Elmomorphus Sharp 1888
Creators: name: Selnekovič, Dávid
name: Jäch, Manfred A.
name: Kodada, Ján
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Dryopidae
Elmomorphus

description: Elmomorphus Sharp, 1888
Elmomorphus Sharp, 1888: 242–243 (type species: E. brevicornis Sharp, 1888, fixed by monotypy).
Dryopidius Grouvelle, 1896: 33 (type species: D. castaneus Grouvelle, 1896, fixed by subsequent designation (Kodada & Jäch 2006a: 61); synonymised by Hinton (1935: 170)).
Elmomorphus subgenus Elmomorphellus Chujô & Satô, 1964: 193 (type species: E. sarawakensis Chujô & Satô, 1964, fixed by monotypy; synonymised by Kodada et al. (2003)).
Elmomorphus – Zaitzev 1910: 19. — Hinton 1935: 170. — Bollow 1940: 59. — Jäch 1984: 313.
Type species
Elmomorphus brevicornis Sharp, 1888, fixed by monotypy.
Differential diagnosis
Elmomorphus is characterised by short, densely setose antennae with moderately enlarged pedicel (Figs 1A, 2A); antennomeres moderately produced mediad and gradually narrowed from the fourth to the terminal antennomere (Figs 1A, D, F, 2A–B); the mesofemur possesses a row of long setae (Fig. 4D); the lateral sensory area on the terminal maxillary palpomere is well delimited, but not located in a depression (Fig. 2F); the microplastron consists of flat oval scales on the dorsal surface (Fig. 4B), and of thin flattened setae on the ventral surface (Fig. 4C); macroplastron absent.
Several Elmomorphus species may resemble Stenomystax Kodada, Jäch, Čiampor, 2003 in the body form, in the sparsely setose dorsal surface, and the similar distribution of the microplastron. However, the latter genus lacks the row of long setae on the mesofemur, the pedicel is enormously enlarged and nearly as long as all following segments combined, the lateral sensory area on the terminal maxillary palpomere is placed in a distinct depression, and the dorsal microplastron consists of long thin flattened setae (see Kodada et al. 2003).
Redescription
Body form variously oblong-ovate to broadly oval, moderately to strongly convex dorsally, length without head (TL) 2.2–4.5 mm. Colouration of most species dark brown to black, except for usually paler reddish-brown mouthparts, antennae, trochanters, and tarsi. Immature specimens paler, sometimes entirely reddish-brown; pronotum and elytra in some species with weak metallic bronze lustre. Punctation consists of round setiferous, variously sized and dense punctures; surface between punctures smooth or microreticulate with irregular polygonal meshes, transverse lines, or minute round dimples; some species with flat ellipsoid microgranules located near edge of punctures. Pubescence uniform, without distinct patterns, consisting of thin, whitish or yellowish hair-like setae. Males of some species with clusters of conspicuous, long and erect setae on labrum, prosternal process, median part of metaventrite, and fifth ventrite. Microplastron consisting of flat oval scales on dorsal surface (Fig. 4B), and long thin flattened setae on ventral surface (Fig. 4C).
Head (Fig. 1) hypognathous, moderately retracted into prothorax, occipital region microreticulate, postoccipital region smooth. Cranium with round setiferous punctures (Fig. 1A); interstices smooth or microreticulate; microplastron present in varying extent or absent; microgranules present or absent. Anterior margin of frontoclypeus straight to weakly emarginate, with row of short, densely arranged setae (Fig. 1A); anterolateral angles rectangular; frontoclypeal suture absent. Eye large, oval, and moderately protuberant, interfacetal setae short (Fig. 1A). Antennal insertion concealed dorsally by margin of antennal fossa (Fig. 1A). Subantennal groove deep, reaching to about midlength of eye (Fig. 1D, F). Foramen occipitale large, shallowly emarginate dorsomedially, divided by narrow tentorial bridge. Anterior and posterior tentorial arms slightly invaginated, with two flat dorsal arms arising from anterior arms before connection with tentorial bridge. Cervical sclerite large; gula short, wider than long, microreticulate, not in the same plane as mentum; gular sutures convergent, straight (Fig. 1F). Submentum short, wider than long, microreticulate, separated from gula by distinct transverse groove corresponding to endocarina (Fig. 1D, F).
Labrum wider than long (Fig. 1B), concealed by clypeus; anterior margin straight or shallowly emarginate in middle; anterolateral angles rounded; dorsal surface with small round setiferous punctures; exposed part microreticulate; setae oriented anteromedially, gradually increasing in length anterolaterally; males in some species with transverse row of conspicuous, long and erect setae. Lateral tormal process narrow, inclined mesally; posteromedian process absent. Epipharynx with short anteromedian squamose setae (Fig. 1C, E), two admedian subapical groups of flat papillae, mesally oriented, thin setae (Fig. 1C, G), and with two dense clusters of medially oriented setae in basal half (Fig. 1C).
Antennae short, pectinate, densely setose (Figs 1A, D, F, 2A–B), 9- to 11-segmented, scapus longest, with transverse constriction dividing scapus into smaller basal and larger apical part (visible only when the antenna is detached); pedicel wider than long, moderately produced and rounded posterolaterally; antennomere 3 small, slightly longer than wide, expanded apically; following antennomeres wider than long, produced medially, each antennomere slightly narrower than preceding one; scapus and pedicel with sensilla chaetica, each following segment with numerous sensilla chaetica and two stout sensilla basiconica, and several bifurcated sensilla.
Mandible with four teeth apically (Fig. 2D–E), two of these teeth overlap in vertical axis and are therefore difficult to spot in dorsal view; exposed dorsolateral parts microreticulate and setose, separated by carinae. Mola short and slightly asymmetrical, without denticles (Fig. 2D). Prostheca well developed (Fig. 2E), broad, apically rounded, with densely arranged, hair-like setae along medial margin, and short conical sensilla dorsoapically.
