A review of Copelatus diving beetles from the Solomon Islands, reporting the discovery of six new species (Coleoptera, Dytiscidae, Copelatinae).
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ABSTRACT:
SUBMITTER: Hajek J
PROVIDER: S-EPMC7973068 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Diving beetles are generally aquatic and live submerged in water during larval and adult stages. A few groups have colonised hygropetric habitats and fewer species still can possibly be referred to as terrestrial. Here we describe six new Copelatine species that were mainly found in dry shallow forest floor depressions in the eastern and northeastern lowland humid forests of Madagascar. Three new species are described in each of the two genera Copelatus and Madaglymbus: Copelatus amphibius sp. nov., Copelatus betampona sp. nov., Copelatus zanatanensis sp. nov., Madaglymbus kelimaso sp. nov., Madaglymbus menalamba sp. nov., and Madaglymbus semifactus sp. nov. Diagnosis, description, known distribution, ecology, and conservation notes are provided for each species. All species are illustrated with a dorsal habitus image, ventral and lateral views of the male penis, and parameres. Photographs of the unusual terrestrial habitats where the species were found are provided. Madaglymbus menalamba sp. nov. is also documented with macrophotos and videorecordings of the terrestrial locomotion and behaviour in the field. Although these species should not be classified as terrestrial, or even semi-terrestrial Dytiscidae, they seem to be specialists of very ephemeral aquatic habitats and stay put instead of disperse when the habitat dries up. It is hypothesised that this lifestyle and behaviour on Madagascar is restricted to the high-precipitation humid forest regions mainly in the east. It may also represent a transition step, or stepping-stone, towards becoming fully terrestrial, a step that the few known terrestrial Dytiscid taxa once passed through. It is very likely that this type of habitat is overlooked for aquatic beetles, not only in Madagascar, and the six species herein described may be just the "tip of the iceberg".
| S-EPMC6700060 | biostudies-literature
Project description:The bio-geographical composition and spatial distribution patterns of dytiscid assemblages in Mongolia are relatively unexplored. In this study, we compiled a list of 99 dytiscid species belonging to 20 genera and five subfamilies recorded in Mongolia and investigated species richness, spatial distribution and bio-geographical composition of the Mongolian dytiscid fauna. This study encompasses the information of currently recorded species and their geographic localities in Mongolia based on our own data and literature sources. We examined how dytiscid species richness was related to sub-basins of surface water network, as well as to geographical elevations within Mongolia. The majority of the Mongolian dytiscid fauna was associated with the sub-basins belonging to Arctic Ocean (80 species, 80.8%) and Central Asian Inland (60 species, 60.6%) basins. Only a few species of dytiscids belonged to the remaining river basins. Species richness of dytiscids and total area of sub-basins were not correlated, but species composition of dytiscids differed significantly among the sub-basins. We observed that most of the species (77 species or 77.8% of total fauna) were recorded in a wide range of elevations and mid-altitudes (1000-2000 m a.s.l.) and showed the greatest diversity of dytiscids. Regarding the bio-geographical composition, species with wide geographical distributions (27.3% of dytiscids), were Palearctic species, while species of Arctic origin (21.2%) together with Boreal elements (16.2%) comprised a large proportion of the dytiscid fauna in Mongolia.
| S-EPMC6565699 | biostudies-literature
Project description:Geographical ranges vary greatly in size and position, even within recent clades, but the factors driving this remain poorly understood. In aquatic beetles, thermal niche has been shown to be related to both the relative range size and position of congeners but whether other physiological parameters play a role is unknown. Metabolic plasticity may be critical for species occupying more variable thermal environments and maintaining this plasticity may trade-off against other physiological processes such as immunocompetence. Here we combine data on thermal physiology with measures of metabolic plasticity and immunocompetence to explore these relationships in Deronectes (Dytiscidae). While variation in latitudinal range extent and position was explained in part by thermal physiology, aspects of metabolic plasticity and immunocompetence also appeared important. Northerly distributed, wide-ranging species apparently used different energy reserves under thermal stress from southern endemic congeners and differed in their antibacterial defences. This is the first indication that these processes may be related to geographical range, and suggests parameters that may be worthy of exploration in other taxa.
