Description
Oedipina berlini is a flat-headed salamander described from three males and one female. The snout-vent length ranges from 30.1 - 38.7 mm, while the total length ranges from 71.1 - 94.8 mm. Its head is wide and flat, with its widest point at the articulation of the jaw. Its snout is rounded, raised anterodorsally, and relatively long with its tip protruding past the lower lip. This species has pronounced cirri, with their blunt, round tips protruding past the upper lip. Its small nostrils are located toward the end of the snout, but they do not protrude. Its internarial area is rounded. The nasolabial grooves originate on the later portions of the nares, angle slightly outward, and end before the cirri. It has a round, strong canthus rostralis. Its intercanthal area curves slightly outward, while its loreal region curves slightly inward. The eyes are large and forward-facing, protruding greatly in life; when euthanized, the specimen’s eyes recede into the skull, making the eyes barely protrude past the outline of the head in preserved specimens. This species’ suborbital groove is pronounced, but this species does not have interorbital or other dermal structures that stand out. This species has a distinct gular fold that wraps from the back of the neck around the head, crossing the salamander’s ventrum as a smooth curve towards the anterior. Oedipina berlini does not have an obviously visible mental gland. It has a distinct nuchal groove as well as a subtle groove starting at the posterodorsal edge of the orbit and extending to the anterior portion of the gular fold. The slender, subcylindrical body has a smooth skin texture across its entire body. There is a light dorsal midline depression that extends from the base of the head to the anterior of the tail. The holotype has 15 costal grooves on the body with additional axillary and inguinal grooves for a total of 17. When the limbs are adpressed along the body towards each other, 6 - 7 costal grooves separate the limbs. The species has long arms with its forearms and upper arms being approximately equal in size. Its hands are small, and longer than wide. Its hands and feet are fully webbed, and the indentation at the interdigital spaces is not obvious. The third finger is the longest digit, with the relative length of the fingers being I < II < IV < III and the relative length of the toes being I < V < II < IV < III. The fingertips do not end in terminal pads. The palms are smooth, and the hands’ dorsal surfaces have distinct interdigital grooves. The long tail has a cylindrical cross section without any grooves or constriction at the base. The tip tapers to a point (Kubicki 2016).

DIAGNOSIS:

Oedipina berlini can be distinguished from other members of its genus found in Costa Rica and Panama by morphology and coloration. More specifically, O. berlini has more maxillary teeth that extend behind the choanae to the anterior edge of the orbit, as well as more vomerine teeth than O. alleni. Oedipina berlini can be distinguished from O. carablanca by the former’s smaller size, paler dorsal coloration, and presence of maxillary teeth. Oedipina berlini has fewer costal folds between adpressed limbs and paler dorsal coloration than O. complex. Oedipina berlini can be distinguished from O. fortunensis by the former having longer hind limbs, fleshy tips on the ends of the third finger and third toe, webbing on the first and second toes, and lack of defined interdigital indentations. Oepidina berlini has paler dorsal coloration, larger and more protruding eyes, and a flatter head than O. maritima. Oepidina berlini has paler dorsal coloration, wider and longer head, larger and more protruding eyes, and a wider intercanthal distance than O. nimaso. Oepidina berlini has a higher number of maxillary teeth than O. savagei (Kubicki 2016). From two more recently described Ecuadorian species, O. villamizariorum and Oepidina ecuatoriana, O. berlini has a flatter head, and larger and more protruding eyes. Additionally from O. villamizariorum, O. berlini is paler and has less densely spotted dorsal coloration (Reyes-Puig et al. 2020).

COLORATION:

In life, O. berlini has a mottled earthy coloration. Its dorsum is light-to-medium brown and red with accents of light pink and black. It is also dorsally speckled with white and gray flecks, primarily on the head and body but not the tail. There is a light diamond-shaped patch of skin on its head, stretching from the tip of the snout to the anterior base of the head. It has similar light patches of skin on its shoulders and the dorsolateral edges of its trunk. Males have a variable faded pinkish ring encircling the base of the tail. Dorsally, this species’ upper arms and legs are a light tan color, while its lower arms and legs are darker brown and red in coloration. Its arms and legs are peppered with black flecks throughout. The dorsal sides of its hands and feet are black with light-colored flecks. For the upper half of the body, this species’ lateral coloration matches its dorsal coloration. For the lower half of the body, it is black with white and light brown specks. Ventrally, Oedipina berlini is light brown and pinkish with black reticulations and small white spots. The gular patch is distinct and white, and the gular folds are pinkish. Its ventral tail is splotched with light brown and pinkish orange. Its irises are black and surrounded by thin gold reticulations (Kubicki 2016).

In preservative, the paratype’s coloration faded significantly over the two years it spent in ethanol (Kubicki 2016).

