adduc-
fused with same dark gray-brown color. Tu- tor muscle. Eleutherodactylus phasma has
bercles offeet also colored gray-brown. Re- a mandibular depressor arrangement (dfsqt)
mainder of all dorsal, ventral and lateral ar- typical of thefitzingeri group.
eas dirty white to light gray-brown. Jaw Relationships among the species within
muscle formula (after Savage 1987) dfsqt the fitzingeri group remain obscure. Eleu-
+ e. — therodactylus melanostictus of montane
Measurements. Measurements were Costa Rica and western Panama (no toe
taken following Lynch and Duellman webs, granulate venter) and E. talamancae
mm
(1980). Standard length (SL) 47.9 (all of the Atlantic lowlands from Nicaragua to
measurements in mm, those in parentheses eastern Panama, (no tarsal fold) are outliers
given as percent of SVL); head length 19.5 in the range of interspecific variation in
(40.8); head width 18.5 (38.6); length of these characters. Lynch (1985) suggested
eye 6.2 (13.0); snout length 6.6 (12.7); lo- that the emarginate disks ofE. emcelae and
748 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
E. monnichorum, both of montane western Organization forTropical Studies (OTS) for
Panama, and E. melanostictus formed a processing permits and Lie. Miguel Rodri-
synapomorphy for this subset of species. guez R. ofthe Servicio de Parques Nacion-
Savage (1987) noted that most species in ales del Ministerio de Recursos Naturales,
the fitzingeri group have some emarginate Energia, y Minas de Costa Rica for issuing
digital disks, and that marked differences collecting permits. KRL's fieldwork was
exist in toe webbing (absent to moderate), supported by ASIH Gaige Fund, SSAR
heel tuberculation (present or absent) and Grants-in-Herpetology, Explorer's Club,
posterior thigh coloration (uniform to large OTS Pew/Mellon Fellowship, University of
light spots or dark bars) among these spe- Miami Tropical Biology Fellowship, Amer-
cies. While these features in various com- ican Museum of Natural History Roosevelt
binations aid in species recognition, we lack Fund, and the National Geographic Society.
confidence that their occurrence in two or This work was also supported by the Na-
more species contains phylogenetic infor- tional Science Foundation under Grant No.
mation (i.e. are non-homoplasious). DEB-9200081 to JMS.
Although E. phasma is similar in mor-
phological features to E. cuaquero (see di-
Literature Cited
agnosis above), they differ markedly in col-
oration and to a lesser extent in habitus.
Holdridge, L. 1982. Life zone ecology. Tropical Sci-
Eleutherodactylus cuaquero appears to be a ence Center, San Jose, Costa Rica.
more robust species but has much longer Lynch, J. D. 1985. A new species of Eleutherodac-
legs (227-230% of standard length) than E. tylus from w—estern Panama (Amphibia: Lepto-
phasma. In these features and in the size of dactylidae). Herpetologica41:443-447.
finger disks III-IV, the new form most . 1986. ThedefinitionoftheMiddleAmerican
closely resembles the sympatric E. crassi- clade of Eleutherodactylus based on j—aw mus-
m culature (Amphibia: Leptodactylidae). Herpe-
digitus, a wide-ranging (40-1800 eleva- tologica 42:248-258.
tion) species found in Costa Rica and Pan- , & W. E. Duellman. 1980. TheEleutherodac-
ama. Eleutherodactylus crassidigitusdiffers tylus ofthe Amazonian slopes ofthe E—cuador-
markedly from E. phasma in having more ian Andes (Anura: Leptodactylidae). Occa-
toe webbing than any other member of the sional Papers Museum ofNaturalHistory, Uni-
versity ofKansas 69:1-86.
fitzingeri group (modal formula: 12" -IWWi Savage, J. M. 1980. A new frog of the genus Eleu-
-3-III2 -3y2lV4- -IViV), predominantly therodactylus (Leptodactylidae) from the Mon-
—
brown upper surfaces and a uniform brown teverde Forest Preserve, Costa Rica. Bulletin
to reddish brown posterior thigh. ofthe Southern CaliforniaAcademy ofScience
79:13-19.
Acknowledgments . 1987. Systematics and distribution of the
We thank the family of Miguel Sandi C. MEleexuitchaenroadancdtyCleunstraglolAlmmeerriicgarnourpa.in—frFoigesldoifantah-e
for their assistance to KRL. We thank the Zoology n.s. 33:1-57.