Description
Diasporus lynchi is a relatively small species of golden frog; male snout-vent length ranges from 19.1 to 19.7 mm in three specimens. The snout is long and tapers slightly in the dorsal view but appears flat and truncate in profile. The canthus rostralis has an angular shape with a weak concavity; the loreal region is slightly concave. The upper eyelid has two or three small tubercles and is narrower (54.1 - 60%) than the interorbital distance. It does not have a tympanic membrane, but the tympanum annulus is visible through the skin and has a length approximately 33 - 40% of the length of the eyes. The supratympanic fold is not well defined. The head lacks a cranial crest. Males have vocal slits and a large subgular vocal sac that forms longitudinal folds. It has smooth skin on the back, belly, throat, and the ventral surfaces of the thighs. It lacks a discoidal fold and dorsolateral folds. There are no ulnar tubercles or lack nuptial pads. The hand has an oval-shaped, undivided palmar tubercle and an oval thenar tubercle is oval that is the same size as the palmar tubercle. Finger I is shorter than finger II. The discs on the fingers are slightly wider than the fingers themselves. The disc on finger I is smaller than that on finger II, and both are smaller than the discs on fingers III and IV. The disc cover on the first finger is unornamented, while papillae are present on the second, third, and fourth digits. The fingers have triangular pads and lateral fringes. The fingers also have lateral fringes. Supernumerary tubercles are low and restricted to the proximal segments of fingers III and IV. Subarticular tubercles are low, with a rounded base, and are larger than the supernumerary tubercles. The heel and tarsus lack tubercles and folds. The inner metatarsal tubercle is oval-shaped, with a length four times its width. The outer metatarsal tubercle is low and conical, about one-fourth the size of the inner metatarsal tubercle. There are no supernumerary plantar tubercles, but subarticular tubercles are present. The toes have lateral fringes with basal webbing. Toe III is shorter than toe V; toe III reaches the midpoint between the penultimate and distal subarticular tubercles of toe IV. Toe V extends to the distal edge of the distal subarticular tubercle of toe IV. Discs on toes III - V are larger than the disc on toe II, and the discs on toes I and V are unornamented. There are minute papillae at the tips of toes II, III, and IV. The toes also have triangular pads (Ospina Sarria et al. 2022).

DIAGNOSIS:

Diasporus lynchi exhibits several distinct characteristics within the genus. It displays a yellowish coloration in life and possesses two chrome orange spots (resembling gland-like protrusions) in the sacral region. The species also stands out due to its smooth ventral skin, basal webbing between the toes, and minute papillae on the disc covers of fingers II - IV and toes II - IV (Ospina Sarria et al. 2022).

More specifically, the yellowish coloration in life necessitates a comparison with D. citrinobapheus, D. gularis, and D. tigrillo, which display similar coloration. Most prominently, D. lynchi can be differentiated from these species by the presence of two distinctive chrome orange spots in the sacral region. Additionally, D. lynchi exhibits basal webbing between the toes, while the tips of the disc covers on fingers II - IV and toes II - IV possess papillae (neither character is present in D. citrinobapheus and D. tigrillo). Basal webbing between the toes and small papillae on toes II - IV are features shared by D. lynchi and D. gularis. However, D. lynchi is further distinguished by its smooth ventral skin (vs. areolate ventral skin of D. gularis) and internal choanae partially concealed by the palatal shelf of the maxillary arch (vs. unconcealed choanae in D. gularis; Ospina Sarria et al. 2022).

In comparison to other congenic species, D. lynchi is readily identified by the presence of basal webbing between the toes (absent in D. amirae, D. anthrax, D. darienensis, D. diastema, D. igneus, D. majeensis, D. pequeno, D. sapo, and D. ventrimaculatus); prominent dentigerous processes of the vomers (absent in D. vocator and D. hylaeformis); and the nearly transparent venter with scattered iridophores, which is distinct from the brown venter with cream flecks in D. quidditus and the gray to dark brown venter with white blotches in D. tinker (Ospina Sarria et al. 2022).

COLORATION:

In life, D. lynchi exhibits a yellow dorsal color with dark markings, while the anterior and posterior surfaces of the thighs are chrome orange. Perhaps its most distinctive feature is the two chrome orange spots in the sacral region, appearing as gland-like protrusions. Canthal, interorbital, and postocular stripes are black, but not well defined. The limbs feature dark markings and the disc covers appear blackish gray. Ventral surfaces of the body are almost transparent with scattered iridophores, while the ventral surfaces of the hind limbs exhibit a chrome orange hue. Palmar and plantar surfaces are dark gray and the digit pads are pale gray. The vocal sac is pale yellow with small black spots. The iris is golden-bronze with a reddish-brown horizontal streak (Ospina Sarria et al. 2022).

In preservative, the vibrant yellow and orange hues of D. lynchi fade into a dull yellow tone. However, the black reticulations on the dorsum, blackish gray coloration on the upper surfaces of the discs, and dark gray shade on the palmar and plantar surfaces keep their original appearance (Ospina Sarria et al. 2022).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Colombia

View distribution map in BerkeleyMapper.

The species occurs at low elevations in the humid tropical regime (54 - 300 m elevation) in southwest Colombia. Known localities are near the Estación Agroforestal Bajo Calima, Departamento de Valle del Cauca, Colombia. The entire type series was collected along streams in primary forest, never at a distance greater than 2 m from a stream (Ospina Sarria et al. 2022).

Life History, Abundance, Activity, and Special Behaviors
The holotype of D. lynchi was found vocalizing in leaf litter. These calls were described as sounding like a ‘‘whistle.’’ Similar to other species of Diasporus (e.g., D. gularis and D. tinker), D. lynchi vocalizes from concealed sites such as dried leaves, making detection of each individual challenging (Ospina Sarria et al. 2022).

Comments

PHYLOGENETIC RELATIONSHIPS:

ETYMOLOGY:

The specific name, “lynchi”, is a patronym serving to honor John D. Lynch, who discovered the species during his explorations of the Bajo Calima region. Dr. Lynch also made significant contributions to understanding the taxonomy and systematics of the superfamily Brachycephaloidea, the most diverse family-group of amphibians also known as Terraranae (Ospina Sarria et al. 2022).

References
Ospina Sarria, J. J., Velásquez Trujillo, D. A., Castaño Saavedra, C. O., Castillo, L. F., and Bolívar-García, W. (2022). A new golden species of Diasporus (Anura: Eleutherodactylidae) from southwestern Colombia, with evaluation of the phylogenetic significance of morphological characters in Diasporus. PeerJ, 10, e12765 [link]

Species Account Citation: AmphibiaWeb 2023 Diasporus lynchi: Anchicaya’s Golden Frog <https://amphibiaweb.org/species/9692> University of California, Berkeley, CA, USA. Accessed Apr 25, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 25 Apr 2024.

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