FIG. l.-Ho lotype of Dendrobates sirensis, NHMW 31892, SVL = 16.8 mm.

VOL. 47

HERPETOLOGICAMARCH 1991 NO.1

Herpetologica , 47(1), 1991, 1-5© 1991 by The Herpetologists League, Inc.

A NEW SPECIES OF POISON-DART FROG(ANURA: DENDROBATIDAE) FROM

THE SERRANiA DE SIRA, PERU

MANFRED AICHINGER

Zoologisches lnstitut , Univ ersitiit Wien ,Althanstraj3e 14, A-1090 Wien, Austria

ABSTRACT: A new species of poison-dart frog, Dendrobates sirens is, is described from theSerrania de Sira , an isolated mountain range in east-central Peru, Departamento Huanuco, at anelevation from 750-1560 m. Adult specimens have a snout-vent length of 15-17 mm. The speciesis easily diagnosed from all dendrobatids by the uniform red coloration of the dorsum and theturquoise-green limbs.

Key words: Anura; Dendrobatidae; Dendrobates sirensis; Peru

THE Serrania de Sira is an isolatedmountain range in the upper Amazon ba­sin between the Rio Pachitea and the RioUcayali in east-central Peru. The highestelevations are about 2400-2500 m (Ter­borgh and Weske, 1975) . For an approx­imate location of this mountain range, seeDuellman and Toft (1979) . Our expeditionfollowed the same route to the Serrania deSira as described by Terborgh and Weske(1975) . Duellman and Toft (1979) first re­ported on a collection of anurans from thisregion, including the dendrobatids Col os­tethus marchesianus, Phyllobates (nowEpipedobates) petersi, and P. (now Epi­pedobates) pictus. During a herpetologicalsurvey from September 1987 to October1988, five specimens of the poison-dart frogwere captured. This new species was col­lected first in the Serrania de Sira in 1976by Werner Hanagarth.

METHODS

Nineteen different measurements (to thenearest 0.1 mm) were made following My­ers (1982). The condition of the om oster-

1

num was judged by dissection. Specimensare deposited in Naturhistorisches Muse­um Wien (NHMW) and Museo de HistoriaNatural "Javier Prado" in Lima (MHNJP).One paratype is in the collection of Staat­liches Museum fiir Naturkunde Stuttgart(SMNS) . Museum abbreviations followFrost (1985).

Dendrobates sirensis sp. nov .Fig. I-Frontispiece

Holotype.-NHMW 31892 (Fig . 1), anadult female, collected on a horizontal tree1.2 m above a stream in the Serrania deSira, Rio Llullapichis drainage, 750 m, De­partamento Huanuco, Peru (9°28' S, 74°47'W), on 10 September 1987, at 0910 h byM. Aichinger.

Paratypes.-MHNJP 11518 and MHN­JP 11519, adult males, same location asholotype, 780 m, on the ground , on 20March 1988, at 1530 h and at 1250 m, inSeptember 1988, both by B. Wallnofer ,SMNS 07092, adult male, same location ,at 1560 m, on the ground , on 23 January1976, by W. Hanagarth.

2 HERPETOLOGICA [Vol . 47 , No.1

Diagnosis.-A very small dendrobatidhaving an adult snout-vent length (SVL)of about 15-17 mm (three males 14.7-15.4mm , 1 female 16.8 mm). Skin on backslightly granular, moderately granular onventer, and smooth on limbs; dorsum uni­form dark red, arms and legs turquoise­green, venter turquoise-green with a rec­tangular red patch on the belly, chin red;neither spots nor reticulation present dor­sally; teeth absent; first finger much shorterthan second; finger discs very conspicuous,enlarged to at least twice finger width;omosternum absent ; tympanum visiblyconcealed posterodorsally.

D. sirensis is tentatively assigned to thequinquevittatus group as characterized bySchulte (1981) , Myers (1982), and Zim­mermann and Zimmermann (1988). It dif­fers from all members of this group (D.captivus, D . fantasticus, D . imitator, D .mysteriosus, D. quinquevittatus, D . retic­ulatus, D. vanzolinii, D. variabilis) by itsuniform red dorsum, its unreticulated feetand venter, and its turquoise-green limbs.Dendrobates sirensis may be confused withother small poison-dart frogs of the genusDendrobates or Minyobates, like D. gran­uliferus, D . pumilio, D . speciosus, M .opisthomelas, and M. steyermarki, whichall have a bright red dorsal coloration.Dendrobates sirensis differs from D . spe­ciosus, M. opisthomelas, and M. steyer­marki in having turquoise-green limbs,from D . granuliferus in having only aslightly granular skin, and from D. pumilioin having a rectangular red patch on theturquoise-green belly .

