The Opiliones superfamily Triaenonychoidea currently includes two families, the monogeneric New Zealand–endemic Synthetonychiidae Forster, 1954 and Triaenonychidae Sørensen, 1886, a diverse family distributed mostly throughout the temperate Gondwanan terranes, with ∼110 genera and ∼500 species and subspecies currently described. Traditionally, Triaenonychidae has been divided into subfamilies diagnosed by very few morphological characters largely derived from the troublesome ‘Roewerian system’ of morphology, and classifications based on this system led to many complications. Recent research within Triaenonychoidea using morphology and traditional multilocus data has shown multiple deeply divergent lineages, non-monophyly of Triaenonychidae, and non-monophyly of subfamilies, necessitating a revision based on phylogenomic data. We used sequence capture of ultraconserved elements across 164 samples to create a 50% taxon occupancy matrix with 704 loci. Using phylogenomic and morphological examinations, we explored family-level relationships within Triaenonychoidea, including describing two new families: (1) Lomanellidae Mendes & Derkarabetian, fam. nov., consisting of Lomanella Pocock, 1903, and a newly described genus Abaddon Derkarabetian & Baker, gen. nov. with one species, A. despoliator Derkarabetian, sp. nov.; and (2) the elevation to family of Buemarinoidae Karaman, 2019, consisting of Buemarinoa Roewer, 1956, Fumontana Shear, 1977, Flavonuncia Lawrence, 1959, and a newly described genus Turonychus Derkarabetian, Prieto & Giribet, gen. nov., with one species, T. fadriquei Derkarabetian, Prieto & Giribet, sp. nov. With our dataset we also explored phylogenomic relationships within Triaenonychidae with an extensive taxon set including samples representing ∼80% of the genus-level diversity. Based on our results we (1) discuss systematics of this family including the historical use of subfamilies, (2) reassess morphology in the context of our phylogeny, (3) hypothesise placement for all unsampled genera, (4) highlight lineages most in need of taxonomic revision, and (5) provide an updated species-level checklist. Aside from describing new taxa, our study provides the phylogenomic context necessary for future evolutionary and systematic research across this diverse lineage.

The field of systematics and our understanding of phylogenetic relationships have been invigorated by the use of molecular data, but analyses based on DNA sequence data are not always corroborated by diagnostic morphological characters. In particular, several taxonomic changes in butterflies (Papilionoidea) have been made solely on the basis of molecular data without identifying morphological synapomorphies that might have aided in diagnosing taxa from butterfly collections or specimens with no accessible DNA. We here focus on the butterfly genus Pseudodebis Forster, 1964 in the so-called ‘Taygetis clade’, which is one of the major clades in the diverse Neotropical nymphalid subtribe Euptychiina. We inferred the evolution of a male genitalic character using the most comprehensive molecular phylogeny for the ‘Taygetis clade’ to date. This approach allowed us to identify a synapomorphy for Pseudodebis Forster, 1964, which can be used to morphologically diagnose this genus and to distinguish it from other genera in the ‘Taygetis clade’. In addition, we describe two new species of Pseudodebis, P. nakamurai Nakahara & Willmott, sp. nov. and P. pieti Nakahara & Willmott, sp. nov., recovered as sister species based on molecular data, with an estimated time of divergence of 0.3 Ma (Bayesian confidence interval 0.03–1.61 Ma). Despite the low genetic divergence between these two Pseudodebis species, they can be readily distinguished by wing morphology. Pseudodebis nakamurai, sp. nov. and P. pieti, sp. nov. occur in partial sympatry across an elevational gradient along the western Andes, and the inferred recent speciation event might be related to a shift in elevation and possibly a change in larval hostplant preference.

The deep-sea malacofauna of temperate Australia remains comparatively poorly known. However, a recent influx of DNA-suitable material obtained from a series of deep-sea cruises has facilitated integrative taxonomic study on the Conoidea (Caenogastropoda : Neogastropoda). Building on a recent molecular phylogeny of the conoidean family Raphitomidae, this study focussed on the genera Gladiobela and Pagodibela (both Criscione, Hallan, Puillandre & Fedosov, 2020). We subjected a representative mtDNA cox1 dataset of deep-sea raphitomids to ABGD, which recognised 14 primary species hypotheses (PSHs), 9 of which were converted to secondary species hypotheses (SSHs). Following the additional examination of the shell and hypodermic radula features, as well as consideration of bathymetric and geographic data, seven of these SSHs were recognised as new to science and given full species rank. Subsequently, systematic descriptions are provided herein. Of these, five are attributed to Gladiobela (three of which are endemic to Australia and two more widely distributed) and two are placed in Pagodibela (one endemic to southern Australia and one widespread in the Pacific). The rarity of many ‘turrids’ reported in previous studies is confirmed herein, as particularly indicated by highly disjunct geographic records for two taxa. Additionally, several of the studied taxa exhibit wide Indo-Pacific distributions, suggesting that wide geographic ranges in deep-sea ‘turrids’ may be more common than previously assumed. Finally, impediments to deep-sea ‘turrid’ taxonomy in light of such comparative rarity and unexpectedly wide distributions are discussed.

