No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
The Phylogeny and Classification of Predaceous Diving Beetles (Coleoptera: Dytiscidae)
Abstract
The phylogenetics and higher (family-group) classification of extant members of the beetle family Dytiscidae (Coleoptera), or predaceous diving beetles, is reviewed and reassessed. A phylogenetic analysis of the family is presented based on 168 species of diving beetles and 9 outgroup taxa from Gyrinidae, Noteridae, Amphizoidae, and Paelobiidae. All currently recognized dytiscid subfamilies and tribes are represented, most by multiple genera and species. Data include 104 morphological characters and approximately 6700 aligned bases from 9 DNA sequence fragments from cytochrome c oxidase I (COI) and II (COII), histone III (H3), 16S rRNA (16S), 12S rRNA (12S), arginine kinase (argkin), RNA polymerase II (RNA pol II), elongation factor 1 alpha (Ef1α), and wingless (wnt). Parsimony and Bayesian analyses were conducted. The topology of the parsimony tree (consensus of 13 equally-parsimonious solutions) exhibits numerous anomalies inconsistent with convincing morphological features and the Bayesian results and has, generally, relatively poor bootstrap support for major clades. The Bayesian topology is more consistent with major morphological features and has strong support for most clades, and conclusions are based primarily on this estimate. Major higher-level phylogenetic relationships with strong support include: (1) monophyly of Dytiscidae Leach, (2) Matinae Branden sister to the rest of Dytiscidae, (3) Agabinae Thomson + Colymbetinae Erichson, (4) Hydrodytinae Miller + Hydroporinae Aubé, (5) Dytiscinae Leach + Laccophilinae Gistel + Cybistrini Sharp + Copelatinae Branden, (6) monophyly of the subfamilies Matinae, Colymbetinae, Copelatinae, Coptotominae Branden, Lancetinae Branden, Laccophilinae (including Agabetes Crotch), Agabinae (support weaker than in other subfamilies) and Hydroporinae (monophyly of Hydrodytinae not tested), (7) paraphyly of Dytiscinae with Cybistrini sister to Laccophilinae (with strong support) and this clade sister to other Dytiscinae, and (8) monophyly of both Agabini (Agabus-group of genera) and Hydrotrupini Roughley (Hydrotrupes Sharp and the Platynectes-group of genera). Major conclusions regarding tribes within Hydroporinae include: (1) monophyly of the tribes Vatellini Sharp, Methlini Branden, Hydrovatini Sharp, Hygrotini Portevin, Hyphydrini Gistel (without Pachydrus Sharp) and Bidessini Sharp (including Peschetius Guignot, Hydrodessus J. Balfour-Browne and Amarodytes Régimbart) (monophyly of Laccornini Wolfe and Roughley and Pachydrini Biström, Nilsson and Wewalka not tested), (2) Pachydrini is a problematic, long-branched taxa resolved here as sister to Hydrovatini but with weak support, (3) Hydroporini monophyletic except for Laccornellus Roughley and Wolfe and Canthyporus Zimmermann, (4) Laccornellus and Canthyporus together monophyletic and sister to Hydroporinae except Laccornini. Four groups are resolved within Hydroporini exclusive of Laccornellus + Canthyporus corresponding to the Deronectes-, the Graptodytes-, the Necterosoma- and the Hydroporus-groups of genera. The classification of Dytiscidae is revised with the following taxonomic changes [2014]: (1) Hydrotrupini is recognized as a tribe of Agabinae including the genus Hydrotrupes and the Platynectes-group of genera, (2) the genus Rugosus García is moved from Colymbetinae to Copelatinae, (3) Cybistrini is elevated from tribe rank within Dytiscinae to subfamily of Dytiscidae, (4) Hyderodini Miller is placed as a junior synonym of Dytiscini, (5) Laccornellus and Canthyporus are removed from Hydroporini and placed in their own tribe, Laccornellini, (6) the following family-group names are resurrected from synonymy with Hydroporini and placed as subtribes within Hydroporini, Deronectina Galewski (for the Deronectes-group of genera), Siettitiina Smrž (for the Graptodytes-group of genera), Sternopriscina Branden (for the Necterosoma-group of genera), and Hydroporina (for the Hydroporus-group of genera), (7) Carabhydrini Watts is placed as a junior synonym of Sternopriscina, and (8) Hydrodessus, formerly incerta sedis with respect to tribe, is placed in Bidessini. Each subfamily, tribe and subtribe is diagnosed and its taxonomic history discussed.
... Laccophilinae presently includes two tribes, Agabetini and Laccophilini. Larval studies (Alarie et al. 2000;Michat et al. 2017) as well as most recent molecular analyses (Miller & Bergsten 2023) postulated a sister relationship of Agabetini and Laccophilini. The phylogenetic relationships of J. niponensis with other Laccophilini, however, remain unclear (Miller & Bergsten 2016), although the fact that this species was originally described by Kamiya (1939) in the genus Neptosternus Sharp, 1882 may suggest that it is related to this group. ...
... To examine the phylogenetic signal of the larval characters of Japanolaccophilus and to test its relationships with other Laccophilini, a cladistic analysis of seven genera of Laccophilini (14 species) with sufficiently detailed larval descriptions (Africophilus, Australphilus, Japanolaccophilus, Laccomimus, Laccophilus, Neptosternus, Philodytes) was conducted using the program TNT. Agabetes, which is postulated to be sister-group to the tribe Laccophilini (Miller & Bergsten 2023;Michat et al. 2017), was used as out-group. Although represented by instar III only, primary sensilla of Africophilus, Australphilus, and Philodytes were tentatively identified by comparison with the Laccophilinae ground plan wherever possible (e.g., Alarie et al. 2000;. ...
The three larval instars of Japanolaccophilus niponensis (Kamiya, 1939) (Coleoptera: Adephaga, Laccophilinae) are described for the first time according to the now genevralized larval descriptive format of Dytiscidae (Coleoptera: Adephaga), which incorporates detailed chaetotaxic and morphometric analyses. A parsimony analysis based on larval characteristics of 14 Laccophilini species in seven genera was conducted using the program TNT. One of the main results is that Japanolaccophilus Satô, 1972, which so far was treated as being related to Neptosternus Sharp, 1882 now stands out as sister to Laccophilus Leach, 1815, and Philodytes J. Balfour-Browne, 1938 with strong support. Additionally, Laccomimus Toledo & Michat, 2015, and Africophilus Guignot, 1948 are resolved as monophyletic and sister to a clade which itself is subdivided into two well supported clades: Neptosternus + Australphilus Watts, 1978, and Japanolaccophilus + (Laccophilus, Philodytes). Philodytes is here newly accepted as junior synonym of Laccophilus.
... During a revisionary investigation of the genus Amarodytes Régimbart, 1900 by the authors it became clear that there are several groups of Bidessini species historically involved in the genus that are seemingly more closely related to other groups in Bidessini than to each other. The type species, A. percosioides Régimbart, 1900, is part of a group that includes species with single-segmented lateral lobes that are related to Hydrodessus J. Balfour-Browne, 1953 andPeschetius Guignot, 1942, which also have single-segmented lateral lobes (Miller et al. 2006;Miller and Bergsten 2014, 2016, 2023Miller 2016b). However, other species assigned to Amarodytes were found to have two-segmented lateral lobes, and, therefore, are misplaced in the genus (Benetti and Régil Cueto 2004). ...
