Yûsuke N. Minoshima

Larval morphology and phylogenetic position of Horelophopsis hanseni Satô et Yoshitomi (Coleoptera, Hydrophilidae, Horelophopsinae)

The subfamily Horelophopsinae was originally proposed as one of the earliest diverging clades of Hydrophilidae (s.s.), but its phylogenetic placement has never been tested. We describe the larva of Horelophopsis hanseni Satô et Yoshitomi, 2004 of the Horelophopsinae. Larval data are based on larval specimens collected together with adults, and unambiguously associated with them by means of DNA barcoding. We perform an analysis testing the phylogenetic position of H. hanseni based on larval and adult morphological characters. Horelophopsis hanseni is unambiguously placed within the hydrophilid subfamily Hydrophilinae and its close relationships to the genus Agraphydrus Régimbart, 1903 (Hydrophilinae, Acidocerini) is recognized. The results suggest that the subfamily Horelophopsinae is unlikely to be a basal taxon of Hydrophilidae, as originally suggested.

A Review of Andotypus and Austrotypus gen. nov., Rygmodine Genera with an Austral Disjunction (Hydrophilidae: Rygmodinae)

Abstract. The taxonomy and morphology of species related to the genus Andotypus Spangler, 1979 (Coleoptera: Hydrophiloidea: Hydrophilidae: Rygmodinae) are reviewed in detail. Austrotypus gen. nov. is established for A. nothofagi sp. nov. (eastern Australia) and A. peruanus sp. nov. (Peru), both of which share the same morphology of the mouthparts and mesoventrite. The genus Andotypus is found to be endemic to central and sourthern Chile, containing two species: A. ashworthi Spangler, 1979 and A. araucariae sp. nov. Andotypus perezdearcei Moroni, 2000 is found to belong to the genus Dactylosternum Wollaston, 1854 (Hydrophilidae: Sphaeridiinae: Coelostomatini), and is a junior subjective synonym of the introduced species D. abdominale (Fabricius, 1792). Adults of all species of Andotypus and Austrotypus are (re)described in detail and important characters are illustrated. Larval morphology and head chaetotaxy is described and illustrated in detail for Andotypus ashworthi and Austrotypus nothofagi, revealing differences in head morphology and abdominal tergites which support the separate status of both genera. The taxonomic position of the genera within the Rygmodinae is briefly discussed, but should be corroborated by formal phylogenetic analysis. We hypothesize that the austral disjunct distribution of Austrotypus as well as current distribution of Andotypus are results of the break-up of Gondwana combined with changes of climate in austral South America, Antarctica and Australia during the Cenozoic. Andotypus and Austrotypus represent an independently evolved lineage of dung- and carrion-associated beetles native to the southern temperate zone, and the fact that their larvae largely resemble those of Sphaeridium Fabricius, 1775 suggests that they may represent a partial ecological analogue of the Old World medium-sized coprophilous hydrophilids of the tribe Sphaeridiini. The syntopical co-occurrence of Austrotypus nothofagi with four similarly colored scarabaeoid dung-inhabiting beetles (Onthophagus sydneyensis Blackburn, 1903, O. arrilla Matthews, 1972, Lepanus ustulatus (Lansberge, 1874) and Liparochrus nanus Paulian, 1980) suggests that Austrotypus nothofagi may be a member of a mimetic complex formed by these species.

A revision of Megagraphydrus Hansen (Coleoptera, Hydrophilidae): synonymization with Agraphydrus Régimbart and description of seven new species.

