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A new genus and species of subterranean diving beetle from Laos (Coleoptera, Dytiscidae, Hydroporinae, Hydroporini)


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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.
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A new genus and species of subterranean diving beetle from Laos
(Coleoptera, Dytiscidae, Hydroporinae, Hydroporini)
Pierre Queney1, Jean-Michel Lemaire2 & Marina Ferrand3
1 10 rue Descartes, F – 92190 Meudon, France <>
2 Attaché scientique au Muséum d’Histoire naturelle de Nice, 2162 chemin du Destey, F – 06390 Contes, France
3 27 avenue Louis Pasteur, F – 92220 Bagneux, France <>
(Accepté le 28.X.2020 ; publié le 10.XII.2020)
Abstract. – The rst 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 dened 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 déni, sans qu’il soit possible, à ce stade, de le rattacher
à l’une des sous-tribus actuellement reconnues.
Keywords. – Stygobiontic, speleology, oriental region, aquatic beetle.
During a speleological expedition to Laos, which took place in March 2019, the third author
(MF) collected three specimens of a small diving beetle in a cave of the Pha Lay mountain
range, near Kasi. Since this was the dry season, she was able to progress in this cave along several
fossil levels (g. 1) for more than 2 km under the range. At the intersection with a muddy sys-
tem of galleries, she reached a more humid lower oor, climbing down a block chaos followed
by a calcite ow; there, water from the last oods remained in residual pools and even ew
along a small channel. The calcite ow was darkened by guano deposits: although no bats
were seen during the visit, they should rest at times in the overhanging fault crack on in the
ceiling. The beetles were found swimming in one of the pools (g. 2). More recently, during
an expedition in March 2020 to the same cave, eight more specimens were found in the lower
fossil level (g. 17). There also, a little water was owing along calcite cascades, coming from
the upper level where a lake stands.
Subterranean genera of beetles are rather numerous in Dytiscidae, and the recent book
of miLLer & Bergsten (2016) has cleared up their classication. However, convergences in
morpho logy due to stygobiontic life are so prominent that determination keys cannot avoid
calling upon geographic distribution. Most of the discovered Dytiscidae belong to Hydroporinae
and the Laotian species is no exception. Nonetheless, a few Copelatinae are also stygobiontic,
in particular Exocelina sugayai Balke & Ribera, 2020, recently described from the Malay
Peninsula (BaLke & riBera, 2020). In the Oriental region, a few Bidessini and Hyphydrini
are known, and also the genus Siamoporus Spangler, 1996, placed among Hydroporini by its
Bulletin de la Société entomologique de France, 125 (4), 2020 : 407-416. ISSN 0037-928X eISSN 2540-2641
author, but considered as incertae sedis in this tribe, and possibly in Hydroporinae as a whole
(miLLer & Bergsten, 2016 : 152).
The morphological features of our specimens have been compared with those of all
known genera of Dytiscidae. A detailed analysis is given below. It appears that they do not
properly t in any known genus. Therefore, a new taxon is described below as Laodytes lapiei
n. gen., n. sp.
Material and Methods
The rst three specimens were collected by hand and immediately put in an Eppendorf
vial containing 70° ethanol. Back in France, MF sent the beetles to the second author (JML)
for study, together with pictures she had taken of them in the preserving uid. One picture
(g. 3) shows the long sensory hairs surrounding the body, which unfortunately did not with-
stood the dry mounting.
