Honduran Lowland Worm Salamander

Diagnosis: A moderately-sized Oedipina (maximum standard length, SL, of 55.5 mm), with phylogenetically distinct mitochondrial haplotypes and a tail that is rectangular in cross-section through nearly its entire length (vs. nearly round for most or all of the tail length, in the Costa Rican species O. cyclocauda, with which O. quadra was previously confused). Distinguished from O. kasios (also previously confused with O. cyclocauda) by the absence of silver white dorsolateral spots and flecks in life (vs. present in O. kasios), and by having a greater number of maxillary teeth and a longer SL. Distinguished from O. leptopoda (also previously confused with O. cyclocauda) by more defined digits and by an inferred smaller size. Distinguished from all other described Honduran species of the subgenus Oedipina (O. ignea, O. stuarti, O. taylori) as follows: from O. ignea by its smaller size and a nearly rectangular tail; from O. stuarti by its smaller size and by the absence of pale brown to dirty white small glandular spots on the head and body (present in O. stuarti); from O. taylori by having maxillary teeth, 19-20 costal grooves and by its smaller size. Distinguished from all described Honduran species in the subgenus Oedipinola (O. elongata, O. gephyra, O. tomasi) by having 19–20 costal grooves (McCranie et al. 2008). Description: SL of adult males ranges from 35.1-43.7 mm, with an average SL of 41.6 mm; females measure 35.6-55.5 mm in SL, with an average SL of 45.0 mm. The head is longer than wide; it is small, narrow, and dorsally flattened, with a rounded snout. Eyes and nostrils are small. Labial protuberances are inconspicuous in females and only weakly developed in males, whose mental glands are also small and barely noticeable and located on the anterior of the lower jaw. Females have 2-6 premaxillary teeth, while males have 1-3 enlarged premaxillary teeth. Both sexes have about the same number of maxillary teeth of 43 (male range 37-47; female range 28-53). Vomerine teeth are present in an arched series, with an average of 17.5 (range 15-20) teeth in males and 19.5 (range 16-22) in females. 19-20 costal grooves are present, with a limb interval of 11.0-13.0. The limbs are tiny and slender. Finger length in decreasing order is 3>2>4>1; the order of toes is 3>2>4>5>1. Digits 1 and 2, 3 and 4 on the manus are fused, with 1 phalange on digit 3 free to move. On the pes, digits 1 and 2, 4 and 5 are fused, leaving only 1 to 2 phalanges on both sides of digit 3 free. Tips of digits range from acutely rounded to bluntly rounded. Subdigital pads are present but weakly developed. The tail is elongated (up to 2.4x the SL). The tail appears rectangular in cross-section except for the distal 1/3 of its length, where it begins to taper off (McCranie et al. 2008).In life, the dorsal surfaces of the head, body and tail are black, and limbs are brownish black. The lateral surfaces of head and body are brownish black. The lateral surfaces of the tail are black. In preservative, the dorsum is black and the ventrum is a slightly paler black. The costal grooves are dirty white. White or dirty white iridophores are observed under magnification (McCranie et al. 2008).Etymology: The specific name quadra means "square" in Latin, referring to the nearly rectangularcross-section of the tail (McCranie et al. 2008).Species authority: McCranie et al. (2008).

Found in Honduras, possibly also in Nicaragua (this has not yet been confirmed). Oedipina quadra occurs from just south of La Ceiba, Atlántida, eastward and southeastward to the Río Coco drainage system of northeastern Honduras. It has been speculated that this species may also occur in suitable habitat on the Nicaraguan side of the Río Coco. Specimens were collected from pristine broadleaf forests with a closed canopy and secondary broadleaf forests with a partially open canopy, in lowland moist forest, from 70-540 m elevation. (McCranie et al. 2008).

This species is found under leaf litter (McCranie et al. 2008).