Elmomorphus siamensis Kodada, Selnekovič & Jäch, 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 : 25-30

Elmomorphus siamensis Kodada, Selnekovič & Jäch sp. nov.

urn:lsid:zoobank.org:act:C608129B-35C2-460F-8D17-DD59FA30F14A

Figs 8–9 , 12B , 107A , 108B

Differential diagnosis

Elmomorphus siamensis sp. nov. ( Fig. 8 ) is characterised by having the dorsal surface covered with plastron, except for a narrow transverse area along the posterior pronotal margin. The ventral plastron is absent only on the median keel of the prosternal process and on the median part of the metaventrite. Elytral punctures are scattered over the entire surface. Aedeagus ( Fig. 9 ): parameres long and slender, apices narrowly rounded; penis long, nearly reaching the apex of the parameres. Proximal and distal part of bursa copulatrix with large sclerotised spines ( Fig. 12B ).

The species most closely resembles E. striatellus , but it differs in the absence of elytral striae. Elmomorphus siamensis sp. nov. is smaller, TL: ♂♂ 2.73–3.20 mm (3.00 ± 0.16, n=10), ♀♀ 2.78– 3.25 mm (2.99 ± 0.14, n =10) versus TL: ♂♂ 3.36–3.84 mm (3.53 ± 0.16, n =10), ♀♀ 3.41–3.77 mm (3.54 ± 0.12, n =10) in E. striatellus , its aedeagus is longer and more slender than in E. striatellus ( Fig. 7 ); and the large sclerotised spines on the proximal and distal part of the bursa copulatrix are less numerous (see Fig. 12A–B ).

Etymology

The epithet is a Latin adjective in the nominative singular referring to Siam, the former name of Thailand.

Type material

Holotype

THAILAND • ♂; “NW Thailand CHON [CHOM] THONG 24-27.IV. 1991 J.Horak lgt.”; NMW.

Paratypes

CAMBODIA • 1 ex.; “CAMBODIA, PREAH VIHEAR, CHOAM KHSANT , 01.- 12.05.2012 LOCAL COLLECTOR”; NMW.

LAOS – Attapeu Province • 3 ex.; “LAOS, ATTAPEU prov. Annam Highlands Mts. Dong Amphan NBCA, ca. 1160 m Nong Fa (crater lake) env., 15°05.9′N, 107°25.6′E Jiří Hájek leg. 30.iv.–6.v.2010 ”; NMPC. – Bolikhamxai Province • 2 ex.; “ LAOS-CE, 1-18.v.2001, Boli Kham Xai prov. , 18°21′N 105°08′E, Ban Nape (8 km NE) ~ 600 m, C.L. Peša leg.”; CKB. – Luang Namtha Province • 5 ex.; “ N-LAOS: Prov. Lg. Nam Tha ca. 5 km S Muang Sing , 650m, Huay Giulom riv., 10.6. 1996, leg. Schillhammer (21)”; NMW • 2 ex.; LAOS north, 24.-30.V.1997 20 km NW Louang Namtha N 21°09.2, E 101°18.7, alt. 900 ± 100 m, E. Jendek & O. Šauša leg.”; CKB .

MYANMAR • 2 ex.; “MYANMAR: Sagaing Division Alaungdaw Katthapa NP 22°19.113′N 94°28.518′E 3.- 13.5.2003, ca. 350 m, light, leg. Boukal & Schillhammer (101)”; NMW • 1 ex.; “ MYANMAR: Sagaing Div. Alaungdaw Kathapa NP Pagoda Str . at Ku Mara Monastery, 6.5.2003 leg. D. Boukal (MBS [Myanmar Biodiversity Survey] 111) | up-stream of Log Cabin Camp , ca. 400 m 22°18.560′N 94°27′679′E”; NMW • 2 ex.; “ MYANMAR: Sagaing Div. Alaungdaw Kathapa NP 8.5.2003 leg. D. Boukal ( MBS 115 )”; NMW • 1 ex.; “ Maronych. Mülleri mihi, Tenasser. II. | TENASSERIM, Birmania coll. J.V. Helfer National Museum Prague”; NMPC .