Miradessus gen. nov. is described for two previously described species, Amarodytes pulchellus Guignot, 1955 from Colombia, with new records from Venezuela, and A. plau-manni Gschwendtner, 1935, from Brazil, and two previously unknown species, Mirades-sus beni sp. nov., from Bolivia and Peru, and Miradessus rikae sp. nov. from Ecuador. The genus is characterized by 1) occipital line absent; 2) basal pronotal striae present; 3) basal elytral stria absent; 4) sutural elytral stria absent; 5) transverse carina on elytral epipleuron at humeral angle absent; 6) distinct marginal bead on anterior clypeal margin absent; and 7) male median lobe deeply multilobed with a dorsal portion separate from a unilobed or bilobed ventral portion.
... También las especies de Celina se caracterizan por tener un escutelo bien desarrollado y visible; contrasta con que la mayoría de las especies de Hydroporinae no lo tienen visible. Estos rasgos comunes de los dos géneros ya fueron apreciados por Sharp (1882), pero fueWolfe (1985Wolfe ( , 1988) quien advirtió algunas sinapomorfías para esta grupo y propuso que presentaba varias plesiomorfías que la acercaban a los génerosLaccornis Gozis, 1914, Laccornellus Roughley & Wolfe, 1987y Canthyporus Zimmermann, 1919; el mismo Wolfe también pensó que la tribu Methlini era hermana del género Hydrovatus Motschulsky, 1853 por la similitud del ápice acuminado posterior del cuerpo (Miller & Bergsten, 2014, Cartago, Guanacaste, Heredia, Limón, Puntarenas y San José). Zoogeográficamente pertenece a la región Neotropical y es considerado como un punto caliente de biodiversidad (Mittermeier et al., 2004).La determinación de los géneros se llevó a cabo mediante las claves de Árce-Pérez & Roughley (1999). ...
The tribe Methlini and the genus Celina are recorded from Costa Rica for the first time. New data, descriptions and records of the species of the genus, Celina aculeata, Celina angustata and Celina debilis are also included.
We describe the larvae of the diving-beetle genus Sandracottus Sharp, 1882 based on S. femoralis Heller, 1934 and S. mixtus (Blanchard, 1843). We include detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, terminal abdominal segment and urogomphi in order to discover useful characters for distinguishing Sandracottus larvae from those of other known Aciliini (Coleoptera: Dytiscidae, Dytiscinae). A provisional parsimony analysis based on larval characteristics of seven Aciliini species in four genera (Acilius Leach, 1817, Graphoderus Dejean, 1833, Sandracottus, Thermonectus Dejean, 1833) was conducted using the program TNT. A clade grouping Eretini and Aciliini stands out as the most strongly supported in this analysis. The tribe Aciliini finds itself monophyletic with also very good support. Our analysis, however, failed to depict any clear phylogenetic relationships within the Aciliini although each of the four genera studied emerged from our study as morphologically distinct.
We list the species of the genera Megadytes,Thermonectus and Hydaticus present in Costa Rica. The record of the genus Thermonectus is new to Costa Rica. Also included are new data and records about the genera Megadytes and Hydaticus.
Entomologica Basiliensia 19(1):621-651. The Agabus optatus Sharp, 1884, group is expanded to include also the former genus Colymbinectes Falkenström (except Platynectes procerus Régimbart, 1899, that is a junior synonym of Agabus conspicuus Sharp, 1873, n. syn.) aqnd the two species in the Nearctic Agabus obtusatus (Say, 1823) group sensu Larson (1989).
The first stygobiontic diving beetle known from Laos, Laodytes lapiei n. gen., n. sp., is described from a cave located in the Vientiane province. Its morphological characters lead to its placement, among Hydroporinae, in Hydroporini. Inside these, the new species could not be assigned to an existing genus. As a result, a new genus has been defined without it being possible, at the present stage, to assign it to one of the currently recognized subtribes. Résumé.-Nouveaux genre et espèce de Coléoptère aquatique souterrain du Laos (Coleoptera, Dytiscidae, Hydroporinae, Hydroporini). Le premier Dytiscidae stygobie connu du Laos, Laodytes lapiei n. gen., n. sp., est décrit d'une grotte de la province de Vientiane. Ses caractères morphologiques conduisent à le placer, parmi les Hydroporinae, dans les Hydroporini. À l'intérieur de ceux-ci, la nouvelle espèce n'a pu trouver place dans aucun genre existant. En conséquence, un nouveau genre a été défini, sans qu'il soit possible, à ce stade, de le rattacher à l'une des sous-tribus actuellement reconnues.
We describe a new subterranean species of the genus Exocelina Broun, 1886 (Coleoptera: Dytiscidae) from the Malay Peninsula. Almost all of the 196 species of that genus are epigean and distributed mainly in New Guinea, Australia, Oceania and New Caledonia. One epigean species is, however, known from China. The discovery of a species on the Malay Peninsula fills that distribution gap to some degree.
How to cite this article: Balke M., Toledo M., Gröhn C., Rappsilber I., Hendrich L. 2019. † Electruphilus wendeli gen.n., sp.n.-the first diving beetle recorded from Saxonian (Bitterfeld) Amber (Coleoptera: Dytiscidae: Laccophilinae) // Russian Entomol.
In this contribution, the larval morphology of Spencerhydrus Sharp, 1882 was studied, an Australian endemic genus in the diving beetle tribe Cybistrini. All instars of the only two species included in the genus ( S. latecinctus Sharp, 1882 and S. pulchellus Sharp, 1882) are described and illustrated with the exception of the third instar of S. latecinctus . Detailed morphometric and primary chaetotaxic analyses were performed to discover useful characters for generic diagnosis and species distinction. Spencerhydrus can be distinguished from other Cybistrini genera by the medial projection of frontoclypeus slightly indented apically, with lamellae clypeales directed forward in a characteristic V-shaped pattern, the median process of prementum strongly developed, the presence of a single ventral sclerite on prothorax, the presence of basoventral spinulae on claws, and the reduced sclerotization of the abdominal segment VII which covers only the anterior half. Larvae of the two species of Spencerhydrus can readily be distinguished by the shape of the median process of prementum, which is visibly broader in S. pulchellus than in S. latecinctus .
The larvae of four species of Platambus Thomson, 1859 from Japan, P. pictipennis (Sharp, 1873), P. convexus Okada, 2011, P. fimbriatus (Sharp, 1884) and P. sawadai (Kamiya, 1932) are described for the first time including a detailed chaetotaxy analysis of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. A provisional parsimony analysis based on 39 informative larval characteristics of 15 species in seven genera of the subfamily Agabinae was conducted using the program TNT. Larvae of the Platambus species studied stand out from those of other genera of Agabinae by the unique presence of a subquadrate last abdominal segment not protruding posteriorly into siphon and the much shorter length of the primary urogomphal seta UR5 compared to seta UR7 in first instar larva.
Sigmodontinae, a diverse subfamily including 106 genera of American Rodents, is currently divided in eleven tribes that still need to be refined based on recently generated phylogenetic hypotheses. Several published names of tribes do not conform to one or more Rules of the International Code of Zoological Nomenclature. In particular, the first arrangement of Sigmodontinae genera in tribes has been overlooked, the different requirements for availability of names proposed before 1931 and after 1930 were not taken into account for at least five names, the requirement that a family-group name be used as valid in the publication where proposed, and the unavailability of names proposed conditionally after 1960 were also ignored on several occasions. Our analysis tries to disclose and fix such nomenclatural problems keeping current usage as much as possible. A new name is proposed for a tribe that currently has been designated only by an unavailable name.
