Journal of Zoological Systematics and Evolutionary Research最新文献

The genus Aulopyge, represented by a single species, the Dalmatian barbelgudgeon, Aulopyge huegelii, is an endemic genus with very restricted distribution range comprising several rivers in southern Croatia and Bosnia and Herzegovina. In this study, molecular genetic analyses based on three molecular markers (one nuclear and two mitochondrial) were performed to confirm the position of Aulopyge within Cyprinidae, obtain data on its evolutionary history, and describe its population genetic structure and diversity. Specimens of A. huegelii were obtained throughout the distribution range. Phylogenetic reconstruction corroborated the independent position of this species and its placement within the Barbinae subfamily. The evolutionary history of A. huegelii started already in the middle Oligocene, whereas intraspecific divergences that left a trace in its current genetic structure and diversity are of much younger origin, starting in the middle Pleistocene. Unlike in other cypriniform species and genera distributed in the Dinaric karst region, there is no significant structuring within A. huegelii, or distribution of haplotypes concordant with the geographic scale. Furthermore, low effective population sizes estimated for most populations and low genetic diversities within them raise strong concerns about the viability and future survival of this endemic species.

Morphology has been used to establish interspecific limits in echimyid rodents. However, using only morphology can be problematic, especially for polymorphic or morphologically cryptic species. Recently, combined data sources have been used to recognize and delimit species and have proven to be especially useful for taxonomic resolutions. Makalata is a taxonomically problematic genus that needs revision. Currently, two species are recognized: M. didelphoides and M. macrura. A third species, M. obscura, is considered questionable. Molecular studies demonstrate that diversity in the genus has been underestimated. In the present study, we identified 14 subclades representing potential species in the genus Makalata using molecular and cytogenetic data. Analysis of species delimitation corroborated this hypothesis. Four lineages in the Guiana Shield, currently considered to be a single taxonomic entity in the literature (M. didelphoides) based only on morphology, were shown to be potential cryptic species, differentiated only by molecular and karyotype data. We verified that the name M. didelphoides cannot be applied to any clade or museum specimen without a genetic approach and sequencing of the holotype. We present an amended diagnosis for M. macrura through examination of the original description, sequencing, and karyotype of topotypic samples allowed us to associate with the name M. macrura represented by subclade I in this study. Karyotype data proved to be a powerful tool in differentiating the Makalata species according to different combinations of diploid number (2n) and fundamental number, as for other genera of spiny tree-rats. Our results demonstrate a heterogeneous status for Makalata, highlighting the importance of using multiple tools to determine the taxonomy of this group and reinforcing the importance of molecular and chromosomal data added to the morphological data to obtain a more accurate picture of the taxonomic diversity of this and other small mammal genera.

Hypostomus Lacépède, 1803, is a species-rich and widespread fish genus from the Neotropical region, but its evolutionary history and systematics remain largely unclear. In addition, species from regions with high levels of species richness and endemism such as the Northeastern Mata Atlântica (NMA) and São Francisco (SF) hydrographic freshwater ecoregions are underrepresented in phylogenetic studies so far. In this study, we performed a broad sampling of Hypostomus in NMA and SF to investigate the interspecific boundaries and phylogenetic relationships using a multilocus approach based on one mitochondrial and three nuclear markers. Seven genetic groups were found for both ecoregions, in addition to one lineage exclusive to the SF represented by populations of the species Hypostomus velhochico. Moreover, multilocus analyses validated 16 formally described species and two new lineages for the NMA and SF ecoregions, as well as putative cases of species complexes. In general, lineages with independent evolutionary histories were revealed within the same ecoregion alongside genetically related groups between NMA, SF, and other ecoregions. These data reinforce the intricate scenario of this group of Neotropical fish and are useful to outline further phylogeographic studies in Hypostomus.

The nudibranch genus Doto is taxonomically problematic in particular, and some species are described on the notion of strict monophagy. Here we perform species delimitation on NE Atlantic species, as well as placing them phylogenetically, using two markers: the mitochondrial COI and the nuclear H3. We also study the morphology of the species including radular ultrastructure and review food specificity. Specimens were first divided into potential species using ABDG on both markers, these groups were used as input species for species delimitation analyses using BPP, and analyses were performed with both markers combined and on H3 only. The analyses delimit 11 and eight species, respectively. With the exception of one species for which only COI was available, the differences are found in D. fragilis, which is split into three groups when COI is included and lumped into one with only H3. Doto hystrix is nested within these groups. We also found that specimens from Sweden seemingly close to D. maculata in external morphology have identical sequences as D. coronata. Analysis of food preferences of the species involved in the study contradicts the notion of strict monophagy within Doto.

