Dineutus spinosus ( Fabricius, 1781 )

Suksai, Benjamart, Gustafson, Grey T., Sites, Robert W. & Sangpradub, Narumon, 2021, The Gyrinidae (Coleoptera) fauna of Thailand: Key to tribes and genera, with new records and keys to species of Dineutini and Gyrinini, Zootaxa 5071 (1), pp. 97-117 : 106-108

publication ID

https://doi.org/10.11646/zootaxa.5071.1.5

publication LSID

lsid:zoobank.org:pub:C7DFE939-E932-4570-8496-7A67A51D4D7A

DOI

https://doi.org/10.5281/zenodo.5725475

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https://treatment.plazi.org/id/03DC697B-FF80-FFD5-77CA-FC60FE77FD3E

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scientific name

Dineutus spinosus ( Fabricius, 1781 )
status

 

Dineutus spinosus ( Fabricius, 1781)

( Figs. 1F, 1J View FIGURE 1 , 4C View FIGURE 4 , 5J–M View FIGURE 5 , 7C, 7E View FIGURE 7 , 8A View FIGURE 8 )

Material examined. THAILAND: Amnat Charoen Province: Kork Stream, Kham Khuean Kaeo Subdistrict, Chanuman District , 16°12'29.9"N 104°52'11.6"E, 188 m a.s.l., 23.XII.2017, leg. B. Suksai, 2 males, 4 females ( THNHM) GoogleMaps . Kalasin Province: Phu Pan Natl. Park, water supply pond at Park HQ, 16°47'38.8"N 103°50'37.8"E, 7.VI.1998, leg. K.B. Simpson & A. Vitheepradit, L-165, 1 male ( UMC) GoogleMaps . Mukdahan Province: Huai Lao Waterfall, Ban Kho Subdistrict, Khamcha-I District , 16°44'36.9"N 104°21'04.7"E, 226 m a.s.l., 22.XII.2017, leg. B. Suksai, 1 female ( THNHM) GoogleMaps ; Tadton Waterfall, Non Yang Subdistrict, Nong Sung District , 16°29'40.2"N 104°18'47.6"E, 208 m a.s.l., 22.XII.2017, leg. B. Suksai, 1 female ( THNHM) GoogleMaps . Nakhon Ratchasima Province: Sakaerat Environmental Research Station, Bon weir, U-dom Sap Subdistrict , Wang Nam Khiao District , 14°29'49.2"N 101°54'55.5"E, 472 m a.s.l., 27.III.2018, leg. P. Chanteenok, 1 male ( THNHM) GoogleMaps ; same locality except for, 29.III.2018, leg. P. Chanteenok, 1 male, 1 female ( THNHM) GoogleMaps ; Thap Lan Natl. Park, Khok Krachai Subdistrict, Khon Buri District , 14°20'13.6''N 102°14'48.0''E, 224 m a.s.l., 27.IV.2014, leg. K. Piraonapicha, 7 males, 8 females ( KKU, THNHM) GoogleMaps ; same locality except for, Wang Tao Waterfall, Khok Krachai Subdistrict, Khon Buri District , 14°19'52.0''N 102°14'05.0''E, 224 m a.s.l., 23.III.2013, leg. K. Piraonapicha, 2 males, 4 females ( KKU) GoogleMaps . Nakhon Si Thammarat Province: Chulabhorn District , 56 km N of Phatthalung, 8°03'N 99°53'E, 21 m a.s.l., 31.V.2003, leg. A. Vitheepradit & M.L. Ferro, L-583, 7 males, 6 females ( UMC) GoogleMaps . Sisaket Province: Huay Sala Wildlife Sanctuary, Sum Sai Waterfall , 14°31.894'N 104°20.419'E, 202 m a.s.l., 12.IV.2004, leg. R.W. Sites & A. Vitheepradit, L-622, 5 males, 3 females ( UMC) GoogleMaps . Songkhla Province: Prince of Songkla University , 2.V.1993, leg. Apinya, 1 female ( UMC) . Surat Thani Province: Ban Tha Rau Tai, Ban Na Doem District , 8°56.567'N 99°15.130'E, 4 m a.s.l., 20.VI.2004, leg. A. Vitheepradit & T. Prommi, L-782, 1 female ( UMC) GoogleMaps . Ubon Ratchathani Province: Huay Sae Stream, Na Pho Klang Subdistrict, Khong Chiam District , 15°32'05.2"N 105°31'06.7"E, 131 m a.s.l., 23.XII.2017, leg. B. Suksai, 3 males, 2 females ( THNHM) GoogleMaps .

