Philosciids with pleopodal lungs? The case of the genusAphilosciaBudde-Lund, 1908 (Crustacea: Isopoda: Oniscidea), with a description of six new species

First amphibious Crinocheta (Isopoda, Oniscidea) from the Neotropics with a troglobitic status: a relictual distribution

The first freshwater amphibian representative of Crinocheta (Oniscidea) from the Neotropics is described from caves within the Brazilian Cerrado biome, state of Mato Grosso do Sul. Kadiweuoniscusrebellisgen. et sp. nov. is placed in the family Philosciidae. The present work represents a significant contribution to future studies seeking to understand the ecological and evolutionary processes of Crinocheta within the Neotropical region. Moreover, it highlights the importance of biodiversity surveys in subterranean environments toward effective conservation efforts of these unique habitats and their surroundings.

Integrative taxonomy reveals a new genus and new species of Philosciidae (Crustacea: Isopoda: Oniscidea) from the Neotropical region

Although new methods and data are conquering space in the field of taxonomy, such as integrative taxonomy, most terrestrial isopod species are still described based only on morphology. Species of the genus Atlantoscia Ferrara and Taiti, 1981 were the first and are the unique terrestrial isopods from the Neotropics for which a molecular phylogeny was already conducted. Previous results indicated that this genus could be paraphyletic, and a more detailed analysis would be required. Our aim was to reconstruct the phylogeny of Atlantoscia using mitochondrial and nuclear markers and test its monophyly by integrating molecular and morphological data. We observed that, indeed, Atlantoscia is paraphyletic. Atlantoscia ituberasensis Campos-Filho, Lisboa and Araujo, 2013 and Atlantoscia rubromarginata Araujo and Leistikow, 1999 were placed in a new genus of terrestrial isopods, Paratlantoscia gen. nov., together with a new species described in the present study, Paratlantoscia robusta sp. nov. The new genus is defined by the presence of specialized respiratory areas in the pleopod exopods and its validity is highly corroborated by molecular analyses and by biogeographic information. This study highlights the importance of multiple and complementary perspectives as a way to improve the quality of species hypothesis and associated descriptions.

New species and new records of terrestrial isopods (Crustacea, Isopoda, Oniscidea) from Brazil

ABSTRACT. A large collection of terrestrial isopods from different Brazilian regions was examined. Two new species of Amazoniscus Lemos de Castro, 1967 (Scleropactidae) are described: A. zimmeri Campos-Filho, Montesanto & Araujo sp. nov. from the state of Pará and A. schmidti Campos-Filho, Montesanto & Taiti sp. nov. from the state of Minas Gerais. Pseudotyphloscia alba (Dollfus, 1898) (Philosciidae) is firstly recorded from Brazil. The systematic position of Venezillo tuberosus (Budde-Lund, 1904) is discussed and transferred to Ctenorillo Verhoeff, 1942. Androdeloscia lejeunei (Lemos de Castro & Souza, 1986) and Diploexochus echinatus Brandt, 1833 from the state of Pará, are redescribed.

Molecular phylogenetic analyses reveal a new southern hemisphere oniscidean family (Crustacea : Isopoda) with a unique water transport system

A significant diversity of terrestrial oniscidean isopods was recently discovered in the subterranean ‘calcrete islands’ of Western Australia, but the species and higher-level systematic status of much of the fauna are currently uncertain. Here we focus on one group of species that was initially assigned to the genus Trichorhina (Platyarthridae), based on several shared characters, and investigate the phylogenetic relationships of these species to 21 oniscidean genera, including 13 known families, using 18S rDNA sequence data. We then present phylogenetic analyses using 28S-only and combined 18S, 28S rDNA and mitochondrial cytochrome c oxidase subunit I (COI) data for a more restricted sampling of taxa, and present results for a detailed morphological study of the antennae and other cephalic structures of exemplar taxa. Bayesian and maximum likelihood analyses of the extended 18S-only, the 28S-only and multi-gene datasets provide strong evidence for a distinct well-supported monophyletic group comprising the new Western Australian and one South American taxon. This clade is unrelated to all included members of Platyarthridae, which appears to be polyphyletic, and it forms a distinct group relative to other oniscidean families. Given these findings and the results of the morphological study, a new southern hemisphere oniscidean family, Paraplatyarthridae Javidkar & King, fam. nov. is erected based on Paraplatyarthrus subterraneus Javidkar & King, gen. & sp. nov. (type genus and species), and several undescribed taxa which occur in the arid (terrestrial and subterranean) regions of Western Australia and subtropical South America. Paraplatyarthridae is distinguishable from all other oniscidian families on a combination of character states including, among others, the presence of fan-like scale setae on the dorsal body, and the ventral second antenna with leaf-like scale setae and a furrow containing elongated hair-like capillary setae that form part of a water conducting system unique within Oniscidea. This study has important implications for the higher-level classification of oniscidean crustaceans and points to the need for a more detailed molecular phylogeny that includes a comprehensive sampling of southern hemisphere taxa.

