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Moss-inhabiting flea beetles form a diversified ecological group of beetles with a number of recently described new species. Here, we present an overview of known species of the moss-inhabiting flea beetle genus Cangshanaltica Konstantinov, Chamorro, Prathapan, Ge & Yang, 2013 which is distributed in Eastern and South-Eastern Asia. We describe three new species: Cangshanaltica guanxiensis sp. nov. from Guanxi, China, C. marginata sp. nov. from Yunnan, China, and C. javana sp. nov., from Java, Indonesia. Additionally, we redescribe Cangshanaltica castanea (Gruev, 1985) comb. nov., a species formerly placed in Ivalia. Based on our studies of the morphological characters, we assume that some of the currently recognized species may in fact represent species complexes. Our findings also extend the known distribution of Cangshanaltica to Indonesia. A key of all described Cangshanaltica species, and an annotated checklist are provided.

The family Cerasommatidiidae was proposed by Brèthes in 1925 for his new genus Cerasommatidia from Brazil, described as an intermediate taxon between Endomychidae and Coccinellidae (Coccinelloidea). This group was neglected for decades until 1994 when the resemblance of Cerasommatidia with the eupsilobiine genus Ibicarella was noticed, and Cerasommatidiidae was synonymized with Eupsilobiinae (Endomychidae). Based on the newly discovered material from the Neotropical and Afrotropical regions with clear resemblance to Cerasommatidia and Ibicarella, the phylogenetic placement of these taxa and new allied genera was reassessed based on phylogenetic analyses of molecular, morphological and combined datasets. The data were analysed under Bayesian (BI), maximum likelihood (ML) and parsimony (MP) frameworks. Our results support the restoration of Cerasommatidiidae as a distinct family in Coccinelloidea. Close affinity of Cerasommatidiidae with Coccinellidae, Eupsilobiidae and Mycetaeidae is recovered and the sister-relationship to Mycetaeidae is highly supported. Ibicarella is found to be a junior synonym of Cerasommatidia. Three new genera and six new species are described and illustrated: Yamuy gen. nov. (type species, Y. marginatus sp. nov.; and Y. constratus sp. nov.) and Karumbe gen. nov. (type species, K. geiseri sp. nov.; K. brethesi sp. nov. and K. pakaluki sp. nov.) from the Neotropics and Mahavelo gen. nov. (type species, M. madagasus sp. nov.) from Madagascar.

Epimetopidae are a small beetle family of the superfamily Hydrophiloidea, comprising 72 described species in three genera: the American Epimetopus Lacordaire, 1854 (56 species), Asian Eumetopus Balfour-Browne, 1949 (eight species) and African Eupotemus Ji & Jäch, 1998 (eight species, of which six are described as new here). In this study we illustrate and compare the adult morphology of all three genera and generate the first DNA sequences for Eumetopus and Eupotemus. The morphological data and sequences of four genes (cox1, 16S, 18S and 28S) are used to reconstruct phylogenetic relationships among genera. Both strongly support the monophyly of Epimetopidae, reveal Eumetopus as the earliest diverging taxon and Epimetopus + Eupotemus as a strongly supported clade with numerous synapomorphies. The reciprocal monophyly of Epimetopus and Eupotemus is strongly supported by DNA data but not in the morphological analysis which reveals Epimetopus paraphyletic. Eumetopus, despite being the earliest branching clade, is characterized by many unique derived structures, e.g. by the presence of the sperm pump in males (unique in Hydrophiloidea). The available data on the biology of Epimetopidae indicate that most species inhabit sandy to muddy margins of streams or rivers. Females of all three genera carry egg cases; Epimetopidae hence are one of three independent lineages of Hydrophiloidea in which this behavior evolved. Larvae are only known for Epimetopus and are characterized by morphological adaptations for feeding by piercing and sucking, a closed tracheal system and abdominal gills; larvae of Eumetopus and Eupotemus remain unknown and further research is needed to confirm whether they show the same adaptations as Epimetopus. The taxonomy of the African genus Eupotemus is re­vised, with six species described as new: E. bilobatus sp. nov. (Nigeria), E. cameroonensis sp. nov. (Cameroon), E. ophioglossus sp. nov. (Gabon, Togo), E. smithi sp. nov. (Côte d’Ivoire), E. taianus sp. nov. (Côte d’Ivoire) and E. uluguru sp. nov. (Tanzania). Eupotemus limicola Delève, 1967 is fixed as the type species of the genus according to ICZN (1999: Art. 70.3). New records of Eumetopus species are provided (E. acutimontis Ji & Jäch, 1998 from Vietnam, E. bullatus (Sharp, 1875) from India: Maharashtra, E. flavidulus (Sharp, 1890) from India: Maharashtra and Andhra Pradesh, E. maindroni (Régimbart, 1903) from India: Maharashtra and Gujarat, and E. weigeli Skale & Jäch, 2003 from India: Uttarakhand). The habitus of all species is illustrated. An updated checklist of the Epimetopus species is provided, and records of two specimens of the E. costatus group from Zambia and Saudi Arabia are considered to result from either accidental introductions or mislabelling.

