Manuel António E. Malaquias

A molecular phylogeny of the Cephalaspidea sensu lato (Gastropoda: Euthyneura): Architectibranchia redefined and Runcinacea reinstated

The monophyly and phylogenetic relationships of the Cephalaspidea sensu lato (sensu Burn and Thompson 1998 ) have been investigated by means of Bayesian, parsimony and distance analyses of nuclear (18S rRNA and 28S rRNA) and mitochondrial cytochrome oxidase I (COI) genes.

Speciation in the dark: Diversification and biogeography of the deep-sea gastropod genus Scaphander in the Atlantic Ocean

Abstract Aim The aim of this work was to improve understanding about the mode, geography and tempo of diversification in deep‐sea organisms, using a time‐calibrated molecular phylogeny of the heterobranch gastropod genus Scaphander. Location Atlantic and Indo‐West Pacific (IWP) oceans. Methods Two mitochondrial gene markers (COI and 16S) and one nuclear ribosomal gene (28S) from six Atlantic species of Scaphander, and four IWP species were used to generate a multilocus phylogenetic hypothesis using uncorrelated relaxed‐clock Bayesian methods implemented in beast and calibrated with the first occurrence of Scaphander in the fossil record (58.7–55.8 Ma). Results Two main clades were supported: clade A, with sister relationships between species and subclades from the Atlantic and IWP; and clade B, with two western Atlantic sister species. Our estimates indicate that the two earliest divergences in clade A occurred between the middle Eocene and late Miocene and the most recent speciation occurred within the middle Miocene to Pleistocene. The divergence between the two western Atlantic species in clade B was estimated at late Oligocene–Pliocene. Main conclusions The prevailing mode of speciation in Scaphander was allopatric, but one possible case of sympatric speciation was detected between two western Atlantic species. Sister relationships between IWP and Atlantic lineages suggest the occurrence both of vicariance events caused by the closure of the Tethyan Seaway and of dispersal between the two ocean basins, probably around South Africa during episodic disruptions of the deep‐sea regional current system caused by glacial–interglacial cycles. Cladogenetic estimates do not support comparatively older diversification of deep‐sea faunas, but corroborate the hypothesis of a pulse of diversification centred in the Oligocene and Miocene epochs. Amphi‐Atlantic species were found to occur at deeper depths (bathyal–abyssal) and we hypothesize that trans‐Atlantic connectivity is maintained by dispersal between neighbouring reproductive populations inhabiting the abyssal sea floor and by dispersal across the shelf and slope of Arctic and sub‐Arctic regions.

A test of color-based taxonomy in nudibranchs: Molecular phylogeny and species delimitation of the Felimida clenchi (Mollusca: Chromodorididae) species complex

Traditionally, species identification in nudibranch gastropods relies heavily on body color pattern. The Felimida clenchi species complex, a group of brightly colored Atlantic and Mediterranean species in the family Chromodorididae, has a history of exceptional controversy and discussion among taxonomists. The most widely accepted hypothesis is that the complex includes four species (Felimida clenchi, F. neona, F. binza and F. britoi), each with a characteristic body color pattern. In this study, we investigated the taxonomic value of coloration in the Felimida clenchi complex, using molecular phylogenetics, species-delimitation analyses (ABGD, GMYC, PTP), haplotype-network methods, and the anatomy of the reproductive system. None of our analyses recovered the traditional separation into four species. Our results indicated the existence of three species, a result inconsistent with previous taxonomic hypotheses. We distinguished an undescribed species of Felimida and redefined the concepts of F. clenchi and F. binza, both highly polychromatic species. For the first time, molecular data support the existence of extreme color polymorphism in chromatic nudibranch species, with direct implications for the taxonomy of the group and its diversity. The polychromatism observed in the F. clenchi complex apparently correlates with the regional occurrence of similar color patterns in congeneric species, suggesting different mimicry circles. This may represent a parallel in the marine environment to the mechanisms that play a major role in the diversification of color in terrestrial and fresh-water chromatic groups, such as heliconian butterflies.

Slipping through the Cracks: The Taxonomic Impediment Conceals the Origin and Dispersal of Haminoea japonica, an Invasive Species with Impacts to Human Health

Haminoea japonica is a species of opisthobranch sea slug native to Japan and Korea. Non-native populations have spread unnoticed for decades due to difficulties in the taxonomy of Haminoea species. Haminoea japonica is associated with a schistosome parasite in San Francisco Bay, thus further spread could have consequence to human health and economies. Anecdotal evidence suggests that H. japonica has displaced native species of Haminoea in North America and Europe, becoming locally dominant in estuaries and coastal lagoons. In this paper we study the population genetics of native and non-native populations of H. japonica based on mt-DNA data including newly discovered populations in Italy and France. The conclusions of this study further corroborate a Northeastern Japan origin for the non-native populations and suggest possible independent introductions into North America and Europe. Additionally, the data obtained revealed possible secondary introductions within Japan. Although non-native populations have experienced severe genetic bottlenecks they have colonized different regions with a broad range of water temperatures and other environmental conditions. The environmental tolerance of this species, along with its ability to become dominant in invaded areas and its association with a schistosome parasite, suggest H. japonica could be a dangerous invasive species.

On the occurrence of the Caribbean sea slug Thuridilla mazda in the eastern Atlantic Ocean

The Caribbean gastropod species Thuridilla mazda was collected for the first time in eastern Atlantic shores, namely on the island of Sao Miguel, archipelago of the Azores. This new record raises the total number of opisthobranch species known in the Azores to 144 and shows the potential importance of the Gulf Stream for dispersal of Caribbean species across the North Atlantic and its putative impact on the marine colonization of the Azores.

