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Research Article
A review of Microdytes J. Balfour-Browne, 1946 from Thailand, Laos, and Cambodia with descriptions of five new species and new records (Coleoptera, Dytiscidae)
expand article infoRyohei Okada‡§, Weeyawat Jaitrong‡, Günther Wewalka|
‡ Thailand Natural History Museum, National Science Museum, Pathum Thani, Thailand
§ Coleopterological Society of Japan, National Museum of Nature and Science, Tsukuba, Japan
| Unaffiliated, Vienna, Austria

Corresponding author: Ryohei Okada ( wasserinsekt@kub.biglobe.ne.jp )

Academic editor: Mariano Michat
© 2023 Ryohei Okada, Weeyawat Jaitrong, Günther Wewalka.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation: Okada R, Jaitrong W, Wewalka G (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: 87-119. https://doi.org/10.3897/zookeys.1159.99218
ZooBank: urn:lsid:zoobank.org:pub:CD97DD12-0549-412F-9765-08D8DE21605B
Open Access

Abstract

The diving beetle genus Microdytes J. Balfour-Browne, 1946 in Thailand, Laos, and Cambodia is reviewed, and five new species are described: Microdytes eliasi Wewalka & Okada, sp. nov. (Thailand, Cambodia), M. jeenthongi Okada & Wewalka, sp. nov. (Thailand), M. maximiliani Wewalka & Okada, sp. nov. (Laos, China), M. sekaensis Okada & Wewalka, sp. nov. (Thailand, Laos), M. ubonensis Okada & Wewalka, sp. nov. (Thailand, Laos). Two species are the first country records: M. balkei Wewalka, 1997 (Laos, Cambodia) and M. wewalkai Bian & Ji, 2009 (Laos). For 12 and 8 species, the first provincial records from Thailand and Laos, respectively, are given. A checklist, a key to the 25 known Microdytes species from these countries, and habitus images and illustrations of diagnostic characters are provided. Distribution maps of the recorded species are presented, and species distribution patterns are also briefly discussed.

Keywords

Diving beetles, faunistics, key to species, Southeast Asia, taxonomy, zoogeography

Introduction

The dytiscid genus Microdytes J. Balfour-Browne, 1946 contains 47 described species classified in the tribe Hyphydrini of the subfamily Hydroporinae (Nilsson and Hájek 2023). These minute diving beetles (adult length up to 2.3 mm) generally occur in small seeps, springs, and streams, and a few are also known to inhabit subterranean and hygropetric environments (Wewalka 1997; Wewalka et al. 2007; Sheth et al. 2020). Microdytes species occur throughout southern and southeastern Asia from Nepal to southern India to southern China, southern Japan, Philippines, and Indonesia (Miller and Wewalka 2010). So far, 16 species were recorded from Thailand, and this country was regarded as the center of distribution of the genus by Wewalka (1997, 2011).

During 2018–2022, as part of the field survey by the senior author to reveal diversity of Thailand diving beetles, a total of 228 Microdytes specimens were collected from 30 localities. For comparative purposes, we also studied specimens from Thailand, Laos, and Cambodia, mainly collected as part of the “NHMB Basel, Laos Expeditions” in 2011 and 2012 (Geiser and Nagel 2013).

In this paper, we describe five new species from Thailand, Laos, and Cambodia, increasing the number of known Microdytes species to 52. New and first regional records from those countries are also given. A checklist and a key to all Microdytes species known from these countries are provided. To facilitate the identification of the species, photographs of habitus and discriminant characters are provided for the first time. Distribution maps of the recorded Microdytes species are also presented, and their distribution patterns and microhabitat preferences are briefly discussed.

Materials and methods

The study was based on the examination of 695 specimens: 241 from Thailand, 420 from Laos, and 34 from Cambodia. These specimens are deposited in the following institutions and private collections:

CGW Collection Günther Wewalka, Vienna, Austria;

CRO Collection Ryohei Okada, Tokyo, Japan;

MNHN Muséum National d’Histoire Naturelle, Paris, France;

NMB Naturhistorisches Museum, Basel, Switzerland;

NMP National Museum (Natural History), Prague, Czech Republic;

NMW Naturhistorisches Museum Wien, Vienna, Austria;

THNHM Thailand Natural History Museum, Pathum Thani, Thailand.

