Previous collections of aquatic Heteroptera from Cambodia have been limited, and the biota of the country has remained essentially undocumented until the past several years. Recent surveys of aquatic Heteroptera in the Cardamom Mountains and adjacent Kirirom and Bokor plateaus of southwestern Cambodia, coupled with previous literature records, demonstrate that 11 families, 35 genera, and 68 species of water bugs occur in this area. These collections include 13 genus records and 37 species records newly listed for the country of Cambodia. The following four new species are described based on these recent surveys: Amemboa cambodiana n. sp. (Gerridae); Microvelia penglyi n. sp., Microvelia setifera n. sp. and Microvelia bokor n. sp. (all Veliidae). Based on an updated checklist provided herein, the aquatic Heteroptera biota of Cambodia as currently known consists of 78 species, and has an endemism rate of 7.7%, although these numbers should be considered provisional pending further sampling.

Two new species of Amemboa Esaki (Heteroptera: Gerridae) from West Bengal, India

Synopsis: Studies of the Papuan region have provided fundamental insights into the evolutionary processes generating its exceptional biodiversity, but the influence of geological processes merits further study. Lying at the junction of five tectonic plates, this region has experienced a turbulent geological history that has not only produced towering mountains allowing elevational specialization and island archipelagos with varying degrees of isolation promoting vicariance, but also active margins where land masses have collided and been subsequently rifted apart creating a mosaic of intermixed terranes with vastly different geological histories. Asterophryine frogs are a hyperdiverse clade representing half the world’s microhylid diversity (over 360 species) centered on New Guinea and its satellite islands. We show that vicariance facilitated by geological history explains this far and wide distribution of a clade that should have poor dispersal abilities. We recovered a mainland tectonic unit, the East Papua Composite Terrane (EPCT), as the center of origin for Asterophryinae and no fewer than 71 instances of what appear to be long-distance dispersal events, 29 of which are between mainland regions, with 42 from the mainland to the islands, some presently as far as 200 km away from source populations over open ocean. Furthermore, we find strong support for a “Slow and Steady” hypothesis for the formation of the northern margin of New Guinea by many separate accretion events during the Miocene, over other major geological alternatives, consistent with the 20 M year age of the clade and arrival via the EPCT. In addition, the historical biogeography of our frogs strongly supports an affiliation of the Louisiade Archipelago and Woodlark Island with the Owen Stanley Range on the EPCT, and the recent proximity of the large New Britain Island. Our results show that Asterophryinae did not have to repeatedly and independently disperse across large ocean barriers to the offshore islands, against the predictions of island biogeography theory, but that the current distribution can be explained through vicariance and short-distance oceanic dispersal as historical land connections disappeared and islands slowly became separated from each other. We show that islands have a life history, changing in distance from other land masses, with consequent opportunities for dispersal, isolation, and cladogenesis of their biotas. More broadly, we can begin to see how the geological history of the Papuan region can result in the rapid accumulation and staggering number of extant species.

Two new genera of cavernicolous Hydrometridae are described from limestone caves in northeastern Brazil: Spelaeometra n. gen., with type species S. gruta n. sp., from the Lapa D’Água do Zezé, Lapa do Nestor, Lapa do Saco Velho, and Lapa do Caboclo caves in Minas Gerais state; and Cephalometra n. gen., with type species C. pallida n. sp., from the Natividade cave in Tocantins state. Both new taxa are flightless, possess reduced eyes, and exhibit other reductional character states linked to life in underground ecosystems. The new taxa are interpreted to be highly aberrant members of the family Hydrometridae, based on the possession of eyes set well forward on the head capsule, the posterior pair of cephalic trichobothria arising from distinct tubercles, the presence of an apical invagination on the fourth antennal segment, and the structure of the male parameres. They are provisionally placed in the subfamily Hydrometrinae based on the apical articulation between the first and second antennal segments. On the basis of a preponderance of shared apomorphic character states these new genera appear most closely allied to Veliometra schuhi Andersen, which is also endemic to Brazil, although currently placed in a different subfamily. Color habitus photographs and line drawings of key characters are provided for both new taxa, accompanied by maps and photographs of the caves in which the species occur.