Identifying cryptic speciation across groundwater populations: first COI sequences of Bathynellidae (Crustacea, Syncarida)

An integrated approach to re-evaluate the validity of the family Leptobathynellidae (Crustacea: Bathynellacea)

The systematic status of the controversial crustacean family Leptobathynellidae is investigated using molecular and morphological methods in this study. Partial sequences of the nuclear 18S gene are studied from 28 genera of Bathynellacea from several continents. The analysis includes some of the most plesiomorphic genera of the family Parabathynellidae, such as Billibathynella and Brevisomabathynella from Australia; Habrobathynella and Parvulobathynella from India; the diverse Iberobathynella; the cosmopolitan genus Hexabathynella; and representative genera of two subfamilies of Bathynellidae (Gallobathynellinae and Bathynellinae). We used a molecular approach to analyse the systematic relationships amongst 64 species from Europe, North America, Australia and Asia, and review the morphological characters relevant at the family level. The molecular phylogeny clearly shows the presence of three highly divergent clades that could represent the three families. This is the first molecular phylogenetic reconstruction of Bathynellacea that can be used to: (1) verify the validity of Leptobathynellidae, (2) explore the diversity of the families and (3) explore the phylogenetic relationships among families. We propose a plausible evolutionary scenario for the order Bathynellacea.

Hábitat inusual para Bathynellacea (Crustacea, Malacostraca): primer registro de este crustáceo de agua subterránea en el sustrato superficial mesovoide (MSS)

En este trabajo se documenta por primera vez el hallazgo de ejemplares de un crustáceo (Malacostraca, Bathynellacea) que vive exclusivamente en las aguas subterráneas de todo el mundo, en un hábitat inusual: el medio subterráneo superficial (MSS), un medio terrestre sin luz y saturado de humedad. Especímenes de la familia Parabathynellidae han sido encontrados en dispositivos de muestreo dispuestos para la recogida de fauna subterránea terrestre en el MSS del Parque Nacional de la Sierra de Guadarrama (Madrid, España). Se han identificado dos especies, de dos géneros diferentes, Hexabathynella nicoleiana Camacho, 1986 y Hexaiberobathynella mateusi (Galhano, 1967), mediante estudio morfológico. Las secuencias del gen 18S de varios ejemplares confirman su adscripción genérica. Estas especies eran ya conocidas en la provincia de Madrid.

Understanding subterranean variability: the first genus of Bathynellidae (Bathynellacea, Crustacea) from Western Australia described through a morphological and multigene approach

The number of subterranean taxa discovered in the north of Western Australia has substantially increased due to the requirements for environmental surveys related to mining development. Challenges in estimating subterranean biodiversity and distributions are related to lack of knowledge of taxa with convergent morphological characters in a largely unobservable ecosystem setting. An integrated approach is warranted to understand such complexity. Bathynellidae occur in most Australian aquifers, but only one species has been described so far, and the group lacks a reliable taxonomic framework. A new genus and one new species from the Pilbara region of Western Australia, Pilbaranella ethelensis, gen. et sp. nov., is described using both morphological and molecular data. Three additional species of Pilbaranella are defined through mitochondrial and nuclear genes, using Automatic Barcode Gap Discovery and Poisson Tree Processes species delimitation methods. A comparison of morphology and 18S rRNA sequences between Pilbaranella, gen. nov. and known lineages provides the evidentiary basis for the decision to establish a new genus. This study provides a morphological and molecular framework to work with Bathynellidae, especially in Australia where a highly diverse fauna remains still undescribed.

The collection of Bathynellacea specimens of MNCN (CSIC) Madrid: microscope slices and DNA extract

This is the first published database of a Bathynellacea Chappuis, 1915 collection of slices and DNA extracts. It includes all data of bathynellaceans (Crustacea: Syncarida) collected in the last 48 years (1968 to 2016) on the Iberian Peninsula and Balearic Islands, studied since 1984. It also includes specimens studied across many countries of Europe (Portugal, Romania, France, Italy, Slovenia, Bulgaria, and England), as well as some specimens obtained from samples of North America (Montana, Washington, Alaska and Texas), South America (Brazil, Chile and Argentina), Asia (China, Thailand, Vietnam, Mongolia and India), Africa (Morocco and Chad) and Australia (New South Wales –NSW- and Queensland). The samples come from groundwater (caves, springs, wells and hyporrheic habitat associated with rivers) obtained from both, sampling campaigns and occasional sampling efforts.

The data set includes 3399 records (2657 slices and 742 DNA extracts) corresponding to three families (Parabathynellidae Noodt, 1965, Leptobathynellidae Noodt, 1965 and Bathynellidae Grobben, 1905) of the order Bathynellacea; the existence of three families is accepted, but this is a controversial issue and here is not the appropriate context to address this problem; 52 genera and 92 species formally described, in addition to 30 taxa under study and, thus, still unpublished. This represents more than half of all the genera known worldwide (80) and almost one third of the species currently known in the world (329, which increases every year).