Beetles were pin mounted on square or triangular card points. Male genitalia were dissected, then put on cards for detailed observation. The holotypes, paratypes, and lectotype of the closely related species were examined. Specimens from Myanmar were also used for comparisons.

The beetles were studied with an Olympus SZX10 compound microscope equipped with Nomarsky optics up to 1000×. Habitus photographs were taken using a Canon EOS 7D Mark II digital camera with attached Canon MP-E65 mm f/2.8 macro lens with 5:1 optics. Male genitalia were illustrated wet, using an Olympus BHT transmitted light microscope with a RICOH GX6 attachment. Composite images were created using the image stacking software Helicon Focus (Helicon Soft Ltd., Kharkov), and subsequently edited with Adobe Photoshop elements (2008) (Adobe Systems Inc., USA) where necessary.

The terminology to denote the orientation of the genitalia follows Miller and Nilsson (2003); the style of the descriptive notes follows Wewalka (1997, 2011) and Miller and Wewalka (2010).

Body measurements were made with a compound microscope equipped with a micrometer eyepiece. The abbreviations of measurements used in this study are as follows: TL (total body length), TL-H (body length without head), MW (maximum width of body). The ratio TL/MW was also calculated. Measurements of holotypes are added between round brackets. Label data of holotype specimens are cited between quotation marks. A backslash (\) indicates separate labels. Our comments are given between square brackets.

All localities where Microdytes species were recorded in Thailand, Laos, and Cambodia are shown in Fig. 1. Literature records (Wewalka 1997, 2011) and additional records in this study are symbolized separately. For interpretation of distribution patterns of Microdytes, we mapped the recorded localities onto terrestrial ecoregions as defined by Olson et al. (2001). The main ecoregions for the distributions of species in Thailand, Laos, and Cambodia are abbreviated as follows:

Figure 1. 

Known localities of Microdytes species in Thailand, Laos, and Cambodia, including literature records, sampling sites and additional records in this study. For those records where specific information of province was not reported, the location was mapped by dotted lines. Ecoregion classification is given following Olson et al. (2001). Thailand: 1 Mae Hong Son 2 Chiang Mai 3 Chiang Rai 4 Lampang 5 Lamphun 6 Phrae 7 Nan 8 Uttaradit 9 Phitsanulok 10 Phetchabun 11 Chaiyaphum 12 Loei 13 Bueng Kan 14 Nakhon Phanom 15 Sakon Nakhon 16 Mukdahan 17 Ubon Ratchathani 18 Tak 19 Uthai Thani 20 Kanchanaburi 21 Saraburi 22 Nakhon Ratchasima 23 Nakhon Nayok 24 Sa Kaeo 25 Chonburi 26 Rayong 27 Chanthaburi 28 Trat. Laos: 29 Phongsaly 30 Luang Namtha 31 Oudomxay 32 Luang Prabang 33 Vientiane 34 Bolikhamxai 35 Khammouane 36 Savannakhet 37 Sekong 38 Champasak 39 Attapeu.

T Thailand;

L Laos;

C Cambodia;

KAY Kayah-Karen montane rain forest;

NIN northern Indochina subtropical forests;

LUA Luang Prabang montane rain forests;

NAN northern Annamites rain forests;

NKH northern Khorat Plateau moist deciduous forests;

SEI southeastern Indochina dry evergreen forests;

CIN central Indochina dry forests;

CAR Cardamom Mountains rain forests;

CHA Chao Phraya lowland moist deciduous forests.

Results

Descriptions

Microdytes eliasi Wewalka & Okada, sp. nov.

https://zoobank.org/8C12C23B-3B90-4F46-9D48-F5ABD6625734
Figs 2, 7, 12, 42C, 43C

Type locality

Cambodia, Koh Hong Province, 20 km SW Koh Hong, Tatai River, 11°34'N, 103°07'E, alt. 50–300 m.