Larvae of water scavenger beetles (Coleoptera: Hydrophiloidea) are adapted to a wide variety of aquatic habitats, butlittle is known about functional and evolutionary aspects of these adaptations. We review the functional morphologyand evolution of feeding strategies of larvae of the families Hydrophilidae and Epimetopidae based on a detailedscanning electron microscope (SEM) analysis, analysis of video records of feeding behaviour and observations ofliving larvae. There are two main types of feeding mechanisms: chewing and piercing-sucking. The character mappingusing the latest phylogenetic hypothesis for Hydrophiloidea infers the chewing system as the ancestral condition. Thepiercing-sucking mechanism evolved at least four times independently: once in Epimetopidae (Epimetopus) and threetimes in Hydrophilidae (Berosini: Berosus + Hemiosus; Laccobiini: Laccobius group; Hydrobiusini: Hybogralius). Thepiercing-sucking apparatus allows underwater extra-oral digestion and decreases the dependence of larvae on an aerialenvironment. A detailed study of the tracheal morphology of the piercing-sucking lineages reveals four independentorigins of the apneustic respiratory system, all of them nested within lineages with piercing-sucking mouthparts. Weconclude that piercing-sucking mouthparts represent a key innovation, which allows for the subsequent adaptation ofthe tracheal system, influences the diversification dynamics of the lineages and allows the shift to new adaptive zones. Fil: Rodriguez, Valeria Georgina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; Argentina Fil: Fikácek, Martin. Karlova Univerzita (cuni); República Checa Fil: Minoshima, Yusuke N. Kitakyushu Museum of Natural History and Human History; Japón Fil: Archangelsky, Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónica. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina Fil: Torres, Patricia Laura Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; Argentina

The water scavenger beetle genus Coelostoma Brullé, 1835 of Taiwan is reviewed based on freshly collected material and museum specimens. Seven species are recognized, of which one new species, Coelostoma (Lachnocoelostoma) taiwanense sp. nov., is described. Distributional data of C. fallaciosum Orchymont, 1936 and C. stultum (Walker, 1858) are summarized. Coelostoma phallicum Orchymont, 1940, C. wui Orchymont, 1940, C. vitalisi Orchymont, 1923 and C. bhutanicum Jayaswal, 1972 are reported for the first time from Taiwan. Coelostoma vagum Orchymont, 1940 is excluded from Taiwanese fauna pending the rediscovery of vouchers or newly collected specimens. A distribution map and key to Taiwanese species of the genus are provided.

The species of the genus Dactylosternum Wollaston, 1854 occurring in China and Japan are reviewed. Ten species are recognized to occur in China, two of which were also recorded from Japan. Four new species are described from China: Dactylosternum nanlingensis Mai et Jia, sp. nov. (Guangdong, Jiangxi) from fungal hyphae on fallen wood, D. songxiaobini Mai et Jia, sp. nov. (Guangxi) from fallen wood with termites, D. pseudolatum Mai et Jia, sp. nov. (Guangdong, Hubei, Hunan, Jiangxi, Fujian, Hainan, Yunnan) and D. frater Mai et Jia, sp. nov. (Yunnan) from banana trees. Dactylosternum latum (Sharp, 1873) and D. salvazai Orchymont, 1925 are reported for the first time from China, and species recorded previously (D. abdominale (Fabricius, 1792), D. corbetti Balfour-Browne, 1942, D. hydrophiloides (MacLeay, 1825) and D. pui Jia, 2002) are redescribed or diagnosed. Dactylosternum abdominale (Fabricius, 1792) is confirmed to occur in Japan. Dactylosternum latum is only known from Japan based on type specimens believed to be collected in Nagasaki by G. Lewis in late 19th century; since the species was never re-collected in Japan later, its distribution in Japan seems doubtful. Dactylosternum vitalisi Orchymont, 1925 is synonymized with D. latum (Sharp, 1873), the variability of the latter species is discussed. We moreover found that the type series of D. vitalisi contains two species, with some paratypes actually belonging to D. pseudolatum Mai et Jia, sp. nov. All species of Dactylosternum living in China and Japan are diagnosed and illustrated and a key allowing their identification is provided. We infer that the compact antennal club and paralleled body form are characters related to the life inside of plant tissues, while loose antennal club and rounded body form is present in free living Dactylosternum species. The combination of characters for distinguishing Dactylosternum from other genera of Coelostomatini is also provided.