THAILAND – Chiang Mai Province • 10 ♂♂, 5 ♀♀, 47 ex.; same collection data as for holotype; CKB • 15 ex.; “ NE Thailand, 23.- 27.4.1991, Chom Thong S. Bilý Leg.”; NMW • 5 ex.; “ NW Thailand 1991 Chom Thong , 24.-27.4., 1. 26. N, 98. 41. E L. Dembický leg.”; NMW • 4 ex.; “ Thailand occ. bor. 24.- 28.4.1991 Chom Thong Jan Farkac leg.”; NMW • 1 ex.; “ NW Thailand 24.- 27.4.1991 Chom Thong Leg. Pacholatko ”; NMW • 13 ex.; “ N-Thailand: Ch. Mai, Chom Thong , 24.-26. 4. 1991 leg. Pacholatko ”; NMW • 1 ex.; “ NW THAI 24.-27.IV. CHON [CHOM] THONG 1991 J.Horak leg.”; CKB • 4 ex.; “ N-THAILAND: Chiang Mai 12 km W Chom Thong Mae Klang riv., 27.12.1998, 550 m, leg. P. Mazzoldi (7)”; NMW • 1 ex.; “ Thailand 91 Thanon Thong Chai D. Král & V. Kubáň | THAI, 25.5. 1991 FANG 300 m 19° 55′ N 99° 12′ E David Král lgt.”; NMW • 4 ex.; “ THAI, 25. 5. 1991 FANG 300m 19° 55′ N 99° 12′E Vit Kubáň leg.”; NMW • l ex.; “ Thailand 91 Thanon Thong Chai D. Král & V. Kubáň, THAI, 26.-28.V. 1991 Palong 750m 19° 55′ N 99° 06′ E Vit Kubáň leg.”; NMW • 1 ex.; “ Thailand 91 Thanon Thong Thai D. Král & V. Kubáň, THAI, 10.-16.v. 1991 Chiang Dao 600 m 19° 24′ N 98° 55′ E Vit Kubáň leg.”; NMW • 2 ex.; “ THAILAND, Mae Ping 19.- 20.6.1991 leg. Malicky ”; NMW • 3 ex.; “ THAILAND, Mae Ping 19.- 20.6.1991 leg. Malicky (Licht) [at light]”; NMW. – Chaiyaphum Province • 70 ex.; “ Thailand: Chaiyaphun , Phu Kheio Wld. Sact . [ Phu Khiao Wildlife Sanctuary ] 12.III.1994, Nam Prom , WDS-A-1037 | Collection W.D. Shepard ”; CSS • 70 ex.; “ Thailand: Chayiaphum , Phu Kheio Wld. Sanct . 4.IV.1994, Nam Prom , William D. Shepard leg. | WDS-A-1053”; CSS. – Loei Province • 5 ex.; “ Thailand: Loei, Kaeng Hai , 9.III.1994, Nam San Khe , WDS-A-1035, William D. Shepard leg.”; CSS • 5 ex.; “ N-THAILAND, Nan Lom Sak - Dan Sai , 17.-19. 5. 1993 Pacholatko & Dembicky ”; NMW • 2 ex.; “ N-THAILAND NW Chiang Mai Pai City, 29.4.1993 Pacholatko & Dembicky ”; NMW. – Mae Hong Son Province • 2 ♂♂, 1 ♀, 3 ex.; “NW THAI 23.-31.V. Mae Hong Son 1200 m Ban Si Lang 1991 J.Horák leg.”; CKB • 10 ♂♂, 8 ♀♀; “NW THAI 1.-8. V. 1992 Mae Hong Son 1200 m Ban Si Lang J. Horák & J. Strnad leg.”; CKB • 10 ex.; “ N-THAILAND Mae Hong Son Huai Sue Tao leg. Dembicky ”; NMW. – Nachon Ratchasima Province • 1 ex.; “ Thailand: Nakhon Ratchasima Prov., Lam Takhong , nr. Khao Yai NP, stream, 380 m 8.1.2009, leg. H. Zettel (50)”; NMW. – Nan Province • 3 ex.; “ NO-THAILAND Nan-Pha Khab 11.-16. V. 1993 leg. Pacholatko ”; NMW. – Petchabun Province • 11 ex.; “ Thailand: Petchabun , 5 km E Sila , 2.III.1994, Mae Nam Pa Sak , WDS-A-1025 William D. Shepard leg. | Collection W.D. Shepard”; CSS. – Phitsanulok Province • 22 ex.; “ THAILAND: 15.4.1996 Tung [=Thung] Salaeng NP, 600m 16°49′N 100°57′E Malicky & Chantaramongkol ”; NMW • 1 ex.; “THAIL.: Prov. Phitsanulok, 6km NNE Chat Trakan , Rd. 1237 km 5, Lam Nam Khwae, Noi Riv. trib., riffle & run, leafpacks, wood, gravel; rural farmland; c. 190 m asl, c. 17°17′N 100°38′E, 10. 1. 2009, leg. Freitag (6)”; CKB. – Songkhla Province • 8 ex. (three of the labels deviate slightly); “S-THAIL. 10.5. 1993 13km W Hat Yai , 50m, 6°59′N 100°22′ E Ban Ko Muang-Malicky ”; NMW. – Tak Province: 6 ♂♂, 7 ♀♀, 43 ex.; “ Thailand 91 Thanon Thong Chai D. Král & V. Kubáň | THAI, 26.IV.-6.V. 1991 UMPHANG 500m 16° 04′ N 98° 53′ E Vit Kubáň leg.”; CKB, NMW • 12 ex.; “ Thailand 91 Thanon Thong Chai D. Král & V. Kubáň | THAI, 26.IV.-6.V.[19]91 UMPHANG 500m 16° 04′ N 98° 53′ E David Král lgt.”; NMW • 1 ♀; “ Thailand 91 Thanon Thong Chai D. Král & V. Kubáň | THAI, 28/IV.-6/V.[19]91 UMPHANG river 16° 07′ N 99° 00′ E lgt. David Král 1000m ”; NMW .