Diagnosis. Male ( Fig. 1F View FIGURE 1 ): Size: 6.4–8.0 mm. Body form oval; apex of flagellomere VI lightly colored; elytral apices weakly serrate, with parasutural and epipleural spines ( Fig. 5J View FIGURE 5 ); lateral margin of pronotum and elytron orange or yellow ( Fig. 1F View FIGURE 1 ); protrochanter apically with single series of few setae on ventral surface ( Fig. 4C View FIGURE 4 ); profemur without sub-apicoventral tooth; protibia wedge-shaped; venter yellow to brown ( Fig. 1J View FIGURE 1 ), epipleura yellow ( Fig. 1J View FIGURE 1 ); aedeagus ( Figs. 5K–L View FIGURE 5 ) with median lobe shorter than parameres, parallel-sided for 2/3 length, slightly narrowed in apical half, acuminate in apical fifth, with tip narrowly rounded, weakly straight in lateral view.

Female: Similar to male except for size: 6.9–8.1 mm; gonocoxae elongate, lateral margin rounded, apex weakly rounded ( Fig. 5M View FIGURE 5 ).

Differential diagnosis. Dineutus spinosus can be distinguished from congeners in Thailand by the lightly colored margin of the pronotum and elytron and by the spinose elytral apex having both parasutural and epipleural spines developed ( Table 1 View TABLE 1 ). No other species of Dineutus in Thailand has this combination of characters. Porrorhynchus marginatus has these features as well, but is much larger in size and can be distinguished by the elongate, triangular labrum in addition to other features of the forelegs.

Distribution. This is a widespread species found in the eastern portion of the Indian subcontinent and throughout Southeast Asia from Sri Lanka and eastern India through Assam, Bangladesh, Myanmar, Thailand, Laos, as far east as Vietnam ( Ochs 1929, 1930; Mouchamps 1949; Brinck 1981; Vazirani 1984), and as far south as Singapore ( Hendrich et al. 2004), Sumatra ( Ochs 1929), and Borneo ( Ochs 1928).

Habitat. It occurs on exposed rivers, streams, ponds, and water tanks ( Figs. 7C, E View FIGURE 7 ). ( Brinck 1981).

Discussion. Dineutus spinosus is currently known from only the northeastern and southern regions of Thailand ( Fig. 8A View FIGURE 8 ) where it occurs at low to medium elevations (4–472 m a.s.l.). It has not been found at high elevation. We suspect that it might occur in other localities in Thailand with the same habitats at similar elevations. Both D. spinosus and the similar congener D. orientalis , which has a primarily more eastern and northern distribution, are known to co-occur in Laos and Vietnam ( Mouchamps 1949; Brinck 1981). The latter species has yet to be encountered in Thailand and was not found during our surveys, despite extensive sampling in northeastern Thailand near the Laotian border ( Fig. 8A View FIGURE 8 ).

Brinck, P. (1981) Taxonomic status and evolutionary trends in the whirligig beetle taxon Spinosodineutes (Coleoptera: Gyrinidae). Entomologia Generalis, 7 (1), 17 - 32. https: // doi. org / 10.1127 / entom. gen / 7 / 1981 / 17

Fabricius, J. C. (1781) Species Insectorum, exhibentes eorum differentias specificas, synonyma auctorum, loca natalia, metamorphosin, adjectis observationibus, descriptionibus. Tome 1. Hamburgi et Kilonii, xxiv + 687 pp. https: // doi. org / 10.5962 / bhl. title. 36509

Hendrich, L., Balke, M. & Yang, C. M. (2004) Aquatic Coleoptera of Singapore: Species richness, ecology and conservation. The Raffles Bulletin of Zoology, 52, 97 - 145.

