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Technicolored, tiny and often dangerous, the gem-like frogs lurking on the Central and South American rainforest floor come in a dazzling variety of liveries

Spotlight

HEREGOOGLE EARTH COORDINATES HERE

A typical Costa Rican specimen of the Blue-jeans frogOophaga pumilio.

COLORFUL AND POISONOUS DENDROBATIDS

RAINFOREST JEWELSCOLORFUL AND POISONOUS DENDROBATIDS

RAINFOREST JEWELS

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TEXT AND PHOTOS BY CESAR BARRIO AMOROS

I t is well known that some ofthe most appealing anurans in theworld are the colorful and poisonousf rogs be longing to the fami lyDendrobatidae (badly called poisonarrow or dart frogs, as just two ofthem, Phyllobates terribilis and P.bicolor from Chocoan Colombiahave been used by Amerindians topoison their darts). Several spots onthe Neotropics stand out by thediversity of such rainforest jewels,such as the Upper Amazon andlower Central America. As I live insouthern Costa Rica, very close tothe Panamanian border, I have oftenhad the opportunity to explore manytimes the Pacific and Caribbeanrainforests of these two countrieswhere these flamboyant frogs live.This is the realm of the Oophagaspecies and morphs. Oophagapumi l io i s probably the mos tpolymorphic species known amongfrogs. It occurs from mid-Nicaraguato northwestern Panama, but the realvariation occurs in Bocas del Toro.Oophaga granulifera is a much lessknown species, similar in size andhabits to pumilio, with a granulardorsal skin, and a few reported colormorphs. Two more species areknown in the western mountains ofPanama, Oophaga speciosa and O.arborea, but these species are rare,and the first at least has not beenseen for many years in the wild. Alast species, O. vicentei, occurs innorthern Panama, further east, and is

continued on page 102 ›

A yellow-green morph ofOophaga granulifera from

southern Costa Rica.

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Two Oophaga pumiliofrom Matina, province of Limòn, Costa Rica.

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Top left,Oophagagranulifera,yellow morph;top right,Dendrobatesauratus fromMareas;bottom left,Phyllobateslugubris;bottom right,anothervariation ofOophagapumilio, thistime from Isla Colòn,Panama.

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Oophaga pumiliofrom Rio Gloria.

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highly arboreal. Furthermore, twospecies of Phyllobates, P. lugubris atthe Caribbean side of Nicaragua,Costa Rica and Panama, and P.vittatus only on the Costa Rica Pacificside could be the most toxic speciesof poisonous frogs in the region. Oneof the smallest dendrobatids alsooccurs in the area, Andinobatesclaudiae, and although it can bequite abundant in many localitiesboth in the islands and mainland, it isa highly secretive species. The lastand largest species to consider isDendrobates auratus, with severalmorphs, especially in Panama. Let’stake a closer look on each species.

Oophaga granulifera: Endemicfrom southwestern Costa Rica. It is a

terrestrial species living in the leaflitter of the rainforest floor. It is easierto see and hear during the rainyseason when males call usually ontop of exposed perches in the forest.The red and red and blue morphs areeasy to spot among the leaf litter,while the yellow and green morphsare much more cryptic, and could beless poisonous. They u t i l izephytotelmata aquatic microhabitats(especially Dieffenbachia) to laysingle eggs which will be fed with anunfer tile egg laid by females. Atnight they are found sleeping onsmall leaves along creeks.

Oophaga pumil io : From midNicaragua to the Caribbean slopesof Cos ta R ica, a l l morphs are

Right,Phyllobates

vittatus, an endemicspecies fromSouth-westernCosta Rica;

far right,another

Oophagapumilio from Rio Gloria,Panama.

predominantly red; some with blue orblack legs and arms, some with onlyhands and feet blue, some red withdark spots, and some burgundy red.In Panama, the situation changesand as ide of red wi th b lue orcompletely red morphs, in Bocas delToro archipelago and immediatemain land a whole fan of crazyvar ie t ies s tar t to show the mostpolymorphic frog species in theworld. In Isla Colon the dominantcolor is greenish yellow with blackspots and orange or green legs; inSolar te they are pure orange orreddish with or without scatteredsmall black spots; in San Cristobalthey are red to orange with verysmall black spots and blue legs;Bastimentos probably shows the

widest variation on a single island,from red to orange to yellow or whitebackground with more or less blackspots, white flanks and legs. Onmain land a lso there i s a hugevariation, from pure sea blue or withblack spots to violet in AguacatePeninsula to black and whi te inRobalo or yellow with long blackspots or stripes with white and blacklegs, to similarly common blue jeans(red with blue legs) or completely redin the norther sector of mainlandBocas del Toro near the border withCosta Rica. Many questions ariseabout this uncommon and amazingvar ia t ion. Why? Why a s ing lespecies is so variable in colors?What advantages this adaptationgives? Are different morphs more

Right,another

colorful morphof Oophagapumilio from

Isla Bastimentos,Panama;

far right, astriking bluemorph of O.

pumiliofrom the

Aguacatepeninsula,Panama.