Two new genera and species are described. Spanglerodessus n. gen. is described to include the single new species, S. shorti n. sp. from localities in eastern Venezuela and western Guyana. This genus is similar to Bidessodes Régimbart and Fontidessus Miller and Spangler, but differs from the first in having overall dark coloration, lack of dorsal color patterns or iridescence, a broad lateral bead, and broad and robust habitus. From Fontidessus the genus differs in being much more robust and lacking natatory setae. Incomptodessus n. gen. is described to include a single new species I. camachoi n. sp. from localities in the upper Orinoco River basin in Amazonas and Bolivar States. This genus differs from similar bidessine genera, Sharphydrus Omer-Cooper, Tyndallhydrus Sharp, Liodessus Guignot and Neobidessus Young, in having impunctate metacoxae and metaventrite and lacking basal striae on the elytra.
Barretthydrus Lea, 1927 is an Australian endemic genus comprised of three species: the more common B. tibialis Lea, 1927 and B. geminatus Lea, 1927, and the rarely collected B. stepheni Watts, 1978. These dyticids are small (adult body length varying from 4.2 mm to 4.5 mm) and mainly live in clear mountain streams in the Great Dividing Range in Victoria and New South Wales (Watts 1978; Miller and Bergsten 2016).
Barretthydrus is included in the tribe Hydroporini (Dytiscidae: Hydroporinae) that consists of a large and diverse group of water beetles mostly distributed in boreal and temperate regions of the northern hemisphere. Worldwide, Hydroporini currently comprises more than 685 species classified in 38 genera (Nilsson 2017). Within Hydroporini, Barretthydrus is postulated to belong to the strictly Australian hydroporine radiation Sternopriscina along with Antiporus Sharp, 1882, Brancuporus Hendrich, Toussaint, and Balke, 2014, Carabhydrus Watts, 1978, Chostonectes Sharp, 1880, Megaporus Brinck, 1943 Necterosoma MacLeay, 1871, Paroster Sharp, 1882, Sekaliporus Watts, 1997, Sternopriscus Sharp, 1880, and Tiporus Watts, 1985 (Miller and Bergsten 2016).
The larvae of Antiporus and Paroster were described in much detail recently (Alarie and Watts 2004; Alarie et al. 2009). The larval morphology of the other members of the subtribe Sternopriscina are only poorly known, but late instars can be identified to genus using the illustrated keys in Watts (2002). The discovery of the larvae of both B. tibialis and B. geminatus provided the impetus for this study, which has the following three goals: (1) to describe, in detail, for the first time the larvae of B. tibialis and B. geminatus; (2) to compare the ground plan of larval features of Barretthydrus with those of other associated Sternopriscina genera for which the larvae have been described comprehensively; and (3) to study the phylogenetic relationships of Barretthydrus within the tribe Hydroporini based on larval characters.
Iberoporusplutosp. n. , the first stygobiont beetle from Portugal (Dytiscidae, Hydroporinae), is described from a single female from the cave Soprador do Carvalho (Coimbra). The species is highly troglomorphic, depigmented, blind, and with elongated appendages not adapted for swimming. A molecular phylogeny based on a combination of three mitochondrial and two nuclear genes showed the new species to be sister to I.cermenius Castro & Delgado, 2001 from Córdoba (south of Spain), within the subtribe Siettitiina of the tribe Hydroporini. Both species are included in a clade with Siettitiaavenionensis Guignot, 1925 (south of France) and Rhithrodytesagnus Foster, 1992 and R.argaensis Fery & Bilton, 1996 (north of Portugal), in turn sister to the rest of species of genus Rhithrodytes Bameul, 1989, in what is here considered the Siettitia group of genera. We resolve the paraphyly of Rhithrodytes by transferring the two Portuguese species to Iberoporus Castro & Delgado, 2001, I.agnus (Foster, 1992), comb. n. and I.argaensis (Fery & Bilton, 1996), comb. n.
The tribe Hygrotini Portevin, 1929 is currently composed of four genera, Heroceras Guignot, 1950, Herophydrus Sharp, 1880, Hygrotus Stephens, 1828 (with two subgenera, Coelambus Thomson, 1860, and Hygrotus s. str.), and Hyphoporus Sharp, 1880. A recent molecular phylogeny of the tribe with ca. 45% of the 137 described species of Hygrotini, including the type species of all genus-level taxa, revealed extended para- or polyphyly of the current genera and subgenera (Villastrigo et al., Zoologica Scripta, in press), for which reason a new classification of the tribe Hygrotini is proposed. Within Hygrotini only two genera are recognised: Clemnius n. gen. (with two subgenera: Clemnius s. str. with type species Hyphydrus decoratus Gyllenhal, 1810, and Cyclopius n. subgen. with type species Hydroporus acaroides LeConte, 1855) and Hygrotus (with four subgenera: Coelambus, Hygrotus s. str., Hyphoporus n. stat. and Leptolambus n. subgen. with type species Dytiscus impressopunctatus Schaller, 1783). Two genera are synonymised under Hygrotus s. str., Herophydrus n. syn. and Heroceras n. syn. The following 67 new combinations, for species thus far treated under the genera Heroceras, Herophydrus, Hygrotus and Hyphoporus, result from the new classification: Clemnius (s. str.) berneri (Young & Wolfe, 1984) n. comb., Clemnius (s. str.) decoratus (Gyllenhal, 1810) n. comb., Clemnius (s. str.) hydropicus (LeConte, 1852) n. comb., Clemnius (s. str.) laccophilinus (LeConte, 1878) n. comb., Clemnius (s. str.) sylvanus (Fall, 1917) n. comb., Clemnius (Cyclopius) acaroides (LeConte, 1855) n. comb., Clemnius (Cyclopius) farctus (LeConte, 1855) n. comb., Clemnius (Cyclopius) marginipennis (Blatchley, 1912) n. comb., Hygrotus (s. str.) assimilis (Régimbart, 1895) n. comb., H. (s. str.) bilardoi (Biström & Nilsson, 2002) n. comb., H. (s. str.) capensis (Régimbart, 1895) n. comb., H. (s. str.) confusus (Régimbart, 1895) n. comb., H. (s. str.) descarpentriesi (Peschet, 1923) n. comb., H. (s. str.) discrepatus (Guignot, 1954) n. comb., H. (s. str.) endroedyi (Biström & Nilsson, 2002) n. comb., H. (s. str.) gigantoides (Biström & Nilsson, 2002) n. comb., H. (s. str.) gigas (Régimbart, 1895) n. comb., H. (s. str.) goldschmidti (Pederzani & Rocchi, 2009) n. comb., H. (s. str.) gschwendtneri (Omer-Cooper, 1957) n. comb., H. (s. str.) hyphoporoides (Régimbart, 1895) n. comb., H. (s. str.) ignoratus (Gschwendtner, 1933) n. comb., H. (s. str.) inquinatus (Boheman, 1848) n. comb., H. (s. str.) janssensi (Guignot, 1952) n. comb., H. (s. str.) kalaharii (Gschwendtner, 1935) n. comb., H. (s. str.) morandi (Guignot, 1952) n. comb., H. (s. str.) muticus (Sharp, 1882) n. comb., H. (s. str.) natator (Biström & Nilsson, 2002) n. comb., H. (s. str.) nigrescens (Biström & Nilsson, 2002) n. comb., H. (s. str.) nodieri (Régimbart, 1895) n. comb., H. (s. str.) obscurus (Sharp, 1882) n. comb., H. (s. str.) obsoletus (Régimbart, 1895) n. comb., H. (s. str.) ovalis (Gschwendtner, 1932) n. comb., H. (s. str.) pallidus (Omer-Cooper, 1931) n. comb., H. (s. str.) pauliani (Guignot, 1950) n. comb., H. (s. str.) quadrilineatus (Régimbart, 1895) n. comb., H. (s. str.) reticulatus (Pederzani & Rocchi, 2009) n. comb., H. (s. str.) ritsemae (Régimbart, 1889) n. comb., H. (s. str.) rohani (Peschet, 1924) n. comb., H. (s. str.) rufus (Clark, 1863) n. comb., H. (s. str.) sjostedti (Régimbart, 1908) n. comb., H. (s. str.) spadiceus (Sharp, 1882) n. comb., H. (s. str.) sudanensis (Guignot, 1952) n. comb., H. (s. str.) travniceki (Šťastný, 2012) n. comb., H. (s. str.) tribolus (Guignot, 1953) n. comb., H. (s. str.) variabilis secundus (Régimbart, 1906) n. comb., H. (s. str.) variabilis variabilis (Guignot, 1954) n. comb., H. (s. str.) verticalis (Sharp, 1882) n. comb., H. (s. str.) vittatus (Régimbart, 1895) n. comb., H. (s. str.) wewalkai (Biström & Nilsson, 2002) n. comb., Hygrotus (Hyphoporus) anitae (Vazirani, 1969) n. comb., H. (Hyphoporus) aper (Sharp, 1882) n. comb., H. (Hyphoporus) bengalensis (Severin, 1890) n. comb., H. (Hyphoporus) bertrandi (Vazirani, 1969) n. comb., H. (Hyphoporus) caliginosus (Régimbart, 1899) n. comb., H. (Hyphoporus) dehraduni (Vazirani, 1969) n. comb., H. (Hyphoporus) elevatus (Sharp, 1882) n. comb., H. (Hyphoporus) geetae (Vazirani, 1969) n. comb., H. (Hyphoporus) josephi (Vazirani, 1969) n. comb., H. (Hyphoporus) kempi (Gschwendtner, 1936) n. comb., H. (Hyphoporus) montanus (Régimbart, 1899) n. comb., H. (Hyphoporus) nilghiricus (Régimbart, 1903) n. comb., H. (Hyphoporus) oudomxai (Brancucci & Biström, 2013) n. comb., H. (Hyphoporus) pacistanus (Guignot, 1959) n. comb., H. (Hyphoporus) pugnator (Sharp, 1890) n. comb., H. (Hyphoporus) severini (Régimbart, 1892) n. comb., H. (Hyphoporus) subaequalis (Vazirani, 1969) n. comb., H. (Hyphoporus) tonkinensis (Régimbart, 1899) n. comb.