Mouchamps, R. (1949) Contribution a la systematique des coleopteres gyrinides I. Dineutus (Spinosodineutes) Hatch. Bulletin & Annales de la Societe Entomologique de Belgique, 85, 216 - 264.

Ochs, G. (1928) Uber die Gyriniden Borneo's. Entomologische Blatter, 24, 41 - 45 + 78 - 85 + 93 - 103.

Ochs, G. (1929) Papers on Malayan aquatic biology. X. Additional notes on the Gyrinidae. Journal of the Federated Malay States Museums, 14 (3 - 4), 401 - 403.

Ochs, G. (1930) Catalogue of Indian insects. Part 19. Gyrinoidea. Government of India Central Publications Branch, Calcutta, 39 pp.

Vazirani, T. G. (1984) The fauna of India. Coleoptera. Family Gyrinidae and family Haliplidae. Zoological Survey of India, Calcutta, 138 pp.

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FIGURE 1. Habitus of Gyrinini and Dineutini species: (A) Gyrinus sericeolimbatus, dorsal view, female; (B) G. smaragdinus, dorsal view, male; (C–D) Dineutus australis, dorsal view: (C) male; (D) female; (E) D. sitesi, dorsal view, male; (F) D. spinosus, dorsal view, male; (G) D. unidentatus, dorsal view, male; (H) Porrorhynchus marginatus, dorsal view, male; (I) D. sitesi, ventral view, male; (J) D. spinosus, ventral view, male. Scale bars = 3 mm.

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FIGURE 4. SEM photographs of protochanters in species of Dineutus and Porrorhynchus (males): (A) D. australis, patch of thick setae (arrow), scale bar = 100 μm; (B) D. sitesi, protrochanter without setae (arrow), scale bar = 1 mm; (C) D. spinosus, setae (arrow), scale bar = 100 μm; (D) D. unidentatus, setae (arrow), scale bar = 100 μm; (E–F) P. marginatus, cluster setae (square and arrow): (E) scale bar = 500 μm; (F) scale bar = 100 μm.

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FIGURE 5. Elytral apex, aedeagus and gonocoxae of species of Dineutus: (A–E) D. australis: (A–B) elytral apex, scale bar = 2 mm: (A) male; (B) female; (C–D) aedeagus, scale bar = 0.5 mm: (C) dorsal view; (D) lateral view; (E) gonocoxae, ventral view, scale bar = 0.5 mm; (F–I) D. sitesi: (F) male elytral apex, scale bar = 2 mm; (G–H) aedeagus, scale bar = 1 mm: (G) dorsal view; (H) lateral view; (I) gonocoxae, ventral view, scale bar = 1 mm; (J–M) D. spinosus: (J) male elytral apex, scale bar = 2 mm, (K–L) aedeagus, scale bar = 0.5 mm: (K) dorsal view; (L) lateral view; (M) gonocoxae, ventral view, scale bar = 0.5 mm.

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FIGURE 7. Habitats of species of Gyrinini and Dineutini: (A–B) G. smaragdinus: (A) stream at Siriphum Waterfall, Doi Inthanon Natl. Park, Chiang Mai Province; (B) pond at Ban Buak Thoei, Chiang Mai Province; (C) D. australis, D. spinosus and D. unidentatus, pond at Sakaerat Environmental Research Station, Nakhon Ratchasima Province; (D) D. sitesi, Tum Din Stream, Thung Salaeng Luang Natl. Park, Phitsanulok Province; (E) D. spinosus, Huay Sae Stream, Ubon Ratchathani Province; (F–G) D. unidentatus, ponds at Ban Kho, Khon Kaen Province; (H) P. marginatus, Lam Takong Stream, Nakhon Ratchasima Province.

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FIGURE 8. (A–B) Distributions of species of Dineutini and Gyrinini in Thailand.

KKU

Herbarium, Department of Biology, Khon Kaen University

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Coleoptera

Family

Gyrinidae

Tribe

Dineutini

Genus

Dineutus