Elmomorphus cuneatus, Selnekovič & Jäch & Kodada, 2024

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), European Journal of Taxonomy 957, pp. 1-229 : 93-97

Elmomorphus cuneatus sp. nov.

urn:lsid:zoobank.org:act:EB7E144C-5B83-4A32-9F33-EBB366976930

Figs 42–43 , 111B

Differential diagnosis

Elmomorphus cuneatus sp. nov. ( Fig. 42 ) is characterised by the presence of a plastron on the dorsal cranial surface and the lateral sides of the pronotum and elytra. Elytral punctures are scattered over the entire surface, and longitudinal striae are absent. These characters are shared by E. sausai sp. nov., E. umphangicus sp. nov., and E. yunnanensis sp. nov. From E. sausai , it can easily be distinguished by the cranial surface being entirely covered with plastron, while in the two other species, the plastron is lacking on a small triangular area on the vertex. All ventrites are covered with plastron in E. cuneatus , whereas the middle of the first two ventrites lack a plastron in the other species. Elmomorphus cuneatus is characterised by its small body dimensions and by the extensive plastron bands on the elytra, each covering more than two-thirds of the elytron width (measured at the elytral midlength). The species most closely resembles E. ellipticus sp. nov. but can easily be recognised by the plastron distributed on the entire cranial surface and along the entire lateral sides of the pronotum.

Etymology

The epithet is a Latin adjective in the nominative singular meaning ‘wedge-shaped’, referring to the narrow wedge-shaped glabrous area on the elytra.

Type material

Holotype

THAILAND – Phang Nga Province • ♂; “THAILAND 2003 PROVINZ PHANGNA, KHAO LAK surr.[oundings] 10.1. leg.: Horst FORSTER ”; NMW.

Paratypes

THAILAND – Phang Nga Province • 2 ♀♀: same collection data as for holotype; NMW • 1 ex.; “ Thailand: Phang-Nga Prov. Takua Pa distr., stream nr. Pak Wip Waterf. , 29.11. 2006, leg. H. Zettel (47)”; NMW • 2 ex.; “ Thailand: Khuraburi distr. Baan Tumnang , W of Si Phang Nga NP, 29.11. 2006, leg. H. Zettel (48)”; NMW. – Chumphon Province • 1 ex. [ex coll. A. Skale]; “ THAILAND, Chumphon Pr. Pha To env. 9°48′, 98°47′ 27.III. - 14.iv.1996 leg. P. Prüdek [=? Pavel Průdek]”; NMW. – Kanchanaburi Province • 2 ♀♀; “ Thailand: 26. 12. 1996, Sankhlaburi , road to Karen vill., Ban Sane Pang , leg. Mazzoldi ”; NMW. – Ranong Province • 9 ex. [ex coll. A. Skale]; “ THAILAND, Ranong Pr. Ban Na env. 9°34′N, 98°42′E leg. P. Prüdek [=? Pavel Průdek]”; CKB, NMW. – Rayong Province • 7 ex.; “ THAILAND 1990 (14) Prov. Rayong Khao Chamao NP , leg. Jäch 12.12.”; CKB, NMW. – Satun Province • 1 ex.; “ THAILAND: Thale Ban NP leg. Madl 1993 ”; NMW. – Trat Province • 1 ex.; “O – THAILAND 1990 Ko Chang (11) am Licht [at light] leg. Jäch 8.-12.12.”; NMW .

Type locality

Thailand, Phang Nga Province, Khao Lak.

Description

Dimensions (mm): TL: ♂♂ 2.69 (n=1), ♀♀ 2.66–2.74 (2.71± 0.04, n=4); PL: ♂♂ 0.61 (n= 1), ♀♀ 058–0.64 (0.61 ± 0.03, n =4); PW: ♂♂ 1.13 (n=1), ♀♀ 1.10–1.21 (1.15± 0.05, n=4); EL: ♂♂ 2.08 (n=1), ♀♀ 2.08–2.11 (2.09 ± 0.02, n =4); EW: ♂♂ 1.27 (n =1), ♀♀ 1.20–1.35 (1.26± 0.07, n= 4); PhL: 0.35 (n =1); PrL: 0.27 (n=1).