VIETNAM – Dong Nai Province • 1 ex.; “VIETNAM: Nam Cat Tien , 11°26′N 107°26′E, 200 m, 17.- 25.6.1995 leg. Malicky ”; NMW. – Thua Thien Hue Province • 10 ex.; “ VIETNAM, Thua Thien Hue Pr ., Phong Điền Distr., Phong Mỹ , 16°31′15.3″N, 107°15′00.3″E, 27 m a.s.l., 18.11.2022, Selnekovič & Kodada leg. (15)”; CKB • 1 ex.; “C- VIETNAM, Thua Thien-Hue Prov. ca. 30 km W Hue , 80 m, 16°17′59″ N, 107°20′22″ E, 10.V.2019, by light river valley leg. A. Weigel | collection NATURKUNDEMUSEUM ERFURT”; NME .

Type locality

Thailand, Chiang Mai Province, Chom Thong.

Description

Measurements (mm): TL: ♂♂ 2.73–3.20 (3.00 ± 0.16, n =10), ♀♀ 2.78–3.25 (2.99 ± 0.14, n=10); PL: ♂♂ 0.59–0.73 (0.67 ± 0.04, n =10), ♀♀ 0.60–0.72 (0.66± 0.04, n=10); PW: ♂♂ 1.09–1.29 (1.21 ± 0.06, n=10), ♀♀ 1.11–1.27 (1.20± 0.05, n= 10); EL: ♂♂ 2.15–2.47 (2.34 ± 0.11, n=10), ♀♀ 2.18–2.54 (2.33 ± 0.11, n=10); EW: ♂♂ 1.30–1.50 (1.43± 0.07, n=10), ♀♀ 1.33–1.53 (1.42± 0.07, n= 10); PhL: 0.52–0.61 (0.57 ± 0.03, n=10); PrL: 0.34–0.37 (0.36 ± 0.01, n=10).

Body ovate, widest around midlength of elytra, moderately convex dorsally with highest point between first and second quarters of elytral length ( Fig. 8 ). Colouration black, except for reddish brown mouthparts, antennae, trochanters, and tarsi. Vestiture consisting of short thin decumbent yellowish setae. Plastron present on entire dorsal surface, except for narrow transverse area at middle of posterior pronotal margin. Plastron present on entire ventral surface, except for median keel of prosternal process and median part of metaventrite.

Head with dorsal surface entirely covered with plastron; and with round setiferous punctures, puncture diameter slightly smaller than eye facet, separated by 0.5–1.0 × puncture diameter. Labrum transverse, anterior margin straight, anterolateral angles rounded, exposed part microreticulate, with small setiferous punctures; setae short, arranged mostly along anterior margin. Anterior margin of clypeus straight. Eyes large, oval, protruding; ID: ♂♂ 0.37–0.45 mm (0.40 ± 0.02, n= 10), ♀♀ 0.39–0.43 mm (0.40 ± 0.01, n= 10). Antennae short, 11-segmented.