Maxilla cardo microreticulate distally (Fig. 2G); basistipes triangular, microreticulate or smooth; mediostipes and palpifer with hair-like and short basiconical sensilla. Basigalea short (Fig. 2G–H), separated from other sclerites by distinct sutures; with row of thick hair-like sensilla along medial margin and thin hair-like sensilla medioventrally. Distigalea flattened (Fig. 2G–H), expanded apically, with transverse rows of dense flat, medially curved sensilla on entire dorsal surface and in apical part of ventral surface, sensilla gradually decreasing in length medially. Lacinia narrow (Fig. 2G–H), pointed apically, with rows of long hair-like sensilla along mesal edge. Maxillary palpus about as long as maxilla (Fig. 2G–H), 4-segmented, palpomeres microreticulate; palpomere 1 short; palpomere 2 ca twice as long as wide, expanded apically; palpomere 3 slightly shorter than preceding ones; palpomere 4 long, fusiform, slightly longer than all preceding segments combined; palpomeres 1–3 with several hair-like sensilla laterally. Palpomere 4 with sensory areas: 1) lateral sensory area consisting of short sensilla arising from deep wide pits (Fig. 2F); 2) apical sensory area consisting of short basiconical sensilla and two elongate oval areas separated by ridge (Fig. 2I); 3) basal sensory area consisting of large flat sensilla with rounded apices (Fig. 2J); additional short basiconical sensilla scattered on basal and apical parts.
Mentum (Fig. 3A) ca 3.0 × as wide as long, microreticulate, with hair-like sensilla; anterior and posterior margin broadly emarginate; lateral margins rounded; anterolateral angles protruding, rounded; mental apodemes short, stout, curved medially. Submentum and mentum flat, prementum inclined dorsally. Palpigers partly concealed by mentum, fused mesally (Fig. 3B). Labial palpus short (Fig. 3B), 3-segmented; palpomere 1 short; palpomere 2 ca twice as long as wide, expanded apically, curved medially; palpomere 3 broad, fusiform; palpomeres 1–2 with long hair-like apical sensilla; palpomere 3 with short basiconical sensilla apically (Fig. 3D) and peg-like sensilla basally. Ligula strongly sclerotised mesally, weakly sclerotised anterolaterally; surface with several hair-like sensilla mesally and row of stout, apically rounded, basiconical sensilla anteriorly (Fig. 3B–C). Hypopharynx with various groups of sensilla; adoral surface with short L-shaped sclerite on each side.
Pronotum transverse, widest at base (Fig. 3E); disc slightly to strongly convex; with round setiferous punctures, smooth or microreticulate, with minute round dimples; microgranules present or absent; setae short, thin, decumbent; microplastron usually present, rarely completely absent; anterior angles deflexed, strongly protruding, acute; posterior angles acute; anterior margin concave, marginal bead broad, often interrupted in middle; posterior margin trisinuate; lateral sides convergent, straight to broadly rounded, sometimes slightly concave near anterior angles, lateral bead complete and narrow. Hypomeron slightly wider than profemur, punctate, covered with microplastron. Prosternum in front of coxae slightly longer than prosternal process (Fig. 3F); surface with microplastron, except for anterior narrow triangular area in some species. Prosternal process wider than long (Fig. 3F), expanded posteriorly; lateral edges divergent, straight to rounded, apical margin rounded or broadly V-shaped; lateral margins often raised, median keel often present; males of some species possess a cluster of long erect setae anterolaterally; microplastron present or absent. Procoxal cavities open posteriorly; trochantin large, strongly sclerotised (Fig. 3F). Mesonotum short, transverse, microreticulate, punctate; scutellar shield abruptly elevated, small, subtriangular; surface smooth or microreticulate, with small sparse setiferous punctures; microplastron absent. Mesoventrite short, with deep cavity for reception of prosternal process, laterally separated from oblique procoxal rests by strongly raised, semicircular carinae protruding near anterior margin. Mesanepisternum large, trapezoidal, with strongly raised oblique carina separating exposed parts from those covered by prosternum; surface with microplastron. Mesepimeron narrow, transverse, covered with microplastron; mesocoxal cavities oval. Metanotum weakly sclerotised, with distinctly separated sclerites. Metaventrite large (Fig. 3G), distinctly longer than prosternum in front of procoxae; lateral parts with microplastron; disc lacking microplastron, convex, flat or depressed, in males of several species with two clusters of long semierect setae (Fig. 3G). Metaventral discrimen present, rather indistinct, forming longitudinal keel in some species; metakatepisternal suture complete, separating laterally narrowed metakatepisterna; metaventral process as wide as prosternal process, lateral margins often raised. Metanepisternum narrow, trapezoidal exposed part covered with microplastron, separated laterally by longitudinal carina. Metanepimerite small, trapezoidal, concealed by elytral epipleuron. Metacoxal cavities large, transverse, oblique.
Elytra ovate to broadly-ovate, moderately to strongly convex; lateral margins variously arched to nearly subparallel; humeral protuberances indistinct; apices acute. Surface microreticulate or smooth, round setiferous punctures scattered over entire surface and large punctures arranged in nine longitudinal rows (striae). Striae variously evolved or absent; microgranules present or absent; microplastron usually present, absent only in a few species; epipleura narrow, covered with microplastron; oval stridulatory ventral area located near elytral base (Fig. 4A).
Hind wing well developed, ca twice as long as elytra (Fig. 5A); subcosta posterior (ScP) subparallel with anterior margin and radial bar; radial bar strong; radial cell incomplete, radial cross vein r4 distinct; radius posterior (RP) reduced basally; cross vein rp-mp2 distinct; media posterior (MP 1+2) distinct; medial spur short; MP 1+2 and MP 3+4 connected by cross-vein; first cubito-anal cell present; second cubito-anal cell absent; medial field with five veins almost reaching margin: MP 3, MP 4, CuA 2, AA 3, AA 4 (according to Lawrence et al. 2011); anal field with single distinct vein AP 3+4; apical field with two pigmented strips interrupted in the middle.
Legs long and strong. Procoxa transverse, trapezoidal, expanded basally; mesocoxa subglobular, with small ventral protuberance near trochanter attachment; metacoxa large, transverse, expanded medially, excavate posteriorly for reception of metafemur. Trochanter prominent, with oblique femoral attachment. Femora all clavate, widest around middle, excavate distally for reception of tibia; surface microreticulate, with small, sparse setiferous punctures; mesofemur dorsally with longitudinal row of long semierect setae (Fig. 4D). Tibiae slightly widened apically, nearly straight or more or less curved medially, with minute sparse setiferous punctures, and with densely arranged short setae on mesal face along apical half (Fig. 4F); tibial spurs short. Males in some species with apically expanded meso- or metatibia, or with metatibia bearing a tooth on the mesal face. Tarsal formula 5/5/5; tarsus shorter than tibia; tarsomeres 1–4 short, subequal in length; tarsomere 5 at least as long as the three preceding segments combined. Claws long (Fig. 4E), large, strongly curved, foreclaws in males of several species shortened and dorsoventrally expanded; empodium with two conspicuous setae.
