Anomaloglossus roraima are small-sized frogs in which adult males have average snout-vent lengths of 16.5–19.0 mm and adult females on average are 16.5–19.3 mm. Head wider than long, greatest width 36% of snout-vent length in males and 35% in females. Snout rounded in lateral view, extending past lower jaw, broadly rounded in ventral and dorsal views. Nares located close to tip of snout, directed posterolaterally; nares visible from front, barely visible from above and not visible from below; internarial distance 33% of greatest head width in both sexes. Canthus rostralis barely defined, rounded; loreal region concave, sloping outward to lip. Interorbital distance slightly shorter than eye length, shorter than upper eyelid. Snout length 104% of eye length in both sexes, 45% (in males) to 46% (in females) of head length; distance from anterior corner of eye to posterior margin of naris 60% (in males) to 62% (in females) of eye length. Postrictal tubercles usually few and inconspicuous. Tympanic membrane poorly recessed, inconspicuous, round, much smaller than eye, concealed posterodorsally by a more or less prominent supratympanic swelling; tympanic annulus usually detectable anteroventrally. Dorsal skin texture fairly variable, from smooth (uncommon) to finely granular, becoming more granular posteriorly and on hind limbs; ventral skin smooth to shagreen. Dorsal surface of hind limbs granular, with usually two distinct symmetrical enlarged tubercles located laterally between urostyle and vent. Forearm subequal to upper arm length, no distinct ulnar fold, but sometimes a row of low tubercles instead. Hand moderate, its length 27% (in males) to 28% (in females) of SVL; hand length 77% (in males) to 79% (in females) of greatest head width. Relative length of fingers III > IV > II > I. Fingers unwebbed. Discs of fingers expanded, disc on Finger IV slightly widest. Fingers with narrow pre- and postaxial unfolded fringes, Finger III faintly swollen in some males (preaxial and postaxial keeling weakly more developed than in females, only visible under magnification. Palmar tubercle large, rounded to ovoid; thenar tubercle smaller, elliptical; one, rarely two round to ovoid subarticular tubercles (one each on Fingers I and II, usually one — rarely two — each on Fingers III and IV, with distal tubercle on these fingers usually barely detectable). No distinct outer metacarpal fringe. Tip of Finger IV reaching or surpassing the base of the distal subarticular tubercle on Finger III when fingers adpressed (when the distal subarticular tubercle on Finger III is visible, which is rarely the case). No fleshy supracarpal fold atop wrist. Hind limbs moderately robust, moderately long, with heel of adpressed leg reaching posterior to anterior corner of eye; tibia 51% (in males) to 52% (in females) of SVL. Relative lengths of adpressed toes IV > III > V > II > I; first toe short, usually, but not always reaching the base of subarticular tubercle of second toe. Toe discs moderately expanded, subequal or slightly larger than finger discs. Feet unwebbed, although rudimentary webbing is sometimes present between Finger III and IV; toes with narrow pre- and postaxial unfolded fringes that are best visible under magnification. Inner metatarsal tubercle small, elliptical; outer metatarsal tubercle small, round, between half and two-third the size of the inner. One to three round to ovoid subarticular tubercles (one each on Toes I and II, two each on Toes III and V, and three on Toe IV, with distal tubercle on Toe IV the smallest and least conspicuous). A medial metatarsal tubercle is detectable at least on one side in 50% of the specimens examined. Outer metatarsal fold absent. A straight or weakly curved tuberclelike tarsal keel not extending from metatarsal tubercle.
Maxillary teeth present, small (Kok et al. 2013).
Anomaloglossus roraima can be distinguished from other geographically overlapping Anomaloglossus because their adult females are smaller, reaching less than 20 mm snout-vent length and because A. roraima do not have toe webbing (Kok et al. 2013).
In life the dorsal background color varies from tan to shades of light brown, sometimes monochromatic, but often with dark brown pigment arranged as limited to heavy mottling; the mottles having no particular shape. The upper surface of arm and forearm are slightly lighter than dorsal background color, sometimes reddish. The upper arm also displays tiny, faint white dots and the forearm has 1–3 transverse dark brown bands. Upper surface of thigh, shank, and heel are identical with dorsal background color and having 1–3 transverse dark brown mottles often forming poorly distinct bands. Dorsal background color is set off from flanks by the same quality of dark brown pigment as dorsal mottles, forming along the contact a poorly defined, slightly lighter, narrow dorsolateral stripe. Dark flank pigment runs posterior from the naris through the middle of the eye and expands to the top of the shoulder arching over the tympanum. Posterior to the shoulder, the flank pigment is sometimes continuously dark brown but in other examples breaks up into the same kinds of mottles mixed with dorsal ground color as on the back. Upper lip under the naris posterior to the shoulder the same uniformly tan to light brown dorsal background color, but sometimes invaded partially by dark flank pigment. Belly yellowish to light rusty color in both sexes, but sometimes heavily suffused with dark brown, uniform or mottled pigmentation in some males. Chin undersurface slightly lighter in tone, sometimes with a few dark brown mottles or completely suffused with dark pigment. The undersurfaces of front and hind legs are darker in tone than the belly and often mottled or completely suffused with dark brown pigment. The undersurfaces of hands, feet, and toes are uniformly dark brown. Toe tips of manus and pes dorsally dark brown set off prominently from the lighter colored dorsal ground color of the rest of the toes by a sky blue narrow transverse band. Iris light rusty brown above, dark brown pigment through the middle of the eye, light rusty brown below. When preserved, the yellow and red pigments disappear leaving only dark gray to brown pigments uniformly suffused over the dorsum and prominent as transverse bands across the forearm, thigh, shank, heel, and foot. Brown pigment also is present on the toe tips, undersurfaces of the manus, pes, forearm, heel, anterior and posterior surfaces of the forearm, and lightly suffused over the dorsal surfaces of the legs between the darker crossbands. The belly, chin, and undersurfaces of the upper arm, leg, and shank are pigmentless (Kok et al. 2013).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Venezuela
Anomaloglossus roraima is currently known only from the upper slopes and summits of three tepuis in southeastern Venezuela and western Guyana: between 1860 – 2700 m elevation on the slopes of Mount Roraima (type locality, currently the westernmost known locality), between 2200 – 2300 m elevation on the summit of Wei-Assipu-tepui, and between 2000 – 2100 m elevation on the summit of Maringma-tepui (currently the easternmost known locality). Anomaloglossus roraima seems restricted to tepui scrub and high-tepui meadow at elevations between 1860 – 2700 m and is probably restricted to the eastern part of the Eastern Pantepui District. It is expected to be discovered in suitable habitat between Mount Roraima and Maringma-tepui in Guyana (e.g. on Yakontipu-tepui and on Appokailang-tepui, both still unexplored herpetologically), and likely between Mount Roraima and Kukenan-tepui in Venezuela (Kok et al. 2013).