The third instars of Coelhydrus brevicollis Sharp and Darwinhydrus solidus Sharp are described and illustrated for the first time, with detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, last abdominal segment, and urogomphi. A key for the identification of the third instars of the genera of Hyphydrini known in detail is provided. A parsimony analysis based on 49 informative larval characteristics was conducted using the program TNT. The consensus tree supports a placement of Coelhydrus Sharp and Darwinhydrus Sharp within the tribe Hyphydrini. Within the Hyphydrini, Coelhydrus is postulated to share a monophyletic origin with Hyphydrus Illiger and Desmopachria Babington. The phylogenetic placement of Darwinhydrus, however, remains contentious as our study found it part of an unresolved polytomy with Andex Sharp and Primospes Sharp.
A comprehensive higher-level phylogeny of diving beetles (Dytiscidae) based on larval characters is presented. Larval morphology and chaetotaxy of a broad range of genera and species was studied, covering all currently recognized subfamilies and tribes except for the small and geographically restricted Hydrodytinae, where the larva is unknown. The results suggest several significant conclusions with respect to the systematics of Dytiscidae including the following: monophyly of all currently recognized subfamilies, although Dytiscinae when considered in a broad context is rendered paraphyletic by Cybistrinae; currently recognized tribes are monophyletic except for Agabini, Hydroporini and Laccornellini; inter-subfamily and inter-tribe relationships generally show weak support, except for a few well supported clades; three distinct clades are recognized within Dytiscinae [Dytiscini sensu lato (i.e. including the genera Dytiscus Linnaeus and Hyderodes Hope), Hydaticini sensu lato, and Cybistrini]; and recognition of Pachydrini as a distinct tribe. Other less robust results include: Methlini sister to the rest of Hydroporinae; relative basal position of Laccornini, Hydrovatini and Laccornellini within Hydroporinae; close relationship of Agabinae and Copelatinae; Matinae nested deep within Dytiscidae, as sister to a large clade including Colymbetinae, Coptotominae, Lancetinae and Dytiscinae sensu lato; the sister-group relationship of Agabetini and Laccophilini is confirmed. The results presented here are discussed and compared with previous phylogenetic hypotheses based on different datasets, and the evolution of some significant morphological features is discussed in light of the proposed phylogeny. All suprageneric taxa are diagnosed, including illustrations of all relevant synapomorphies, and a key to separate subfamilies and tribes is presented, both in traditional (paper) format and as an online Lucid interactive identification key.
Rompindessus jenisi Balke, Bergsten & Hendrich, gen. n. et sp. n. is described from near Rompin village in West Malaysia. The new genus is characterized by the presence of an occipital line and basal pronotal striae, the presence of a thick anterior bead on clypeus and two-segmented parameres as well as by the absence of basal elytral striae, the absence of sutural line on elytron, the absence of basal epipleural transverse carina, and the absence of longitudinal elytral carina. Moreover, male pro- and mesotarsus appear stout, and distinctly dilated laterally; the pronotum is comparably long and parallel-sided and the colour of beetle conspicuous dark orange. Leiodytes kualalipis Balke, Wang, Bergsten & Hendrich, sp. n. is described from West Malaysia (Pahang) and South Vietnam (Cat Tien). It is well characterized by its large size, elongate body and the form of the median lobe. Limbodessus fijiensis (J. Balfour-Browne, 1944), comb. n. described from Fiji is a new synonym of Limbodessus curviplicatus (Zimmermann, 1927) described from Samoa.
Stygoporus oregonensis Larson & LaBonte is a little-known subterranean diving beetle, which, until recently, had not been collected since the type series was taken from a shallow well in western Oregon, USA, in 1984. Here we report the discovery of additional specimens collected from a nearby well in the Willamette Valley. Sequence data from four mitochondrial genes, wingless, and histone III place Stygoporus Larson & LaBonte in the predominantly Mediterranean subtribe Siettitiina of the Hydroporini. Morphological support for these results is discussed, and details of the collecting circumstances of the new specimens are presented. We argue that the biogeographic patterns of Nearctic Siettitiina highlight the likelihood of additional undiscovered subterranean dytiscids in North America.
Novadessus viracocha gen. n. and sp. n. is described from Peru. The genus distinctly is characterized by having the following combination: (1) a transverse occipital line absent on the head; (2) the anterior clypeal margin not modified; (3) a pair of basal pronotal striae present; (4) the basal elytral stria absent; (5) the elytral sutural stria absent; (6) the elytron without longitudinal carinae; (7) the epipleuron without a transverse carina at the humeral angle; (8) the lateral lobes of the male aedeagus two-segmented; (9) the overall habitus elongate and oval, with lateral pronotal and elytral margins discontinuous; (10) without distinct denticles along the posterior margins of the abdominal sternites; (11) the male genitalia (both median lobe and lateral lobes) bilaterally symmetrical; and (12) the metatrochanter small relative to the metafemur, approximately 0.6 × the length of the metafemur. The genus is diagnostically similar to Fontidessus Miller and Spangler and Neobidessodes Hendrich and Balke, but is superficially more similar to Liodessus Guignot. The habitus and male genitalia are illustrated, and a distribution map is provided.