Abdomen with five ventrites (Fig. 4G); lateral margins of ventrites feebly arched; all ventrites covered with microplastron, which may be absent in median parts of ventrites 1, 2 and 5; ventrite 1 usually with two longitudinal admedian keels, intercoxal process rounded. Apex of male ventrite 5 rounded, excised or emarginate (Fig. 4H), in some species with clusters of long setae (Fig. 4J). Female ventrite 5 rounded at apex, usually with short narrow longitudinal keel (Fig. 4I). Most tergites weakly sclerotised; tergite VIII membranous medially. Sternite VIII in both sexes sclerotised laterally, membranous medially; in males with short strut on anterior edge (Fig. 5B); in females, strut almost as long as abdomen (Fig. 5D). Sternite IX in males clavate, strongly sclerotised laterally, strut long (Fig. 5C); in females forming part of the ovipositor. Phallobase tubular, expanded proximally; partly overlapping parameres; with basal opening on left side. Parameres long, curved ventrad, narrowed apically, bearing scattered short sensilla. Median lobe shorter than parameres, apex narrowly rounded in ventral aspect; basal apophyses short; ventral sac without spines; sclerotised fibula absent or present, varying in size. Each of the two testes consists of three tubular follicles in peritoneal membrane; vas deferens relatively short; glandulae accessoriae large; ductus ejaculatorius covered by muscle tissue. Bursa copulatrix often with microspines. Spermatheca tubular, accessory gland large. Ovipositor long (Fig. 5E), strongly sclerotised; valvifers fused medially, expanded distally, up to 4.0 × as long as right coxite; coxites flattened laterally, acute apically, right one ca 1.30 × as long as left one, bearing scattered short sensilla. Six ovarioles on each side joined to lateral oviducts connecting to oviductus communis.
Secondary sexual dimorphism
Males of several species possess clusters of conspicuous semierect setae on the labrum, prosternal process, metaventrite, and near the apex of the fifth ventrite (Fig. 3G). Metaventral disc often depressed in males. Male mesotibiae in some species abruptly expanded in the distal half (Fig. 72); metatibiae of some species with a more or less prominent subapical tooth on the mesal face (Figs 68, 70, 72). Male ventrite 5 in some species with transverse depression and apical convexity.
Females lack long setae on the labrum, prosternal process and metaventrite; tibiae simple; ventrite 5 often with a short longitudinal subapical keel (Fig. 4I) and posterior margin excised in some species.
Immature stages
The larva of E. brevicornis was described by Hayashi & Kadowaki (2008) and Hayashi (2015). It was found in submerged rootlets of Salix and Carex (Hayashi, pers. comm.).
Distribution
From Sri Lanka northwards to the Himalayas, eastwards to China, Korea and Japan, southwards through SE Asia (incl. the Philippines, see Freitag et al. 2016) to New Guinea.
Habitat
Adults inhabit streams and rivers, primarily in forested areas (Fig. 107). Specimens can be found in waterlogged packs of partly decaying leaves, on rootlets and submerged wood, where they probably feed on algae or decaying plant tissue.
Key to the species of Elmomorphus Sharp, 1888 of India, Nepal, Bhutan, Myanmar, China, Thailand, Laos, Cambodia, and Vietnam
1. Elytra at least partly covered with plastron ....................................................................................... 2
– Elytra without plastron, or with only several plastron scales along lateral sides ............................ 35
2. Elytra entirely covered with plastron................................................................................................. 3
– Elytra partly covered with plastron.................................................................................................... 8
3. Pronotum almost entirely covered with plastron, only narrow transverse area along posterior pronotal margin without plastron..................................................................................................................... 4
– Pronotal disc smooth, plastron present only in lateral bands............................................................. 5
4. Elytron has nine hardly discernible rows of large punctures in shallow striae (Fig. 6). Parameres in lateral aspect subequal in width from base nearly to apical third, then gradually moderately narrowed to relatively broad, rounded apex (Fig. 7); phallobase wide. Bursa copulatrix with few moderately sized sclerotised spines in proximal and distal parts (Fig. 12A). Body large, TL: ♂♂ 3.36–3.84 mm (3.53 ± 0.16, n=10), ♀♀ 3.41–3.77 mm (3.54 ±0.12, n =10). Distribution: Laos, Vietnam ..................................................................................................... E. striatellus Delève, 1968
– Elytron without longitudinal rows of large punctures and striae (Fig. 8). Parameres in lateral aspect gradually narrowed nearly from base to narrow, rounded apex (Fig. 9), phallobase slender. Bursa copulatrix with numerous moderately large, sclerotised spines (Fig. 12B) scattered along whole length. Body small, TL: ♂♂ 2.73–3.20 mm (3.00 ± 0.16, n =10), ♀♀ 2.78–3.25 mm (2.99 ± 0.14, n =10). Distribution: Cambodia, Myanmar, Thailand, Laos, Vietnam ................................................ .............................................................................. E. siamensis Kodada, Selnekovič & Jäch sp. nov.
5. Male with conspicuous long erect setae on labrum, and small clusters of setae on prosternal process, median part of metaventrite and ventrite 5. Body elongate oval, slender; legs slender (Fig. 10). Lateral pronotal sides convergent and nearly straight (Fig. 10). Lateral plastron bands on pronotum wide, each ca one-third of pronotal width. Phallobase remarkably long in relation to parameres (Fig. 11A– B); PhL/PrL: 2.59–2.89 mm (n =3). TL: ♂♂ 3.04–3.18 mm (3.12 ± 0.07, n =4), ♀♀ 3.27–3.47 mm (3.38± 0.09, n=6). Distribution: China (Fujian, Guangdong, Hunan) .... E. parabrevicornis sp. nov.
