Elmomorphus prosternalis Hinton, 1935

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 : 84-86

Elmomorphus prosternalis Hinton, 1935

Figs 39A , 110E

Elmomorphus prosternalis Hinton, 1935: 171 (original description).

Elmomorphus prosternalis – Shepard & Sites 2016: 93.

Differential diagnosis

Elmomorphus prosternalis is characterised by the presence of a plastron on the dorsal cranial surface (except for a small area on the vertex), on the anterolateral portions of the pronotum, and the lateral sides of the elytra. Elytral punctures are scattered over the entire surface, striae absent. The species most closely resembles E. montanus and E. paramontanus sp. nov. but differs in the prominent and strongly arched median keel of the prosternal process and the presence of a short median keel along the posterior part of the metaventrite ( Fig. 39A ).

Type material

Holotype

THAILAND – Nakhon Si Thammarat Province • ♀; “PENINSULAR SIAM [last third of the “M” cut off] NAKON SRI TAMARA [last “A” slightly cut off at the end] [modern spelling: Nakhon Si Thammarat] KHAO RAM [all printed] at light 750 [handwritten, with printed underlining] FT. [printed] March 2 sd [handwritten, with printed underlining] 1922 H. M. PENDLEBURY [printed] | Type [printed on cirular label with red frame] | comp.type [printed] prosternalis [handwritten] H.E. Hinton [printed] [pink rectangular label] | H. E. Hinton collection. B.M. 1977—566 [printed on white label] | Elmomorphus prosternalis HINTON det. Kodada & Jäch [printed on white label]”; NHMUK. Photographs of the holotype and its labels are available at: https://www.flickr.com/photos/nhm_beetle_id/52809944410/in/album-72177720297734809 (holotype, labels); https://www.flickr.com/photos/nhm_beetle_id/52809739549/in/album-72177720297734809/ (holotype, ventral view); https://www.flickr.com/photos/nhm_beetle_id/52809538071/in/album-721777 20297734809/ (holotype, dorsal view).

Remarks

The holotype is an immature female of light brown colour; femora, tibiae and tarsi of hind legs missing.

Type locality

South Thailand, Nakhon Si Thammarat Province, ca 230 m a.s.l. According to the label data, the holotype was collected at a place called “Khao Ram”, which was spelled “Khao Rom” in the original description ( Hinton 1935). It probably refers to Khao Ram Rome [mountain], which lies inside Khao Luang National Park, east of the city of Nakhon Si Thammarat.

Redescription of holotype

Measurements (mm): TL: 3.20; PL: 0.70; PW: 1.20; EL: 2.50; EW: 1.40.

Body elongate oval, moderately convex dorsally, widest close before midlength of elytra; brown, legs slightly paler. Dorsal plastron present on frontoclypeus, anterolateral portions of vertex, anterolateral portions of pronotum and lateral bands on elytra. Ventral plastron absent on prosternal process, median part of metaventrite, and middle of first two ventrites.

Cranial surface with round setiferous punctures, each about as wide as an eye facet, separated by approximately a puncture diameter. Plastron present on frontoclypeus and anterolateral portions of vertex, posteromedian portion without plastron about as wide as eye (dorsal aspect). Labrum transverse, exposed portion microreticulate, with decumbent setae along anterior margin.

Pronotum moderately convex, widest at base, PW/PL: 1.71; round setiferous punctures slightly larger than those on head; plastron confined to anterolateral angles; anterior margin slightly arcuate; anterolateral angles strongly deflexed, acute. Prosternal process with lateral edges rounded; lateral margins posteriorly expanded and distinctly separated from conspicuously strongly arched median keel ( Fig. 39A ). Metaventrite convex, median portion without plastron; discrimen distinct, with short keel and adjacent groove posterior of metakatepisternal suture ( Fig. 39A ). Elytra moderately convex, EL/ EW: 1.79; weakly microreticulate; punctures scattered on entire surface; plastron forming two lateral bands, almost reaching elytral base, slightly widening posteriorly and connecting at elytral apices.

Ventrites covered with plastron, except for middle of ventrites 1–2.

Secondary sexual dimorphism

Male unknown.

Distribution

Southern Thailand ( Fig. 110E ). This species (and the genus Elmomorphus ) was erroneously recorded as new for Thailand by Shepard & Sites (2016).

Figures

Fig. 39. A. Elmomorphus prosternalis Hinton, 1935, holotype (BMNH), prosternal process and median part of metaventrite. B. E. montanus (Grouvelle, 1913), syntype, male (MNHN), prosternal process and median part of metaventrite. C. E. montanus, syntype (MNHN), aedeagus, lateral aspect. D. Same, ventral aspect, detail of parameres and penis. E. Same, ventral aspect. Scale bars: 0.1 mm.

Fig. 110. Distribution maps.A. Elmomorphus corpulentus sp. nov.B. E. ellipticus sp. nov.C. E. mazzoldii sp. nov. D. E. bryanti Hinton, 1935. E. E. prosternalis Hinton, 1935. F. E. montanus (Grouvelle, 1913).