Description.-Size small, SVL of adults14.7-16.8 mm; (three males 14.7-15.4 mm;one female 16.8 mm): head narrower thanbody; in all specimens, greatest head width32-34% of SVL. Males lacking vocal slitsand vocal sacs. Teeth absent, omosternumabsent.

Skin on the back is slightly granular inlife, moderately granular on venter, andsmooth on limbs. Snout subtruncate in dor­sal aspect and sloping in lateral aspect (Fig.2). Naris situated near tip of the snout anddirected laterally; both nares visible fromfront and from below but not from above.Canthus rostralis rounded; loreal region

more or less flat. Interorbital area widerthan upper eyelid. Center of naris to edgeof eye/eye length = 0.75-0.86. Tympa­num seemingly vertically elliptical, butconcealed posterodorsally; its approximat­ed diameter 56-64% of the eye length.

Hand relatively large (Fig. 3); its length(proximal edge of metacarpal tubercle totip of longest finger) 78-87% of greatesthead width; relative length of adpressedfingers 3 > 4 > 2 > 1; adpressed first fingerroughly three-fourths the length of secondfinger. Discs conspicuously expanded onall but first finger . Disc of third finger 2­2% times wider than distal end of adjacentphalanx; widths of discs without apparentsexual dimorphism. A circular metacarpaltubercle at base of palm, a smaller innermetacarpal tubercle at base of first finger ,and one or two usually prominent subar­ticular tubercles on fingers (one each onfingers 1, 2, 4, two on finger 3). Distalsubarticular tubercle on finger 3 small andinconspicuous, but all other tubercles onhand prominently raised; surfaces of discsrounded; lack of pigment contributing toprominent appearance of tubercles.

Hind limbs of moderate length, withheel of adpressed limb reaching tympa­num. Tibia 36-39% of SVL. Relative lengthof adpressed toes 4 > 5 > 3 > 2 > 1; firsttoe short, reaching bottom of subarticulartubercle on base of second toe, and withunexpanded disc; other toes with discs dis­tinctly expanded (but smaller than fingerdiscs) . Moderate-sized inner and small out­er metatarsal tubercles, somewhat protu­berant but with rounded surfaces. One tothree subarticular tubercles (slightly pro­tuberant tubercles, one each on toes 1, 2,two each on 3, 5; nonprotuberant tuber­cles, one each on toes 3, 5, three on toe 3).Hands and feet lack webbing, supernu­merary tubercles, or a lateral fringe (Fig .3).

Measurements (in mm) of holotype.­The holotype is a female containing twomature ovarian eggs in both ovaries. Mea­surements of paratypes are given in Table l.

Length from snout-vent 16.8; tibialength from heel to fold of skin on knee6.4; greatest head width (between anglesof jaws) 5.4; head width at level of eyes

March 1991] HERPETOLOGICA

oI

5m m

3

FI G. 2.- Dorsal and lat er al view of the hea d of th eholotype of Dendroba tes sirensis, NHMW 3 1892.

5.3;approximate width of interorbital area2.1; head length from tip of snout to angleof jaw 4.0; tip of snout to center of naris0.8; center of naris to anterior corner ofeye 1.5; distance between center of nares2.0; eye length from anterior to posteriorcorner 1.8; approximated horizontal di­ameter of tympanum because tympanumposteriorl y indistinct 1.0 ; corner of mouthto lower edge of tympanic rin g 0.6.

Length from pr oximal edge of large me­dial palmar tubercle to tip of longest (third)finger 4.7; width of third finger disc 1.1 ;width of third finger (pe nultimate pha­lanx) below disc 0 .5.

Width of di sc of third toe 0.7 ; width ofthird toe proximal to d isc 0 .5; width ofdisc of fourth toe 1.0; width of fourth toe(penultimate phalanx) pr oximal to disc 0.5.

o 5mm

F IG . 3.-Palma r and plantar surfaces of right handand foot of holotype of Dendrobates sire nsis , N H MW3 1892.

Coloration in life.-Head and dorsumdark red , no di stinct spots or str ipes ; tym­panum dark brown; iris black . Arms andlegs turquoise-gr een; turquoise colora tionlighter on th e ante rodorsal side of proxim alhalf of upper a rm and in gro in anteroven­trally on proxim al part of th igh extend ingonto th e bod y. Vente r turquoise-gr een witha rect an gular red pat ch on th e bell y (ap­pr oxim at ely 5 x 3 mrn): chin dark red ;venter below rectangular pat ch and th eventral sur faces of th e legs dark turquoise .Surfaces of palms and soles black .

Parat ype MHNJP 11519 had an indis­tinct brown spot in th e interorbital area.One individual which esca ped from cap­tivit y (sex unknown) showed a di spositionof a rather wide , ill-defin ed red lat er alst ripe exte nd ing horizontally fr om th egroin one -third of the dorsum to th e head(M. Henzl , personal com m unica t ion) . Acolor tr ansparency of this specimen sug­gests that this stripe is not homologous withth e incomplet e oblique lat eral lin e thatch ar acterizes many dendrobatids.

