Enigmatic and extravagant genitalia in the spider genus Mastigusa (Araneae, Cybaeidae) - a taxonomic revision.

Mastigusa is a genus of small palearctic spiders that has recently been moved to the family Cybaeidae after the first inclusion of the genus in a phylogenetic matrix. Three species are currently recognised: M. arietina , M. lucifuga and M. macrophthalma . The status and delimitation, though, has always been problematic due to inconsistency in the characters used to discriminate between these, leading to great confusion in identity and distribution. We present a detailed morphological redescription of the genus and a taxonomic revision of the included species by the combined use of morphological data and molecular species-delimitation techniques based on the mitochondrial COI gene. The status of the three currently described species has been reevaluated and Mastigusa diversa was revalidated based on material from the Iberian Peninsula, North Africa and the United Kingdom. The distribution of Mastigusa species is updated based on novel taxonomic considerations, and comments on the natural history and ecological differences observed in the species are provided. ZooBank: urn:lsid:zoobank.org:pub:AAD3FAED-440F-4295-B458-455B1D913F81.

Molecular systematics and phylogenetics of the spider genus Mastigusa Menge, 1854 (Araneae, Cybaeidae).

The palearctic spider genus Mastigusa Menge, 1854 is characterized by a remarkable morphology and wide ecological variability, with free-living, cave dwelling and myrmecophile populations known. This genus has a long and tangled taxonomic history and was placed in different families in the past, all belonging to the "marronoid clade", an informal grouping of families characterized by the lack of strong synapomorphies. Three species are currently recognized, but their identity and circumscription has been long debated. A molecular approach was never applied for trying to solve these uncertainties, and doubts still remain both about its phylogenetic placement and about the taxonomic status of the described species. For the first time the genus Mastigusa is included in a molecular phylogenetic analysis and strong support is found for its placement within the family Cybaeidae, in sister relationship with the genus Cryphoeca Thorell, 1870. An analysis of Mastigusa populations spanning across the distribution range of the genus identifies a high and previously overlooked genetic diversity, with six distinct genetic lineages showing a strong geographic pattern. Divergence times between Mastigusa and its sister genus and between the distinct Mastigusa lineages are estimated, and the groundwork is laid for a taxonomic revision of the species belonging to the genus.

Exploring mitogenome evolution in Branchiopoda (Crustacea) lineages reveals gene order rearrangements in Cladocera.

The class Branchiopoda, whose origin dates back to Cambrian, includes ~ 1200 species which mainly occupy freshwater habitats. The phylogeny and systematics of the class have been debated for long time, until recent phylogenomic analyses allowed to better clarify the relationships among major clades. Based on these data, the clade Anostraca (fairy and brine shrimps) is sister to all other branchiopods, and the Notostraca (tadpole shrimps) results as sister group to Diplostraca, which includes Laevicaudata + Spinicaudata (clam shrimps) and Cladoceromorpha (water fleas + Cyclestherida). In the present analysis, thanks to an increased taxon sampling, a complex picture emerges. Most of the analyzed mitogenomes show the Pancrustacea gene order while in several other taxa they are found rearranged. These rearrangements, though, occur unevenly among taxa, most of them being found in Cladocera, and their taxonomic distribution does not agree with the phylogeny. Our data also seems to suggest the possibility of potentially homoplastic, alternative gene order within Daphniidae.