Revision of the Neotropical Genus Hemibidessus Zimmermann (Coleoptera: Dytiscidae: Hydroporinae: Bidessini)

The genus Hemibidessus Zimmermann, 1921 is revised. Six species are recognized in the genus. Two new species are described, H. spirodiscus sp. n. from Bolivia and H. spangleri sp. n. from Argentina. A key for identifying the species is presented. The female genitalia are thoroughly illustrated and described for the first time for any species of Bidessini. Other important diagnostic structures are also illustrated including the male genitalia. A cladistic analysis is presented for 8 species (6 ingroup and 2 outgroup species) and 13 characters. A single most parsimonious cladogram was found.     

Review of the genus Fontidessus Miller & Spangler, 2008 (Coleoptera,Dytiscidae, Hydroporinae,Bidessini) with description of four new species

The genus Fontidessus Miller & Spangler, 2008 (Coleoptera: Dytiscidae: Hydroporinae: Bidessini) is reviewed. The genus now includes seven species with three previously described, and four new species described here: F. microphthalmus Miller & Montano, sp. n.; F. bettae Miller & Montano, sp. n.; F. christineae Miller & Montano, sp. n., and F. aquarupe Miller & Montano, sp. n. Each species is diagnosed and described, including the previously known species, based on new specimens and new information. Habitus, male genitalia and other diagnostic features are illustrated for each species. A key to the seven species is provided. Fontidessus species are unique to hygropetric habitats in the Guiana Shield craton of northern South American.     

Description of Two New Bidessini Species from the Afro-tropical Region (Coleoptera,Dytiscidae)

Uvarus pinheyi sp. n. is described from Zambia and Hydroglyphus pseudoctoguttatus sp. n. from Angola. Distinguishing characteristics are given for the new taxa.     

Clypeodytes geiseri sp. n., an enigmatic Bidessini from Laos (Coleoptera: Dytiscidae,Bidessini)

Here, we describe Clypeodytes geiseri sp. n. from Champasak Province in southwestern Laos. This very distinct species belongs to the subgenus Hypoclypeus Guignot, 1950 and can be distinguished from all other Clypeodytes species by its larger size and almost completely blackish or dark ferrugineous dorsal surface, except for some weak testaceous markings on the elytra. The habitus and the median lobe of the new species are illustrated, and a map is provided. Altogether, six species of subgenus Hypoclypeus are now known from Asia.

urn:lsid:zoobank.org:pub:FC01425F-9D3A-482E-8FE4-D2BF3D4943DF     

Larvae of four species of the Hyphydrus lyratus species-group (Coleoptera: Dytiscidae: Hydroporinae)

Abstract  The third instars of the Australian species Hyphydrus lyratus Swartz, H. contiguus Wehncke, H. elegans (Montrouzier) and H. decemmaculatus Wehncke (Coleoptera: Adephaga: Dytiscidae) are described, including a chaetotaxic analysis of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. Larvae of these species morphologically resemble other species of Hyphydrus Illiger for which the larvae have been described. A key to identify larvae of the Australian species of Hyphydrus is provided. Larvae of H. effeminatus Watts appear identical to those of H. decemmaculatus . A 822 bp fragment of the CO1 gene of larvae and adults of these species showed very slight differences, suggesting the possibility that, in Australia at least, H. decemmaculatus is polymorphic.     

Sensilla,punctation, reticulation,and body shape in the Hydroporinae (Coleoptera : Dytiscidae)

The purposes of this study were to illustrate reticulation, punctation, and sensilla with the scanning electron microscope, to briefly speculate on function and hydrodynamic consequences of surface structure variation, and to discuss ecological implications of body shape. The emphasis of the study was on the subfamily Hydroporinae of Dytiscidae (Coleoptera). Use of SEM revealed five basic kinds of reticulation in hydroporines: (1) completely or almost completely effaced; (2) hexagonal-pentagonal; (3) transverse; (4) asterisk or star-shaped; (5) scale-like. Four basic types of sensilla are recognized: (1) sensillum placoideum; (2) sensillum basiconicum; (3) sensillum trichoideum type 1; (4) sensillum trichoideum type 2.Surface features do not reduce drag through the “golf ball” effect. Rather, it is suggested that they are modifications for optimization of reception of stimuli and reduction of backflow within the boundary layer.Surface features (reticulation, punctation, sensilla) are too variable to be phylogenetically useful in higher dytiscid classification. The following generalizations, however, are pointed out: (1) sensilla placoidea are known only in members of Deronectes, Lioporeus, and Phreatodessus hades; (2) kidney-shaped placoid punctures are evident only in elongate species of Oreodytes; (3) species of Hydroporus s. str., Neoporus, and Heterosternuta have hexagonal-pentagonal reticulation and mostly long, sensilla trichoidea; (4) reticulation is most often effaced in taxa placed in Hygrotus, Hyphydrini, and Hydrovatini.Body shape seems to be more variable among hydroporines than in any other dytiscid subfamily. More spherical shapes decrease stability, but increase maneuverability. This is most critical in lotic situations. It is predicted that most lotic nearctic species which occupy habitats that expose them to current will tend to have rather spherical, deep body shapes.     