– Male with several hardly discernible erect setae on labrum, and clusters of setae on prosternal process and median part of the metaventrite or lacking such setae. Body wider, legs shorter and stouter (Figs 13, 14, 16). Lateral pronotal sides convergent and weakly rounded. Phallobase short to relatively long (Figs 15, 17); PhL/PrL at most 2.30 .......................................................................... 6
6. Phallobase long and slender (Fig. 11C), PhL/PrL: 1.84–2.26 (2.09 ±0.16, n =10). Male with several long and erect setae on labrum, and with inconspicuous clusters of erect setae on prosternal process and median part of metaventrite. Lateral plastron bands on pronotum wide, each at least one-third of pronotal width. Large species, TL: ♂♂ 3.07–3.38 mm (3.23± 0.09, n =10), ♀♀ 3.06–3.51 mm (3.29 ± 0.14, n=10). Distribution: Vietnam ..................................................... E. auripilosus sp. nov.
– Phallobase short (Figs 15, 17), PhL/PrL up to 1.83. Male without long and erect setae on labrum, prosternal process, or median part of metaventrite. Moderately large species, TL up to 3.21 mm ..... ........................................................................................................................................................... 7
7. Lateral plastron bands on pronotum narrow, each covering about one fifth of pronotal width. Body broadly ovate (Fig. 14), strongly convex, moderately large, TL: ♂♂ 2.69–3.07 mm (2.89 ± 0.09, n =20), ♀♀ 2.89–3.21 mm (3.03 ± 0.09, n =22); elytral sides broadly rounded. Parameres in lateral aspect weakly curved ventrad and weakly narrowed apically (Fig. 15). Bursa copulatrix with distal cluster of spines, and one small sclerite near midlength (Fig. 18B). Distribution: China (Anhui, Fujian, Guangdong, Jiangxi, Zhejiang). ................................................................ E. auratus sp. nov.
– Lateral plastron bands on pronotum moderately wide, each covering about one quarter of pronotal width. Body narrow, small, TL: ♂♂ 2.21–2.67 mm (2.49 ±0.13, n= 10), ♀♀ 2.21–2.89 mm (2.61± 0.20, n= 10); elytral sides less rounded (Fig. 16). Parameres in lateral aspect more strongly curved and strongly narrowed apically (Fig. 17). Bursa copulatrix with distal cluster of numerous small spines and with several larger spines scattered on proximal and intermediate parts (Fig. 18C). Distribution: Cambodia, Myanmar, Thailand, Vietnam ...................................................................... ................................................................................... E. horaki Kodada, Selnekovič & Jäch sp. nov.
8. Elytron with large strial punctures arranged in nine longitudinal rows, striae usually well impressed; small punctures scattered over entire surface .................................................................................... 9
– Elytron without larger punctures arranged in striae, small punctures scattered over entire surface ... ......................................................................................................................................................... 14
9. Large species, elongate-oval (Fig. 19), TL: ♂♂ 3.86–4.13 mm (4.00 ±0.11, n=7), ♀♀ 3.95–4.29 mm (4.17 ± 0.14, n=5). Cranium almost entirely covered with plastron, except for narrow median line on vertex. Pronotum with large microgranules. Elytra with plastron arranged in wide lateral bands reaching from elytral side to third stria. Distribution: China (Yunnan)............. E. fusiformis sp. nov.
– Moderately large species, TL up to 3.60 mm. Head with triangular or semicircular area on vertex without plastron. Pronotum without microgranules. Lateral plastron bands on elytra narrower, reaching fourth longitudinal row at most......................................................................................... 10
10. Males with conspicuous long setae on labrum, and with clusters of setae on prosternal process and metaventrite. Body elongate, slender, weakly to moderately convex, widest behind elytral midlength ..........................................................................................................................................11
– Males without long setae on labrum, prosternal process, or metaventrite. Body wide and strongly convex.............................................................................................................................................. 12
11. Pronotum with narrow plastron bands along entire lateral sides. Body elongate, weakly convex (Fig. 21), widest behind elytral midlength, TL: ♂♂ 2.47–2.68 mm (2.55± 0.06, n=10), ♀♀ 2.65– 2.94 mm (2.81 ±0.09, n =10). Lateral pronotal sides straight. Parameres narrow, subequal in width nearly to apex, strongly curved in apical half (lateral aspect); phallobase almost straight (Fig. 22). Proximal and distal parts of bursa copulatrix with large sclerotised spines (Fig. 28A). Longitudinal rows on elytra may be obliterated and hardly discernible in some specimens. Distribution: Vietnam ................................................................................................................ E. elmoides sp. nov.
– Pronotal plastron confined to anterolateral parts. Body convex (Fig. 23) and large, TL: ♂♂ 3.17– 3.35 mm (3.25 ± 0.06, n =7), ♀♀ 3.15–3.45 mm (3.30 ± 0.11, n= 10). Lateral pronotal sides distinctly rounded. Parameres wider, gradually narrowed from base nearly to apex, nearly straight (lateral aspect); phallobase strongly curved (Fig. 24). Bursa copulatrix without sclerotised spines (Fig. 28B). Distribution: China (Guangxi), Vietnam ................................................................. E. calvus sp. nov.
12. Elytron with nine longitudinal rows of large punctures, but without distinct striae (Fig. 25). Plastron bands in anterior two-thirds of elytra narrow, reaching only eighth longitudinal row. Prosternal process with median keel flat, without depression. Ventrite 1 lacking plastron medially. Aedeagus as in Fig. 26. TL: ♂♂ 2.31–2.55 mm (n= 3), ♀♀ 2.53–2.94 mm (2.71± 0.17, n=4). Distribution: China (Hong Kong)...................................................................................................... E. hongkong sp. nov.
– Elytron with nine well impressed striae with large punctures. Plastron bands in anterior two-thirds of elytra wider, reaching sixth stria.................................................................................................. 13
13. Prosternal process with transverse depression posteromedially. Strial punctures separated by ca 0.5–1.0 × puncture diameter. Ventrite 2 entirely covered with plastron. TL: 3.58 mm (n= 1). Bursa copulatrix without microsclerites (Fig. 28C). Distribution: China (Guangxi) .. E. depressus sp. nov.
– Prosternal process without depression posteromedially. Strial punctures close to each other, often confluent. Ventrite 2 without plastron medially. Parameres shorter than phallobase, widest at basal third, strongly narrowed to acute apices, dorsal outline strongly arcuate, ventral one almost straight (Fig. 30) (all in lateral aspect); phallobase narrow, PhL/PrL: 1.40–2.00 (1.80 ±0.17, n=10). TL: ♂♂ 2.36–2.61 mm (2.44 ±0.08, n=10), ♀♀ 2.53–2.76 mm (2.63 ±0.07, n=10). Distribution: China (Fujian, Guangdong, Guangxi) ............................................................................. E. sulcatus sp. nov.
