Allobates flaviventris is a medium-sized Dendrobates frog species with a mean snout-vent length in males of 18.8 mm (range 16.7 - 19.7) and in females of 20.4 mm (range 19.3 - 21.1). This species has a slender body, a head wider than longer, and a general head width that is 31.4% of snout-vent length. The snout is blunt, broadly rounded to nearly truncate in dorsal view and acutely rounded in lateral view; the snout is 21.5% of the head length. The internarial distance is 50% of head width. The distance from the corner of the eye to center of the nostril is 1.25 times greater than the eye length. Nostrils are lateral, slightly protuberant, and opening posterolateral. The tympanum is round and posterolaterally directed with an inconspicuous tympanic membrane. The tympanic annuli are 46.9% of the eye diameter. The tongue is nearly twice as long as wide, attached anteriorly, fringed along posterior margin. The median lingual process is absent, vocal sac and vocal slits present, choanae small placed anteriorly, maxillary teeth present. Skin on dorsum granular, but granulations are weaker on head than dorsum. The skin is also granular on dorsal surface of legs, but skin smooth on ventral surfaces. Dorsolateral stripe absent; ventrolateral stripe diffuse consisting of small spots near upper lip and becoming more intense posterior to tympanum and reaching the groin. The forearm is slender, 88.3% of upper arm. Ulnar folds are absent. Relative finger lengths are III>I>II>IV with finger I longer than finger II when appressed, Basal webbing between fingers absent as is the subarticular tubercle in finger III absent. Finger III is not swollen. The disc width of finger III is 0.5 mm. Relative toe lengths are IV> III> V> II> I. Webbing is absent between toes III and IV (Melo-Sampaio et al. 2013).
Allobates flaviventris is diagnosed by the following combination of characteristics: median lingual process absent; canthus rostralis rounded in both lateral and dorsal profile. Dorsolateral stripe absent in both sexes; ventrolateral stripe represented by irregular spots in males, but present in females; short, diffuse oblique lateral stripe present only in inguinal region in both sexes. Males with gray to violet-gray throat and golden-yellow belly; females with yellow throat and golden-yellow belly. Finger III of males not swollen in both sexes, disc on finger III wider than diameter of finger; basal webbing absent on hands. Webbing absent between toes III and IV; relative toe length IV> III> V> II> I. In general, Allobates flaviventrisï¿½ lack of color patterns differentiates it from the aposematic Allobates. Its yellow venter differentiates it from non-Amazonian Allobates, and its larger size differentiates it from A. insperatus and A. niputidea while at the same time it is smaller than A. kingsburyi. The unswollen finger III and dorsal pattern differentiates the species from A. fuscellus and A. gasconi respectively. Its advertisement call differentiates it from A. grilisimilis and A. marchesianus (Melo-Sampaio et al. 2013)
The dorsum color of Allobates flaviventris usually varies from light grayish brown to brown with pale cream. It also has brown hourglass markings, sometimes diffuse, diamond, or triangular, extending from between orbits to sacral region. Surface of upper arm is pale cream-tan; upper surfaces of legs are light brown with dark brown cross bands on thigh, legs, and feet in many specimens. Adult males have violet-gray throats with evenly dispersed melanophores on vocal sac. The chest and belly are golden yellow. A dark line is sometimes present on the lower lip. Adult females have pale yellow center parts of their throat and chest. The belly coloration is cream, yellow, or golden yellow. Lateral and ventral surface of the thigh are golden yellow. The posterior surface of legs and feet are light gray and the internal surface of the arm golden yellow. An oblique lateral stripe colored pale gray to pale brown, forming several diffuse areas is present, extending from groin to middle of body or sometimes insertion of arm. A ventrolateral band consisting of a series of white, irregular, elongated spots is found extending from anterior corner of eye to groin. The iris is bronze centrally with metallic gold edges and black reticulations. The pupil is uniform black. In preservative, the "hourglass" pattern on dorsum of specimens is sometimes slightly darkened in the central region of the back (Melo-Sampaio et al. 2013).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Bolivia, Brazil
This species is known from southwestern Amazonia, in the states of Acre (municipalities of Senador Guiomard and Rio Branco) and Amazonas, Brazil. Also known from Cobija, Departamento Pando, in Bolivia (Melo-Sampaio et al. 2013).
Life History, Abundance, Activity, and Special Behaviors
Allobates flaviventris inhabits open forest with bamboo near streams. The tadpoles are carried by adult male into small ponds on forest floor. Call is composed of two notes, ranging from 18 to 37 calls/min (Melo-Sampaio et al. 2013).
Trends and Threats
While not yet accessed by the IUCN, habitat loss and fragmentation from logging is a noted threat to this species (Melo-Sampaio et al. 2013).
Possible reasons for amphibian decline
General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
The species authority for Allobates flaviventris is: Melo-Sampaio, Souza & Peloso 2013
The species epithet, flaviventris, comes from the Latin flavo, meaning yellow and ventris, meaning ventral surface or belly and refers to the golden-yellow bellies in both sexes (Melo-Sampaio et al. 2013).
Melo-Sampaio, P.R., Souza, M.B., Peloso, P.L.V. (2013). ''A new, riparian, species of Allobates Zimmermann and Zimmermann, 1988 (Anura: Aromobatidae) from southwestern Amazonia.'' Zootaxa, 3716(3), 336–348.
Written by: Paulo Roberto Melo-Sampaio (2013-10-02)
Edited by: Ann T. Chang (2013-10-02)
Species Account Citation: AmphibiaWeb 2013 Allobates flaviventris: Yellow-bellied stream frog <https://amphibiaweb.org/species/8072> University of California, Berkeley, CA, USA. Accessed Apr 14, 2021.
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Citation: AmphibiaWeb. 2021. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 14 Apr 2021.
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