This dataset contains especially relevant collection that includes holotypes and type series of 43 new species of Bathynellacea (33 from the Parabathynellidae and ten from the Bathynellidae) described by Ana I. Camacho (AIC hereinafter); eleven of these are the type species for new genera described from all around the world, ten belonging to the Parabathynellidae and one from the Bathynellidae. As previously mentioned, these new species come from all continents, although 26 of them are from the Iberian Peninsula.

The most important feature of this collection is that it has been created and reviewed by a specialist of the group (AIC), and each specimen, regardless of its shape (either permanent slices or DNA extracts), includes taxonomic, geographical and authorship information. The specialist has been involved in all stages of the process, from field sampling to the digitization of the results we are now presenting, and has worked in close collaboration with the curators responsible for the different collections involved in this project.

Diversity and phylogeny of south-east Queensland Bathynellacea

The crustacean order Bathynellacea is amongst the most diverse and widespread groups of subterranean aquatic fauna (stygofauna) in Australia. Interest in the diversity and biogeography of Australian Bathynellacea has grown markedly in recent years. However, relatively little information relating to this group has emerged from Queensland. The aim of this study was to investigate bathynellacean diversity and phylogeny in south-east Queensland. Relationships between the south-east Queensland fauna and their continental relatives were evaluated through the analysis of combined mitochondrial and nuclear DNA sequence data. Bathynellaceans were collected from alluvial groundwater systems in three catchments in south-east Queensland. This study revealed a diverse bathynellacean fauna with complex evolutionary relationships to related fauna elsewhere in Queensland, and on the wider Australian continent. The multifamily assemblage revealed here is likely to represent several new species, and at least one new genus within the Parabathynellidae. These taxa likely have relatively restricted geographic distributions. Interestingly, the south-east Queensland Bathynellacea appeared to be distantly related to their north-east Queensland counterparts. Although it was not possible to determine the generic identities of their closest relatives, the south-east Queensland Parabathynellidae appear to be most closely affiliated with southern and eastern Australian lineages. Together with previous survey data, the findings here suggest that there is likely to be considerable bathynellacean diversity in alluvial groundwater systems across the wider Queensland region. Further assessment of stygofauna distributions in south-east Queensland is necessary to understand the biological implications of significant groundwater use and development in the region.

Iberian Peninsula and Balearic Island Bathynellacea (Crustacea, Syncarida) database

This is the first published database of Bathynellacea. It includes all data of bathynellids (Crustacea, Bathynellacea) collected in the last 64 years (1949 to 2013) on the Iberian Peninsula and Balearic Island. The samples come from groundwater (caves, springs, wells and hyporrheic habitat associated rivers) from both sampling campaigns and occasional sampling conducted throughout the Iberian Peninsula and Balearic Islands. The dataset lists occurrence data of bathynellids distribution, sampling sites (with localities, county and geographic coordinates), taxonomic information (from family to species level) and sampling sources (collector and sampling dates) for all records. The descriptions of new species and species identifications have been carried out by an expert taxonomist (AIC) with 25 years experience in the bathynellids studies (see references). Many of the sampling sites are type localities of endemic species from Iberian Peninsula. The dataset includes 409 samples record corresponding to two families, 12 genera and 58 species, 42 of them formally described plus 16 taxa unpublished and 47 samples in study. All species known from the study area are included, which nearly sum up a quarter of species of Bathynellacea known in the world (250 species).

Difficulties barcoding in the dark: the case of crustacean stygofauna from eastern Australia

The eastern Australian aquifers remain mostly unexplored; however, recent surveys suggest that there could be substantial levels of subterranean biodiversity hidden in these aquifers. Groundwater fauna (stygofauna) is often characterised by short-range endemism. Furthermore, high levels of cryptic species, and lack of formal taxonomic descriptions and taxonomic expertise for many of the groups demand innovative approaches for assessing subterranean biodiversity. Here we evaluate the potential of using DNA barcoding as a rapid biodiversity assessment tool for the subterranean groundwater fauna of New South Wales, Australia. We experienced low amplification success using universal and more taxon-specific primers for PCR amplification of the barcoding gene (COI) in a range of crustacean stygofauna. Sequence comparisons of the most commonly used COI universal primers in selected crustacean taxa revealed high levels of variability. Our results suggest that successful amplification of the COI region from crustacean stygofauna is not straightforward using the standard ‘universal’ primers. We propose that the development of a multiprimer (taxon specific) and multigene approach for DNA barcode analyses, using next-generation sequencing methodologies, will help to overcome many of the technical problems reported here and provide a basis for using DNA barcoding for rapid biodiversity assessments of subterranean aquatic ecosystems.