Body elongate oval, moderately convex, widest around elytral midlength ( Fig. 42 ). Colouration black, mouthparts, antennae, trochanters, and tarsi reddish brown, remaining parts of legs brown. Dorsal pubescence consists of short thin decumbent setae arising from small round punctures. Dorsal plastron present on entire cranial surface, along lateral sides of pronotum and elytra. Ventral plastron present on entire ventral surface, except on prosternal process and median part of metaventrite.

Cranium with small round punctures, smaller than an eye facet, separated from each other by ca 0.5–1.0 × puncture diameter; plastron covering entire surface. Labrum transverse, anterior margin straight, exposed portion microreticulate with small setiferous punctures; setae concentrated along anterior margin, equal in length in both sexes. Anterior margin of clypeus straight. Eyes large, oval, moderately protruding, ID: ♂♂ 0.38 mm (n=1), ♀♀ 0.37–0.43 mm (0.40 ±0.03, n= 4). Antennae short, 10-segmented, densely setose.

Pronotum transverse, moderately convex, widest at base, PW/PL: ♂♂ 1.85 (n= 1), ♀♀ 1.84–1.90 (1.87 ± 0.03, n=4); plastron forming posteriorly narrowed band along lateral sides; pronotal disc smooth, with round setiferous punctures larger than those on head and elytra, punctures separated from each other by about half a puncture diameter; anterior angles protruding and deflexed; lateral pronotal sides convergent and rounded. Prosternal process with lateral and posterior edges rounded, lateral margins slightly raised, without clusters of erect setae, median keel arched. Scutellum longer than wide, smooth, with several setiferous punctures. Metaventral process with lateral margins slightly raised; metaventral disc flat, area without plastron widened posteriorly. Elytra oval, widest around middle, EL/EW: ♂♂ 1.63 (n=1), ♀♀ 1.56–1.74 (1.66 ±0.08, n =4); plastron forming broad, posteriorly widened lateral bands, each band covering more than two-thirds of elytron width (measured at elytral midlength); median area without plastron V-shaped, weakly microreticulate. Tibiae straight, protibia ca 1.3× as long as protarsus, PrTL/PL: ♂♂ 1.15 (n=1), ♀♀ 1.02–1.20 (1.12 ± 0.07, n =4). Terminal protarsal segment somewhat longer than all preceding segments combined; male foreclaws long, narrow, strongly curved, similar to female ones.

Ventrites completely covered with plastron; intercoxal process short and wide, without admedian keels; ventrite 5 in both sexes evenly convex, apex slightly emarginate in males, and arcuate with small longitudinal keel in females. Aedeagus ( Fig. 43 ): phallobase short, PhL/PrL: 1.31 (n =1); parameres long and slender, narrowly rounded apically (lateral aspect); penis remarkably short, broadly rounded apically; sclerotised fibula rather long.

Secondary sexual dimorphism

Apex of ventrite 5 slightly emarginate in males, arcuate and with short longitudinal keel in females.

Distribution

Thailand ( Fig. 111B ).

Figures

Fig. 42. Elmomorphus cuneatus sp. nov., holotype, male (NMW), TL: 2.69 mm.

Fig. 43. Elmomorphus cuneatus sp. nov., holotype (NMW), aedeagus. A. Lateral aspect. B. Ventral aspect. Scale bar: 0.1 mm.

Fig. 111. Distribution maps. A. Elmomorphus paramontanus Kodada, Selnekovič & Jäch sp. nov. B. E. cuneatus sp. nov. C. E. umphangicus Kodada, Selnekovič & Jäch sp. nov. D. E. parvulus sp. nov. E. E. sausai Kodada, Selnekovič & Jäch sp. nov. F. E. longitarsis sp. nov.