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Right, twoOophagagranuliferaamong the dark, wet

forest litter; far right,

a dazzlingspecimen ofDendrobates

auratus.

prone to acquire sexual partners orescape predators than others? Manyinvestigators are still answering theseand many other questions about theadaptation and evolution of thisspecies. In different islands andlocalities in mainland I visited I canrealize how different the variousmorphs are not only in color but alsoin behavior. While in mainland somered morphs are ter res t r ia l , thepainted (black and white and yellowand black: all highly aposematic)ones are arboreal. Same with redand orange morphs in the islands(Solar te , San Cr is tobal andBastimentos), being more terrestrialthan yellow or greenish in Colón forexample; whi le b lue and v io le tmorphs are equally terrestrial and

arboreal. Also is notable a change insize, for example Red and bluepumi l ios (both in Cos ta R ica,Nicaragua and Panama) are muchlarger than spotted or bluish morphs. A paper by the team of Heike Pröhlback in 2007 treated the geneticdiversity finding that three clades arepresent, one north or Rio Reventazónin Costa Rica to Nicaragua, with theavai lable name of Dendrobates(Oophaga) typographus. Anotherclade from the Escudo de Veraguasisland, which would correspond to anew species to describe, and thepumilio sensu stricto from southernCosta Rica and western Panama.Still much investigation must be doneto solve the multiple mysteries of thisoutstanding species.

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Oophaga vecentei: This is a hardspecies to find, due to its highlyarboreal habits. They inhabit largebromeliads from 3 to 20 m above thefloor, and call frenetically all daylong. Only in a few places vicenteican reach the soi l or on largebromeliads. At Santa Fe, Panama,two morphs occur, one red, andother green. We failed to see the redone, on the top of a hill, but despitehearing many calls in the lowlandsaround, we only could see one greenfemale at a large bromeliad 3 mabove the forest floor.

Dendrobates auratus: This is thelargest Dendrobatidae of CentralAmerica, attaining up to 4 cm. It isalso quite variable, especially inPanama. Unfortunately I couldn’t seeyet the mos t as tonish ing co lormorphs. Where I l ive, in Pacif icCosta Rica, they are predominantlyblack with green; in the Costa RicanCaribbean side and close Panama(including Bocas del Toro) are greenwith black; but further east someincredible morphs start to show, likeblack with white or intense blue withblack, or entirely black with smallgreen spots. I only managed to seeone population of chocolate colorwith dirty white, interesting enoughthough.

Andinobates claudiae: On thecontrary, this is the smallest speciesof dendrobatid (with A. minutus) ofCent ra l Amer ica, both bare lysurpassing one cm in length. It was alittle difficult to figure out where itwas to be found. André Schreiber

and I were searching for Phyllobateslugubris and pumilio along a creek ina forest in Isla Colón, when he sawsometh ing he be l ieved to be ajuvenile P. lugubris. Then we heard aweird call, and immediately knewthat it was claudiae. Very fast, andescaping by hopping much longerthan expected, at last we could takea few pictures and then released it.

Phyl lobates lugubris : Th isspecies is the smallest of two inCentral America. It is quite abundantin proper habitats both in Costa Ricaand Panama (I don’t have experienceyet in Nicaragua) , bu t can beextremely rare at others. They arebasically black with two narrowyellow dorsolateral stripes, somewhite spots on flanks and ventrallyand pinkish with black marbled onlegs. Contrary to other aposematicdendrobatids, Phyllobates likes tocall while well hidden in holes orunder debris. They like dark andnarrow ravines, where they can hidein crab holes. At night I have foundthem sleeping on medium sized rocksin small creeks.

Phyllobates vittatus: This largerspecies has also brighter colors,b lack wi th orange to red widerdorsolateral stripes, white and blackreticulation on flanks and venter andbluish with black marbled on legs. Italso inhabits narrow or dark creeksinside holes, and hides immediatelyif they see any danger. This specieshas proven to be the most poisonousspecies in Central America, but notas much as the i r Colombian

A typical portrait ofOophaga granuliferaby a South-westernCosta Rica creek

and waterfall.

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Right, atypical specimen

of Oophagagranulifera;

far right, the lessflamboyantly

patternedPhyllobates

lugubris. The relative size

of the smallforest floor cupmushroom givesa good idea of

how tinyDendrobatids

really are.

counterpar ts. I t is endemic fromsouthwestern Costa Rica.

A final note on my research: I havebeen accompanied in the field bymany colleagues and friends, someof which I guided, some of whichhave guided me. I am highly gratefulto all who share this passion withme: Angel Sosa, Claudia Koch,Eileen Marie Rivera, Gerardo Boa,the Tropical Herping team andAndré Schreiber. In wri t ing thisarticle I simply want to share with allthe amazing variation of colors andmorphs of these beautiful frogs. In nocase I am encouraging collection,and thus, I don’t g ive deta i ledlocalities for any species or morph.

About travelling in Costa Rica andPanama: These two small CentralAmerican countries are easy to visitand quite secure. Just taking normalcare of your belongings and notleaving anything without properattention is enough to enjoy yourtour. In both countries US dollars arewidely accepted. In Costa Rica thereare plenty of good guides that canhelp organizing a trip and getting tothe most incredible places (lookingfor frogs or whatever you want).

I arrange herping tours in Costa Ricaand western Panama, as well asother South American countries.Interested parties can contact mewriting to cesarlba@yahoo.com .