Graptodytes laeticulus (SHARP, 1882) from northern Africa was treated
as a junior subjective synonym of G. varius (AUBÉ, 1838) since a long time ago. It is
here re-instated as a valid species and the differences between the two species are
illustrated and described. Both belong to a complex of species which includes also G.
ignotus (MULSANT & REY, 1861), G. fractus (SHARP, 1882), and G. kuchtae (BREIT,
1908). Some notes on the latter species and on the var. pauper (O. SCHMIDT, 1903) of
G. varius are added. Notes on Hydroporus narentinus ZIMMERMANN, 1915 (a junior
subjective synonym of G. bilineatus (STURM, 1835)) and the var. dalmatinus
ZIMMERMANN, 1932 of G. bilineatus are given. New Algerian records of G. pietrii
NORMAND, 1933 are added. Graptodytes parisii GRIDELLI, 1939 is only known from
the female holotype, which was collected 1936 in the Tassili mountain range in southeastern
Algeria. The holotype could be studied for the first time after its original
description. It shows some characters which make its attribution to any of the known
genera impossible – even the correct subtribe is unclear. Thus, it was necessary to
introduce the new genus Tassilodytes nov.gen. and to give an exhaustive redescription
of the species. Lectotypes are designated for Hydroporus kuchtae BREIT, 1908,
Hydroporus laeticulus SHARP, 1882, and Hydroporus narentinus ZIMMERMANN, 1915.
The genus Graptodytes SEIDLITZ, 1887 has still 22 members, two of them bitypic.
Remarks on specific names formed from personal names are added.
K e y w o r d s: Coleoptera, Dytiscidae, Hydroporinae, Graptodytes, Tassilodytes,
new genus, lectotype, re-instatement of rank.
The underlying mechanisms responsible for the general increase in species richness from temperate regions to the tropics remain equivocal. Many hypotheses have been proposed to explain this astonishing pattern but additional empirical studies are needed to shed light on the drivers at work. Here we reconstruct the evolutionary history of the cosmopolitan diving beetle subfamily Colymbetinae, the majority of which are found in the Northern hemisphere, hence exhibiting an inversed latitudinal diversity gradient. We reconstructed a dated phylogeny using 12 genes, to investigate the biogeographical history and diversification dynamics in the Colymbetinae. We aimed to identify the role that phylogenetic niche conservatism plays in the inversed diversification pattern seen in this group. Our results suggest that Colymbetinae originated in temperate climates, which supports the hypothesis that their distribution is the result of an ancestral adaptation to temperate environmental conditions rather than tropical origins, and that temperate niche conservatism can generate and/or maintain inverse latitudinal diversity gradients.
In recent years, several new genera have been erected in the subfamily Copelatinae, including the description of endemic taxa from Madagascar, New Guinea, South Africa, and Venezuela. Here we build upon a recent molecular phylogeny of this subfamily to investigate the phylogenetic placement of Rugosus García, 2001, a genus comprising two species from the Guiana Shield region of Venezuela. We sequenced one mitochondrial and one nuclear gene fragment of Rugosus emarginatus García, as well as a specimen of Aglymbus leprieurii Aubé from Guyana in order to reassess the phylogenetic placement of the genus in the subfamily Copelatinae. Bayesian Inference analyses unambiguously indicate that Rugosus is nested within Aglymbus Sharp, 1880. As a result, Rugosus is synonymized with Aglymbus. Based on these results and on recent collecting data, the distribution of Aglymbus now includes Guyana, Suriname, and Venezuela. High-resolution images of the holotype specimens and labels of Aglymbus emarginatus (García), new combination and Aglymbus pubis (García), new combination are provided, as well as comments on the habitat of species in the "A. leprieurii species-group" of Aglymbus.
The male genitalia of the water beetle Amarodytes duponti (Aubé, 1838) are described and illustrated. The species was collectedin small pools of rainwater on the margins of a river. A. duponti is distinguished from other species of the genus by the presence of bi-segmented parameres. This species is related to Bidessodes Régimbart, Hypodessus Guignot and Tepuidessus Spangler.
Hydrovatus onigiri Watanabe and Biström, new species is described from Japan. The new species is similar to Hydrovatus subtilis Sharp, 1882, but it is distinguishable from the latter by male antennomeres 4–6 being the broadest (rather than antennomeres 6–8), poorly developed male stridulatory apparatus, and an almost evenly curved penis apex. Hydrovatus onigiri, new species is the 20th species of the H. confertus species group, and 10th Hydrovatus Motschulsky species known from Japan.
New methods for parsimony analysis of large data sets are presented. The new methods are sectorial searches, tree-drifting, and tree-fusing. For Chase et al.'s 500-taxon data set these methods (on a 266-MHz Pentium II) find a shortest tree in less than 10 min (i.e., over 15,000 times faster than PAUP and 1000 times faster than PAUP*). Making a complete parsimony analysis requires hitting minimum length several times independently, but not necessarily all "islands" for Chase et al.'s data set, this can be done in 4 to 6 h. The new methods also perform well in other cases analyzed (which range from 170 to 854 taxa).
The long-term geological stability of aquatic habitats has been demonstrated to be a determinant in the evolution of macroinvertebrate fauna, with species in running (lotic) waters having lower dispersal abilities, smaller ranges and higher gene flow between populations than species in standing (lentic) environments. Lotic species have been hypothesized to be more specialised, but the diversification dynamics of both habitat types have not been studied in detail. Using a speciose lineage of water beetles we test here whether diversification rates are related to the habitat preference of the species and its consequences on turnover, which we expect to be higher for lotic taxa. Moreover, we tested whether life in lotic environments is acting as an evolutionary dead-end as it is considered as ecological specialisation. We built a comprehensive molecular phylogeny with 473 terminals representing 421 of the 689 known species of the tribe Hydroporini (Coleoptera, Dytiscidae), using a combination of sequences from four mitochondrial and two nuclear genes plus 69 mitogenomes obtained with NGS. We found a general pattern of gradual acceleration of diversification rate with time, with 2 to 3 significant diversification shifts. However, habitat is not the main factor driving diversification in Hydroporini based on SecSSE analyses. The most recent common ancestor of Hydroporini was reconstructed as a lotic species, with multiple shifts to lentic environments. Most frequent transitions were estimated from lentic and lotic habitats to the category “both”, followed by transitions from lotic to lentic and lentic to lotic respectively, although with very similar rates. Contrary to expectations, we found little evidence for differences in diversification dynamics between habitats, with lotic environments clearly not acting as evolutionary dead-ends in Hydroporini.
We provide the first report of the Nearctic diving beetle subfamily Coptotominae Van den Branden, 1885 for the Paleactic Region, based on † Coptotomus balticus sp. n. from Baltic amber. Coptotomus Say, 1830 is otherwise distributed with five extant species and one subspecies in the Nearctic Region. The new species is the smallest species of the genus and thus readily separated from the extant taxa.
The larvae of three species of Agabus s. str. Leach, 1817, A. bifarius (Kirby, 1837), instar III, A. disintegratus (Crotch, 1873), instars I-III, and A. falli (Zimmermann, 1934), instars I-III, are described including for the first time a detailed chaetotaxy analysis of the cephalic capsule, head appendages, legs, last abdominal segment and uro-gomphi. Larvae of A. falli show several unique morphological features that differentiate them from those of the other species of Agabini studied. A provisional parsimony analysis based on 55 lar-val characteristics of 17 species in seven genera of the subfamily Agabinae was conducted using the program TNT. As a result of this analysis, Agabini was recovered as polyphyletic while Platynectini and Hydrotrupini are deemed monophyletic.