Water scavenger beetles (Coleoptera: Hydrophilidae) are a broadly distributed group with high extant diversity. However, reliable records from Baltic amber (Eocene) are scarce and limited to two un...

We are reporting a recent discovery of Coelostoma ( Lachnocoelostoma ) thienemanni Orchymont, 1932 (Coleoptera: Hydrophilidae: Sphaeridiinae: Coelostomatini) from northern Vietnam, which represents the first record of the species since 1929 and its first record from continental Asia. The species is redescribed and illustrated, and transferred from the subgenus Holocoelostoma Mouchamps, 1958 to Lachnocoelostoma Mouchamps, 1958. The species is unusual among Asian Coelostoma by its complex three-dimensional shape of the median lobe of the aedeagus, in which it is only similar to C. tangliangi Jia et al ., 2017 in Asia. The species is also unusual by its very long dorsal tarsal swimming hairs, indicating that it is an aquatic species.

A new species of the water scavenger beetle, Laccobius (Glyptolaccobius) motuoensissp. nov., is described from Motuo County, Xizang, China and its diagnostic characters are illustrated. Examination of this new species and re-examination of previously described species revealed that the separation of the subgenus Glyptolaccobius Gentili, 1989 and Cyclolaccobius Gentili, 1991 is artificial: both subgenera are hence combined here. Cyclolaccobiussyn. nov. is synonymized with Glyptolaccobius, and the latter is shown to be diagnosed by 7-segmented antennae as a unique synapomorphy. All species treated until now under Cyclolaccobius are here transferred to Glyptolaccobius, with the only exception of L. hingstoni Orchymont, 1926, L. jumlanus Gentili, 2015 and L. zugmayeri Knisch, 1910 which are tentatively transferred to the subgenus Hydroxenus Wollaston, 1867, as their antennae bear eight antennomeres. Three species are recorded for the first time from China: L. (Microlaccobius) orientalis Knisch, 1924 from Xizang, Laccobius (M.) exilis Gentili,1974 from Xinjiang, and Laccobius (M.) sublaevis J. Sahlberg, 1900 from Xinjiang. Additional faunistic data from China are provided for the following species: L. (Microlaccobius) hammondi Gentili, 1984, Laccobius (M.) formosus Gentili, 1979, Laccobius (Hydroxenus) hingstoni d’Orchymont, 1926, Laccobius (Glyptolaccobius) yunnanensis Gentili, 2003, Laccobius (Compsolaccobius) decorus (Gyllenhal, 1827), Laccobius (Dimorpholaccobius) bipunctatus (Fabricius, 1775), Laccobius (D.) striatulus (Fabricius, 1775), Laccobius (s. str.) bedeli Sharp, 1884, L. (s. str.) binotatus d’Orchymont, 1934, Laccobius (s. str.) cinereus Motschulsky, 1860, and Laccobius (s. str.) minutus (Linnaeus, 1758).

The Old World genus Thysanarthria Orchymont, 1926 is reviewed taxonomically and compared to the related genus Chaetarthria Stephens, 1835. Chaetarthria is considered to consist of three groups differing in the morphology of male genitalia and surrounding sclerites: (1) large Old World Chaetarthria which seems to stand apart of the remaining groups, and (2) European Chaetarthria plus (3) American Chaetarthria which both share the male sternite 8 with a long median projection with Thysanarthria. The reduced mesal part of male sternite 9 is shared by European Chaetarthria and Thysanarthria, supporting their close relationship proposed by previous molecular analyses. Sixteen species are recognized within Thysanarthria which differ in the details of the morphology of the aedeagus illustrated for all species. Seven species are described as new: T. bifida sp. nov. (Thailand), T. cardamona sp. nov. (India: Kerala), T. chui sp. nov. (Taiwan), T. persica sp. nov. (southern Iran), T. saurahana sp. nov. (Nepal), T. trifida (Laos), and T. wadicola sp. nov. (Oman). New records are provided for T. ceylonensis Hebauer, 2001 (new to India: Madhya Pradesh), T. championi (Knisch, 1924) (new to Afghanistan, India: Arunachal Pradesh, China: Yunnan, and Myanmar), T. madurensis Hebauer, 2001 (new to Nepal and India: Kerala), and T. siamensis Hebauer, 2001 (new to India: Uttarkhand, Nepal and Laos). Chaetarthriomorphus sulcatus Chiesa, 1967 is revealed as a junior synonym of Chaetarthria championi Knisch, 1924, and lectotypes are designated for both these taxa. An undescribed species of the American group of Chaetarthria is recorded from Saudi Arabia either as an accidental introduction or due to mislabeling; the species is illustrated but not described.