With miLLer & Bergsten (2016) at hand, JML recognized that those diving beetles, two
males and one female, did not appear to t any species mentioned in this book; he therefore
asked the rst author (PQ) to lend a helping hand. PQ succeeded in extracting the genitalia of
one male. Given its tiny size (0.2 mm), we decided to mount it on a glass slide in DMHF resin;
we thus could obtain a clear view of the organ (g. 14), at the cost of some attening by the
coverslip. Later, with eight more specimens available, JML mounted another male genitalia
in a drop of mounting media DMHF without coverslip, to obtain more natural views of the
organ (g. 15-16). These pictures were taken with an Olympus™ TG4 camera, adapted to an
Olympus CX21 optical microscope through a LM-Scope™ adapter. High-resolution pictures
of the external morphology (g. 4-12) have been kindly taken by Michel Perreau on a Keyence™
VHX5000 microscope equipped with a VH-Z250T camera lens. The lateral view (g. 13) was
obtained with a Toupcam™ 14 Mp CMOS camera mounted on an Olympus™ SZX9 stereo-
microscope, from several shots assembled with HeliconFocus™ v.7.6.
Fig. 1. – View of the Tham Pha cave.
Queney et al.Un nouveau Dytiscidae souterrain du Laos
Laodytes n. gen.
Type species: Laodytes lapiei n. sp.
Diagnosis. – The new genus is distinguished by the following combination of characters:
Body very small (< 1.5 mm), broad, parallel-sided; dorsal and ventral surfaces mainly reticulate
and matt. Head wide, encased between strongly protruding pronotal angles. Second anten-
nomere conspicuously wider than the rst, the middle ones ovoid, the last one elongated and
tapered. Pronotum transverse, without a lateral longitudinal stria on each side, its lateral edges
in continuity with those of fused elytra. Prosternal process lanceolate, with apex not reaching
metaventral process. Metacoxal lines absent; interlaminary bridge of metacoxae broadly exposed;
hind margin obtusely emarginate medially, lateral lobes incised and not rounded. Ventrites
(visible sternites) 2 and 3 fused. Fore and mid legs rather thick, hind legs slender. Sucker cups
on male pro- and mesotarsus absent. Median lobe of aedeagus gutter-like, nearly symmetrical
in sagittal view, and almost straight beyond the basal bend in lateral view; apex rounded; para-
meres symmetrical, single segmented, slightly longer that the median lobe, each lobe in the
shape of an elongated triangle, narrowly tapered with a single bristle at tip.
Etymology. – A combination of Lao, the name of the people and language of Laos, and dytes (δύτης),
diver in Greek.
Laodytes lapiei n. sp.
Holotype: ♂, grotte Tham Pha, Ban Phato, Laos, alt. 460 m, 19.III.2020, Marina Ferrand
leg., deposited in Muséum national d’Histoire naturelle, Paris.
ParatyPes: 4 ♂, 3 ♀, same data; 2 ♂, 1 ♀, same locality, 18.III.2019, Marina Ferrand leg., in coll.
P. Queney and J.-M. Lemaire.
Type locality. – Laos, district of Kasi, province of Vientiane: cave Tham Pha, near Ban
Phato, 17 km SW to Kasi, 19.13204°N 102.12079°E, altitude 460 m.
Description of male. – Habitus (g. 4-5): body length 1.35 mm, maximum width 0.62 mm; species
blind and depigmented, uniformly pale orange; body stocky, parallel-sided, weakly convex in lateral
view; in dorsal view, lateral outline showing an almost perfect continuity between pronotum and elytra.
Head (g. 6-7) wide, front margin semicircular, very deeply inserted in pronotum. Eyes totally
absent; clypeal suture reduced to a short depression on the sides. Surface glabrous, with an isodiametral
reticulation, forming a rather regular hexagonal lattice, strong on frons but vanishing on clypeus and
sides. Antennae with a cylindrical scape and a thicker and swollen pedicel (g. 6-7), middle segments
globular (g. 4-5), segments 6-10 slightly thicker than 3-5, apical segment elongate and conical in the
distal half; clypeus slightly and shortly rimmed above antennae. Maxillary palpi four-segmented, with
the last segment 2.5 times longer than wide, ovoid basally and acuminated at tip. Ligula triangular and
acute, labial palpi three-segmented, the last segment twice longer than wide (g. 7).
