Uncovering hidden diversity: Three new species of the Keratella genus (Rotifera, Monogononta, Brachionidae) of high altitude water systems from central Mexico

Abstract

The correct identification of species is an essential step before any study on biodiversity, ecology or genetics. Keratella is a genus with a predominantly temperate distribution and with several species being endemics or restricted geographically. Its diversity may be underestimated considering the confusing taxonomy of species complexes such as K. cochlearis. In this study, we examined genetic diversity and morphology among some Keratella populations from Mexico in order to determine if these populations represent different species. We analyzed a dataset of previously published and newly generated sequences of the mitochondrial COI gene and the nuclear ITS1 marker. We conducted phylogenetic analyses and applied three methods of species delimitation (ABGD, PTP and GMYC) to identify evolutionary significant units (ESUs) equivalent to species. Morphological analyses were conducted through scanning electron microscope (SEM) and morphometry under a compound microscope. In the present study, three new species Keratella cuitzeiensis sp. nov., Keratella huapanguensis sp. nov., and Keratella albertae sp. nov., are formally described. These species were collected in high-altitude water bodies located in the Central Plateau of Mexico. Combining DNA results through COI and ITS1 molecular markers and morphology it was possible to confirm the identity of the new species.