Microdytes maculatus (Motschulsky, 1860)

Okada, Ryohei, Jaitrong, Weeyawat & Wewalka, Guenther, 2023, A review of Microdytes J. Balfour-Browne, 1946 from Thailand, Laos, and Cambodia with descriptions of five new species and new records (Coleoptera, Dytiscidae), ZooKeys 1159, pp. 87-119 : 87

Microdytes maculatus (Motschulsky, 1860)

Figs 25 , 39C , 41

Hydrovatus maculatus Motschulsky, 1860: 42; Sharp 1882: 814, 973; Régimbart 1899: 231; Zaitzev 1915: 293; Zimmermann 1920: 34.

Desmopachria maculatus : Gschwendtner 1936: 367; Balfour-Browne 1946: 106 (uncertain assignment).

Microdytes maculatus : Vazirani 1969: 301; Vazirani 1977: 24; Satô 1981: 68; Wewalka 1997: 27; Biström et al. 1997: 75; Miller and Wewalka 2010: 35; Wewalka 2011: 29; Nilsson and Hájek 2023: 211.

Type locality.

"Ind or", "Dohen [a place with this name exists in Pakistan, Jammu and Kashmir Province, but it is very unlikely that this is the type locality]".

Material examined.

Thailand: Chiang Mai Province. 6♂♂, 1♀, Chom Thong District, Ban Luang St. 165 (alt. 360 m), 15.VIII.2020, R. Okada leg. (CGW, CRO) (Fig. 25 ) ; 9 exs., Mae Chaem District, Tha Pha St. 166 (alt. 720 m), 15.VIII.2020, R. Okada leg. (CGW, CRO) ; 1♂, 1♀, Chiang Dao District, Ping Khong St. 226 (alt. 430 m), 20.III.2021, R. Okada leg. (CRO) ; Chiang Rai Province. 3♀♀, Wiang Kaen District, Muang Yai St. 70 (alt. 470 m), 2.VIII.2019, R. Okada leg. (CRO) ; Lampang Province. 5♂♂, 9♀♀, Thoen District, Mae Pa St. 197 (alt. 200 m), 15.XI.2020, R. Okada leg. (CGW, CRO) ; Mae Hong Son Province. 3♂♂, Pai District, Mueang Paeng St. 93 (alt. 760 m), 1.XII.2019, R. Okada leg. (CRO) ; 3♂♂, 2♀♀, Pha Bong, ca. 12 km S Mae Hong Son , 12.XI.1995, H. Zettel leg (CGW, NMW); Phrae Province. 1♂, 15 km E Phrae , Mae Khaem , 16.XI.1995, H. Zettel leg. (NMW) ; Uttaradit Province. 2♂♂, 1♀, Nam Pat District, Saen To St. 184 (alt. 210 m), 13.IX.2020, R. Okada leg. (CRO) ; Phetchabun Province. 1♀, Huai Nam Phang , S Ban Nam Nao, 25.XI.1995, H. Zettel leg. (NMW) ; Bueng Kan Province. 2♂♂, Seka District, Ban Tong St. 206 (alt. 190 m), 27.XII.2020, R. Okada leg. (CGW, CRO) ; Nakhon Phanom Province. 12 exs, Bang Phaeng District, Phai Lom St. 203 (alt. 200 m), 27.XII.2020, R. Okada leg. (CGW, CRO) ; Sakon Nakhon Province. 1♀, Charoen Sin District, Huai Yang St. 208 (alt. 320 m), 29.XII.2020, R. Okada leg. (CRO) ; 2♂♂, 2♀♀, Tao Ngoi District, Nan Tan St. 210 (alt. 310 m), 29.XII.2020, R. Okada leg. (CGW, CRO) ; Ubon Ratchathani Province. 1♂, 1♀, Si Mueang Mai District, Nam Thaeng St. 221 (alt. 190 m), 26.II.2021, R. Okada leg. (CRO) ; 1♂, 1♀, Nam Yuen District, Dom Pradit St. 224 (alt. 190 m), 27.II.2021, R. Okada leg. (CRO) ; Kanchanaburi Province. 1♂, Si Sawat District, Na Suan St. 28 (alt. 310 m), 12.I.2019, R. Okada leg. (CRO) .

Laos: Luang Prabang Province. 4 exs., Thong Khan , 19°35'N, 101°58'E, alt. ca. 750 m, 11-12.V.2002, V. Kubáň leg. (CGW, NMB) .

Comments.

The lectotype of Microdytes maculatus (Fig. 41 ) has a rhomboid-like habitus similar to that of most specimens from Myanmar, northern Thailand, and China, while most specimens from northeastern Thailand and Laos have a more regularly rounded habitus, but this is not a discriminant character.

There is also a geographic variation in the shapes of the median lobe and the apical part of the parameres. In specimens from Myanmar, northern Thailand, and China, the two parts of the median lobe have obtuse apical medial angles (Fig. 42A ), and the parameres have narrow tips (Fig. 43A ), while in those of northeastern Thailand and western Laos the two parts of the median lobe have almost right apical medial angles (Fig. 42B ) and the parameres have rounded tips (Fig. 43B ). Because some specimens show an intermediate status and no other distinguishing character can be found, they are treated as geographic variations belonging to the same species. Molecular biological studies are required to establish if they are different species within a complex.

Distribution.

India: southern Andaman Islands; Myanmar: Chin and Shan states, Saganing Division; Thailand: Chiang Mai, Chiang Rai (first record), Lampang (first record), Lamphun, Mae Hong Son, Uttaradit (first record), Phetchabun (first record), Bueng Kan (first record), Mukdahan, Nakhon Phanom (first record), Sakon Nakhon (first record), Ubon Ratchathani (first record), and Kantchanaburi provinces, Khao Yai NP [Nakhon Ratchasima or Nakhon Nayok Province]; Laos: Vientiane, Luang Prabang (first record) and Khammouan provinces; China: Yunnan Province.

Figures

Figures 18 - 37. Habitus of 18 Microdytes akitai 19 M. balkei 20 M. dimorphus 21 M. feryi (paratype, from Myanmar) 22 M. franzi 23 M. gabrielae 24 M. heineri 25 M. maculatus 26 M. mariannae 27 M. menopausis 28 M. paoloi 29 M. pasiricus 30 M. pederzanii 31 M. rocchii 32 M. schoedli 33 M. schoenmanni (from Myanmar) 34 M. schwendingeri 35 M. shepardi 36 M. shunichii 37 M. zetteli. Scale bar: 1.0 mm.

Figures 38 - 40. Diagnostic characters of Microdytes species. 38 Impression of lateral side (M. maximiliani sp. nov.) 39 ventral surface A with setae (M. heineri) B with very coarse punctures (M. schoedli) C with coarse punctures (M. maculatus) D with fine punctures (M. balkei) E with very fine punctures (M. jeenthongi sp. nov.) 40 clypeus bead A not bordered (M. ubonensis sp. nov.) B finely bordered (M. schwendingeri) C produced (M. dimorphus).

Figures 41 - 43. 41 Lectotype of Microdytes maculatus (photograph by Christophe Rivier, Museum national d'histoire naturelle, Paris) 42 median lobe of A M. maculatus from northern Thailand B from northeastern Thailand C M. eliasi sp. nov. 43 paramere of A M. maculatus from northern Thailand B from northeastern Thailand C M. eliasi sp. nov.