This study summarizes available data on karyotypes of water scavenger beetles (Coleoptera: Hydrophiloidea: Hydrophilidae), based on newly acquired data of 23 genera and 64 species. We combine these data with previously published data, which we review. In total, karyotypes are available for 33 genera and 95 species, covering all subfamilies and tribes. Available data indicate that most groups of the Hydrophilidae are diploid and sexually reproducing, with XY (♂) and XX (♀) sex chromosomes; the Y chromosome is always minute and does not recombine with X during meiosis. Exceptions are known in Anacaena, with parthenogenetic diploid or triploid populations in some species and sex chromosomes fused with autosomes in others. The diploid number of chromosomes is 2n = 18 in the subfamilies Acidocerinae, Chaetarthriinae, Enochrinae and Hydrophilinae. Variations are known in species of Anacaena and Berosus (both usually with 2n = 18) and in Hydrochara and Hydrophilus with an increased number of chromosomes (2n = 30). The number of chromosomes is increased in the subfamily Cylominae (2n = 24–30) and in all subclades of the subfamily Sphaeridiinae (2n = 22–32). We summarize protocols for obtaining chromosome slides used for this study and provide step-by-step guidelines to facilitate future cytogenetic studies.

Phylogenetic analyses testing the monophyly of the tribe Hydrobiusini and the relationships among its genera are performed based on a data matrix including characters of larval morphology and morphometrics, larval chaetotaxy and adult morphology, including eight of the nine hydrobiusine genera plus 15 outgroup taxa. The head chaetotaxy of six genera of the tribe Hydrobiusini is described (Ametor, Hybogralius, Hydramara, Limnohydrobius, Limnoxenus and Sperchopsis). Morphometric characters derived from the head capsule and mouthparts are included. All characters are illustrated in detail. The analyses performed on the above datasets and their combinations reveal the monophyly of the Hydrobiusini except for Hybogralius, and reconstruct the internal topology of the tribe, largely corresponding to results of previous molecular analyses. Hybogralius groups with genera having larvae adapted to underwater feeding in all analyses. The position of the genus Tritonus within the Laccobiini is questioned by our analyses, which suggest a closer relationship with the tribes Hydrophilini or Hydrobiusini. Larval characters are revealed as highly homoplastic, with chaetotaxic characters performing slightly worse than usual larval morphology. Nonetheless, they are phylogenetically informative and useful for testing phylogenetic hypotheses resulting from analyses of molecules or adult morphology. A key to larvae of the genera of the Hydrobiusini is presented.

Taiwanese species of the genus Laccobius Erichson, 1837 (Coleoptera: Hydrophilidae) are reviewed based on newly collected material and published records. Five species classified in two subgenera are recorded for the region, including L. (Glyptolaccobius) politus Gentili, 1979, L. (Microlaccobius) formosus Gentili, 1979, L. (M.) hammondi Gentili, 1984, L. (M.) roseiceps Régimbart, 1903 and a new species from central and southern Taiwan: L. (M.) hoi. sp.nov. Laccobius philipinus Gentili, 2005 is excluded from Taiwanese fauna. We failed to re-collect Laccobius fragilis Nakane, 1966 despite sampling the area from which it was recorded, and its occurrence in Taiwan hence needs re-confirmation. Distribution data of all Taiwanese species is summarized, and a key of Taiwanese Laccobius and photographs of all species are provided.

Summary The Triassic was a crucial period for the early evolution and diversification of insects, including Coleoptera1–3—the most diverse order of organisms on Earth. The study of Triassic beetles, however, relies almost exclusively on flattened fossils with limited character preservation. Using synchrotron microtomography, we investigated a fragmentary Upper Triassic coprolite, which contains a rich record of 3D-preserved minute beetle remains of Triamyxa coprolithica gen. et sp. nov. Some specimens are nearly complete, preserving delicate structures of the legs and antennae. Most of them are congruent morphologically, implying that they are conspecific. Phylogenetic analyses suggest that T. coprolithica is a member of Myxophaga, a small suborder of beetles with a sparse fossil record, and that it represents the only member of the extinct family Triamyxidae fam. nov. Our findings highlight that coprolites can contain insect remains, which are almost as well preserved as in amber. They are thus an important source of information for exploring insect evolution before the Cretaceous-Neogene "amber time window." Treated as food residues, insect remains preserved in coprolites also have important implications for the paleoecology of insectivores, in this case, likely the dinosauriform Silesaurus opolensis.

