The mysterious deep-sea shrimp Physetocaris microphthalma Chace, 1940 remains a challenge for the understanding of caridean shrimp systematics. Upon first description in 1940, the unique morphology in combination with lack of material made the allocation of P. microphthalma to any family or superfamily difficult, therefore the monotypic superfamily Physetocaridoidea and family Physetocarididae were described. The rarity of the species, only documented a few times in scientific literature, in combination with a circumglobal distribution, makes the advancement of the systematics and biology of this shrimp challenging. Current literature places Physetocaridoidea as a superfamily with a sister relationship to Pandaloidea but this relationship has never been tested using molecular data. Recent expeditions to the northern Gulf of Mexico and north-eastern Pacific Ocean provided fresh material for inclusion in phylogenetic analyses. Here, we used a molecular systematics approach to investigate the phylogenetic placement of this species within the infraorder Caridea and test for cryptic diversity across oceanic basins. We sequenced five genes (12S rRNA, 16S rRNA, H3, NaK and PEPCK) and built phylogenetic trees including specimens across Pandaloidea and other carideans (n = 75) using maximum-likelihood and Bayesian approaches. Our results strongly support the inclusion of P. microphthalma within the family Pandalidae and superfamily Pandaloidea, indicating that the superfamily Physetocaridoidea and family Physetocaridae are not valid. In addition, the inclusion of specimens from the Atlantic and Pacific Oceans does not support evidence of cryptic diversity, suggesting the global distribution of P. microphthalma. This is the first study to provide genetic data for this species, resulting in an updated classification for the infraorder Caridea and highlighting that deep-pelagic species can be rare yet still widely distributed.

Helotidae is a small and morphologically uniform family in Nitiduloidea. In this study, we report an unusual form of helotids, represented by Lobatihelota lescheni Li, Liu & Cai gen. nov., sp. nov. and L. iridescens Li, Liu & Cai sp. nov. from mid-Cretaceous Burmese amber. Lobatihelota is unique within the family in having a leg morphology typical of some Nitidulidae and Kateretidae (tibia widened distally, tarsomeres 1–3 bilobed, tarsomere 4 shortened). Additionally, new diagnostic characters are suggested for Trihelota from the same deposit (prosternum and mesoventrite with paired carinae, metanepisterna short, metacoxae meeting elytra laterally), and the morphological divergence of representative genera of the superfamilies Erotyloidea, Nitiduloidea and Cucujoidea is visualised using a phylomorphospace approach.

ZooBank: urn:lsid:zoobank.org:pub:FE0E4D6A-8157-4E14-9240-7B87F285AEA5

South-western Western Australia is a global biodiversity hotspot renowned for exceptional diversity of plants and animals. The evolutionary processes that have generated this high biodiversity are not always clear, particularly for invertebrates, yet the area supports a very large number of endemic species that have diversified in situ. We use an integrative taxonomic approach based on adult and immature morphology, ecology, behaviour and molecular data to investigate the taxonomic status of a sympatric but seasonally isolated form (Neolucia agricola occidens Waterhouse & Lyell, 1914 form ‘Julimar’) of the polyommatine butterfly Neolucia agricola (Westwood, 1851) in south-western Western Australia. Our molecular dataset comprised 112 samples representing all Neolucia Waterhouse & Turner, 1905 species (100 COI 5′ sequences, 658 bp, plus 12 COI 3′, tRNA Leu, COII and EF1-α sequences, 3303 bp). Maximum likelihood phylogenetic analysis of the combined dataset recovered form ‘Julimar’ and N. agricola as reciprocally monophyletic, with a mean uncorrected ‘p’ pairwise divergence of 5.77% for the ‘barcode’ region of COI. Based on this and other evidence we recognise form ‘Julimar’ as a new species, Neolucia bollami Eastwood, Braby & Graham, sp. nov., sister to N. agricola and endemic to south-western Western Australia. As a result of these findings, we evaluated the evolutionary history of the two Neolucia species in WA and the processes that may have contributed to the diversification in sympatry or allopatry. We conclude that the multiple effect traits associated with a host shift, including host fidelity and temporal divergence, played an important role in the diversification process and in maintaining the reproductive integrity of the nascent allochronic species.

ZooBank: urn:lsid:zoobank.org:act:53D9AD14-9694-4B5E-889C-A8D533E7F57D

The Euconulidae is a globally distributed land snail family but there is no record of this family from Thailand. In this study, we describe a new genus, Siamoconus gen. nov., based on comparative studies of the shell characteristics, external morphology of animals, radula, genital and spermatophore structures, and molecular phylogeny. We performed phylogenetic analyses of two mitochondrial gene fragment (cytochrome c oxidase I, COI; and 16S rRNA) and one nuclear (28S rRNA) gene fragment to clarify the relationships with other euconulid genera and its position in the superfamily Trochomorphoidea. We also analysed shell morphometrics, male genitalia and mantle pigmentation of Siamoconus gen. nov., confirming the status of three new species with keeled shells (S. boreas sp. nov., S. coleus sp. nov. and S. geotrochoides sp. nov.) and one new species with a rounded shell (S. destitutus sp. nov.). These new species are restricted to limestone areas in northern and north-eastern Thailand. We also re-examined the status of other genera in the superfamily Trochomorphoidea based on shell features, body pigmentation, radula, genital anatomy, spermatophore morphology, and a phylogenetic analysis of all available trochomorphoidean DNA sequences. Our analysis suggests that the family Geotrochidae, previously synonymised with the Trochomorphidae, should be resurrected to represent the genus Geotrochus from Borneo, and this family is retrieved as the sister clade of the Dyakiidae.

ZooBank: urn:lsid:zoobank.org:pub:C5205F4E-5DDE-42E6-A532-761CAFE099C3