Type material

Holotype (NMB): ♂ “Cambodia SW, Tatai riv. 20 km SE Koh Hong 11°34'N, 103°07'E, 3.–19.v.2005, 50–300 m, E. Jendek, O. Šauša leg.” [printed white label] \ “HOLOTYPUS Microdytes eliasi sp. nov. Wewalka & Okada 2022” [printed red label]. Paratypes: (47 exs.): 7♂♂, 14♀♀, with same data as the holotype (CGW, CRO, NMB, NMP); 2♂♂, Thailand, Saraburi Province, Kaeng Khoi District, Ched Khot St. 122 (alt. 140 m), 14°28'26"N, 101°09'59"E, 30.V.2020, R. Okada leg. (CRO, THNHM); 4♂♂, 4♀♀, Thailand, Sa Kaeo Province, Mueang Sa Kaeo District, Ban Kaeng St. 277 (alt. 80 m), 13°58'47"N, 102°11'29"E, 30.I.2022, R. Okada leg. (CGW, CRO, THNHM); 2♂♂, 3♀♀, Thailand, Chonburi Province, Bo Thong District, That Thong St. 107 (alt. 100 m), 13°15'01"N, 101°22'34"E, 14.III.2020, R. Okada leg. (CGW, CRO, THNHM); 2♂♂, 2♀♀, same locality St. 298 (alt. 100 m), 13.VII.2022, R. Okada leg. (CGW, CRO); 1♀, same province, Si Racha District, Bang Phra St. 269 (alt. 90 m), 13°14'39"N, 101°02'20"E, 26.XII.2021, R. Okada leg. (CRO); 3♂♂, 2♀♀, Thailand, Chanthaburi Province, Khaeng Hong Maeo District, Kaeng Hong waterfall St. 257 (alt. 160 m), 13°02'57"N, 101°45'35"E, 26.VI.2021, R. Okada leg. (CGW, CRO, THNHM); 1♀, same district, Kha riv. St. 258 (alt. 90 m), 12°57'38"N, 101°46'30"E, 26.VI.2021, R. Okada leg. (CRO). All paratypes are provided with printed red paratype labels.

Diagnosis

Microdytes eliasi sp. nov. very closely resembles M. maculatus (Motschulsky, 1860) (Figs 25, 41) in size and coloration but differs from this species by the more regularly oval habitus, the laterally expanded median lobe at apex and constricted tips of paramere (Figs 12, 42C, 43C) (see also comments in M. maculatus). It is also similar to M. feryi Wewalka, 2011 (Fig. 21) in habitus and coloration, but it is smaller and can be distinguished by male genitalia [compared with a male paratype from Myanmar, “Tenasserim, Birma Coll. V. Helfer National Museum Prague” (CGW)].

Description

Measurements. TL = 1.64–1.85 mm (1.76 mm), TL-H = 1.49–1.65 mm (1.55 mm), MW = 1.12–1.25 mm (1.24 mm), TL/MW = 1.33–1.44 (1.42). Body regularly oval, moderately convex (Fig. 2).

Coloration. Head reddish brown. Pronotum reddish brown, narrowly dark brown along anterior and posterior margins. Elytron dark brown with yellowish brown markings forming a distinct transverse band near base not reaching suture connected along lateral margin with a post-median transverse lateral band, with a small post-median spot near suture, and a triangular spot near apex (Figs 2, 7). Ventral surface of head, prothorax and elytral epipleuron yellowish brown; thorax and abdominal ventrites reddish brown to dark brown. Legs, antennae and palpi yellowish brown.

Figures 2–6. 

Habitus of 2 Microdytes eliasi sp. nov., female, paratype 3 M. jeenthongi sp. nov., male, holotype 4 M. maximiliani sp. nov., male, holotype 5 M. sekaensis sp. nov., male, holotype 6 M. ubonensis sp. nov., male, holotype. Scale bar: 1.0 mm.

Figures 7–11. 

Variation of markings of 7 Microdytes eliasi sp. nov. 8 M. jeenthongi sp. nov 9 M. maximiliani sp. nov. 10 M. sekaensis sp. nov. 11 M. ubonensis sp. nov. Scale bar: 1.0 mm.

Sculpture and structure. Head finely, sparsely, and relatively regularly punctured; anterior half to two-thirds finely microreticulate; clypeus not bordered. Pronotum quite regularly, sparsely, and fairly strongly punctured, with coarser punctures along posterior margin; without microreticulation; lateral margins finely bordered, regularly rounded. Elytron quite regularly, moderately densely and fairly strongly punctured, progressively finer and sparser towards lateral margin; without longitudinal rows of stronger punctures; highly polished and shining; without microreticulation. Ventral surface: metacoxae and metasternum strongly but sparsely punctured, abdomen finely and sparsely punctured; without microreticulation.

Male. The two parts of the median lobe expanded laterally at apex in ventral aspect (Figs 12A, 42A); slightly curved in lateral aspect (Fig. 12B). The tips of parameres twisted in lateral aspect (Fig. 12C, D); constricted in ventral aspect (Fig. 43C).