The available data on the biology of the water scavenger beetle genus Protosternum Sharp, 1890 (Hydrophilidae: Sphaeridiinae: Protosternini) are summarized, indicating an obligate association of Protosternum beetles with banana plants (Musaceae): they inhabit decaying tissues of old banana stems in which adult feeding, larval development and pupation takes place. Second and third instar larvae and pupa of the Taiwanese-endemic P. abnormale (Orchymont, 1913) are described in detail, based on field-collected specimens associated with co-occurring adults by cox1 DNA barcodes. Larvae are unique in the Hydrophiloidea by having strongly asymmetrical mouthparts with a large basal bifid tooth on the right mandible, indicating a specialized prey preference. Putative larval synapomorphies of the Protosternini are revealed, based on the comparison of the Protosternum larva with that of Sphaerocetum. Taxonomic status of P. abnormale is revealed to be confused by previous authors due to the absence of male specimens and is clarified here. Two new species are described based on specimens previously misidentified as P. abnormale: P. malayanum sp. nov. from Sumatra and Peninsular Malaysia, and P. hainanense sp. nov. from Hainan.

Entomological collections are the target of various insect pests, e.g. carpet beetles (Dermestidae) and booklice (Psocoptera) which can damage and completely destroy dry specimens in a relatively short time. Collections in the National Museum, Czech Republic (NMP) including the entomological ones are protected by fumigation using commercially available smoke shells ‘Cytrol Super SG’; fumigation is performed twice a year. The active insecticidal substance of these smoke shells is cypermethrin (6.25%). We tested whether the repeated cypermethrin fumigation of the NMP entomological collections negatively affects the quality of mitochondrial DNA in dry specimens and prevents the subsequent use of these samples for molecular analyses required for identification, taxonomy, systematics, and phylogenetic studies. We used 32 freshly fixed specimens of the flower chafer Oxythyrea funesta (Poda von Neuhaus, 1761) and 32 freshly fixed specimens of the brown-tailed cockroach Supella longipalpa (Fabricius, 1798). One half of specimens of both species was stored outside NMP and not fumigated (negative control), and the other half was deposited in collection hall with the NMP insect collection and directly exposed to the fumigation. Subsequently, all specimens were processed in a molecular laboratory under a standardized protocol using one leg as the source tissue after each fumigation, and the 658 bp long barcoding region of the cytochrome oxidase I (cox1) as the testing gene fragment. Results of the PCR product electrophoresis and the sequences acquired confirmed that the repeated fumigation had no negative effect on tested samples.

The morphology and head chaetotaxy of the second and third instar larvae of Laccobius (Yateberosus) sp. are described based on specimens collected in New Caledonia. The larvae agree with those of other subgenera of Laccobius Erichson, 1837 in most morphological characters including the morphology of head and mouthparts and the head chaetotaxy, which undoubtedly supports its assignment to Laccobius (Yateberosus). It differs from other Laccobius in the closed spiracular system, reduced spiracular atrium and long abdominal tracheal gills, in which they resemble the larvae of Berosus Leach, 1817. We demonstrate that the ‘Berosus-likeʼ larval morphology evolved at least four times independently in Hydrophiloidea, and briefly discuss the possible reasons for it.

Dated species-level phylogenies are crucial for understanding the origin and evolutionary history of modern faunas, yet difficult to obtain due to the frequent absence of suitable age calibrations at species level. Substitution rates of related or more inclusive clades are often used to overcome this limitation but the accuracy of this approach remains untested. We compared tree dating based on substitution rates with analyses implementing fossil data by direct node-dating and indirect root-age constraints for the New Zealand endemic Berosus water beetles (Coleoptera: Hydrophilidae). The analysis based solely on substitution rates indicated a Miocene colonization of New Zealand and Pleistocene origin of species. By contrast, all analyses that implemented fossil data resulted in significantly older age estimates, indicating an ancient early Cenozoic origin of the New Zealand clade, diversification of species during or after the Oligocene transgression and Miocene-Pliocene origin of within-species population structure. Rate-calibrated time trees were incongruent with recently published Coleoptera time trees, the fossil record of Berosus and the distribution of outgroup species. Strong variation of substitution rates among Coleoptera lineages, as well as among lineages within the family Hydrophilidae, was identified as the principal reason for low accuracy of rate-calibrated analyses, resulting in underestimated node ages in Berosus. We provide evidence that Oligocene to Pliocene events, rather than the Pleistocene Glacial cycles, played an essential role in the formation of the modern New Zealand insect fauna.