An undescribed small, banded morphotype of Rhagada land snails occurs widely in the rocky inland Pilbara region, Western Australia. Phylogenetic analysis of mitochondrial COI and 16S rRNA genes revealed that this novel morphotype is polyphyletic, comprising four distinct major clades, with divergences up to 21.4% at COI. These clades are apparently morphologically cryptic, with no obvious shell differences. Two of these species are associated with the major clade of Rhagada in the Pilbara mainland, one of which appears to be a variant of the larger, more globose species R. pilbarana, which occurs within 20 km proximity. The other two small, banded species are phylogenetically distinct from each other and all other known Rhagada. This small, banded morphotype shows evidence for both plesiomorphy and homoplasy. The morphotype has evolved independently at least twice, and is associated with the reasonably uniform habitat and harsh conditions in the elevated hinterland of the inland Pilbara. The broad distribution of the inland, small, banded morphotype conforms to the pattern of broad-scale uniformity of shells of the more coastal species of Rhagada. Its repeated evolution, however, confirms that the morphological uniformity is not simply because of common ancestry, supporting the theory that shell form in Rhagada is adapted to a broadly homogenous environment. Shell morphology in this genus has been demonstrated on more than one occasion to have the potential to adapt to different available environments, and hence shells should be used with a degree of caution for taxonomic interpretation.

The epigean spiders of the genus Cybaeus L. Koch, 1868 are known to have diversified in western North America and the Japanese Archipelago. To date, ∼80 species of Cybaeus are known from Japan, but they have not previously been recorded from the Ryukyu Islands that harbour a diversity of endemic species. Here we describe eight new species of Cybaeus from the Ryukyu Islands, extending the range of Cybaeus southward to the central Ryukyus. Both sexes of each of the new species are described, and their phylogenetic relationships are estimated using nuclear and mitochondrial gene markers. Although Cybaeus okumurai, sp. nov. and C. kumadori, sp. nov. possess genital features that are common in the other Japanese congeners, the other six species (C. yakushimensis, sp. nov., C. kodama, sp. nov., C. amamiensis, sp. nov., C. aikana, sp. nov., C. tokunoshimensis, sp. nov., and C. hikidai, sp. nov.) are characterised by an elongated embolus and tubular spermathecae. These unique genital characteristics and the phylogeny recovered here suggest that these features evolved independently among the Japanese and Ryukyu Cybaeus species. Phylogenetic analyses highlight an unusual biogeographical pattern in which C. yakushimensis and C. kodama endemic to Yakushima Island in the northern Ryukyus are related to species distributed in the central Ryukyus. In contrast, our phylogeny suggests that C. okumurai from Tanegashima Island in the northern Ryukyus is sister to C. ashikitaensis (Komatsu, 1968), distributed in Kyushu of the Japanese Archipelago. The retreat constructs and sympatric distribution of Cybaeus found among the Ryukyus are also briefly discussed.

The genus Carinina Hubrecht, 1885 has long been considered the most ‘archaic’ nemertean taxon because its members are distinguished by the basiepidermal position of the brain and lateral nerve cords, characters thought to be plesiomorphic for the phylum. Here we describe two new species, Carinina yushini sp. nov. from the Sea of Japan (Russia) and C. chocolata sp. nov. from the north-east Pacific (Oregon, USA), distinguished by brown body colour. A phylogenetic analysis based on partial sequences of five nuclear and mitochondrial gene regions, 18S rRNA, 28S rRNA, histone H3, 16S rRNA and COI, confirms the monophyly of Carinina (Family Carininidae), and points to a close relationship to Carinoma (Family Carinomidae). The two groups together form a sister clade to the rest of the palaeonemerteans (Family Tubulanidae + Family Cephalotrichidae s.l.). Carinina plecta most likely belongs to the Tubulanidae. A morphological synapomorphy of the clade Carininidae + Carinomidae is a larva with a single midventral eye (in contrast to eyeless larvae of the Tubulanidae and two-eyed larvae of the Cephalotrichidae). Our phylogenetic analysis suggests that the basiepidermal position of the central nervous system is an autapomorphy of Carininidae (and, independently, C. plecta), rather than a plesiomorphy of the phylum Nemertea or the class Palaeonemertea, emphasising that the genus Carinina is no more archaic than any other palaeonemertean genus.