In preservative , th e red coloration ap­pears pale gray; turquoise changes to black.The red colora tion of par at ype MHNJP11519 cha nged to black. Parat ype SMNS07092 became pale brown but th e color­ation in life was as described above (W.Hanagarth , per sonal com m un ica tion).

Life history notes.-The holot ype con ­tained two we ll-developed eggs in bothovaries (d iameter 2.0, 2.1 mrn) as we ll as

4 HERPETOLOGICA [Vol . 47 , No.1

T ABLE I.-Measurements (in mm) from paratypes.

MHNJP MHNJP SMNS11518 11519 7092

Characteristic Male Male Male

Length from snout to vent 14.7 14.8 15.4Tibia length from heel to fold of skin on knee 5.3 5.8 6.0Tibia/SVL 36 .1% 39 .2% 39 .0%Greatest head width (between angles of jaws) 5.0 4.8 4.7Head width/SVL 0.3 0.3 0.3Head width at level of eyes 4.8 4.7 5.1Width of interorbital area 1.6 1.7 2.0Head length from tip of snout to angle of jaw 3.0 3.2 3.8Tip of snout to center of naris 0.7 0.8 0.8Center of naris to anterior corner of eye 1.2 1.2 1.4Distance between center of nares 1.7 1.7 2.0Eye length from anterior to posterior corner 1.6 1.4 1.4Naris-edge of eye/eye length 75.0% 85.7% 100 .0%Horizontal diameter of tympanum (posteriorly indistinct) 0.9 0.9 0.9Diameter tympanum/eye length 56.3% 64.3% 64.3%Corner of mouth to lower edge tympanic ring 0.6 0.6 0.6Length from proximal edge of large medial palmar tubercle

to tip of longest (3rd) finger 3.9 4.0 3.9Length hand/greatest head width 78 .0% 83 .3% 83 .0%Width of third finger disc 0.9 0.9 1.0Width of third finger (penultimate phalanx proximal to disc) 0.4 0.4 0.5Third finger disc /width 3rd finger 2.3 2.3 2.0Width of disc of third toe 0.6 0.6 0.7Width of third toe (penultimate phalanx) below disc 0.4 0.4 0.4Width of disc of fourth toe 0.8 0.6 0.9Width of fourth toe below disc 0.4 0.4 0.4

three small eggs (diameter < 1 mm). Anun preserved female laid a single egg onthe surface of a leaf in a plastic box a fewdays after capture (M. Henzl, personalcommunication) . Individuals are very ag­ile, jumping continuously.

The species seems to be extremely rareor secretive. During one year of investi­gation, only five individuals were observed(two escaped from captivity).

Etymology.-The species is named af­ter the type locality, the Serrania de Sira.

DISCUSSION

Dendrobates sirensis is known only fromthe Serrania de Sira in east-central Peru atan elevation from 750-1560 m and seemsto be endemic in this isolated mountainrange. There it lives in sympatry with D.quinquevittatus, which was found fromthe lowland rainforest at 260 m up to1080 m.

Based on characters that were attributedto the genus by Silverstone (1975), the newspecies is assigned to Dendrobates. These

characters are first finger shorter than thesecond, well expanded finger discs, and abright coloration in life.

Dendrobates sirensis may be highly ar­boreal, judging from the relatively longhand with the well developed discs. Oneindividual showed an indication of lightred lateral stripes. A female contained onlytwo mature ovarian eggs. Considering thesefacts, D. sirensis is tentatively assigned tothe D. quinqueoittatus group. Based oncharacteristic behavioral parameters, Zim­mermann and Zimmermann (1988) attrib­uted the following characters to the quin­quevittatus group: the arboreal frogs livein middle to upper strata in tropical rain­forest; females lay only few eggs; malescarry one or two tadpoles to bromeliads;larvae feed facultatively on unfertilizedeggs laid by the female.

Schulte (1981), Myers (1982), and Zim­mermann and Zimmermann (1988) placedthe following eight species in the quin­quevittatus group: D. captivus, D. fan­tasticus, D . imitator, D . mysteriosus, D.

March 1991] H ER PETO LO GI CA 5

quinqueoittaius, D. reticulatus, D. van­zolinii, and D . variabilis. Myers (1982)could not document a relationship of D .captivus and D . mysteriosus to th e quin­quevittatus group and left th em as possibleclose relatives to th at group. Dendrobat esquinquevittatus is widespread throughoutthe Ama zon Basin , inhabiting primarilylowland rainforest (Lescure and Bechter,1981; Silverstone , 1975). All othe r speciesof the quinquevittatus group occ ur onl yin compa ra tively small ar eas in th e west­ern Amazonian lowl ands (Kne lle r, 1983;Myers, 1982 ; Schulte , 1986; Zimmermannand Zimmermann , 1984, 1988). Dendrob­ates captivus, D . imitator, and D. mys­teriosus may be restricted to single local­ities in montane rainfor est. Except for D .mysteriosus, which is known only from asingle spec imen (Myers, 1982), D . quin­quevittatus lives sym patrically with allother species.