Eco-morphological studies on pleopodal lungs and cuticle in Armadillidium species (Crustacea, Isopoda, Oniscidea)

Terrestrial isopods (Crustacea, Isopoda, Oniscidea) have adapted to land life by diverse morphological, physiological and behavioral changes. Woodlice species exhibit a large variety in this respect, their preferences ranging from moist to dry habitats. These moisture preference values are related to various morphological adaptations, rendering terrestrial isopods amenable to studying morphological adaptations to terrestrial life. We performed a comparison of four Armadillidium species (Armadillidium zenckeri, Armadillidium nasatum, Armadillidium versicolor, Armadillidium vulgare), by quantifying two morphological traits: the extent of the interfacial endothelium between the respiratory space and the hemolymph within pleopodal lungs and the thickness of tergite cuticle, which are 'key factors' in determining protection from desiccation. These values were measured from light micrographs of cross-sectioned lungs. The cosmopolitan A. vulgare, as a habitat generalist, seems to be the most resistant against desiccation and other environmental conditions, while A. zenckeri is the most sensitive one. Light microscopic studies revealed that the four species can be ordered similarly, if we compare them by the extension of the endothelial interface and cuticle thickness, suggesting that these morphological traits are important determinants of their distribution on habitat, microhabitat scales and through the existence of suitable habitats - together with many other factors - the geographical pattern of species occurence.

Morphology and evolution of the respiratory apparatus in the family Eubelidae (Crustacea, Isopoda, Oniscidea)

The morphology of the respiratory apparatus in the pleopodal lungs of the family Eubelidae was investigated. The family is a monophyletic group including more than 240 species in 53 genera (three of which are nomina dubia), mostly distributed in the Afrotropical Region (tropical Africa and Arabian Peninsula). In all the Eubelidae, except for the monospecific genus Parelumoides and two species of the genus Elumoides, the exopods of pleopods have lungs. All the pulmonary morphologies present in the entire suborder Oniscidea are found: 1) uncovered lungs, composed of a pleated respiratory surface, directly exposed to the air (Atracheodillo-type) or partially enclosed within the appendage (Synarmadilloides-type); 2) covered lungs with several spiracles and respiratory trees, housed within the appendages, with spiracles surrounded by a specialized, nonrespiratory, structure (perispiracular area) (Eubelum- and Somaloniscus-types); 3) covered lungs with only one spiracle, with or without perispiracular area, and one respiratory tree (Aethiopopactes- and Periscyphis-types), which in taxa with Periscyphis-type lung crosses the insertion of the appendage and penetrates into the pleon with bundles of respiratory tubules. The evolution of the various types of lungs is discussed. It is concluded that the two main evolutionary lines, i.e., uncovered lungs and covered lungs, originated independently from an ancestral respiratory structure-the semilunar area. A first mechanism of development of the semilunar area by folding of its surface produced the Atracheodillo-type (all folds coplanar with the surface of the exopod) and Synarmadilloides-type (folds partly coplanar and partly intraflexed inside the exopod) uncovered lungs. A second mechanism of development by tubular invagination of the cuticle of the semilunar area produced the polyspiracular Eubelum-type lungs (numerous arborescent invaginations) and the monospiracular Aethiopopactes-type lungs (only one arborescent invagination), probably passing through a common intermediate pattern. From the common pattern, both the poly- and monospiracular types would have inherited the characteristic concave cell arrangement of the perispiracular area. The Somaloniscus-type and Periscyphis-type lungs are forms specialized for arid environments, directly derived from the Eubelum-type and Aethiopopactes-type, respectively.

Molecular evolution of the small subunit ribosomal DNA in woodlice (Crustacea, Isopoda, Oniscidea) and implications for Oniscidean phylogeny

The small subunit ribosomal DNA (ssu rDNA) of 13 isopods was sequenced. The entire length of the ribosomal gene is unusually long, resulting from the presence of five expansion elements accounting for more than 40% of the gene. We found that in terrestrial isopods the length of the ssu rDNA ranges from 2414 bp (Ligidium hypnorum) to 3537 bp (Cubaris murina). This is the longest metazoan ssu rDNA reported to date. The conserved regions are highly informative for analysis of the early nodes of the tree, whereas the variable expansion elements are better suited to reconstruction of the branching pattern between closely related taxa. The suggested relationship among Synochaeta, Crinochaeta, and Diplochaeta based on the conserved regions confirms that based on previous morphological analyses. In contrast, the phylogeny within the Crinochaeta based on the entire ssu rDNA including the variable domains is in conflict with that based on most of the morphological analyses. The phylogenetic analyses of the ssu rDNA support a repeated independent evolution of the three different types of pleopodal lungs in the Crinochaeta.