The larvae of the Australian endemic species Megaporus gardnerii (Clark, 1862) and M. hamatus (Clark, 1862) are described and illustrated for the first time, with detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, last abdominal segment, and urogomphi. We explore implications for understanding the evolution of larval morphological traits amongst selected Sternopriscina genera. A parsimony analysis based on 84 larval characteristics of seven species in five genera was conducted using the program TNT. Larvae of Megaporus Brinck are characterized by the primary seta AB3 articulated distad of seta AB2, a very elongate siphon, and predominantly elongate and hair-like secondary setae on the urogomphi. Megaporus is postulated to be closely related phylogenetically to Chostonectes Sharp in the context of this study, which reinforces previous hypotheses based on adult and molecular data sets. These results provide a phylogenetic framework for future studies of the larvae of the Sternopriscina.
Abstract. Adephaga is the second largest suborder of beetles (Coleoptera) and they serve as important arthropod predators in both aquatic and terrestrial ecosystems. The suborder is divided into Geadephaga comprising terrestrial families and Hydradephaga for aquatic lineages. Despite numerous studies, phylogenetic relationships among the adephagan families and monophyly of the Hydradephaga itself remain in question. Here we conduct a comprehensive phylogenomic analysis of the suborder using ultraconserved elements (UCEs). This study presents the first in vitro test of a newly developed UCE probe set customized for use within Adephaga that includes both probes tailored specifically for the suborder, alongside generalized Coleoptera probes previously found to work in adephagan taxa. We assess the utility of the entire probe set, as well as comparing the tailored and generalized probes alone for reconstructing evolutionary relationships. Our analyses recovered strong support for the paraphyly of Hydradephaga with whirligig beetles (Gyrinidae) placed as sister to all other adephagan families. Geadephaga was strongly supported as monophyletic and placed
sister to a clade composed of Haliplidae + Dytiscoidea. Monophyly of Dytiscoidea was strongly supported with relationships among the dytiscoid families resolved and strongly supported. Relationships among the subfamilies of Dytiscidae were strongly supported but largely incongruent with prior phylogenetic estimates for the family. The results of our UCE probe comparison showed that tailored probes alone outperformed generalized probes alone, as well as the full combined probe set (containing both types of probes), under decreased taxon sampling. When taxon sampling was increased, the full combined probe set outperformed both tailored probes and generalized probes alone. This study provides further evidence that UCE probe sets customized for a focal group result in a greater number of recovered loci and substantially improve phylogenomic analysis.
The diving beetle genus and species, Kakadudessus tomweiri gen.n., sp.n. are described from the Northern Territory (Kakadu National Park, headwaters of Mary River) and north-eastern Queensland (Cape York Peninsula) of Australia. The new species has an elongate, almost flat habitus and elytra with pale yellowish markings. The head has a cervical line between the hindmargin of the eyes and the clypeus is anteriorly bordered. Pronotum and elytra have well developed striae, the latter without sutural lines and accessory striae. The posterior part of the basal cavity of epipleura has no transverse carina, the fairly elongate and narrow prosternal process reaches the metaventrite. The latter is provided with rows of punctures at its midline and the metacoxal lines are longer than the distance between them and strongly diverging anteriorly. The parameres are bi-segmented, very thin, slender and elongate, and slightly bifid apically. The combination of all these characters separates the new species and, thus, also the new genus from all other Bidessini. Morphologically, Kakadudessus resembles species of Leiodytes Guignot, 1936, Limbodessus Guignot, 1939 and Uvarus Guignot, 1939, the parameres resemble those of species of Allodessus Guignot, 1953. DNA sequence data from the mitochondrial genes cytochrome oxidase subunit I (cox1) and the large ribosomal subunit (16S rRNA), however, suggest that Kakadudessus does not belong to any of the known Oriental and Australasian Bidessini genera. Most importantly, recognition of Kakadudessus does not create paraphyly. All specimens were collected in small pools of shaded and intermittent streams and rivers with sandy or gravely bottom and without any vegetation.
Hamadiana chapadensis gen. n. and sp. n. is described based on a single male specimen collected in Central Brazil. The new species belongs to the diving beetle tribe Laccophilini but could not be assigned to any existing genera, therefore a new genus is described to accommodate it. Hamadiana gen. n. is unique among Laccophilini in having the hind margin of the metacoxal process deeply incised and medially slightly protruded backwards. In addition, it differs from other genera of the tribe by having the antennomeres simple, not expanded, the metacoxal lines not straight, and the metatibiae with two simple apical spurs. The habitus, male genitalia, and diagnostic features are illustrated, and a distribution map is provided. A recently published key to Laccophilini is modified to include the new genus.
The larvae of the Australian endemic species Chostonectes gigas (Boheman, 1858) and C. johnsonii (Clark, 1862) are described and illustrated for the first time, with detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. A parsimony ana- lysis based on 83 informative larval characteristics of six species in four genera of the subtribe Sternopriscina was conducted using the program TNT. The monophyletic origin of the four Sternopriscina studied was strongly supported. Members of Paroster Sharp, 1882 characterise by the presence of three labial palpomeres, a unique feature within the subfamily Hydroporinae. Larvae of Barretthydrus Lea, 1927, Antiporus Sharp, 1882 and Chostonectes Sharp, 1882 evolved the presence of natatory setae on femora, tibia and tarsi. At the moment, Chostonectes is postu- lated to be closely related phylogenetically to Antiporus in the context of this study.
A new genus, Fontidessus n. gen., and three new species F. toboganensis n. sp., F. ornatus n. sp., and F. wheeleri n. sp., are described from Venezuela. The new genus is similar to Uvarus and Bidessodes but is distinguished from all other Bidessini (including these) by a combination of the following: 1) transverse occipital line absent, 2) basal pronotal striae present, 3) basal elytral stria absent, 4) elytral sutural stria faintly present in some specimens, 5) anterior clypeal margin unmodified, 6) elytron without longitudinal carinae, 7) epipleuron without transverse carina at humeral angle, 8) lateral lobes of aedeagus two-segmented, 9) habitus elongate, oval, with lateral pronotal and elytral margins nearly continuously and shallowly curved, and 10) metatrochanter extremely large relative to metafemur, approximately 0.6 × length of metafemur.
Hydrotrupes chinensis Nilsson, 2003 described from the holotype collected in Anhui Province, China, is newly recorded from three localities in Guangdong Province, ca. 750 km southwest from the type locality. The species seems to inhabit hygropetric habitats exclusively, with diurnal larvae and nocturnal adults hidden under stones or in cracks in rock during the day; when disturbed, the adults readily jumped off the rock surface. The adult is rede-scribed. The larvae are described and illustrated for the first time, with detailed morphometric and chaetotaxic analyses of the ceph-alic capsule, head appendages, legs, last abdominal segment, and urogomphi. Whereas similar morphologically to the Nearctic endemic Hydrotrupes palpalis Sharp, 1882, the first instar larva of H. chinensis distinguishes by presence of six lamellae clypeales, two additional spine-like setae both on the last abdominal segment and urogomphomere 1, and the strongly developed egg bursters. ARTICLE HISTORY
We provide the first report of the subfamily Laccophilinae Gistel, 1848 from Baltic amber, based on a female specimen collected in Russia, Kaliningrad Region, Yantarnii (Jantarny) mine. This specimen represents a new species and could be assigned to the extant genus Japanolaccophilus Satô, 1972. To date this genus was monotypic with one species in Japan. The new species is here described as †J. beatificus sp. n. and compared with the extant Japanolaccophilus niponensis (Kamiya, 1939). We also provide a modified key to the Laccophilinae genera of the World, as we found minor errors or ambiguities in recent keys.