Figures 12–14. 

12 Microdytes eliasi sp. nov. 13 M. jeenthongi sp. nov. 14 M. maximiliani sp. nov. A median lobe in ventral aspect B median lobe in lateral aspect C left paramere in lateral aspect D right paramere in medial aspect. Scale bar: 0.25 mm.

Female. Without secondary sexual characters. Sclerotized spermatheca not found.

Variation

Variation of markings is shown in Fig. 7.

Etymology

This species is dedicated to Elias Bramböck, Vienna, Austria. The species epithet is a name in the genitive singular.

Habitat

In Thailand, this species was collected in small streams at low altitude lower than 200 m (Fig. 45).

Distribution

Thailand: Saraburi, Sa Kaeo, Chonburi, and Chanthaburi provinces; Cambodia: Koh Hong Province.

Microdytes jeenthongi Okada & Wewalka, sp. nov.

https://zoobank.org/D3B3AE52-D18B-49E8-AAB7-E0DC2F5E6CD1
Figs 3, 8, 13, 39E

Type locality

Thailand, Chiang Mai Province, Mae Chaem District, Tha Pha, 18°30'46"N, 98°25'25"E, alt. 720 m.

Type material

Holotype (THNHM): ♂, “THAI: Chiang Mai Mae Chaem Dist., Tha Pha St. 166 (alt. 720 m) 15.VIII.2020” [printed white label] \ “HOLOTYPE Microdytes jeenthongi sp. nov. Okada & Wewalka 2022 [printed red label]”. Paratypes (3 exs.): 2♂♂, same data as the holotype (CGW, NMW); 1♂, same locality, 4.VII.2020, R Okada leg (CRO). All paratypes are provided with printed red paratype labels.

Diagnosis

Microdytes jeenthongi sp. nov. resembles M. shunichii Satô, 1995 (Fig. 36) and M. zetteli Wewalka, 1997 (Fig. 37) in habitus, coloration and very finely punctured metasternum and metacoxae. From M. shunichii it differs by the reddish brown pronotum and very finely and sparsely punctured elytra. From M. zetteli it can be distinguished by larger size, less finely and sparsely punctured head.

Description

Measurements. TL = 1.77–1.82 mm (1.79 mm), TL-H = 1.23–1.26 mm (1.26 mm), MW = 1.18–1.23 mm (1.23 mm), TL/MW = 1.46–1.50 (1.49). Body regularly oval, moderately convex (Fig. 3).

Coloration. Head reddish brown. Pronotum reddish brown, along the anterior margin narrowly and along the posterior margin more widely dark brown, especially medially. Elytron dark brown with a distinct transverse band at the base not reaching suture, continuing along the margin to a post-median transverse band and a triangular spot near the apex, and a small round post-median spot near suture (Figs 3, 8). Ventral surface of head and prothorax yellowish brown; thorax, abdominal ventrites and elytral epipleuron reddish brown to dark brown. Legs, antennae and palpi yellowish brown.

Sculpture and structure. Head finely and sparsely, slightly irregularly punctured; anterior forth finely microreticulate; clypeus not bordered. Pronotum punctured moderately irregularly, finely, and sparsely, very coarsely along posterior margin; without microreticulation; lateral margins finely bordered, regularly rounded. Elytron very sparsely and finely punctured, progressively finer and sparser towards lateral margin; one longitudinal row of punctures distinct; highly polished and shining; without microreticulation. Ventral surface: metasternum and metacoxae very finely, sparsely, and irregularly punctured; abdomen almost without punctures; without microreticulation.

Male. The two parts of the median lobe expanded and pointed at apex forming the unique arrowhead shape in ventral aspect (Fig. 13A); almost straight and slightly expanded downwards at apex in lateral aspect (Fig. 13B). Parameres moderate triangular in lateral aspect (Figs 13C, D).

Female. Unknown.

Variation

Variation of markings is shown in Fig. 8.

Etymology

This species is dedicated to Tadsanai Jeenthong, collection manager of National Science Museum, Thailand. The species epithet is a name in the genitive singular.

Habitat

This species was collected in a small, shallow stream with gravel bottom flowing through a small valley. In this stream, specimens were collected from a restricted point where tree roots were exposed along the river bottom (Fig. 46).

Distribution

Thailand: Chiang Mai Province.

