Exceptional diversity of Pristimantis Landfrogs (Anura: Terraranae) on the Wokomung Massif, Guyana, with descriptions of three new species

Abstract

We describe three new species of landfrogs, genus Pristimantis, from near the summit of Mt. Kopinang, one of the several high points of the Wokomung Massif, a large horseshoe-shaped tepui (= mesa) in west-central Guyana. Pristimantis koki n. sp. is known from 1,067 to 1,525 m elevation. It is characterized by small-sized adults averaging 12.4 mm SVL (snout-vent length) in males and 18.4 mm in females; a pointed, depressed, elongated snout; lack of an obvious tympanum, vocal slit, or sac; and diagnostically black pigment prominently arranged around the anus fringed by light pigment. When handled, P. koki seems to emit volatile organic compounds and leaves a slightly numbing taste at the base of the human tongue. Pristimantis kopinangae n. sp. is known from three specimens collected at approx. 1,385 m elevation on the Wokomung Massif and two specimens from slightly higher in elevation on Mt. Ayanganna. About the size of most Pristimantis inhabiting the Guyana uplands and highlands (20-30 mm SVL), it is characterized by 2-3 light yellow inguinal flash-mark blotches, short broadly round snout, large eye with a blue iris, white skin of chin and areolate belly with dark brown vermiculations; and absence of a tympanum. Pristimantis kalamandeenae n. sp. is known from three specimens collected on the Wokomung Massif including an amplexing pair at approx. 1,550 m elevation. Similar in size to P. kopinangae, it is characterized by an acuminate snout, black iris, obvious tympanum, and uniform tan pigmentation dorsally after dark that becomes uniformly dark brown in daytime. Phylogenetic results show that P. koki and P. kopinangae are sister species and are members of a larger assemblage of related species endemic to the Pantepui Region within the P. unistrigatus species group. Pristimantis kalamandeenae is not closely related to these species, instead forming a clade with the P. lacrimosus species group. The three new species occur in sympatry with at least five other Pristimantis species on the Wokomung Massif, the greatest known Pristimantis species richness on a single tepui of the Guiana Shield.