The Crenicichla mandelburgeri species complex from the Middle Paraná shows parallel evolution of ecomorphs to the unrelated Crenicichla missioneira species complex from the Uruguay River. In this article, we describe a new species pair (C. sp. Piray Guazú and C. sp. Piray Guazú Line) from the C. mandelburgeri species complex that has evolved a parallel morphological and ecological dichotomy to another species pair from the same species complex (Crenicichla ypo, Crenicichla yjhui) and also to species in the unrelated C. missioneira species complex (C. missioneira, Crenicichla celidochilus). The new species pair is endemic to a single tributary (the Piray Guazú) of the Middle Paraná River where it is sympatric and partly syntopic. Mitochondrial DNA phylogeny shows the two new species as distantly related within the C. mandelburgeri species complex, each with a sister species in the Iguazú rather than in the neighbouring Paraná river tributaries. Reduced genome representation ddRAD analyses of the nuclear genome demonstrate their close relationship, which is however complicated by the hybrid origin of one of the new species (C. sp. Piray Guazú Line). The hybrid origin of this species is demonstrated by sharing the ancestral genetic stock with its sympatric sister species (C. sp. Piray Guazú) while having an admixture from the widespread species C. mandelburgeri from the main Middle Paraná channel. In this study we also review the role of biogeography and mitonuclear discordance during evolution of the whole C. mandelburgeri species complex.

The Mesoamerican dry forests (MDF), rich in species and in endemic taxa, are distributed nearly continuously nearly continuously along the American Pacific slope from Mexico to Costa Rica; however, several of the bird species inhabiting the MDF show clear phenotypic differentiation recognized through the description of subspecies. There are two currently recognized species of magpie-jays of the genus Calocitta (Corvidae) distributed throughout the MDF: the monotypic black-throated magpie-jay (C. colliei) and the polytypic white-throated magpie-jay (C. formosa). These two species have sometimes been considered conspecific and have been reported to hybridize in sympatric areas, where birds with intermediate plumage characters are recorded. Using mitochondrial and nuclear DNA markers from individuals of the two species, we analyze the phylogeographic structure and the genetic diversity within Calocitta under an isolation with migration (IM) model. The results showed strong genetic structure, in which the two currently recognized species and some of the C. formosa subspecies grouped into four well-supported and reciprocally monophyletic clades. IM analyses suggested divergence dates for the split between C. colliei and C. formosa that were congruent with geological factors, as well as with the deep divergence of the three lineages within C. formosa. These factors likely led to a dynamic demographic history in all lineages. We also found strongly limited gene flow, null or near null migration values, and large genetic fixation and genetic distance values. We suggest that the strong genetic differentiation between lineages is the result of allopatric differentiation with later secondary contact, further supporting a highly dynamic biotic history in MDF.

Despite the importance of rodents as agricultural pests and reservoirs of zoonoses, the taxonomy and evolutionary history of many groups is still not sufficiently understood. The genus Mastomys (multimammate mice or rats) comprises abundant and intensively studied rodents, widespread across sub-Saharan Africa. Here, we used an extensive dataset of mitochondrial DNA markers comprising of nearly 2700 individual sequences from 30 African countries to update the information about the geographical distribution of their genetic diversity. In the next step, we sequenced complete mitogenomes, six nuclear markers, and produced anchored phylogenomic data (355 loci) and, for the first time, sufficiently resolved phylogenetic relationships among all extant Mastomys species and reconstructed their evolutionary history. The results suggest eight species of Mastomys occupying various non-forested environments. Some species are very widespread (Mastomys natalensis, Mastomys kollmannspergeri, and Mastomys erythroleucus; for the latter we provide first records from Tanzania, thus significantly extending its distribution), while others have their distribution restricted to particular geographical areas (Mastomys coucha in South African region, Mastomys awashensis in Ethiopia, and Mastomys angolensis in Angola and southern DRC) or to particular habitat, that is, wetlands in western (Mastomys huberti) or southwestern (Mastomys shortridgei) Africa. The first split separating M. angolensis (with five pairs of mammae only) from remaining multimammate taxa occurred in mid-Pliocene, but the most intensive radiation occurred in mid-Pleistocene and was likely driven by the intensification of climate oscillations. The resolved phylogeny of Mastomys will facilitate their further use as model taxa, for example, in understanding proximate mechanisms of evolution of the multimammate phenotype.