The systematics and the phylogenetic position of the Caribbean representatives of Phaenonotum Sharp (Coleoptera: Hydrophilidae) are investigated in order to understand the composition of the Caribbean fauna and its origin. Phylogenetic analysis based on mitochondrial and nuclear genes has revealed the Caribbean species to be situated in three deeply nested clades, inferring multiple colonization of Caribbean islands from the continent. Time-tree analysis and BioGeoBEARS analyses of ancestral ranges estimated the oldest clade, consisting of wingless single-island endemics of Cuba ( P. delgadoi ), Jamaica ( P. ondreji sp. nov. ) and Hispaniola ( P. laterale sp. nov. ), to have diverged ca. 46.6 Ma from the South American ancestor and subsequently colonizing the Caribbean most likely via the GAARlandia land bridge connecting South America with Greater Antilles. The remaining three Caribbean species, including the Puerto Rican endemic, P. borinquenum sp. nov. , are of more recent (Miocene to Pliocene) origin and colonized the Greater Antilles by over-water dispersal. All the Caribbean species are illustrated and diagnosed and three new species are described. The genus Phaenonotum , excluding P. caribense Archangelsky, is confirmed as a monophylum. We demonstrate that species-level taxonomy of Phaenonotum is difficult to solve by morphology alone, and ideally requires the combination of morphology and molecular markers.

Cretocrenis burmanicus , gen. et sp. nov. is described from Burmese amber and represents the oldest known amber inclusion of the family Hydrophilidae (Coleoptera: Polyphaga). The new genus resembles the small-bodied modern genera of the tribe Anacaenini and the subfamily Acidocerinae, and the morphology of the venter and male genitalia suggest that it belongs to the Horelophus+Crenitis clade of the tribe Anacaenini. The fossil is described in detail, illustrated, and compared with extant hydrophilid genera.

The egg case and larvae of all three instars of the cascade beetle Tritonus complanatus Short, 2008 (Coleoptera: Hydrophilidae) are described based on specimens found co-occurring with adults and associated with them by comparing histone 3 nDNA sequences. The morphology of the larva is congruent with the phylogenetic position of Tritonus Mulsant, 1844 in the Paracymus-group of the Laccobiini, but also exhibits characters shared with larvae of Hydrobiusini, and some presumed adaptations to the hygropetric life style. The larva has open mesothoracic and abdominal spiracles situated on top of long spiracular tubes in the first instar, likely working as ‘spiracular snorkels’, and on low tubercles in later instars, along with a well-developed spiracular atrium. Similar spiracular morphology was found in the larva of the terrestrial laccobiine genus Tormus Sharp, 1884, and a brief examination of larvae of few other genera (Oocyclus Sharp, 1882, Hydrobius Leach, 1815) reveals that the peripneustic spiracular system (mesothoracic plus 8 abdominal functioning spiracles) may be more widespread in larval Hydrophilidae than currently believed.

Original set of pictures obtained under MicroCT technology and used to reconstructthree-dimensional models of hydrophilid beetles embedded in Baltic amber. Abstract Water scavenger beetles (Coleoptera: Hydrophilidae) are a broadly distributed group with high extant diversity. However, reliable records from Baltic amber (Eocene) are scarce and limited to two undescribed species previously reported in the literature. Here we study these two specimens plus four additional ones. All specimens were sub-optimal in terms of preservation and visibility of their morphology using traditional light microscopy. Opaque bubbles, cracks in the amber pieces and contracted appendages obscured most of the crucial characters, preventing their formal description and making them prone to misidentification. Here we used X-ray micro-computed tomography (μCT) to reconstruct the morphology of the embedded specimens and described three new species: Anacaena morla sp. nov., Crenitis profechuyi sp. nov. and Helochares fog sp. nov. Micro-CT reconstructions allowed us to visualize the morphology of the specimens to an extent where it was possible to hypothesize possible phylogenetic relations of the new taxa as well as the biogeographic implications of these relationships.

Data files for the paper.