| S-EPMC4938042 | biostudies-literature
Project description:Ten new species of Exocelina Broun, 1886 from New Guinea are described: Exocelina andakombensissp. n., Exocelina garainasp. n., Exocelina injiensissp. n., Exocelina kabwumensissp. n., Exocelina marawagasp. n., Exocelina posmanisp. n., Exocelina tekadusp. n., Exocelina variratasp. n., Exocelina wareagasp. n., and Exocelina woitapensissp. n. All of them together with five already described species are united into the newly defined Exocelina danae-group (with Exocelina miriae-subgroup), a polyphyletic complex of related species with lateral setation on the median lobe. In the light of newly available material, all previously described species of the Exocelina rivulus-group are considered to belong to a single species, Exocelina damantiensis (Balke, 1998), which is now placed into the Exocelina danae-group, and three new synonyms are therefore proposed: Exocelina madangensis (Balke, 2001) syn. n., Exocelina patepensis (Balke, 1998) syn. n., and Exocelina rivulus (Balke, 1998) syn. n. Exocelina tarmluensis (Balke, 1998) syn. n. is a junior synonym of Exocelina danae (Balke, 1998). Redescription of Exocelina atratus (Balfour-Browne, 1939) is provided based on its type material. An identification key to all known species of the group is provided, and important diagnostic characters are illustrated. Data on the species distribution are given, showing that whilst most species are local endemics, Exocelina damantiensis is extremely widely distributed.
| S-EPMC5090162 | biostudies-literature
Project description:High species diversity and endemism within Madagascar is mainly the result of species radiations following colonization from nearby continents or islands. Most of the endemic taxa are thought to be descendants of a single or small number of colonizers that arrived from Africa sometime during the Cenozoic and gave rise to highly diverse groups. This pattern is largely based on vertebrates and a small number of invertebrate groups. Knowledge of the evolutionary history of aquatic beetles on Madagascar is lacking, even though this species-rich group is often a dominant part of invertebrate freshwater communities in both standing and running water. Here we focus on large bodied diving beetles of the tribes Hydaticini and Cybistrini. Our aims with this study were to answer the following questions 1) How many colonization events does the present Malagasy fauna originate from? 2) Did any colonization event lead to a species radiation? 3) Where did the colonizers come from--Africa or Asia--and has there been any out-of-Madagascar event? 4) When did these events occur and were they concentrated to any particular time interval? Our results suggest that neither in Hydaticini nor in Cybistrini was there a single case of two or more endemic species forming a monophyletic group. The biogeographical analysis indicated different colonization histories for the two tribes. Cybistrini required at least eight separate colonization events, including the non-endemic species, all comparatively recent except the only lotic (running water) living Cybister operosus with an inferred colonization at 29 Ma. In Hydaticini the Madagascan endemics were spread out across the tree, often occupying basal positions in different species groups. The biogeographical analyses therefore postulated the very bold hypothesis of a Madagascan origin at a very deep basal node within Hydaticus and multiple out-of-Madagascar dispersal events. This hypothesis needs to be tested with equally intense taxon sampling of mainland Africa as for Madagascar.
| S-EPMC4368551 | biostudies-literature
Project description:Nine new species groups of Exocelina Broun, 1886 from New Guinea are introduced with keys to their representatives. Four groups are monotypic and include three new species: the E. aipomek group, the E. koroba group: E. koroba sp. nov., the E. mekilensis group: E. mekilensis sp. nov., and the E. morobensis group: E. morobensis sp. nov. The remaining five species groups include 18 species with 12 new species and one new subspecies: the E. bacchusi group: E. akameku sp. nov., E. oiwa sp. nov., E. oksibilensis sp. nov., and E. bacchusi herzogensis ssp. nov.; the E. jaseminae group: E. aseki sp. nov., E. kailaki sp. nov., and E. pseudojaseminae sp. nov.; the E. larsoni group: E. warahulenensis sp. nov.; the E. takime group: E. mianminensis sp. nov.; and the E. warasera group: E. haia sp. nov., E. kobau sp. nov., E. pulchella sp. nov., and E. warasera sp. nov. Diagnoses of five already described species of these groups are provided, as well as comparatives notes on all species. Exocelina santimontis (Balke, 1998) syn. nov. is a junior synonym of E. aipomek (Balke, 1998). Data on the distribution of the species are given, showing that most of the species of these groups occur in the Papua New Guinea.