Microdytes maximiliani Wewalka & Okada, sp. nov.

https://zoobank.org/E1377AC3-9A63-4D0A-BEEF-FEEFA69E26F3
Figs 4, 9, 14, 38

Type locality

Laos, Louang Namtha Province, 10 km E Muang Sing, 21°09–10'N, 101°13–15'E, alt. 750–1400 m.

Type material

Holotype (NMB): ♂, “Laos, Louang Namtha prov., 10 km E Muang Sing, 750–1400 m, Ban Oudonsinh B. Nam Det \ B. Nam Mai, 21°09–10'N \ 101°13–15'E, 14.–20.V.2011” \ “NHMB Basel Laos 2011 Expedition D. Hauk & M. Geiser” [printed white labels] \ “HOLOTYPUS Microdytes maximiliani sp. nov. Wewalka & Okada 2022” [printed red label]. Paratypes (4 exs.): 2♂♂, 1♀, with same data as the holotype (CGW, NMB, NMP); 1♀, China: Yunnan, Xishuangbanna, ca. 10 km NW Menglun, ca. 700–800 m, 7.XI.1999, M. Jäch et al. (CWBS 360) (NMW). All paratypes are provided with printed red paratype labels.

Diagnosis

Microdytes maximiliani sp. nov. resembles M. satoi Wewalka, 1997 in coloration of pronotum and elytra but differs from this species by darker head, larger size, a distinct impression on lateral side in anterior third of elytron (Fig. 38) and male genitalia. It is similar to M. paoloi Wewalka, 2011 in size and coloration of pronotum but can be distinguished by elytral markings, the impression on lateral side of elytron and male genitalia. The shape of median lobe of aedeagus of M. maximiliani is very similar to that of M. schoenmanni Wewalka, 1997, but this species is much smaller and differs in coloration, punctation and a missing impression on lateral side of elytron.

Description

Measurements. TL = 1.60–2.00 mm (1.86 mm), TL-h = 1.40–1.80 mm (1.61 mm), MW = 1.30–1.35 mm (1.30 mm), TL/MW = 1.23–1.43 (1.43). Body broad and regularly oval, quite convex (Figs 4, 38).

Coloration. Head dark reddish brown, darker on vertex and along eyes. Pronotum dark brown. Elytron dark brown with yellowish brown markings forming a distinct transverse band near base not reaching suture and lateral margin, a post-median lateral spot often connected with a triangular spot near apex (Figs 4, 9). Elytral epipleuron and ventral surface dark brown to black. Legs, antennae and palpi reddish brown.

Sculpture and structure. Head finely and sparsely punctured, stronger punctures along eyes and on vertex; with fine microreticulation missing on vertex; clypeus not bordered. Pronotum irregularly punctured with sparse fine punctures and strong punctures concentrated along posterior margin and sparsely on disc; without microreticulation; lateral margins finely bordered, scarcely rounded. Elytron quite regularly, moderately densely and fairly strongly punctured, with traces of two longitudinal rows of punctures; highly polished and shining; without microreticulation; with a distinct impression on lateral side in anterior third (Fig. 38). Ventral surface: metacoxae, metasternum and abdomen moderately strongly but very sparsely punctured; without microreticulation.

Male. Median lobe of aedeagus in ventral aspect slightly tapered from base to apex, expanded before apex, apex truncate (Fig. 14A); in lateral aspect straight, tapered in apical ninth, apex bent downwards (Fig. 14B). Parameres narrow triangular in lateral aspect (Fig. 14C, D).

Female. Without secondary sexual characters. Sclerotized spermatheca not found.

Variation

Variation of markings is shown in Fig. 9.

Etymology

This species is dedicated to Maximilian Bramböck, Vienna, Austria. The species epithet is a name in the genitive singular.

Habitat

The species was collected in Yunnan in a 1–2-m wide stream flowing through dense primary forest (Jäch and Ji 2003).

Distribution

Laos: Louang Namtha Province; China: Yunnan Province.

Microdytes sekaensis Okada & Wewalka, sp. nov.

https://zoobank.org/FC40E421-E223-493B-A4C8-9F9B94978DE2
Figs 5, 10, 15

Type locality

Thailand, Bueng Kan Province, Seka District, Ban Tong, 18°08'16"N, 103°59'35"E, alt. 190 m.