The beetle superfamily Dytiscoidea, placed within the suborder Adephaga, comprises six families. The phylogenetic relationships of these families, whose species are aquatic, remain highly contentious. In particular the monophyly of the geographically disjunct Aspidytidae (China and South Africa) remains unclear. Here we use a phylogenomic approach to demonstrate that Aspidytidae are indeed monophyletic, as we inferred this phylogenetic relationship from analyzing nucleotide sequence data filtered for compositional heterogeneity and from analyzing amino-acid sequence data. Our analyses suggest that Aspidytidae are the sister group of Amphizoidae, although the support for this relationship is not unequivocal. A sister group relationship of Hygrobiidae to a clade comprising Amphizoidae, Aspidytidae, and Dytiscidae is supported by analyses in which model assumptions are violated the least. In general, we find that both concatenation and the applied coalescent method are sensitive to the effect of among-species compositional heterogeneity. Four-cluster likelihood-mapping suggests that despite the substantial size of the dataset and the use of advanced analytical methods, statistical support is weak for the inferred phylogenetic placement of Hygrobiidae. These results indicate that other kinds of data (e.g. genomic meta-characters) are possibly required to resolve the above-specified persisting phylogenetic uncertainties. Our study illustrates various data-driven confounding effects in phylogenetic reconstructions and highlights the need for careful monitoring of model violations prior to phylogenomic analysis.
The subtribe Deronectina Galewski, 1994 (Dytiscidae, Hydroporinae, Hydroporini) is distributed in the Nearctic, in the north of the Neotropical region, and in the Palaearctic and Afrotropical regions. It is currently composed of 194 species and 13 subspecies in eight genera: Amurodytes Fery & Petrov, 2013, Boreonectes Angus, 2010, Deronectes Sharp, 1882, Nebrioporus Régimbart, 1906, Oreodytes Seidlitz, 1887, Scarodytes Gozis, 1914, Stictotarsus Zimmermann, 1919, and Trichonectes Guignot, 1941. We present a morphological and a molecular phylogeny of the species of the subtribe, and a revision of their taxonomy to accommodate our phylogenetic results. The morphological phylogeny is based on the study of 54 characters of the adults of 189 species and 2 subspecies, of which 114 species and the 2 subspecies were coded in the morphological matrix. For the molecular phylogeny we investigated 115 species and 11 subspecies, using a combination of fragments of four mitochondrial (COI, 16S rRNA, tRNA-Leu and NAD1) and two nuclear genes (18S rRNA and H3), analysed with maximum likelihood and Bayesian methods. For both datasets we included the type species of all genus-group taxa. The morphological, molecular and combined phylogenies mostly agree with the current classification of the group, but in some cases our results are in contradiction with established genera. Most remarkable are the polyphyly of Stictotarsus and Nebrioporus, the low support for the monophyly and internal phylogeny of Oreodytes, and the low support for the monophyly of Deronectina with molecular data. Thus, we introduce some taxonomic changes in the current classification to accommodate the generic concepts to our phylogenetic results. Nine new genera are established: Clarkhydrus n. gen. (type species Hydroporus roffii Clark, 1862), Hornectes n. gen. (type species Hydroporus quadrimaculatus Horn, 1883), Iberonectes n. gen. (type species Deronectes bertrandi Legros, 1956), Larsonectes n. gen. (type species Potamonectes minipi Larson, 1991), Leconectes n. gen. (type species Hydroporus striatellus LeConte, 1852), Mystonectes n. gen. (type species Deronectes neomexicanus Zimmerman & Smith, 1975), Nectoboreus n. gen. (type species Hydroporus aequinoctialis Clark, 1862), Nectomimus n. gen. (type species Oreodytes okulovi Lafer, 1988), and Zaitzevhydrus n. gen. (type species Hydroporus formaster Zaitzev, 1908). Three genera are reinstated as valid: Deuteronectes Guignot, 1945 (stat. rest.) (type species Hydroporus picturatus Horn, 1883), Nectoporus Guignot, 1950 (stat. rest.) (type species Hydroporus abbreviatus Fall, 1923), and Neonectes J. Balfour-Browne, 1940 (stat. rest.) (type species Hydroporus natrix Sharp, 1884). Thirty-six new combinations for species and subspecies thus far treated in the genera Boreonectes, Nebrioporus, Oreodytes and Stictotarsus result from the new classification: Clarkhydrus corvinus (Sharp, 1887) n. comb., C. decemsignatus (Clark, 1862) n. comb., C. deceptus (Fall, 1932) n. comb., C. eximius (Motschulsky, 1859) n. comb., C. falli (Nilsson, 2001) n. comb., C. interjectus (Sharp, 1882) n. comb., C. minax (Zimmerman, 1982) n. comb., C. opaculus (Sharp, 1882) n. comb., C. roffii (Clark, 1862) n. comb., C. spectabilis (Zimmerman, 1982) n. comb., Deuteronectes angustior (Hatch, 1928) n. comb., Hornectes quadrimaculatus (Horn, 1883) n. comb., Iberonectes bertrandi (Legros, 1956) n. comb., Larsonectes minipi (Larson, 1991) n. comb., Leconectes striatellus (LeConte, 1852) n. comb., Mystonectes coelamboides (Fall, 1923) n. comb., M. grammicus (Sharp, 1887) n. comb., M. neomexicanus (Zimmerman & Smith, 1975) n. comb., M. panaminti (Fall, 1923) n. comb., M. titulus (Leech, 1945) n. comb., Nectoboreus aequinoctialis (Clark, 1862) n. comb., N. dolerosus (Leech, 1945) n. comb., N. funereus (Crotch, 1873) n. comb., Nectomimus okulovi (Lafer, 1988) n. comb., Nectoporus angelinii (Fery, 2015) n. comb., N. congruus (LeConte, 1878) n. comb., N. crassulus (Fall, 1923) n. comb., N. obesus obesus (LeConte, 1866) n. comb., N. obesus cordillerensis (Larson, 1990) n. comb., N. rhyacophilus (Zimmerman, 1985) n. comb., N. sanmarkii sanmarkii (C.R. Sahlberg, 1826) n. comb., N. sanmarkii alienus (Sharp, 1873) n. comb., N. sierrae (Zimmerman, 1985) n. comb., N. subrotundus (Fall, 1923) n. comb., Zaitzevhydrus formaster formaster (Zaitzev, 1908) n. comb., and Z. formaster ulanulana (C.-K. Yang, 1996) n. comb.
Changes in morphology are often thought to be linked to changes in species diversification, which is expected to leave a signal of Early Burst (EB) in phenotypic traits. However, such signal is rarely recovered in empirical phylogenies, even for groups with well-known adaptive radiation. Using a comprehensive phylogenetic approach in Dytiscidae, which harbors ~4,300 species with as much as 50-fold variation in body size among them, we ask whether pattern of species diversification correlates with morphological evolution. Additionally, we test if the large variation in body size is linked to habitat preference and if the later influences species turnover. We found, in sharp contrast to most animal groups, that Dytiscidae body size evolution follows an Early Burst model with subsequent high phylogenetic conservatism. However, we found no evidence for associated shifts in species diversification, which point to an uncoupled evolution of morphology and species diversification. We recovered the ancestral habitat of Dytiscidae as lentic (standing water), with many transitions to lotic habitat (running water) that are concomitant to a decrease in body size. Finally, we found no evidence for difference in net diversification rates between habitats nor difference in turnover in lentic and lotic species. This result, together with recent findings in dragonflies, contrasts with some theoretical expectations of the Habitat Stability Hypothesis. Thus, a thorough reassessment of the impact of dispersal, gene flow and range size on the speciation process is needed to fully encompass the evolutionary consequences of the lentic-lotic divide for freshwater fauna.