14. Pronotum with plastron present at least anterolaterally, or along entire lateral sides. Elytral plastron in lateral band .................................................................................................................................. 15
– Pronotum without plastron. Elytra with plastron confined to posterolateral parts .......................... 28
15. Pronotum with plastron confined to anterolateral parts................................................................... 16
– Pronotum with plastron along entire lateral sides............................................................................ 22
16. Elytral plastron bands narrow, covering less than one-tenth of elytron width (in elytral midlength); plastron absent on basal fourth of elytra. Elytra widest around midlength (Fig. 31). Broadly oval and strongly convex. Phallobase short and robust; parameres long and narrow, moderately curved (Fig. 32). TL: ♂ 3.32 mm (n =1), ♀ 3.31 mm (n =1). Distribution: China (Fujian) ........................... ........................................................................................................................ E. corpulentus sp. nov.
– Plastron bands on elytra moderately wide, each covering at least one-quarter of elytron width (in elytral midlength); plastron nearly reaching elytral base. Body form slenderer. Aedeagus different from above....................................................................................................................................... 17
17. Elytra widest before middle............................................................................................................. 18
– Elytra widest at or behind the middle. Usually larger species......................................................... 19
18. Plastron bands on elytra wide, each covering nearly half of elytron width (in elytral midlength). Pronotum and elytra weakly convex (Fig. 33). Larger, TL: ♂ 2.71 mm (n =1), ♀♀ 2.79–3.01 mm (n= 2). Phallobase moderately long and slender; parameres long and slender, PhL/PrL: 1.53 (n =1) (Fig. 34). Distribution: China (Guangxi)............................................................. E. ellipticus sp. nov.
– Plastron bands on elytra narrow, each covering approximately one-quarter of elytron width (in elytral midlength). Pronotum and elytra strongly convex (Fig. 35). Smaller, TL: ♂ 2.63 mm (n= 1), ♀♀ 2.60–2.83 mm (n =2). Phallobase short and wide, parameres short, PhL/PrL: 1.67 (n =1) (Fig. 36). Distal part of bursa copulatrix with numerous scattered spines (Fig. 37B). Distribution: Thailand .............................................................................................................. E. mazzoldii sp. nov.
19. Male with transversal row of long setae on labrum and two clusters of long setae in lateral portions of prosternal process. Plastron bands on elytra wide, each covering approximately two-thirds of elytron width (behind elytral midlength). Parameres long and slender, PhL/PrL: 1.36 (Fig. 38). TL: 2.60–2.80 mm. Distribution: Malaysia,? Thailand ....................................... E. bryanti Hinton, 1935
– Male without clusters of long setae on labrum and prosternal process. Plastron bands on elytra narrower than above ........................................................................................................................ 20
20. Prosternal process with strongly arched median keel (Fig. 39A). Metaventrite posteriorly with short median keel (raised discrimen). [Description based on a single female from southern Thailand; no additional specimens known.] ............................................................... E. prosternalis Hinton, 1935
– Prosternal process with median keel only moderately raised. Metaventrite without median keel.. 21
21. Phallobase long and robust, 2.3 × as long as parameres (Fig. 39C–E). TL 3.35 mm. Known only from NE India (Arunachal Pradesh)........................................................... E. montanus (Grouvelle, 1913)
– Phallobase shorter and slenderer, 1.37–1.81× as long as parameres; parameres longer and slenderer (Fig. 41). TL: ♂♂ 2.90–3.33 mm (3.07± 0.12, n =26), ♀♀ 2.88–3.35 mm (3.20 ± 0.14, n= 9). Distribution: China (Guangdong, Hong Kong, Yunnan), Laos, Malaysia, Myanmar, Thailand, Vietnam ......................................................... E. paramontanu s Kodada, Selnekovič & Jäch sp. nov.
22. Cranium and ventrites entirely covered with plastron. Elytra with wide lateral plastron bands, each covering more than two-thirds of elytron width (measured in elytral midlength) (Fig. 42). Phallobase short and robust (Fig. 43). Body small, TL: ♂♂ 2.69 mm (n= 1), ♀♀ 2.66–2.74 mm (2.71± 0.04, n =4). Distribution: Thailand ............................................................................... E. cuneatus sp. nov.
– Head with small, triangular, or semicircular area on vertex without plastron. First two ventrites medially without plastron ................................................................................................................ 23
23. Body ovate, elytra widest behind middle (Fig. 44). Small, TL: ♂♂ 2.64–2.90 mm (2.76 ± 0.10, n =5), ♀♀ 2.46–3.12 mm (2.83± 0.30, n =6). Pronotal disc weakly convex; pronotal sides nearly straight. Elytral plastron band covers nearly half of elytron width (in midlength). Body with weak bronze lustre. Parameres rather short and broad (Fig. 45). Distribution: Thailand .......................................................... E. umphangicus Kodada, Selnekovič & Jäch sp. nov.
– Body oval, elytra widest around middle (Figs 46, 48, 52, 54) ........................................................ 24
24. Small species, TL: ♂♂ 2.41–2.62 mm (2.54 ±0.07, n=6), ♀♀ 2.60–2.81 mm (2.71 ±0.07, n= 6). Pronotal disc strongly convex; pronotal sides distinctly rounded (Fig. 46). Tarsus short; terminal protarsomere approximately as long as preceding segments combined. Distal part of bursa copulatrix with numerous small microsclerites arranged in row dorsally and with small clusters of microsclerites in lateral parts (Fig. 55A). Aedeagus as in Fig. 47. Distribution: Thailand ......... E. parvulus sp. nov.
– Moderately large species, with TL at least 2.93 mm. Pronotal disc weakly to moderately convex. Terminal protarsomere as long as, or longer than preceding tarsomeres combined. Microsclerites on bursa copulatrix not arranged in dorsal row .................................................................................... 25
25. Elytral plastron bands wide, each covering approximately two-thirds of elytron width (in elytral midlength). Elytra oval, widest around middle (Fig. 48). Pronotum and elytra black with weak bronze lustre. Aedeagus as in Fig. 49. TL: ♂♂ 3.07–3.15 mm (3.10 ± 0.03, n=4), ♀♀ 3.15–3.28 mm (3.21± 0.05, n=5). Distribution: Vietnam .................. E. sausai Kodada, Selnekovič & Jäch sp. nov.