Life History, Abundance, Activity, and Special Behaviors
Anomaloglossus roraima breeds in the large terrestrial bromeliad Brocchinia tatei. The species is locally common and was found sympatric with A. praderioi on the upper slopes of Mount Roraima only. All specimens were collected during the day, in large terrestrial tank bromeliads or on the ground close to these bromeliads, usually along rivulets and small puddles. A very small juvenile was collected moving on the ground close to bromeliads, another one was found during patch sampling (5 × 5 m patch) among plant rootlets under the ground. Males emitted vocalizations the entire day, but significantly more males were calling during misty days. The advertisement call consists of a single note repeated at a rate of 8.5 – 17 notes/min with a dominant frequency ranging from 4107 to 4362 Hz. Courtship was not observed. Eggs are deposited in low number (ca. five) on the leaves of terrestrial tank bromeliads. The tadpole is large, black, exotrophic, arboreal, LTRF 2(2)/3. No male was found carrying tadpoles on his back, and it is hypothesized that reproduction in this species is similar to that in its sister species Anomaloglossus beebei. Up to 29 tadpoles were found in a same bromeliad phytotelma, which indicates that several clutches can be deposited in a same plant (Kok et al. 2013).
Also found in the breeding sites of A. roraima at Wei-Assipu-tepui and at the base of the ultimate cliffs of the “Prow” of Mount Roraima were small (< 15 cm), brown earthworms (Clitellata: Glossoscolescidae) and a small aquatic cricket, Hydrolutos roraimae (Orthoptera: Anostostomatidae), the latter may be a predator on frog eggs and tadpoles (Kok et al. 2013).
Trends and Threats
Populations currently seem stable, but due to its restricted range (area of occupancy severely fragmented and estimated to be less than 2000 km2, with species found at less than 10 locations) and continuing decline of habitat quality caused by (1) the many local fires affecting tepui slope vegetation ignited by Amerindians in Venezuela, (2) an increase of mostly unregulated tourism on Mount Roraima, and (3) global warming the species is at risk, hence the re-description authors suggest classifying it as Vulnerable according IUCN criteria (Kok et al. 2013).
Possible reasons for amphibian decline
Subtle changes to necessary specialized habitat
Climate change, increased UVB or increased sensitivity to it, etc.
The species authorities for Anomaloglossus roraima are La Marca (1998), who wrote the original description based on a single immature specimen and Kok et al. (2013), who re-description of the species based on more than 20 individuals.
Anomaloglossus roraima was named after the type locality, Mount Roraima in Venezuela (La Marca 1998).
Anomaloglossus roraima is sister to A. beebei. Both species are the only known Anomaloglossus that use bromeliad phytotelmata as habitat for their larvae. Kok et al. (2012, in their Supplemental Information) showed that the clade containing A. beebei, which have arboreal tadpoles and trophic egg-laying, and A. roraima, which are highly hypothesized to have trophic egg-laying, are sister to a clade containing A. kaiei, A. praderioi, and a still undescribed taxon from Mount Wokomung (lentic tadpoles. Anomaloglossus kaiei also have confirmed trophic egg-laying, and trophic egg laying is possible in A. praderioi and the still unnamed taxon. The clade containing these species with arboreal/lentic tadpoles diverged from clades containing species mostly with lotic or endotrophic tadpoles (Kok et al. 2012 and 2013).
Kok P.J.R., MacCulloch R.D., Means D.B., Roelants K., Van Bocxlaer I., Bossuyt F. (2012). ''Low genetic diversity in tepui summit vertebrates.'' Current Biology, 22, 589-590.
Kok, P.J.R., Willaert, B., Means, D.B. (2013). ''A new diagnosis and description of Anomaloglossus roraima (La Marca, 1998) (Anura: Aromobatidae: Anomaloglossinae), with description of its tadpole and call.'' South American Journal of Herpetology, 8(1), 29-45.
La Marca, E. (1998). ''Ranas del género Colostethus (Amphibia: Anura: Dendrobatidae) de la Guyana Venezolana con la descripción de siete especies nuevas.'' Publicaciones de la Asociación de Amigos de Doñana, 9, 1-64.
Written by Philippe J. R. Kok (philippe.kok AT naturalsciences.be), Royal Belgian Institute of Natural Sciences & Vrije Universiteit Brussel, Belgium
First submitted 2013-06-05
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