Like Minyobates abditus and M . ste y­ermarki, which Myer s and Daly (1976) as­signed to th e minutus group as defin ed bySilverstone (1975), and M . opisthomelas,Dendrobat es sirensis might be a terminalrelict of an ancestor whose range wa s frag­mented by climatic vegetational changesthat occur red in th e Andes during Qua­ternar y time. F urthe r stud ies on skin al ­kaloids, knowledge of tadpoles, and th ereproductive biology of this species will benecessar y to define th e exact ge ne ric andgroup relationships of D . sirensis.

R ESUM E N

Se describe Dendrobat es siren sis, unanueva especie de batracio ven en oso de laSerrania de Sira , Departamento Huanuco ,Peru , a una elevacion de 750 a 1560 m. Esuna rana diminuta (15- 17 mm) que sepuede facil d istinguir de otros dendroba­tidos por su color acion . La coloracion dor­sal del cuerpo es roja y la de las extre m i­dades, verde turqui.

Acknowledgments.-I thank B, W allnofer for col­lecting specim ens an d M. Henzl for obse rva tiona l

da ta . I am indebted to A. Schliiter (Stu ttgart ) and N.Cari llo (Li m a ) for the loan of specimens. Thanks area lso du e to M. H enzl, W . Hodl, K.-H. Jungf er , A.Schliite r, and E . Zimmermann for ca re fullv review ­ing th e m anuscript and to th e Direccion Ge'ner al Fo­res ta l y de Fauna for permits (06 2-87-AG-DGFF­DR FF-SDFF). F ina ncial support was de rived from"os terreichische r Fonds zur Fiirderung der wissen­schaftlichen Forschung" (projec t P6399B) and "Bun­desm ini ster iu m Iur W issensc haft und Forschung, os­terre ich".

LIT E RATURE CITED

D UELLMA:-I , W . E., AND C. A. TOFT. 1979. Anuransfro m the Serrania de Sira , Amazonian Peru: T ax­onomy an d biogeography. H er pet ologica 35 :60-70.

F HOST, D. R. 1985. Am phib ian Species of the W orld .Allen Pr ess an d th e Associati on of Syste matics Co l­lecti on s, Lawrence, Kansas.

KNELLER, M. 1983. Beobachtungen an Dendroba­tes fantast icus im na tiir lichen Lebensraum un d imTerrarium . Herpetofauna 5 :15-18.

LESCURE, J., Al':D R. BECHTER. 1982. Le comporte­ment de reproduction en captivite et Ie pol ymor­ph isme de Dendrobates quinquevit tatus Stein­dachner. Revu e fro Aq ua rio!. 8 :107- 118 .

MYERS, C. W . 1982. Spo tted poison frogs: Descrip­tion of three new Dendrobates from weste rn Ama­zonia , and resurrecti on of a lost species from "Chi­riq ui" . Am. Mu s. Nov it . 2721 :1-23.

MYEHS, C. W ., ANDJ. W . DALY. 1976. A ne w speciesof poison fr og (Dendrobates) fr om Ande an Ecu a­dor including an ana lysis of its skin toxins . Occ.Pa p. Mu s. Nat. H ist. Un iv. Kan sas 59:1-12.

SCHULTE, R. 1981. Dendrobat es qui nqueoittat us ;iikologie, Haltung und Zucht. Herpet ofauna 3:24­28.

---. 1986. Eine neu e Den drobates-Art aus Ost­pe ru (Am phibia ; Salientia ; Den drobatidae ). Sauria8:11-20.

SILVERSTONE, P. A. 1975. A revision of th e poison­dart fro gs of th e ge nus Dendrobat es W agler. Nat.Hi st. Mu s. Los Angeles Co . Sci. Bull . 21:1-53.

T EHBORGH, J. , ANDJ. S. W ESKE. 1975. The ro le ofcompetit ion in th e d istributi on of Andean bird s.Ec ology 56:5 62-576.

ZIMMERMANN, H. , AND E. ZIMMERMANI':. 1984.D ur ch Nachzucht er ha lten : Baumsteigerfr iischeDendrobat es quinqu evittatus und D. reticula tus.Aq u. Mag. 18:35-41.

1988. Etho- T axon om ie und zoogeogra­ph ische Ar tengruppenbild ung bei Pfeilgift fr iisch­en (Anur a: Dendrobatidae ). Salamandra 24 :125­160.

Accepted: 26 Ap ri l 1990Associate Editor: David Cannate lla