Pronotum transverse, widest at base, moderately convex, PW/PL: ♂♂ 1.71–1.88 (1.82± 0.06, n=10), ♀♀ 1.74–1.92 (1.82 ± 0.06, n=10); plastron present on entire surface, except for narrow transverse area at middle of posterior margin; round setiferous punctures slightly larger than those on head, separated by 2–3× puncture diameters. Anterior pronotal angles strongly deflexed, produced, acute; lateral sides convergent, weakly arcuated along entire length. Prosternal process with lateral and posterior sides rounded; lateral parts raised, without plastron; median keel strongly raised, without plastron. Scutellum longer than wide, smooth with several setiferous punctures. Metaventrite covered with plastron, except for median, posteriorly narrowed part; disc flat; lateral sides of metaventral process raised. Elytra oval, convex, widest slightly behind middle, EL/EW: ♂♂ 1.57–1.71 (1.64± 0.04, n =10), ♀♀ 1.59–1.68 (1.64 ± 0.03, n=10); surface entirely covered with plastron; small setiferous punctures scattered. Tibiae straight, male protibia slightly longer than protarsus, PTiL/PL: ♂♂ 1.12–1.25 (1.17± 0.04, n=10), ♀♀ 1.06–1.21 (1.13± 0.04, n=10). Terminal segment of male tarsus ca 1.2 × as long as all preceding segments combined; tarsal claws large, strongly curved.

Ventrites entirely covered with plastron. Lateral sides of intercoxal process slightly raised; admedian keels absent. Ventrite 5 evenly arcuate, narrowly truncate at apex. Aedeagus ( Fig. 9 ): phallobase short, slightly expanded proximally, PhL/PrL: 1.45–1.74 (1.59 ±0.09, n=10); parameres long, moderately curved ventrad, narrowly rounded at apices (lateral aspect); penis long, nearly reaching apices of parameres, narrowly rounded at apex; sclerotised fibula long and slender. Proximal and distal part of bursa copulatrix with large sclerotised spines on lateral parts ( Fig. 12B ).

Secondary sexual dimorphism

The average body size is similar in both sexes. The only apparent difference is the presence of a small subapical keel on the female ventrite 5.

Distribution

Cambodia, Laos, Myanmar, Thailand, and Vietnam ( Fig. 108B ).

Figures

Fig. 8. Elmomorphus siamensis Kodada, Selnekovič & Jäch sp. nov., paratype, male from Umphang, Thailand (CKB), TL: 3.00 mm.

Fig. 9. Elmomorphus siamensis Kodada, Selnekovič & Jäch sp. nov., paratype from Umphang, Thailand (CKB), aedeagus. A. Lateral aspect. B. Ventral aspect. Scale bar: 0.1 mm.

Fig. 12. Bursa copulatrix and vagina. A. Elmomorphus striatellus Delève, 1968, Cuc Phuong, Vietnam (CKB). B. E. siamensis Kodada, Selnekovič & Jäch sp. nov., paratype, Umphang, Thailand (CKB). C. E. parabrevicornis sp. nov., paratype from type locality (NMW). Scale bar: 0.1 mm.

Fig. 107. Habitats of selected species of Elmomorphus Sharp, 1888. A. Vietnam, Phong Mỹ, Sông Ô Lâu River (16°31′15.3″ N, 107°15′00.3″ E); E. striatellus Delève, 1968 and E. siamensis Kodada, Selnekovič & Jäch sp. nov. were found in clumps of leaves and on rootlets of Neptunia sp. B. Vietnam, Thành SƠn (20°30′01.4″ N, 105°06′19.3″ E); E. dentipes sp. nov., and E. similis sp. nov. were found in clumps of leaves.C. Vietnam, ThànhSƠn,Kho Mường(20°28′51.3″N,105°07′51.6″E); E. paramontanus Kodada, Selnekovič & Jäch sp. nov., E. similis sp. nov., and E. cf. sulcatus were found on submerged rootlets of bamboo and banana trees. D. Same locality, showing submerged rootlets. E. Vietnam, Trung Mỹ (21°23′35.3″N, 105°42′52.7″E); E. cf. sulcatus was found in clumps of leaves and on submerged rootlets of bamboo, Bauhinia sp., and Sterculia lanceolata Cav. F. Same locality, clump of leaves and partly submerged rootlets.

Fig. 108. Distribution maps. A. Elmomorphus striatellus Delève, 1968. B. E. siamensis Kodada, Selnekovič & Jäch sp. nov. C. E. parabrevicornis sp. nov. D. E. auripilosus sp. nov. E. E. auratus sp. nov. F. E. horaki Kodada, Selnekovič & Jäch sp. nov.

Fig. 7. Elmomorphus striatellus Delève, 1968, aedeagus, specimens from Sa Pa, Vietnam (CKB). A. Lateral aspect. B. Lateral aspect. C. Ventral aspect. Scale bar: 0.1 mm.