– Elytral plastron bands narrower, each covering less than half of elytron width (in elytral midlength)........................................................................................................................................ 26
26. Tarsi rather short, terminal protarsomere as long as preceding segments combined (Fig. 53A). Pronotum moderately convex, elytra strongly so (Fig. 52). Distal part of bursa copulatrix with several small lateral microsclerites, except distally (Fig. 55B). Aedeagus as in Fig. 51. TL: ♂♂ 3.29–3.67 mm (3.37 ± 0.15, n= 4), ♀♀ 3.51 mm (n= 1). Distribution: China (Yunnan) .......................................................... E. yunnanensis Kodada, Selnekovič & Jäch sp. nov.
– Tarsi long, terminal protarsomere approximately 1.3× as long as preceding segments combined..... ......................................................................................................................................................... 27
27. Bursa copulatrix with four, rather large, lateral spines (Fig. 55C). Small and slender species (Fig. 52), TL: ♂♂ 2.93–3.09 mm (n=3), ♀♀ 3.15–3.32 mm (n =2). Aedeagus as in Fig. 53C. Distribution: Thailand ............................................................................................................ E. longitarsis sp. nov.
– Bursa copulatrix on each side with one sizeable sclerite bearing one spine (Fig. 55D). Moderately large and wide species (Fig. 54), TL: ♀♀ 3.38–3.54 mm (n =3). Distribution: China (Hunan) ........................................................................................................... E. bispinosus sp. nov.
28. Male: labrum, prosternal process, and median part of metaventrite without conspicuous clusters of long setae; disc of metaventrite weakly convex; tibiae without teeth, not abruptly expanded in distal half. Female: distal part of bursa copulatrix with large separate spines located laterally and dorsally, or with dorsal and lateral microsclerites bearing small spines (Fig. 60) ......................................... 29
– Male: labrum with conspicuous long erect setae in a transverse row; anterolateral parts of prosternal process and median part of metaventrite with small clusters of setae; disc of metaventrite depressed; metatibiae simple (Figs 61, 63, 65), or each with conspicuous tooth (Figs 68, 70, 72). Female: distal part of bursa copulatrix with small spines arranged in dorsal row or scattered over lateral parts (Figs 67, 74)..................................................................................................................................... 30
29. Pronotum moderately convex, lateral sides straight (Fig. 56). Plastron areas on elytra narrower than length of metatarsus (measured along elytral suture). Elytra with weak but apparent microreticulation. Aedeagus (Fig. 57): phallobase long and slender, slightly widened near base, PhL/PrL: 1.70–2.19 (1.92± 0.15, n =8); parameres widest near base, toward apices almost equally wide and moderately curved ventrad, apex widely rounded (lateral aspect); penis narrowly rounded apically (lateral aspect); sclerotised fibula long, relatively slender. Bursa copulatrix with one dorsal and two lateral microsclerites bearing small spines (Fig. 60A). TL: ♂♂ 2.41–2.70 mm (2.59 ± 0.10, n =8), ♀♀ 2.65– 3.06 mm (2.86 ± 0.12, n=11). Distribution: Bhutan, Nepal ......................... E. nepalensis Satô, 1981
– Pronotum strongly convex, lateral sides broadly rounded (Fig. 58). Plastron areas on elytra as wide as, or wider than metatarsus length (measured along elytral suture). Elytral microreticulation almost inapparent. Aedeagus (Fig. 59): phallobase relatively short and slender, slightly expanded toward base, PhL/PrL: 1.35–1.48 (n =3); parameres evenly narrowed to apices, slightly curved ventrad, apex narrowly rounded (lateral aspect); penis narrowly rounded apically. Bursa copulatrix with sizeable, separate dorsal and lateral spines (Fig. 60B). TL: ♂♂ 2.55–2.68 mm (n =3), ♀♀ 2.65–2.95 mm (n= 2). Distribution: China (Yunnan).............................................................. E. punctulatus sp. nov.
30. Male metatibia simple, without tooth (Figs 61, 63, 65); mesotibia not abruptly expanded in distal half ................................................................................................................................................... 31
– Male metatibia with conspicuous tooth; mesotibia sometimes abruptly expanded in distal half (Figs 68, 70, 72)............................................................................................................................... 33
31. Smaller, slender, less convex species (Fig. 61), TL: ♂♂ 2.59–2.97 mm (2.81 ± 0.09, n=25), ♀♀ 2.91–3.19 mm (3.01± 0.08, n=20). Penis weakly expanded before apex (lateral aspect) (Fig. 62). Distal part of bursa copulatrix with dorsal spines, sometimes forming irregular dorsal row (Fig. 67A). Distribution: Vietnam ......................................................................................... E. simplipes sp. nov.
– Larger, wider, and more convex species, TL over 3.0 mm (Figs 63, 65). Penis not expanded apically, rounded in lateral aspect (Figs 64, 66). Distal part of bursa copulatrix with spines arranged in dorsal row and small groups laterally; spines may also be present on ventral side of proximal part of bursa copulatrix (Fig. 67B–D)................................................................................................................... 32
32. Bursa copulatrix (Fig. 67B–C) with large sclerite; spines arranged in distinct dorsal row and in two small groups ventro-laterally; proximal part of bursa copulatrix with semicircular sclerotised strip ventrally. TL: ♂♂ 3.09–3.50 mm (3.30 ±0.10, n =20), ♀♀ 3.35–3.66 mm (3.51 ±0.09, n =19). Distribution: China (Jiangxi, Yunnan), Vietnam ...... E. donatus Kodada, Selnekovič & Jäch sp. nov.
– Distal part of bursa copulatrix with spines dorsally and lateraly, and also ventrally on proximal part (Fig. 67D). TL: ♂♂ 2.97–3.58 mm (3.24 ±0.14, n=20), ♀♀ 3.14–3.79 mm (3.34± 0.14, n =20). Distribution: China (Guizhou, Yunnan)........... E. paradonatus Kodada, Selnekovič & Jäch sp. nov.