Pronotum (g. 6) not cordiform but widely rectangular, almost parallel-sided seen from above, but
strongly sinuated in lateral view: edge strongly concave bottomwards, in the basal third, then slightly
concave upwards to the front angles; almost as wide as elytra and strongly wider than the head, with
protruding front angles encasing the head to the basal third; front margin straight along the posterior part
of head; base V-shaped in the middle, sinuated towards right posterior angles; sides with a rimmed gutter,
the anterior two-thirds of which contain 6-7 setigerous punctures, provided with deciduous sensory bristles; in
lateral view (g. 13), the side edge sinuated and not in continuity with the elytral edge. Surface strongly
reticulated as on hind part of head, the meshes polygonal but a little wider, reticulation vanishing on
sides; the posterior margin showing a short and faint notch near the external third, followed externally by
Bulletin de la Société entomologique de France, 125 (4), 2020 : 407-416
Fig 2-5. – Laodytes lapiei n. gen., n. sp. – 2, Specimen alive, in situ. – 3, Specimen in preserving uid. 4-5, Habitus,
male: 4, dorsal view; 5, ventral view.
Queney et al.Un nouveau Dytiscidae souterrain du Laos
Fig. 6-12. – Laodytes lapiei n. gen., n. sp., ♂. – 6, Head and pronotum, dorsal view. – 7, Head, ventral view. – 8, Pro-
sternal process. – 9, Metaventrite and metacoxae. – 10, Metacoxal process. – 11, Protarsus. – 12, Metatarsus.
Bulletin de la Société entomologique de France, 125 (4), 2020 : 407-416
shorter and weaker creases; small punctures distributed
along an irregular row along the front margin, other
smaller punctures scattered on the disk. Pronotum
and elytra seem welded together.
Elytra (g. 4) 1.45 times as long as wide
together and fused, sides almost parallel on basal
third, then regularly narrowing into a semi-circular
apex when seen from above; basal surface reticu-
lated, with larger meshes than on the pronotum;
on the disk, those meshes turning into small round
cavities, getting longer than wide and then fading
apically; a vestigial sutural stria visible on the distal half; about 25 pores, provided with long sensory bristles,
distributed along the lateral edges. Hind wings absent.
Ventral surface (g. 5) uniformly pale, like the dorsal surface, and largely reticulate; prosternal
process (g. 8) lanceolate with acuminate apex not reaching anteromedial metaventral process (g. 9);
epipleuron getting regularly narrower to the metacoxae level, without oblique carina near shoulder; metepi-
sternum in right triangle, about twice longer than wide; metaventral wings very narrow; metacoxal lines
absent (g. 9): only a attened raised plate visible on each side of the median groove; metacoxal process
(g. 10) with median part extended backwards; hind margin obtusely emarginate medially, with each side
obliquely cut and both margins converging forward; lateral lobes not rounded, deeply incised and at;
disk of metacoxae reticulated; metacoxal process with median part extended backwards slightly above
the abdomen; the latter with ve visible ventrites, the second and third, usually distinct in Dytiscidae, being
fused; reticulation isodiametral on the anterior part of this second ventrite, transverse on its posterior part
and on the next two ventrites, isodiametral on the last.
Legs. Pro- and mesotarsi four-segmented, rather wide, pro- and mesotibiae short and dilated on
the distal half (g. 5), pro- and mesotarsomeres 1-2 with adhesive setae but without distinct sucker
cups (g. 11), hind legs thinner with oblong femora and large oval hind trochanters (g. 10); mesotibiae
densely adorned with spiny setae; metatrochanters reticulated with transversely elongated meshes; meta-
tarsal claws of subequal length (g. 12).
Aedeagus (Figs. 14–16): as described in the genus diagnosis.
Fig. 13. – Laodytes lapiei n. gen., n. sp., habitus, right
lateral view.
Fig. 14-16. – Laodytes lapiei n. gen., n. sp., aedeagus. – 14, Ventral view (slide with coverslip). – 15, Oblique view
(with genital segment). – 16, Lateral view.
