The Jerusalem cricket subfamily Stenopelmatinae is distributed from south-western Canada through the western half of the United States to as far south as Ecuador. Recently, the generic classification of this subfamily was updated to contain two genera, the western North American Ammopelmatus, and the Mexican, and central and northern South American Stenopelmatus. The taxonomy of the latter genus was also revised, with 5, 13 and 14 species being respectively validated, declared as nomen dubium and described as new. Despite this effort, the systematics of Stenopelmatus is still far from complete. Here, we generated sequences of the mitochondrial DNA barcoding locus and performed two distinct DNA sequence-based approaches to assess the species' limits among several populations of Stenopelmatus, with emphasis on populations from central and south-east Mexico. We reconstructed the phylogenetic relationships among representative species of the main clades within the genus using nuclear 3RAD data and carried out a molecular clock analysis to investigate its biogeographic history. The two DNA sequence-based approaches consistently recovered 34 putative species, several of which are apparently undescribed. Our estimates of phylogeny confirmed the recent generic update of Stenopelmatinae and revealed a marked phylogeographic structure within Stenopelmatus. Based on our results, we propose the existence of four species-groups within the genus (the faulkneri, talpa, Central America and piceiventris species-groups). The geographic distribution of these species-groups and our molecular clock estimates are congruent with the geological processes that took place in mountain ranges along central and southern Mexico, particularly since the Neogene. Our study emphasises the necessity to continue performing more taxonomic and phylogenetic studies on Stenopelmatus to clarify its actual species richness and evolutionary history in Mesoamerica.

Deep-sea shrimp of the family Sergestidae Dana, 1852 provide a unique system for studying the evolution of bioluminescence. Most species within the family possess autogenic bioluminescent photophores in one of three distinct forms: lensed photophores; non-lensed photophores; or internal organs of Pesta. This morphological diversity across the Sergestidae has resulted in recent major taxonomic revisions, dividing the two major genera (Sergia Stimpson, 1860 and Sergestes Milne Edwards, 1830) into 15. The present study capitalises on molecular data to construct an updated genus-level phylogeny of sergestid shrimp. DNA was successfully extracted from ~87 individuals belonging to 13 of the 15 newly proposed genera. A 'genome skimming' approach was implemented, allowing the capture of mitochondrial genomic data across 19 sergestid species. Additional individuals have been incorporated into the phylogeny through Sanger sequencing of both nuclear (H3 and NAK) and mitochondrial (16S and COI) genes. The resulting molecular phylogeny is compared with previous morphological trees with specific attention to genus-level relationships. The -sergestes group was rendered non-monophyletic and the -sergia group was recovered as monophyletic. Ancestral state reconstructions of light organ type indicate that organs of Pesta is the ancestral state for the family. Non-lensed photophores evolved once across the -sergia group, but were later lost in the deepest living genus, Sergia. Lensed photophores also evolved once within the genera Prehensilosergia Vereshchaka, Olesen & Lunina, 2014, Lucensosergia Vereshchaka, Olesen & Lunina, 2014 and Challengerosergia Vereshchaka, Olesen & Lunina, 2014. These findings identify preliminary patterns across light organ type and species' depth distributions; however, future research that incorporates finer-scale depth data and more species is needed to confirm our findings.

Neoentomelas asatoi Hasegawa, 1989 is a parasitic nematode that infests only the scincid lizard Ateuchosaurus pellopleurus (Hallowell, 1861) that inhabits the forest floor in the Northern and Central Ryukyu Archipelago, Japan. As a member of Rhabdiasidae, the reproductive mode of N. asatoi is characterised by the alternation of the protandrous hermaphroditic mode and gonochoristic mode throughout the life cycle. The intrafamily phylogenetic position and intraspecific diversity of this nematode species were inferred by molecular phylogenetic analyses. The results revealed the phylogenetic distinctiveness of Neoentomelas Hasegawa, 1989 in Rhabdiasidae that supports the unique generic status of Neoentomelas within the family. The intraspecific phylogenetic analyses of N. asatoi revealed a minor concordant phylogenetic pattern with the host and mosaic geographic arrangement of the major clades that was discordant with the host. The analyses and distribution pattern of subclades suggested that this geographic arrangement can be explained by at least three dispersal events and subsequent switching to indigenous host populations. Colonisation events might be promoted by the high establishment rate of new populations stemming from the parthenogenesis-like reproduction mode of N. asatoi. This study demonstrated that reproductive modes can affect the intraspecific genetic diversity of parasites.

Cyphalonotus is a poorly studied Old World araneid spider genus of which the phylogenetic proximity remains unknown due to the paucity of morphological and molecular data. We test the phylogenetic placement and the taxonomic composition of Cyphalonotus and place the male and female size variation of Cyphalonotus and related genera in an evolutionary context. Our collection and field observations from Taiwan and China facilitate description of a new and a known species, and original sequence data enable species delimitation and phylogenetic analyses. The phylogenetic results reject all four classification hypotheses from the literature and instead recover a well-supported clade comprising Cyphalonotus + Poltys. We review the male and female size variation in Cyphalonotus, Poltys and related genera. These data reveal that all known species of Poltys are extremely sexually size dimorphic (eSSD = females over twice the size of males) reaching values exceeding 10-fold differences, whereas Cyphalonotus and other genera in phylogenetic proximity are relatively sexually monomorphic (SSD < 2.0). This confirms an independent origin of eSSD in Poltys, one of multiple convergent evolutionary outcomes in orbweb spiders.

Morphological variability within Cassiopea is well documented and has led to inaccuracies in the establishment of species boundaries in this taxon. Cassiopea medusae specimens from the Western Pacific (Japan and the Philippines) were analysed using multiple lines of complementary evidence, including types of cnidae, macro-morphology and molecular data. These observations lead to the recognition of two distinct species: Cassiopea mayeri, sp. nov. and a previously synonymised variety now raised to species level (Cassiopea culionensis, stat. nov.). These species can be distinguished from each other using morphological features. Herein, sexually dimorphic traits are included for the first time in the descriptions of Cassiopea species. Nematocyst types not previously observed in the genus are also reported. Molecular analyses, based on individual and combined markers (16S + cytochrome c oxidase I, COI), also support two distinct species; they are not sister taxa, and both are nested together within a clade of other Cassiopea members from the Australian and Indo-Pacific regions. Species richness is underestimated in the Western Pacific region, and integrative approaches are helpful to reveal and describe species. The systematics of Cassiopea is far from completely understood, but the present study represents an important further step.