Some species of the diving beetle tribe Hygrotini (subfamily Hydroporinae) are among the few insects able to tolerate saline concentrations more than twice that of seawater. However, the phylogenetic relationships of the species of Hygrotini, and the origin and evolution of tolerance to salinity in this lineage, are unknown. In this work, we aim to reconstruct how many times salinity tolerance did evolve in Hygrotini, whether this evolution was gradual or if tolerance to hypersalinity could evolve directly from strictly freshwater (FW) species, and to estimate the probabilities of transition between habitats. We build a phylogeny with ca. 45% of the 137 species of Hygrotini, including all major lineages and almost all of the known halophile or tolerant species. We used sequence data of four mitochondrial (COI-5′, COI-3′, 16S + tRNA and NADH1) and three nuclear (28S, 18S and H3) gene fragments, plus ecological data to reconstruct the history of the salinity tolerance using Bayesian inference. Our results demonstrate multiple origins of the tolerance to salinity, although most saline and hypersaline species were concentrated in two lineages. The evolution of salinity was gradual, with no direct transitions from FW to hypersaline habitats, but with some reversals from tolerant to FW species. The oldest transition to saline tolerance, at the base of the clade with the highest number of saline species, was dated in the late Eocene-early Oligocene, a period with decreasing temperature and precipitation. This temporal coincidence suggests a link between increased aridity and the development of tolerance to saline waters, in agreement with recent research in other groups of aquatic Coleoptera.
Among the hundreds of thousands of species of beetles, there is one family, containing some 4,300 species, that stands out as one of the most diverse and important groups of aquatic predatory insects. This is the Dytiscidae, whose species are commonly known as diving beetles. No comprehensive treatment of this group has been compiled in over 130 years, a period during which a great many changes in classification and a near quadrupling of known species has occurred. In Diving Beetles of the World, Kelly B. Miller and Johannes Bergsten provide the only full treatments of all 186 Dytiscid genera ever assembled. Entomologists, systematists, limnologists, ecologists, and others with an interest in aquatic systems or insect diversity will find these extensively illustrated keys and taxon accounts immensely helpful. The keys make it possible to identify all taxa from subfamily to genera, and each key and taxon treatment is accompanied by both photographs and detailed pen-and-ink drawings of diagnostic features. Every genus account covers body length, diagnostic characters, classification, species diversity, a review of known natural history, and world distribution. Each account is also accompanied by a range map and at least one high-resolution habitus image of a specimen. Diving beetles are fast becoming important models for aquatic ecology, world biogeography, population ecology, and animal sexual evolution and, with this book, the diversity of the group is finally accessible.
A reclassification of several species traditionally included in Rhantus Dejean, 1833 is given: Nartus Zaitzev, 1907 is reinstated as genus with one species in the Nearctic and one in the Palaearctic region; two new genera are erected: Meridiorhantus n. gen., with M. antarcticus (Germain, 1854) n. comb., M. calidus (Fabricius, 1792) n. comb., M. limbatus (Aubé, 1838) n. comb., M. orbignyi (Balke, 1992) n. comb., M. validus (Sharp, 1882) n. comb. in the Neotropical Region (M. calidus also in the southern USA and along the eastern coast as far north as New York City), and the monotypic Caperhantus n. gen., with C. cicurius (Fabricius, 1787) n. comb. in south Africa. Furthermore, nine Pacific and Australian Rhantus are transferred to the genus Carabdytes Balke, Hendrich & Wewalka, 1992: C. alutaceus (Fauvel, 1883) n. comb., C. guadalcanalensis (Balke, 1998) n. comb., C. monteithi (Balke, Wewalka, Alarie & Ribera, 2007) n. comb., C. novaecaledoniae (J. Balfour-Browne, 1944) n. comb., C. oceanicus (Balke, 1993b) n. comb., C. pacificus (Boisduval, 1835) n. comb., C. plantaris (Sharp, 1882) n. comb., C. poellerbauerae (Balke, Wewalka, Alarie & Ribera, 2007) n. comb. and C. pseudopacificus Balke, 1993b) n. comb. All changes are based on a previous comprehensive molecular phylogenetic analysis of Colymbetinae. Diagnostic characters are given for all genera mentioned above and each of them is
illustrated with one or more habitus pictures. An updated key to all genera of Colymbetinae is also given.
The evolution of a secondary terrestrial lifestyle in diving beetles (Coleoptera: Dytiscidae) has never been analysed in a phylogenetic framework before. Here we study Terradessus caecus Watts, a terrestrial species of the subfamily Hydroporinae endemic to Australia. We infer its phylogenetic placement using Bayesian inference and maximum-likelihood methods based on a multilocus molecular dataset. We also investigate the divergence time estimates of this lineage using a Bayesian relaxed clock approach. Finally, we infer ancestral ecological preferences using a likelihood approach. We recover T. caecus nested in the genus Paroster Sharp with strong support. Therefore, we establish a synonymy for both species of Terradessus with Paroster: Paroster caecus (Watts) n.comb. and Paroster anophthalmus (Brancucci & Monteith) n.comb. Paroster is an endemic Australian genus that has a remarkable number of subterranean species in underground aquifers with highly derived morphologies. Our results highlight one of the most remarkable radiations of aquatic beetles with independent ecological pathways likely linked to palaeoclimatic disruptions in the Neogene. Paroster caecus (Watts) n.comb. originated from a mid-Miocene split following the onset of an aridification episode that has been ongoing to the present day. The deep changes in ecological communities in association with the drying-out of palaeodrainage systems might have pushed this lineage to colonize a new niche in terrestrial habitats.
Crinodessus amyae n. gen. and n. sp. is described from southwestern Texas, U.S.A. The genus is separable from all other genera of Bidessini by the combination of 1) cervical line posterior of and separated from posterior margin of the eye, 2) separation of the genal line from the ventral margin of the eye broad, 3) apical segment of the paramere elongate, 4) dense microreticulation on the ventral surface consisting of minute, isodiametric cells, 5) relatively large size for members of the tribe, 6) distinctive habitus with the pronotum cordate and the body elongate and depressed, and 7) anterior clypeal margin extended anteriorly and prominently angulate. The similarity in habitus and other characters between Crinodessus and Boongurrus Larson is hypothesized to be a result of homoplasy due to similar behavior and common adaptation to a similar habitat. Liodessus Guignot is tentatively proposed to be the sister genus of Crinodessus.
The origin of biodiversity in the Neotropics predominantly stems either from Gondwana breakup or late dispersal events from the Nearctic region. Here, we investigate the biogeography of a diving beetle clade whose distribution encompasses parts of the Oriental region, the Indo-Australian archipelago (IAA) and the Neotropics. We reconstructed a dated molecular phylogeny, inferred diversification dynamics and estimated ancestral areas under different biogeographic assumptions. For the Oriental region and the IAA, we reveal repeated and complex colonization patterns out of Australia, across the major biogeographic lines in the region (e.g. Wallace's Line). The timing of colonization events across the IAA broadly coincides with the proposed timing of the formation of major geographic features in the region. Our phylogenetic hypothesis recovers Neotropical species nested in two derived clades. We recover an origin of the group in the early Eocene about 55 million years ago, long after the break-up of Gondwana initiated, but before a complete separation of Australia, Antarctica and the Neotropics. When allowing an old Gondwanan ancestor, we reconstruct an intricate pattern of Gondwanan vicariance and trans-Pacific long-distance dispersal from Australia toward the Neotropics. When restricting the ancestral range to more plausible geological area combinations in the Eocene, we infer an Australian origin with two trans-Pacific long-distance dispersal events toward the Neotropics. Our results support on one hand a potential Gondwanan signature associated with regional extinctions in the Cenozoic and with Antarctica serving as a link between Australia and the Neotropics. On the other hand, they also support a trans-Pacific dispersal of these beetles toward the Andean coast in the Oligocene. This article is protected by copyright. All rights reserved.