Queney et al.Un nouveau Dytiscidae souterrain du Laos
Female. – External sexual dimorphism limited to the protarsi, thinner than those of the male and
without visible adhesive setae.
Etymology. – We dedicate the new species to Guillaume Lapie, biospeleologist and team partner of
the discoverer. The specic epithet is a substantive in the genitive case.
Habitat. – Stygobiontic, found swimming in calcite pools.
Distribution. – So far, only known from the type locality in Laos.
Following miLLer & Bergsten (2016) and the presentation given by Fery & riBera (2018),
the new taxon clearly belongs to Hydroporinae, in view of the following characteristic features:
– scutellum invisible;
– anteromedial part of prosternum not on the same plane as its process;
– pro- and mesotarsi with four visible segments;
– metatarsomeres with distal margins not lobed.
Fig. 17. – Topography of the Tham Pha cave (© EEGC 2020).
Bulletin de la Société entomologique de France, 125 (4), 2020 : 407-416
Table I. – Comparison of Sinodytes hubbardi Spangler, 1996, and Laodytes lapiei n. gen., n. sp. Main differences
noted from sPangLer (1996) and present description.
Laodytes lapiei Sinodytes hubbardi
– total length 1.35 mm 1.68 mm
– maximum width 0.62 mm 0.72 mm
– total length/ maximum width 2.17 2.33
Outline of the body angle between pronotum and
elytron sides inconspicuous
angle between pronotum and
elytron sides very notable
Dorsal surface
– head
width/ height: 2.02
head height/pronotum height: 0.86
discal area reticulate
width/ height: 1.57
head height/pronotum height: 1.15
discal area punctured
– pronotum
sides parallel;
protruding front angles encasing
higher and straighter the head;
base V-shaped in the middle but
very rounded
strongly reticulate with small
punctures scattered on the disk
sides converging towards the base;
protruding front angles little
encasing the head;
base V-shaped and angular in the
disk reticulate and coarsely
– elytra
sides not parallel and narrowing
downwards fairly regularly
basal surface reticulate, on the
disk meshes turning into small
round cavities
sides parallel then strongly
rounded downwards
coarsely punctured
antennomere II very big and
nearly twice longer than III;
antennomeres II-X short and
antennomere II only 1.33 longer
than III; antennomeres II- X
long and not ovoid-shaped
Maxillary palps last segment elongated last segment dilated
Ventral surface
– labium gula and gena narrow in height gula and gena wide in height
– prosternal process
lanceolate with acuminate apex
behind mesocoxae
ending in an acute apex but
widening in a curve behind
– metacoxal plates a attened raised area visible on
each side of the median groove
no raised area visible in the middle
– metepisternum very wide narrow
– metaventral wing very narrow narrow
– metaventrite
suture between metaventrite and
metacoxae broadly rounded
suture between metaventrite and
metacoxae angular medially
– last ventrite regularly rounded pointed in shape
– metatrochanter ovoid-shaped slightly pointed in shape
Queney et al.Un nouveau Dytiscidae souterrain du Laos
Within Hydroporinae, the following combination of characters rules out all other tribes
than Hydroporini:
– pronotum and elytra without a pair of basal striae (or plicae);
– metepisternum reaching mesocoxal cavities;
– metafemur along the dorsal margin broadly separated from the metacoxal lobe by meta-
– metatarsal claws subequal in length;
– medial portion of metacoxae in a different plane from the base of abdomen;
– parameres of aedeagus single-segmented.
Assigning the new taxon to one of the presently admitted subtribes of Hydroporini,
Hydro porina, Siettitiina and Deronectina, is not obvious. After taking into account the key of
miLLer & Bergsten (2016) and the arguments of Fery & riBera (2018), we were unable to
conclude to which subtribe the new genus should be attached. We encountered difculties that
other subterranean genera have already met in the past. The closest case to the new genus is
probably that of Siamoporus Spangler, 1996, from Thailand, currently considered as incertae
sedis (miLLer & Bergsten, 2016 : 152) among Hydroporinae.