VARIATION:

The female paratype has a shorter snout length (0.9 mm, versus the snout lengths of 1.3 - 1.5 mm in the males). The female’s internarial distance is also narrower (1.0 mm, versus the 1.4 - 1.7 mm internarial distance in the males). The males have a pinkish-orange ring encircling the base of the tail, which the female does not. This ring varies in how distinct its coloration is (Kubicki 2016).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Costa Rica

View distribution map in BerkeleyMapper.

Oedipina berlini was originally found in two sites in the central Caribbean slopes of Costa Rica, composed of Premontane Rainforest, at elevations of 540 - 850 m above sea level. More specifically, it has been found in leaf litter on the forest floor (Kubicki 2016). As of 2020, it has been found in the Guayacán Rainforest Reserve, the Veragua Rainforest, Turrialba Volcano National Park, and Cordillera Volcanica Central (IUCN 2020).

Life History, Abundance, Activity, and Special Behaviors
Oedipina berlini has not been observed extensively, but given its habitat it is likely a terrestrial leaf litter specialist. There is no data on this species’ association with bodies of water, but it has been found primarily following medium-to-heavy rains, and has only been observed during the day once, suggesting that it may be nocturnal (Kubicki 2016).

Salamanders in the Oedipina genus tend to be specialized for fossorial burrowing (Brame1968). Given O. berlini’s scarce number of observations, its narrow and lengthened body plan, and its tendency to be found beneath leaf litter, this could be the case for this species (Kubicki 2016).

This species likely participates in courtship and oviposition in its leaf litter habitat (Kubicki 2016).

Because it is a member of the family Plethodontidae, it likely engages in direct development (Wake and Hanken 1996).

Larva
Because it is a member of the family Plethodontidae, it likely engages in direct development (Wake and Hanken 1996).

Trends and Threats
This species’ population is stable. It is mainly found in protected areas where its habitat is not threatened. Namely, it has been found in the Guayacán Rainforest Reserve and the Veragua Rainforest, both of which are protected, either privately by the Costa Rican Amphibian Research Center or publicly by the government. It has also been found in Turrialba Volcano National Park as well as Cordillera Volcanica Central, in which the four main volcanoes are protected as national parks. However, this species could potentially be threatened by the salamander chytrid fungus (Batrachochytrium salamandrivorans) if it arrives in the Americas (IUCN 2020).

Possible reasons for amphibian decline

Disease

Comments

PHYLOGENETIC RELATIONSHIPS:

Initial Maximum Likelihood and Bayesian analyses of 16S and cytB mtDNA placed O. berlini as sister to a clade composed of O. complex and O. maritima (Kubicki 2016). However, later Maximum Likelihood analysis on seven mtDNA genes, and including previously undescribed species, placed O. berlini as sister to the clade composed of O. complex, O. villamizariorum, and an undescribed species, with O. maritima being the next most closely related species (Reyes-Puig et al. 2020). In both studies, O. parvipes is the next most closely related clade after these relationships. However, all of the relationships should be considered with caution as Reyes-Puig et al. (2020) note that there is a lack of genetic material for specimens of the genus.

Oedipina berlini was also assigned to the genus Oedipina because it has more than 13 costal grooves and placed into the subgenus Oedopinola because it has fewer than 20 costal grooves (Kubicki 2016).

ETYMOLOGY:

The specific epithet, “berlini”, honors Mr. Erick Berlin, a close friend of the describer of the species, Brian Kubicki. Berlin works on conservation of the central Caribbean region of Costa Rica, particularly the northeastern portion of Volcán Turrialba (Kubicki 2016).

References
Brame, A. H. (1968). Systematics and evolution of the Mesoamerican salamander genus Oedipina. Journal of Herpetology, 2(1/2), 1–64. [link]

IUCN SSC Amphibian Specialist Group. 2020. Oedipina berlini. The IUCN Red List of Threatened Species 2020: e.T112686013A112686053. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T112686013A112686053.en. Accessed on 09 May 2022.

Kubicki, B. 2016. A new species of salamander (Caudata: Plethodontidae: Oedipina) from the central Caribbean foothills of Costa Rica. Mesoamerican Herpetology 3, 819–840. [link]

Reyes-Puig C., Wake D. B., Kotharambath R., Streicher J. W., Koch C., Cisneros-Heredia D. F., Yánex-Muñoz M. H., Ron S. 2020. Two extremely rare new species of fossorial salamanders of the genus Oedipina (Plethodontidae) from northwestern Ecuador. PeerJ 8, e9934 [link]

Wake D. B., Hanken J. 1996. Direct development in the lungless salamanders: what are the consequences for developmental biology, evolution and phylogenesis? Int J Dev Biol. 40(4), 859-69. [link]

Species Account Citation: AmphibiaWeb 2023 Oedipina berlini: Berlin's Flat-headed Salamander <https://amphibiaweb.org/species/8566> University of California, Berkeley, CA, USA. Accessed Apr 18, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 18 Apr 2024.

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