Macario-González, L.; Cohuo, S.; Elías-Gutiérrez, M.; Vences, M.; Pérez, L.; Schwalb, A. (2018). Integrative taxonomy of freshwater ostracodes (Crustacea: Ostracoda) of the Yucatán Peninsula, implications for paleoenvironmental reconstructions in the northern Neotropical region. Zoologischer Anzeiger. 275: 20-36.
Macario-González, L.; Cohuo, S.; Elías-Gutiérrez, M.; Vences, M.; Pérez, L.; Schwalb, A.
2018
Integrative taxonomy of freshwater ostracodes (Crustacea: Ostracoda) of the Yucatán Peninsula, implications for paleoenvironmental reconstructions in the northern Neotropical region
A three-step integrative taxonomy approach combining molecular, morphological and ecological
methods was successfully used to delimit species boundaries within three freshwater ostracode
taxa of the Yucatán Peninsula (Mexico): Darwinulidae, Cypretta and Cypridopsis. These species
groups were selected because they are well-suited paleobioindicators for late Pleistocene-early
Holocene climatic reconstructions in the region, but their high inter-population morphological
variability in recent communities represents a challenge for accurate transfer of information to
fossil assemblages.
As a first step, we analyzed the independent congruence of two genes of different inheritance, the
mitochondrial COI (cytochrome c-oxidase subunit 1), and the nuclear 18S rDNA (small-subunit
rDNA). Second, we tested the lineages discriminated for concordant differentiation in
morphology, using morphometry of the carapace and typological analysis of the appendages. The
third step assessed the association of occurrences and abundances of lineages to environmental
variables. The integration of these methods revealed six hidden species within clades previously considered as a single widely distributed nominal species. Of these, Cypretta elongata sp. nov.
and Alicenula yucatanensis sp. nov. are herein formally named and described given their
morphological distinctness. Three species of Cypridopsis: Cypridopsis sp. [Ca1 ECO-CH-Z09396], Cypridopsis sp. [Ca2 ECO-CH-Z-09398], Cypridopsis sp. [Ca3 ECO-CH-Z-09401] and
a species that may represent a new genus, Cyprididae sp. [Ca1 ECO-CH-Z-09402], are allocated
to a confirmed candidate full species status. Cypretta maya and Cypretta sp., considered a priori
as separate species, are recognized as a single species with phenotypic plasticity, attributed to its
broad ecological tolerances. For paleoenvironmental reconstructions these results have relevance
because the particular carapace morphology of the new species can be correlated with specific
ecological traits, thus constituting a potential tool for refining interpretations of fossil
assemblages.