The New Zealand endemic beetle genus Saphydrus Sharp, 1884 (Coleoptera:Hydrophilidae:Cylominae) is studied in order to understand its phylogenetic position, species-level systematics, biology and distribution, and to reveal reasons for its rarity. The first complete genus-level phylogeny of Cylominae based on two mitochondrial (cox1, 16S) and two nuclear genes (18S, 28S) covering 18 of 19 genera of the subfamily reveals Saphydrus as an isolated lineage situated in a clade with Cylorygmus (South America), Relictorygmus (South Africa) and Eurygmus (Australia). DNA is used to associate two larval morphotypes with Saphydrus: one of them represents the larvae of S. suffusus Sharp, 1884; the other, characterised by unique characters of the head and prothorax morphology, is revealed as sister but not closely related to Saphydrus. It is described here as Enigmahydrus, gen. nov. with a single species, E. larvalis, sp. nov., whose adult stage remains unknown. Saphydrus includes five species, two of which (S. moeldnerae, sp. nov. and S. tanemahuta, sp. nov.) are described as new. Larvae of Enigmahydrus larvalis and Saphydrus suffusus are described and illustrated in detail based on DNA-identified specimens. Candidate larvae for Saphydrus obesus Sharp, 1884 and S. tanemahuta are illustrated and diagnosed. Specimen data are used to evaluate the range, altitudinal distribution, seasonality and population dynamics over time for all species. Strongly seasonal occurrence of adults combined with other factors (winter occurrence in S. obesus, occurrence at high altitudes in S. tanemahuta) is hypothesised as the primary reason of the rarity for Saphydrus species. By contrast, Enigmahydrus larvalis underwent a strong decline in population number and size since the 1970s and is currently known from a single, locally limited population; we propose the ‘nationally threatened’ status for this species. http://zoobank.org/urn:lsid:zoobank.org:pub:28D87163-29E8-418C-9380-262D3038023A

The terrestrial genus of Hydrophilidae, Agna Smetana (tribe Megasternini), specialized on rotten cacti, is reviewed. The genus is redescribed and illustrated. The known species are diagnosed and redescribed and a new one, A. zaragozai sp. nov. from central Mexico (Hidalgo, Puebla and Oaxaca)is described and its molecular barcode is provided. Other species of Hydrophilidae known to be collected in cacti are listed and commented. Dactylosternum cacti (LeConte) (Coelostomatini) is recorded for the first time from Mexico and Cryptopleurum impressum Sharp (Megasternini) is recorded for the first time from Mexican states Jalisco and San Luis Potosí.

Two new species of Cercyon Leach, 1817 are described from China: Cercyon (s.str.) bellus sp. nov. from Hebei, Hubei, and Jiangxi Provinces, and Cercyon (s.str.) biltoni sp. nov. from Sichuan. Five species are recorded from China for the first time: Cercyon ( Acycreon ) punctiger Knisch, 1921, Cercyon ( Paracercyon ) analis Seidlitz, 1888, Cercyon (s.str.) algarum Sharp, 1973, Cercyon (s.str.) borealis Baranowski, 1985, Cercyon (s.str.) tristis (Illiger, 1801). Additional faunistic data from China are provided for Cercyon (s.str.) alinae Ryndevich, 2004, Cercyon (s.str.) inquinatus Wollaston, 1854, Cercyon (s.str.) kabaki Ryndevich, 2004, Cercyon (s.str.) olibrus Sharp, 1874, Cercyon (s.str.) ovillus Motschulsky, 1860, Cercyon ( Clinocercyon ) incretus dʼOrchymont, 1941, Cercyon ( Clinocercyon ) hanseni Jia, Fikacek & Ryndevich, 2011 and Cercyon ( Paracercyon ) honorabilis Shatrovskiy, 1999. A checklist to all species of the genus known from China is provided.

Opinion

The morphology and head chaetotaxy of third instar larva of the endemic Cuban B. chevrolati Zaitzev, 1908 are described. We provided the diagnosis of third instar larvae of B. exiguus (Say, 1825) and B. cf. undatus (Fabricius, 1792). This study is based on specimens collected in Cuba and identified by associations with adults. Larvae of B. exiguus and B. cf. undatus agree well with previously described larvae of Berosus. In contrast, B. chevrolati represents an unusual morphotype, characterised by narrow and strongly projecting nasale and well-developed right epistomal lobe. We also revise the adult diagnosis of B. undatus, which was incorrectly provided by Deler-Hernandez, Fikacek, and Cala-Riquelme (2013), and provide additional characters to distinguish this species from B. interstitialis Knisch, 1924 and B. infuscatus LeConte, 1855.