The genus Megagraphydrus Hansen, 1999 is revised. Eleven of the twelve previously described species are recognized as valid, with Megagraphydrus wangi Hebauer, 2000 syn. nov. found to be a junior synonym of M. politus Hansen, 1999. Most significantly, Megagraphydrus itself is found to be a junior synonym of Agraphydrus Régimbart, 1903. The species are assigned to the subgenus Agraphydrus. This nomenclatural act results in the following new combinations: Agraphydrus (Agraphydrus) anhuianus (Hebauer, 2000) comb. nov., A. (A.) attenuatus (Hansen, 1999) comb. nov., A. (A.) jaechi (Hansen, 1999) comb. nov., A. (A.) luteilateralis (Minoshima & Fujiwara, 2009) comb. nov., A. (A.) malayanus (Hebauer, 2000) comb. nov., A. (A.) politus (Hansen, 1999) comb. nov., A. (A.) puzhelongi (Jia, 2010) comb. nov., A. (A.) regularis (Hansen, 1999) comb. nov., A. (A.) siamensis (Hansen, 1999) comb. nov., A. (A.) superans (Hebauer, 2000) comb. nov., and A. (A.) uvaensis (Hebauer, 2000) comb. nov. All species are redescribed with the exclusion of A. superans, A. luteilateralis, and A. puzhelongi. Seven new species are described: Agraphydrus (Agraphydrus) biprojectus sp. nov., A. (A.) coronarius sp. nov., A. (A.) decipiens sp. nov., A. (A.) insidiator sp. nov., A. (A.) masatakai sp. nov., A. (A.) montanus sp. nov., A. (A.) thaiensis sp. nov. Digital and SEM photographs are provided, and the male and female genital segments are illustrated and described.

Morphology and biology of the flower-visiting water scavenger beetle genus Rygmodus (Coleoptera: Hydrophilidae): Morphology and biology of Rygmodus

Hydrophilidae (water scavenger beetles) is well known as an aquatic beetle family; however, it contains ca. 1,000 secondarily terrestrial species derived from aquatic ancestors. The New Zealand endemic genus Rygmodus White is a member of the hydrophilid subfamily Cylominae, which is the early‐diverging taxon of the largest terrestrial lineage (Cylominae + Sphaeridiinae) within the Hydrophilidae. In this paper we report that Rygmodus beetles are pollen‐feeding flower visitors as adults, but aquatic predators as larvae. Based on analyses of gut contents and a summary of collecting records reported on museum specimen labels, adult Rygmodus beetles are generalists feeding on pollen of at least 13 plant families. Rygmodus adult mouthparts differ from those of other (saprophagous) hydrophilid beetles in having the simple scoop‐like apex and mola with roughly denticulate surface, resembling the morphology found in pollen‐feeding staphylinid beetles. Larvae were found along the sides of streams, under stones and in algal mats and water‐soaked moss; one collected larval specimen was identified using DNA barcoding of two molecular markers, mitochondrial cytochrome oxidase 1 (cox1) and nuclear histone 3 (H3). Larvae of two species, Rygmodus modestus and Rygmodus sp., are described in detail and illustrated; they closely resemble ambush‐type predatory larvae of the hydrophilid tribe Hydrophilini in the head morphology. Rygmodus is the only known hydrophilid beetle with adults and larvae inhabiting different environments.

Larval Morphology and Biology of the New Zealand-Chilean Genera Cylomissus Broun and Anticura Spangler (Coleoptera: Hydrophilidae: Rygmodinae)

Abstract Larval morphology of the monotypic rygmodine genera Anticura Spangler, 1979 from Chile and Cylomissus Broun, 1903 from New Zealand is described, based on field-collected larvae associated with adults and authenticated by CO1 and 18S DNA sequences. General morphology and chaetotaxy of the head capsule is described and illustrated for all three instars of Anticura flinti Spangler, 1979 and the first and third instar of Cylomissus glabratus Broun, 1903. Both genera are similar in larval morphology, sharing several unique larval characters (e.g., bidentate nasale in the first instar, presence of numerous additional setae on parietale in the first instar), which support their close phylogenetic relationship and provides morphological support for the transfer of Anticura to the Rygmodinae. The presence of numerous additional setae on the parietale of all instars and characteristic chaetotaxy of the maxillary stipes are hypothesized as potential larval synapomorphies of the subfamily Rygmodinae. Field observations show that larvae and adults of both genera are aquatic, most frequently collected from moss in the splash zone at the sides of stony streams and small rivers.

Breaking a Disjunct Distribution: A Review of the Southern Hemisphere Genera Cylorygmus and Relictorygmus gen. nov. (Hydrophilidae: Cylominae)

Abstract. The southern hemisphere water scavenger beetle genus Cylorygmus Orchymont, 1933 (Coleoptera: Hydrophilidae: Cylominae) is revised. Three species are recognized, one in Chile and two in South Africa. The morphological differences indicate that the African species are not congeneric with the Chilean one. Relictorygmus gen. nov. is established for the African R. trevornoahi sp. nov. (type species) and R. repentinus (Hebauer, 2002), both known from few localities in the Western Cape province of the Republic of South Africa. The genus Cylorygmus with the only species C. lineatopunctatus Orchymont, 1933 is endemic to a small region in central Chile. Its larva is described in detail based on specimens collected in association with adults. Both genera and all species are diagnosed, described and illustrated, and an identification key for adults is provided. Our study demonstrates that the trans-Atlantic disjunct distribution of Cylorygmus was based on inaccurate taxonomic treatment and did not reflect the real evolutionary history of these beetles.