33. Parameres constricted in the middle (ventral aspect); apices subtruncate in lateral aspect (Fig. 69). Distal part of bursa copulatrix with spines scattered over lateral parts, dorsal row absent (Fig. 74A). TL: ♂♂ 2.94–3.33 mm (3.13 ± 0.08, n =29), ♀♀ 2.81–3.32 mm (3.11 ± 0.12, n =22). Distribution: China (Guangdong, Yunnan), Laos, Vietnam .......................................................... E. similis sp. nov.
– Parameres evenly narrowed to apices or slightly constricted medially; apices narrowly rounded (Figs 71, 73). Distal part of bursa copulatrix always with distinct dorsal row of spines; sometimes few spines scattered on lateral parts (Fig. 74B–C) .......................................................................... 34
34. Male: metatibia slender, straight; mesotibia without expansion on mesal side of distal half (Fig. 70). Female: Distal part of bursa copulatrix with spines arranged in dorsal row and scattered over lateral parts (Fig. 74B). TL: ♂♂ 2.67–3.32 mm (2.89 ± 0.14, n=63), ♀♀ 2.71–3.37 mm (3.03 ±0.15, n =38). Distribution: Myanmar, China (Yunnan), Laos, Thailand, Vietnam .................................................... ................................................................................. E. dentipes Kodada, Selnekovič & Jäch sp. nov.
– Male: metatibia strongly curved; mesotibia with expansion on mesal side of distal half (Fig. 72). Female: distal part of bursa copulatrix with spines arranged in dorsal row, lateral spines absent (Fig. 74C). TL: ♂♂ 2.78–3.48 mm (3.22± 0.11, n =66), ♀♀ 2.83–3.45 mm (3.24± 0.14, n =27). Distribution: China (Anhui, Fujian, Guangdong, Guangxi, Hong Kong, Hunan, Jiangxi, Yunnan, Zhejiang), Vietnam ............................................................................................... E. curvipes sp. nov.
35. Plastron on pronotum distinct, covering large areas anterolaterally. Cranial surface almost entirely covered with plastron, except for small median longitudinal area on vertex. Remarkedly large, elongate oval (Fig. 75), TL: ♂♂ 4.06–4.34 mm (n =3), ♀♀ 4.46 mm (n=1). Aedeagus as in Fig. 76. Distribution: China (Shaanxi)............................................................................. E. catenatus sp. nov.
– Pronotum without plastron, or rarely (E. jendeki sp. nov.) with several plastron scales in extremities of anterior angles ............................................................................................................................. 36
36. Elytra with nine longitudinal rows of large punctures, usually located in striae. Small punctures scattered over entire elytral surface. Ventrite 1 without plastron medially (except E. jii sp. nov.) ..... ......................................................................................................................................................... 37
– Elytra with small punctures scattered over entire surface, longitudinal rows of larger punctures usually absent, if present (E. superficialis sp. nov.), then first ventrite entirely covered with plastron....... 44
37. Head covered with plastron, except for median semicircular area on vertex. Anterior angles of pronotum seldom with several plastron scales. Relatively large species, TL: ♂♂ 3.47–3.85 mm (3.60 ± 0.14, n=7), ♀♀ 3.64–4.16 mm (3.87 ± 0.17, n=10). Aedeagus as in Fig. 78. Distribution: Vietnam ..................................................................... E. jendeki Kodada, Selnekovič & Jäch sp. nov.
– Plastron on head confined to small areas around antennal insertions. Pronotum without plastron..... ......................................................................................................................................................... 38
38. Pronotal surface between punctures with distinct microreticulation forming minute, densely arranged dimples............................................................................................................................................. 39
– Pronotal surface between punctures smooth, without microreticulation......................................... 40
39. Larger species, TL: ♂♂ 4.15–4.36 mm (4.27 ± 0.07, n=8), ♀♀ 4.03–4.38 mm (4.24 ±0.13, n= 5). Elytra widest behind middle (Fig. 79). Pronotum and elytra microgranulate on entire surface. Lateral sides of pronotum distinctly rounded. Phallobase remarkably long and slender (Fig. 80). Distribution: China (Guizhou) ......................................................................................... E. schillhammeri sp. nov.
– Smaller species, TL: ♂♂ 3.42–3.56 mm (n =2), ♀♀ 3.42–3.70 mm (3.55± 0.09, n=10). Elytra widest before middle (Fig. 81). Microgranules present on posterolateral parts of pronotum, absent on elytra. Lateral sides of pronotum weakly rounded. Distribution: China (Guizhou, Hubei, Hunan) ................................................................................................................. E. globosus sp. nov.
40. Cranial surface strongly microreticulate, with large confluent punctures and microgranules. Microgranules also present on entire surface of pronotum and elytra. Phallobase very long and slender (Fig. 84), PhL/PrL: 2.85 (n =1). Ventrite 5 rounded at apex in both sexes. Large, TL: ♂♂ 3.80–3.84 mm (n= 2), ♀♀ 3.87–4.13 mm (n =3). Distribution: China (Yunnan) ...................................................................... E. ovalis Kodada, Selnekovič & Jäch sp. nov.
– Microgranules confined to lateral parts of pronotum, absent on elytra; head sometimes with minute, rather indistinct microgranules ........................................................................................................ 41
41. Males with long erect setae on labrum, small setal clusters on prosternal process and median part of metaventrite. Ventrite 5 rounded at apex. Head with indistinct microgranules in some specimens. Elytral microreticulation formed by small irregular meshes. Body relatively small, TL: ♂♂ 2.92–3.27 mm (3.10 ± 0.15, n= 4), ♀ 3.58 mm (n =1). Aedeagus as in Fig. 86. Distribution: China (Yunnan) ............................................................................................................... E. minutus sp. nov.
– Specimens of both sexes without groups of long setae on labrum, prosternal process, or median part of metaventrite................................................................................................................................. 42
42. Vertex surface distinctly microreticulate. Elytral microreticulation formed by irregular meshes. Ventrite 5 rounded at apex. Phallobase short in relation to parameres (Fig. 88), PhL/PrL: 1.28–1.32 (n= 2). TL: ♂ 3.72 mm (n =1), ♀♀ 4.05–4.13 mm (n=2). Distribution: China (Hunan)................... ........................................................................................................................................ E. jii sp. nov.