Indeed, Siamoporus shows some similarities with the new species: male pro- and meso-
tarsi four-segmented, pro- and mesotarsomeres 1-2 with adhesive setae but without distinct
sucker cups, metacoxal process medially emarginate and strongly incised posterolaterally for
reception of metatrochanter, the latter large, elongate and inated, ventrites (visible sternites)
2 and 3 fused; on the other hand, the Laotian insect differs from Siamoporus in many ways:
pronotum not cordiform but rectangular, elytra fused, metacoxal lines absent, aedeagus very
Another case of incertae sedis genus is Sinodytes Spangler, 1996. It was described on a
single female, which seems to be lost (miLLer & Bergsten, 2016 : 253), and was provisionally
assigned to Bidessini by its author. The Laotian species cannot belong to this tribe because of
its non-segmented parameres, but one must acknowledge that it bears a strong similarity of
habitus with Sinodytes hubbardi Spangler, 1996, at least on the basis of the only known repre-
sentation of this species (sPangLer, 1996: g. 39-40).
If Spangler’s drawing is accurate, the outline of the body, and proportions of the head and
prothorax are so different that the Laotian species cannot be the same as Sinodytes hubbardi. We
detail in table I the main differences we noted in the comparison of the two species. Nevertheless,
although many features in Spangler’s description seem to differ from ours, the assignment
of our species to Sinodytes remains plausible and supported by biogeography. However, this
would imply redening the genus Sinodytes and in particular moving it away from Bidessini.
In the absence of a male specimen and even of the holotype, we feel more appropriate to create
the new genus Laodytes on the Laotian specimens, keeping in mind that the discovery of a
male from Jiazhai Taiping cave may lead to synonymizing Laodytes with Sinodytes, or not !
acknowLedgements. The authors congratulate the caving association EEGC (Études et Explorations des
Gouffres et des Carrières) for having organized the so-called Phouhin Namno expeditions in the Kasi area since 2010,
which led to the discovery of several cave-dwelling animals new to Science. Pictures inside the Tham Pha cave were
taken by François Lallier. We warmly thank our colleague and friend Michel Perreau for the high denition focus
stacked pictures of a male paratype.
BaLke m. & riBera i., 2020. A subterranean species of Exocelina diving beetle from the Malay Peninsula
lling a 4,000 km distribution gap between Melanesia and southern China. Subterranean Biology,
34 : 25-37.
Bulletin de la Société entomologique de France, 125 (4), 2020 : 407-416
Fery H. & riBera i., 2018. – Phylogeny and taxonomic revision of Deronectina Galewski, 1994 (Coleo-
ptera: Dytiscidae: Hydroporinae: Hydroporini). Zootaxa, 4474 (1) : 1-104.
miLLer k. B. & Bergsten J., 2016.Diving Beetles of the World: Systematics and Biology of the Dytiscidae.
Baltimore : Johns Hopkins University Press, 320 p.
sPangLer P. J., 1996. Four new stygobiontic beetles (Coleoptera: Dytiscidae; Noteridae; Elmidae).
Insecta Mundi, 10 : 241-259.
Queney et al.Un nouveau Dytiscidae souterrain du Laos
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.
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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.
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.
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.
Four new species and three new genera of stygobiontic beetles are described: Dytiscidae: Siamoporus deharvengi, new genus, new species from Thailand; Sinodytes hubbardi, new genus, new species, hom China; Noteridae: Speonotenus bedosae, new genus, new species, from Indonesia; Elmidae: Neoelmis sketi, new species, from Ecuador. All of the taxa were collected from aquatic habitats in caves and bring the total known stygobiontic beetles to 23 species, 1 subspecies, and 20 genera, in 5 families. A list of the described stygobiontic beetles is included. Line drawings and/or micrographs illustrate the taxa and a map shows the type localities.
  • P J Spangler
sPangLer P. J., 1996. -Four new stygobiontic beetles (Coleoptera: Dytiscidae; Noteridae;