Redescription and lectotype designation of Chasmogenus abnormalis (Sharp), with notes on its distribution

Chasmogenus Sharp, 1882 is a relatively small genus of 43 described species of aquatic beetles assigned to the subfamily Acidocerinae of Hydrophilidae (Hansen 1999; Short & Hebauer 2006; Short & Fikáček 2011, 2013; Clarkson & Ferreira-Jr. 2014). It is distributed in all zoogeographic regions except the Nearctic, with the highest species richness known from the Afrotropical (18 spp.) and Neotropical (15 spp.) Regions. Only four species have been described from the Oriental Region: C. abnormalis (Sharp, 1890), C. rubricollis (Régimbart, 1903), C. larsi Hebauer, 1995, and C. cattienus Hebauer, 2002. Of these, only C. abnormalis was recorded multiple times after its description.

Taxonomic review of Agraphydrus from Japan (Coleoptera: Hydrophilidae: Acidocerinae)

The Japanese species of the genus Agraphydrus are revised. Five species are recognized, including Agraphydrus ogatai sp. nov. from Honshu, Shikoku and Kyushu. The new species can be distinguished by the coarse ground punctures on the pronotum and elytra, and by the shape of parameres. All species except A. luteilateralis are redescribed. All species are diagnosed, relevant morphological characters are illustrated, distributional records are summarized and an updated key is provided.

Complete mitochondrial DNA sequence of the alien hornet Vespa velutina (Insecta: Hymenoptera) invading Kyushu Island, Japan

Abstract We analyzed the complete mitochondrial genome of the invasive Asian hornet Vespa velutina from Kyushu Island, Japan. The mitochondrial genome of V. velutina was identified as a circular molecule of 16,388 bp. We predicted that the genome contains 13 protein-coding genes (PCGs), 22 tRNA genes, and 2 rRNA genes, along with one A + T-rich control region. The average AT content is 81.68%. Molecular phylogenetic analysis using the 13 mitochondrial PCGs from 11 closely related taxa of Vespidae indicated that the V. velutina invading the Japanese Islands of Kyushu and Tsushima have a common origin.

Egg-Case and Pupa of Enochrus (methydrus) japonicus (Sharp) (Coleoptera: Hydrophilidae)

Enochrus Thomson, 1859 is a genus of the subfamily Enochrinae containing more than 220 species worldwide (Short and Fikáček 2011, 2013). Together with Berosus Leach, 1817 (ca. 270 spp.) and Laccobius Erichson, 1837 (ca. 240 spp.), the genus represents one of the most diverse genera of aquatic Hydrophilidae (Short and Fikáček 2011). Despite the high species diversity of Enochrus, the immature stages of the genus remain poorly known. The immature stages of ca. 25 species have been described so far, and the pupal morphology has been described for only ten species (Byttebier and Torres 2009; Minoshima and Hayashi 2011). We obtained eggcases and pupae of Enochrus (Methydrus) japonicus (Sharp, 1873) by rearing from field-collected adults. Larval stages of the species were described by Minoshima and Hayashi (2011) in detail, but its eggcase and pupa remain undescribed. In this paper, we describe the eggs, egg-case, and pupa ofE. japonicus and briefly comment on oviposition behavior. Methods for examination of specimens generally followed Archangelsky (1997) and Minoshima et al. (2012). Composite images were created using the Image Stacking Software CombineZP (Hadley 2010). Photos were modified using Adobe Lightroom and Photoshop CC (2015) as necessary. Pupae were fixed with 80% ethanol or hot water and preserved in screw-cap vials with 80% ethanol. Because we used all egg-cases for rearing, egg-cases were damaged by hatched larvae. Specimens are deposited in the authors’ collections. Morphological terminology and classification follows Archangelsky (1997) and Fikáček et al. (2015), respectively.