Microkayla chapi, Riva & Chaparro & Castroviejo-Fisher & Padial, 2018

Microkayla View in CoL

Six putative new species are supported by our results, two from Peru and four from Bolivia ( Fig. 1C). In Peru, M. chapi sp. nov. from the Hirigache Valley of the Apolobamba mountains near the village of Sina (Department Puno) was found as the sister group of a clade composed of M. boettgeri from the eastern Carabaya mountains (the northern and westernmost known species of Microkayla ) and P. chilina sp. nov. from the Peruvian part of the Apolobamba mountains in the valley of Sandia ( Fig. 1C). All three species are allopatric and occur in distant valleys separated by high Andean slopes, are diagnosable morphologically, and have genetic distances of 2.5%–5.8% ( Table 2).

Genetic distances were calculated for a 518 bp fragment of the 16S gene. For B. wilakunka , which lacked the homologous fragment, we report genetic distances with its sister species ( B. tocra ) based on a similarity alignment of 519 nucleotides of a different fragment of 16S. Sample size for each species is in parentheses.

In Bolivia, a population from Coscapa at 3550 m in the eastern slopes of the Condoriri (Kunturiri) massif of the Cordillera Real of La Paz was recovered as the sister group of Microkayla teqta ( Fig. 1C), from the Pablo Amaya Valley (La Paz), further northwest in the Cordillera Real. These populations are allopatric and morphologically distinct (see diagnosis), with a genetic distance of 1.3%–1.7% (for distances to other species, see Table 2).

A Bolivian population formerly considered part of Microkayla quimsacruzis , from the Khatu River of the cordillera Quimsa Cruz in La Paz, at 3730 m, is reciprocally monophyletic to nominal M. quimsacruzis in parsimony analyses, and sister to M. illimani , from the slopes of the Illimani mountain in the Cordillera Real, in maximum likelihood analyses with a resampling frequency of 68% ( Fig. 1C). While nominal M. quimsacruzis is restricted to the Choquetanga Valley on the northern versant of the cordillera, the population of the new species is restricted to a southern valley that belongs to another river drainage, the Khatu River of the Quime-Inquisivi Valley. Both populations, reciprocally monophyletic in parsimony and non-sister in maximum likelihood, show distinct morphological differences and have genetic distances of 2.5%– 2.6% (for distances to other species, see Table 2).

A population from Utururo, on the Andean slopes that conform the upper basin of the Chapare river system in Cochabamba, at 3800 m, is found as the sister group of a clade associated with the name M. iatamasi (non-monophyletic) in parsimony analyses, and as the sister group of a clade composed of M. adenopleura (Aguayo-Vedia & Harvey, 2001) and M. kempffi (De la Riva, 1992) in maximum likelihood analyses ( Fig. 1C). This population is morphologically diagnosable and differs from its closest relatives by genetic distances of 1.9%–2.7% ( Table 2).

Potentially sympatric specimens of M. iatamasi from the Andean slopes of the Chapare river basin in Cochabamba are found in two different clades ( Fig. 1C). The clade with nominal P. iatamasi ranges from 3000 to 4192 m in the upper basin of the Chapare river and is the sister group of a larger clade that includes other species from that part of the Andes ( M. adenopleura , M. cf. iatamasi , M. kempffi and Microkayla sp. from Utururo). Microkayla cf. iatamasi is found as the sister group of Microkayla sp. from Utururo in parsimony analyses, and as the sister group of a larger clade ( M. adenopleura , M. kempffi and Microkayla sp. from Utururo) in maximum likelihood analysis with a resampling frequency of 88%. Accordingly, we consider M. cf. iatamasi a different species. Morphological differences are unknown because specimens were not available for study. Genetic distances between this species and nominal M. iatamasi are 4.0%– 4.8 % (for distances to other species, see Table 2).