A new adephagan beetle embedded in Burmese amber from northern Myanmar is described as Burmapseudomorphus planus gen. et sp. nov. From its broad and flat habitus, the lack of a pronoto-elytral angle, the short and broad head, the short mesoventrite, and the lancet-shaped elongate prosternal process it resembles beetles belonging to the aquatic Dytiscoidea. The metacoxal plates are similar to those of Noteridae. However, pubescent antennal flagellomeres, an anisochaetous protibial antenna cleaner, transversely oriented metepimera, and metacoxae not reaching beyond the lateral margin of the metaventrite identify the fossil as an atypical species of Carabidae. Externally closed procoxal cavities, lacking procoxal rests of the mesoventrite, a narrow mesepimeron not reaching the mesocoxal cavity, and lobate metepimera indicate a placement in a clade comprising Harpalinae and Brachininae. This is supported by analyses of morphological data and a Hennigian character evaluation. The short and transverse head, the streamlined body without pronoto-elytral angle, and the secondarily elongated prosternal process suggest a placement as stem group member of the specialized Pseudomorphini. In contrast to species of the crown group of this lineage, a distinct submento-mental suture is present, ventral cephalic antennal grooves are missing, and the elytra are not truncated posteriorly. The fossil is the first record for Pseudomorphini and documents an origin of this specialized group of Carabidae at least dating back to the Cretaceous. A superficial similarity with the extant migadopine genus Stichonotus (e.g. broad and oval body, apically pointed prosternal process) is the result of convergence.

The hydrophilid genusCycreonOrchymont, 1919, previously known from two historical specimens only, is reviewed based on the numerous material collected recently from the inflorescences of various Araceae species in the Malay Peninsula and Borneo. Four species are recognized in the genus:C.sculpturatusOrchymont, 1919 from Sumatra,C.armandiShatrovskiy, 2017 from Singapore,C.adolescenssp. n.from peninsular Malaysia, andC.floricolasp. n.with two subspecies, the nominotypical one from Peninsular Malaysia, andC.floricolaborneanussubsp. n.from Borneo. All species are very similar, differing only by the pronotal punctation, shape of the clypeus and the mentum, and the form of the median lobe of the aedeagus. Specimens ofC.floricolasp. n.andC.adolescenssp. n.were collected from inflorescences of various genera of the family Araceae. The field observations and analysis of mid gut contents indicates that they feed on organic material on internal organs of the inflorescences, including the pollen of the host plant. They were also observed to carry a large amount of pollen and are likely pollinators of their host species of Araceae.

— 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.

Tharina gen. nov. along with T. antennalis (as type species), T. ecuadoriensis, T. micra, and T. peckorum spp. nov. (Coleoptera: Endomychidae: Endomychinae) from Venezuela, Ecuador, and Bolivia are described, diagnosed, and illustrated. Mouthpart structures, in this genus, which are unique within the family Endomychidae, are discussed in terms of their function. Notes on the unusual female genitalia in one species are provided.

India and Madagascar drifted apart more than 80 Mya, yet few taxonomic groups currently found in these regions bear any signature of this split. When drifting in isolation, extensive volcanic activity covered almost half of India in lava flows, likely triggering widespread extinction on the island. Consequently, most of India's rich extant flora and fauna are considered to be the result of recent Cenozoic dispersal, and no lineages are conclusively a result of ancient vicariance. Many of Madagascar's lineages also stem from either Cenozoic diversification or dispersal events, with the latter being a result of the close proximity of the island with mainland Africa. In the present study, we focus on two remarkable lineages of cascade beetles in the genera Scoliopsis and Tritonus (Coleoptera, Hydrophilidae), respectively, dwelling in the mountains of south India and Sri Lanka, as well as in Madagascar. Based on a molecular phylogeny of the family Hydrophilidae dated with eight fossils, we show that these two lineages are sister taxa, and diverged when Madagascar and Greater India (India, Sri Lanka, Seychelles) separated, suggesting a pattern of Gondwanean vicariance. The results of the present study show that, despite geological upheaval, the present-day fauna of India still retains traces of its Gondwanan past.

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 o...

Asian species of the Cercyon unipunctatus species group are reviewed. Nine species are recognized in Asia, three of which are described as new: C. flavimarginatus sp. nov. and C. kubani sp. nov. from Yunnan province of China, and C. undulipennis sp. nov. from Sichuan and Yunnan provinces in China. Besides these, the species group contains the following Asian species: C. divisus Hebauer, 2002 (newly recorded from northern India and China), C. quisquilius (Linnaeus, 1761) (newly recorded from Kyrgyzstan, Turkmenistan, Syria and Iran), C. unipunctatus (Linnaeus, 1758), C. unipustulatus Nakane, 1982 and C. verus Shatrovskiy, 1989. All species are (re)described, illustrated and a summary of the known distribution is provided. An identification key to the Asian species of C. unipunctatus group is provided, and the species are also briefly diagnosed from similar Palaearctic and Oriental Cercyon species.