Revision and phylogenetic analysis of the Central American endemic genus Phalangogonia Burmeister (Coleoptera: Scarabaeidae: Rutelinae: Anoplognathini)

Abstract.  Phalangogonia Burmeister is revised and now includes eight species: P . dispar Ohaus, P . jamesonae , sp.n., P . lacordairei Bates, P . obesa Burmeister, P . parilis Bates, P . punctata Franz, P . ratcliffei , sp.n. and P . sperata Sharp. Phalangogonia debilidens Ohaus is placed in synonymy with P . sperata . Lectotypes are designated for the following nominal species: P . dispar Ohaus, P . lacordairei Bates, P . parilis Bates and P . championi Bates. Neotypes are designated for: P . obesa Burmeister, P . sperata Sharp, P . stipes Sharp and P . debilidens Ohaus. A cladistic analysis of the species of Phalangogonia was executed using thirty-two morphological characters of adults.     

Taxonomic review of the genus Copelatus Erichson (Coleoptera: Dytiscidae) in Korea

A taxonomic review of the genus Copelatus Erichson (Coleoptera: Dytiscidae) in Korea is presented. In the present study, five species of Copelatus are recognized from Korea, including one unrecorded species, C. kammuriensis. We provide a key to the Korean species of Copelatus, diagnosis of one unrecorded species, habitus photographs, scanning electron micrographs of the elytron, and illustrations of the aedeagus.     

Evolution of subterranean diving beetles (Coleoptera: Dytiscidae: Hydroporini, Bidessini) in the arid zone of Australia

Calcrete aquifers in arid inland Australia have recently been found to contain the world's most diverse assemblage of subterranean diving beetles (Coleoptera: Dytiscidae). In this study we test whether the adaptive shift hypothesis (ASH) or the climatic relict hypothesis (CRH) is the most likely mode of evolution for the Australian subterranean diving beetles by using a phylogeny based on two sequenced fragments of mitochondrial genes (CO1 and 16S-tRNA-ND1) and linearized using a relaxed molecular clock method. Most individual calcrete aquifers contain an assemblage of diving beetle species of distantly related lineages and/or a single pair of sister species that significantly differ in size and morphology. Evolutionary transitions from surface to subterranean life took place in a relatively small time frame between nine and four million years ago. Most of the variation in divergence times of the sympatric sister species is explained by the variation in latitude of the localities, which correlates with the onset of aridity from the north to the south and with an aridity maximum in the Early Pliocene (five mya). We conclude that individual calcrete aquifers were colonized by several distantly related diving beetle lineages. Several lines of evidence from molecular clock analyses support the CRH, indicating that all evolutionary transitions took place during the Late Miocene and Early Pliocene as a result of aridification.     

A taxonomic review of Korean Hydroglyphus Motschulsky (Coleoptera: Dytiscidae: Hydroporinae) with a description of new species

A taxonomic study of Hydroglyphus Motschulsky in Korea is presented. Four species are recognized including a new species, Hydroglyphus coreanus sp. nov. Hydroglyphus flammulatus (Sharp) is reported for the first time in the Korean peninsula and H. geminus (Fabricius) is a new addition to the South Korean fauna. Habitus and SEM photographs, distribution maps, and key to the Korean species are provided.     

Hyphydrini Sharp, 1882, nomen protectum and Actobaenidae Gistel, 1856, nomen oblitum(Coleoptera: Dytiscidae: Hydroporinae)

The genus name Echinopus Gattolliat, 2002 is preoccupied and therefore must be considered as unavailable. Modaechinopus gen. nov. is proposed as a replacement name with the two new combinations Madaechinopus giboni (Gattolliat, 2002) and M. minutus (Gattolliat, 2002).     

Revision of the Neotropical genus Leptochromus Motschulsky (Coleoptera: Scydmaenidae)

Abstract The Neotropical genus Leptochromus Motschulsky (Coleoptera: Scydmaenidae) is revised, and a phylogenetic analysis of Clidicini is presented. Leptochromus includes five species distributed from Veracruz, Mexico to Manaus, Brazil. Leptochromus fulvescens Motschulsky, L. mexicanus (Sharp) and L. agilis (Sharp) are considered valid species. Leptochromus bicolor O'Keefe, sp.n. from Veracruz, Mexico and L . palaeomexicanus O'Keefe, sp.n. from Miocene amber from Chiapas are described. Male genitalia and antennae are illustrated for each of the extant species. Female genitalia, mouthparts and other morphological features are illustrated for the type species L. fulvescens. For the phylogenetic analysis of Clidicini, Palaeoleptochromus O'Keefe was placed as the sister taxon to Leptochromus , and Papusus Casey was placed as the sister taxon to Leptochromus  + Palaeoleptochromus . Papusus is elevated from synonomy with Leptochromus and the biogeography of Clidicini is discussed.     

On the habitats of three species of the genus Hygrotus Stephens (Coleoptera: Dytiscidae)

SUMMARY. 1. Adult Hygrotus beetles were collected from about 400 localities out of 621 sampled in the Netherlands. Distribution of the three Dutch species of this genus has been related to different environmental variables, principally by use of the Index of Representation (I.R.).
2. Hygrotus decoratus is an acidophilous and haloxenous species. It inhabits small water bodies such as peat-ditches, reed-lands and overgrown ditches where emergent plants are abundant. Hygrotus inaequalis occurs in all of the habitats studied and has no clear preferences or aversions with respect to the environmental variables examined. Hygrotus versicolor inhabits permanent water bodies such as clay- and sand-canals which have a rich growth of submerged plants and a weak current. The species has a significant preference for waters with a pH between 7.1 and 8.0 and a chlorinity between 60 and 200 mg 1-⁻¹.
3. H. decoratus and H. versicolor rarely co-exist because of their different environmental requirements, but both species often co-exist with H. inaequalis. Structural environmental variables such as water depth and abundance and growth-form of the aquatic plants play a greater role than chemical factors in habitat selection by Hygrotus spp.