Systematics, phylogeny, and natural history of Bullacta exarata (Philippi, 1849): an endemic cephalaspidean gastropod from the China Sea

In this paper new data on the systematics, phylogeny, and trophic ecology of Bullacta exarata (Philippi, 1849) are presented. B. exarata is a cephalaspidean gastropod endemic to the China Sea that lives in estuaries along the north-eastern Chinese and western South Korean coastlines. The systematic position of this species is controversial and has been a matter of continuous debate. Therefore, in order to produce new insights into the phylogenetic position of this species, morphological and anatomical features have been analysed through fine dissection work and scanning electron microscopy (SEM), together with DNA sequence data. Bayesian phylogenetic inference based on concatenated sequences of the mitochondrial gene cytochrome c oxidase subunit I (COI) and nuclear genes 18SrRNA and 28SrRNA, suggests the inclusion of B. exarata in the family Haminoeidae. SEM analysis of gut contents revealed that B. exarata feeds upon diatoms.

The family Diaphanidae (Gastropoda: Heterobranchia: Cephalaspidea) in Europe, with a redescription of the enigmatic species Colobocephalus costellatus M. Sars, 1870

Diaphanidae has traditionally been considered the basal family of the heterobranch gastropod clade Cephalaspidea with 14 species present in Europe ascribed to five genera. The monophyletic status of the family is controversial because of lack of sound synapomorphies. In this paper we present a review of the diversity of Diaphanidae in Europe and give new data on the morphology and anatomy of 50% of the species together with a synopsis of the relevant systematic characters to distinguish between all European species and genera. The rare species Colobocephalus costellatus is redescribed and shown alive for the first time.Further evidence supporting the non-monophyly of Diaphanidae is given; no synapomorphies were found to unite traditional Diaphanidae taxa, but three groups can be recognized: (1) Diaphaninae with genus Diaphana is united by a globose external, thin, and umbilicate shell and radulae with a bilobed rachidian tooth; (2) Toledoniinae, with genera Toledonia and Bogasonia share the presence of a shell with elevated spire and radulae with a unicuspid rachidian tooth; and (3) an unnamed group, with Colobocephalus and Colpodaspis which are the only genera with internal shells, sculptured and globose with short but protruding spires, and radulae lacking rachidian tooth and with smooth hook-shaped lateral teeth.

Diet preferences of the Aglajidae: a family of cephalaspidean gastropod predators on tropical and temperate shores

Aglajidae is a family of tropical and temperate marine Cephalaspidea gastropod slugs regarded as active predators. In order to better understand their food habits and trophic interactions, we have studied the diet of all genera through the examination of gut contents. Specimens were dissected for the digestive tract and gut contents were removed and identified by optical and scanning electron microscopy. Our results confirmed that carnivory is the only feeding mode in aglajids and showed a sharp preference for vagile prey (94% of food items). We suggest that the interaction between crawling speed, presence of sensorial structures capable of detecting chemical signals from prey, and unique features of the digestive system (e.g. lack of radula, eversion of the buccal bulb, thickening of gizzard walls) led aglajid slugs to occupy a unique trophic niche among cephalaspideans, supporting the hypothesis that dietary specialization played a major role in the adaptive radiation of Cephalaspidea gastropods.

The opisthobranch gastropods (Mollusca: Heterobranchia) from Venezuela: an annotated and illustrated inventory of species

The Caribbean waters of Venezuela are composed by a large variety of habitats, with over 2800 km of coastline, islands, and islets. This area is a transitional zone between two main biogeographic provinces, the Caribbean and the Brazilian, separated by the fresh water outflows of the Orinoco and Amazon rivers, and is therefore expected to be an area of high species diversity. However, concerning the study of molluscs, Venezuela is probably the poorest known region in the Caribbean. The best compilation of opisthobranch species known in Venezuela was produced almost a decade ago, mentioning the occurrence of 57 species, plus seven determined only to genus level. In this work, 134 species are reported for Venezuela (71 are illustrated), representing about 40 % of the entire diversity of opisthobranchs known in the Caribbean. Among the species occurring in Venezuela, 49 have here the southern limit of their distribution range and only one the northern limit. Forty-six species are recorded for the first time to the country and one is a new record for the Caribbean Sea, namely Placida cremoniana. In addition, the distribution and ecology of the species are given based in literature and new data.

New records for the opisthobranch fauna of the Archipelago of the Azores (north-east Atlantic Ocean)

ricardo cordeiro, manuel anto’nio e. malaquias, guillem mas, irene figueroa, jose’ p. borges and se’rgio p. a’vila CIBIO, Centro de Investigacao em Biodiversidade e Recursos Geneticos, InBIO Laboratorio Associado, Polo dos Acores, Universidade dos Acores, Campus de Ponta Delgada, Apartado 1422, 9501-801 Ponta Delgada, Acores, Portugal, Departamento de Biologia, Universidade dos Acores, Campus de Ponta Delgada, Apartado 1422, 9501-801 Ponta Delgada, Acores, Portugal, Phylogenetic Systematics and Evolution Research Group, University Museum of Bergen, Natural History Collections, University of Bergen, PB 7800, 5020-Bergen, Norway, Grup de Recerca d’Opistobranquis de Catalunya, Mas Castellar, s/n, Pontos 17773, Girona, Spain, CREAF, 08193 Cerdanyola del Valles, Spain, Instituto Portugues de Malacologia, Zoomarine, EN 125 km 65, Guia, 8200-864 Albufeira, Portugal