| S-EPMC6791902 | biostudies-other
Project description:The genus Copelatus in Australia is revised and nine species are recognised. One new species, Copelatus martinbaehri sp. nov., is described from Papua New Guinea (Central Province) and Cape York Peninsula (Iron Range NP and Mt Tozer). Copelatus divisus Watts, 1978, syn. nov., is considered a junior synonym of C. portior Guignot, 1956, described from New Guinea. Species delimitation is based on the morphological characters and Cox1 data. All species are (re)described, and their important species characters (median lobes, parameres, habitus and colour patterns) are illustrated. A key to all nine species is provided. The known distribution and habitat preferences of each species are outlined briefly. In Australia, all nine species are distributed in the northern half of the continent. Four species are also reported from New Guinea: in addition to C. martinbaehri sp. nov., we record C. clarki Sharp, 1882 for the first time from southern New Guinea, and consider literature records of C. irregularis W.J. Macleay, 1871 and C. marginatus Sharp, 1882 from New Guinea as doubtful. Copelatus portior is widely distributed in Australasia, while C. tenebrosus is widely distributed in the Indomalayan and Australasian realms. All Australian Copelatus are confirmed to be lentic, found in a large variety of stagnant water, mainly in lowland areas up to 250 m.
| S-EPMC6872603 | biostudies-literature
Project description:Morphology and mitochondrial DNA sequence data are used to reassess the taxonomy of Australian diving beetles previously assigned to the genera Uvarus Guignot, 1939 and Gibbidessus Watts, 1978. Gibbidessus was described as a monotypic genus for Gibbidessus chipi Watts, 1978. The genus is significantly extended here. Based on molecular systematic evidence, Uvarus pictipes (Lea, 1899) is transferred to Gibbidessus. Gibbidessus chipi and Gibbidessus pictipes comb. nov. are redescribed, and six new species are described: Gibbiddessus atomus sp. nov. (SW Australia, Northcliffe area) [the smallest epigean diving beetle in Australia], G. davidi sp. nov. (SW Australia), G. drikdrikensis sp. nov. (Victoria), G. kangarooensis sp. nov. (SA Kangaroo Island), G. pederzanii sp. nov. (SW Australia, Nannup area), and G. rottnestensis sp. nov. (SW Australia). Species are delineated using characters such as male genital structure and beetle size, shape and colour pattern. Mitochondrial Cox1 data for 27 individuals, representing five species, were generated, and revealed clusters congruent with the morphological evidence. Gibbidessus occur in southern Australia, with the centre of diversification in the isolated peat- and wetlands of SW Australia. All species occur in very shallow water of seasonal, exposed or half-shaded wetlands and flooded meadows.
| S-EPMC7572521 | biostudies-literature
Project description:Thermal tolerance limits in animals are often thought to be related to temperature and thermal variation in their environment. Recently, there has been a focus on studying upper thermal limits due to the likelihood for climate change to expose more animals to higher temperatures and potentially extinction. Organisms living in underground environments experience reduced temperatures and thermal variation in comparison to species living in surface habitats, but how these impact their thermal tolerance limits are unclear. In this study, we compare the thermal critical maximum (CTmax) of two subterranean diving beetles (Dytiscidae) to that of three related surface-dwelling species. Our results show that subterranean species have a lower CTmax (38.3-39.0°C) than surface species (42.0-44.5°C). The CTmax of subterranean species is ∼10°C higher than the highest temperature recorded within the aquifer. Groundwater temperature varied between 18.4°C and 28.8°C, and changes with time, depth and distance across the aquifer. Seasonal temperature fluctuations were 0.5°C at a single point, with the maximum heating rate being ∼1000x lower (0.008°C/hour) than that recorded in surface habitats (7.98°C/hour). For surface species, CTmax was 7-10°C higher than the maximum temperature in their habitats, with daily fluctuations from ∼1°C to 16°C and extremes of 6.9°C and 34.9°C. These findings suggest that subterranean dytiscid beetles are unlikely to reach their CTmax with a predicted warming of 1.3-5.1°C in the region by 2090. However, the impacts of long-term elevated temperatures on fitness, different life stages and other species in the beetle's trophic food web are unknown.
| S-EPMC9387432 | biostudies-literature
Project description:Liodessuspicinus sp. nov. is described from the Páramo de Sumapaz near Bogota D.C. at 3,500 m above sea level. The species can be distinguished from the other Colombian Liodessus species by its dark coloration, discontinuous habitus, shiny surface of the pronotum and elytron, presence of a distinct occipital line, distinct basal pronotal striae, short or even faint basal elytral striae, as well as by its distinct geographic distribution and cox1 signature.
| S-EPMC8443537 | biostudies-literature