– Vertex smooth, without microreticulation or microgranules ........................................................... 43
43. Elytral microreticulation formed by transverse lines. Pronotum strongly convex, anterior angles strongly deflexed. Ventrite 5 in males with small excision at apex. Phallobase long (Fig. 91A), PhL/ PrL: 2.03 (n =1); parameres wide, their ventral outline nearly straight almost to apex, dorsal one along basal half and then moderately curved to narrow, acute apices (lateral aspects). TL: ♂ 2.98 mm (n= 1), ♀♀ 3.07–3.21 mm (n =2). Distribution: China (Guangxi).............. E. schoenmanni sp. nov.
– Elytral microreticulation formed by polygonal meshes. Pronotum less convex, anterior angles moderately deflexed. Ventrite 5 without apical excision in both sexes. Phallobase long (Fig. 91B– C), PhL/PrL: 1.76–2.29 (2.02 ± 0.13, n= 9); parameres with moderately curved ventral and dorsal outline, widest basally, gradually evenly narrowed to narrow acute apices (lateral aspect). TL: ♂♂ 3.14–3.34 mm (3.27 ± 0.06, n =9), ♀♀ 3.36–3.47 mm (3.41± 0.05, n =4). Distribution: Vietnam ......................................................................................................... E. vietnamensis sp. nov.
44. Elytral microreticulation strong, consisting of dense irregular meshes (Fig. 92). Elytral punctures very small, indistinct, scattered. Aedeagus as in Fig. 93. TL: ♂♂ 3.00– 3.54 mm (3.30 ± 0.17, n =11), ♀♀ 3.29–3.50 mm (3.39± 0.10, n= 4). Distribution: China (Hainan) .................................... ......................................................................................................................... E. reticulatus sp. nov.
– Elytral microreticulation fine, consisting of small irregular meshes. Punctures on elytra distinct, scattered; if arranged in longitudinal rows, then ventrite 1 entirely covered with plastron ............ 45
45. Elytra with large shallow punctures arranged in nine longitudinal rows and small punctures scattered over entire surface............................................................................................................................ 46
– Elytra with small, scattered punctures, longitudinal rows absent.................................................... 47
46. Smaller species, TL: ♂♂ 3.21–3.52 mm (3.36± 0.10, n =13), ♀♀ 3.24–3.75 mm (3.49± 0.14, n =13), body strongly convex and broadly oval (Fig. 94). Punctures on pronotal disc approximately as large as those on head. Parameres near apex slightly curved ventrad (Fig. 95, lateral aspect). Distribution: China (Anhui, Fujian, Jiangxi) ...................................................................... E. superficialis sp. nov.
– Larger species, TL: ♂♂ 3.58–4.11 mm (3.75 ± 0.14, n =10), ♀♀ 3.74–4.00 mm (3.88± 0.08, n =10), body moderately convex and elongate (Fig. 96). Punctures on pronotal disc distinctly smaller than those on head. Parameres near apex strongly curved ventrad (Fig. 97, lateral view). Distribution: China (Hunan) ..................................................................................................... E. hamatus sp. nov.
47. Plastron covering almost entire frontoclypeus. Body oblong oval, moderately convex (Fig. 98), TL: ♂♂ 3.21–3.50 mm (3.34± 0.09, n =8), ♀♀ 3.42–3.58 mm (3.48 ±0.05, n =8). Ventrite 5 emarginate at apex in males. Aedeagus as in Fig. 99. Distal part of bursa copulatrix with numerous scattered small spines (Fig. 106B). Distribution: Vietnam ................................. E. oblongus sp. nov.
– Plastron on head confined to small areas around antennal insertions.............................................. 48
48. Ventrite 5 in both sexes strongly convex anteriorly, deflexed posteriorly; plastron absent on large median portion; conspicuous long setae absent in both sexes. TL: ♂♂ 3.14–3.63 mm (3.39 ± 0.11, n =15), ♀♀ 3.36–3.70 mm (3.50 ± 0.12, n =10). Distribution: China (Fujian, Guangdong, Guangxi, Hong Kong) .................................................................................................... E. glabriclunis sp. nov.
– Ventrite 5 evenly convex in both sexes; simple or with large oval area bearing long conspicuous setae in males ................................................................................................................................... 49
49. Ventrite 5 simple in both sexes, without plastron along posterior margin. Punctures on pronotum and elytra weak. Aedeagus (Fig. 103) with parameres moderately curved behind middle, widest at base, then evenly gradually narrowed into rounded apices (lateral aspect). Phallobase robust, expanded near middle, moderately curved, longer than parameres, PhL/PrL: 1.39–1.75 (1.55± 0.10, n =15). Distal part of bursa copulatrix with small scattered lateral microsclerites (Fig. 106D). TL: ♂♂ 3.36– 3.89 mm (3.57 ± 0.12, n=15), ♀♀ 3.24–3.96 mm (3.70 ±0.20, n =15). Distribution: China (Fujian, Hunan, Jiangxi, Zhejiang)...................................................................................... E. simplex sp. nov.
– Ventrite 5 in male with large oval area bearing long setae, conspicuously protruding posterior margin of ventrite (Fig. 104). Punctures on pronotum and elytra rather deep. Aedeagus (Fig. 105) with parameres strongly curved near middle, widest at base; subequal in width until apical third, then distinctly narrowed into acute apices (lateral aspect). Phallobase as long or moderately longer than parameres: PhL/PrL: 1.00–1.24 (1.14± 0.07, n=7), relatively robust, widest and moderately bent near middle. Bursa copulatrix with numerous small microsclerites scattered on proximal and distal part (Fig. 106E). TL: ♂♂ 3.59–3.87 mm (3.69 ±0.08, n=10), ♀♀ 3.41–4.03 mm (3.69± 0.26, n= 5). Distribution: China (Fujian, Guangdong)..................................................... E. comosiclunis sp. nov.
The species of Elmomorphus Sharp, 1888 of India, Nepal, Bhutan, Myanmar, China, Thailand, Laos, Cambodia, and Vietnam
The species are listed in the same sequence as they appear in the identification key.
description: Published as part of Selnekovič, Dávid, Jäch, Manfred A. & Kodada, Ján, 2024, Taxonomic revision of the genus Elmomorphus Sharp, 1888. II. Redescription of the genus and review of the species from India, Nepal, Bhutan, Myanmar, China, Thailand, Laos, Cambodia, and Vietnam (Coleoptera: Dryopidae), pp. 1-229 in European Journal of Taxonomy 957 on pages 4-21, DOI: 10.5852/ejt.2024.957.2651, http://zenodo.org/record/13773385