The point on Opaliopsis atlantis (Gastropoda: Epitoniidae) distribution: new data from the Mediterranean and implications

Specimens of the rare amphi-Atlantic epitoniid Opaliopsis atlantis have been recorded in the Strait of Messina (central Mediterranean) from a hydrozoan stylasterid-rich habitat. The record, which adds a new site to the sporadic occurrences of this prevalently deep-water species, may be considered the first contextualized report from Mediterranean Sea. Opaliopsis atlantis displays a planktotrophic larval development functional for long-range colonization of favorable habitats. Its discontinuous distribution all over its broad geographic range highlights the potential role of Atlantic seamounts as stepping-stones for transoceanic dispersal. Although no conclusive information is yet available upon the feeding requirements of O. atlantis all over its range, we suggest that this cnidarian-ectoparasitic prosobranch could adapt to different hosts, as a strategy that may enhance its wide biogeographic distribution.

Redescription of Promecostethus unifalculatus, the only known harvestman from Crozet Islands (Opiliones: Triaenonychidae)

Promecostethus unifalculatus Enderlein, 1909, is the only representative of the order Opiliones from the Crozet Islands. The species belongs to the family Triaenonychidae and is biogeographically interesting because it is a candidate for transoceanic dispersal, a very rare event in this ancient family. Despite this significance, P. unifalculatus is taxonomically still poorly known, and a redescription of this species using modern taxonomic standards is urgently needed. Here we redescribe the species, offer the first description and illustrations of the male genitalia and provide a full exomorphological survey of the species using scanning electron microscopy. Furthermore, we provide an emended diagnosis for the genus Promecostethus and discuss its relationship with some morphologically similar genera.

Allaeotes niger, a weevil introduced to Cuba and the only known New World Stromboscerini (Coleoptera: Curculionidae: Dryophthorinae)

Allaeotes niger He, Zhang and Pelsue, a weevil hitherto known only from the type series collected in China, is for the first time reported from Cuba. In addition to three historical Cuban specimens, approximately one hundred adults were observed in 2018 under bark of fallen logs at a plantation of (likely non-native) pines in westernmost Pinar del Río province. This is the only New World record of a member of the monophyletic core of the tribe Stromboscerini, otherwise distributed in a triangle delimited by Japan, Sri Lanka and northern Australia (plus a single mysterious record from Uganda). Phylogenetic analysis of one mitochondrial (COI) and two nuclear (ITS2 and 28S) markers recovered the Cuban specimens nested within the tribe, but not in a clade with two unnamed congeners from Vietnam. Adults of all four known Allaeotes species are illustrated, including both named ones. Remarkably, both Cuban and Ugandan records of extraterritorial Stromboscerini pertain to species associated with dead wood, a biological trait possibly facilitating human-assisted transoceanic dispersal. Cuban populations of A. niger are interpreted as a pre-1990 human-mediated introduction. Two additional specimens of A. niger intercepted at US ports of entry arriving from China and the Dominican Republic, respectively, corroborate this hypothesis and suggest China as a likely origin of the Cuban introduction. All data used herein (specimen images, geographical localities, DNA sequences) are available online in a public dataset dx.doi.org/10.5883/DS-VGDS012.

From mainland to islands: colonization history in the tree frog Kurixalus (Anura: Rhacophoridae)

The origin and colonization history of Kurixalus, a genus of small arboreal tree frogs breeding exclusively in shallow swamps, is under disputed. On the basis of comprehensive sampling program, the evolutionary history of Kurixalus is investigated based on 3 mitochondrial genes. Our results indicate that the genus Kurixalus originated in the Asian mainland and subsequently arrived at its current distribution in Borneo, Taiwan, Ryukyu, and Hainan islands by a series of dispersal events. Moreover, the colonization of Taiwan from mainland Asia has occurred 2 times. The initial colonization of Taiwan occurred at 3.46–8.68 Mya (95% highest posterior density), which rejects the hypothesis that Kurixalus probably originated from Taiwan during the early Oligocene and favors the model of Neogene-origin rather than the model of Quaternary-origin for Taiwanese Kurixalus. Kurixalus eiffingeri has dispersed from Taiwan to the Ryukyus once or 2 times pending more data. Both transoceanic dispersal and landbridge dispersal have played a role in the colonization process; the former resulted in the colonization of Taiwan and the Ryukyus and the latter led to the colonization of Borneo and Hainan.

Molecular phylogeny and biogeography of the temperate Gondwanan family Triaenonychidae (Opiliones : Laniatores) reveals pre-Gondwanan regionalisation, common vicariance, and rare dispersal

Triaenonychidae Sørensen in L. Koch, 1886 is a large family of Opiliones with ~480 described species broadly distributed across temperate forests in the Southern Hemisphere. However, it remains poorly understood taxonomically, as no comprehensive phylogenetic work has ever been undertaken. In this study we capitalise on samples largely collected by us during the last two decades and use Sanger DNA-sequencing techniques to produce a large phylogenetic tree with 300 triaenonychid terminals representing nearly 50% of triaenonychid genera and including representatives from all the major geographic areas from which they are known. Phylogenetic analyses using maximum likelihood and Bayesian inference methods recover the family as diphyletic, placing Lomanella Pocock, 1903 as the sister group to the New Zealand endemic family Synthetonychiidae Forster, 1954. With the exception of the Laurasian representatives of the family, all landmasses contain non-monophyletic assemblages of taxa. To determine whether this non-monophyly was the result of Gondwanan vicariance, ancient cladogenesis due to habitat regionalisation, or more recent over-water dispersal, we inferred divergence times. We found that most divergence times between landmasses predate Gondwanan breakup, though there has been at least one instance of transoceanic dispersal – to New Caledonia. In all, we identify multiple places in the phylogeny where taxonomic revision is needed, and transfer Lomanella outside of Triaenonychidae in order to maintain monophyly of the family.