Type material

Holotype (THNHM): ♂, “THAI: Bueng Kan Seka Dist., Ban Tong St. 206 (alt. 190 m) 28.XII.2020 R. Okada leg. \ HOLOTYPE Microdytes sekaensis sp. nov. Okada & Wewalka 2022” [printed red label]. Paratypes (37 exs.): 1♂, with same data as the holotype (CGW); 36 exs., Laos, Bolikhamsay Province, Nam Kading NPA, Tad Paloy campsite, 18°21–23'N, 104°09'E, alt. 250–400 m, 24.–28.V.2011, NHMB Basel Laos 2011 Expedition, M. Geiser, D. Hauk, A. Phantala & E. Vongphachan leg. (CGW, CRO, NMB, NMP). All paratypes are provided with printed red paratype labels.

Diagnosis

Microdytes sekaensis sp. nov. resembles M. hainanensis Wewalka, 1997 and M. schwendingeri Wewalka, 1997 (Figs 34, 40B) in habitus and size but differs by elytral markings and clypeus not bordered. Size and coloration of M. sekaensis sp. nov. is also similar to those of M. gabrielae Wewalka, 1997 (Fig. 23), but it is distinguishable from the latter by the more rounded-oval body and finely and sparsely punctured ventral surface.

Description

Measurements. TL = 1.34–1.36 mm (1.36 mm), TL-h = 0.92–0.93 mm (0.93 mm), MW = 0.99–1.01 mm (1.01 mm), TL/MW = 1.35–1.36 (1.35). Body broadly oval, strongly convex (Fig. 5).

Coloration. Head yellowish brown. Pronotum yellowish brown, along posterior margin narrowly dark brown. Elytron reddish brown to dark brown with two yellowish brown spots: one basal spot not reaching base, one anterior lateral spot continuing along the lateral margin to a post-median lateral spot and a transverse spot near apex, also with a round median spot near suture (Figs 5, 10). Ventral surface predominantly yellowish brown. Legs, antennae and palpi yellowish brown.

Sculpture and structure. Head very finely and sparsely, slightly irregularly punctured; entirely and distinctly microreticulate; clypeus not bordered. Pronotum quite irregularly, finely, and sparsely punctured on the disc, additionally with coarser punctures at medial part of posterior margin; without microreticulation; lateral margins finely bordered, regularly rounded. Elytron fairly finely, regularly, and moderately densely punctured, progressively finer and sparser towards lateral margin; two longitudinal rows of punctures moderately distinct; highly polished and shining; without microreticulation. Ventral surface: metacoxae and metasternum finely and sparsely punctured, epipleura and abdomen almost without punctures; without microreticulation.

Male. Median lobe of aedeagus in ventral aspect slightly tapered from base to apex and narrowly constricted before apex, apex spoon shaped (Fig. 15A); in lateral aspect slightly curved with an arrowhead shaped apical expansion (Fig. 15B). Paramere narrowly trapezoid in lateral aspect (Fig. 15C, D).

Figures 15, 16. 

15 Microdytes sekaensis sp. nov. 16 M. ubonensis sp. nov. A median lobe in ventral aspect B median lobe in lateral aspect C left paramere in lateral aspect D right paramere in medial aspect. Scale bar: 0.25 mm.

Female. Without secondary sexual characters. Sclerotized spermatheca not found.

Variation

Variation of markings is shown in Fig. 10.

Etymology

This species is named after the district name of the type locality.

Habitat

This species was collected in the remaining water pools in a dried-up stream which had a sandy bottom with rich leaf deposits (Fig. 47).

Distribution

Thailand: Bueng Kan Province; Laos: Bolikhamsay Province.

Microdytes ubonensis Okada & Wewalka, sp. nov.

https://zoobank.org/007C27AC-BD23-48EE-9659-05448237A6EE
Figs 6, 11, 16, 40A

Type locality

Thailand, Ubon Ratchathani Province, Si Mueang Mai Dist., Nam Thaeng, 15°32'19"N, 105°24'08"E, alt. 200 m.

Type material

Holotype (THNHM): ♂, “THAI: Ubon Ratchathani Si Mueang Mai Dist., Nam Thaeng St. 242 (alt. 200 m) 23.V.2021 R. Okada leg.” [printed white label] / HOLOTYPE Microdytes ubonensis sp. nov. Okada & Wewalka 2022” [printed red label]. Paratypes (52 exs.): 3♂♂, 1♀, with same data as the holotype (CGW, CRO); 4♀♀, Thailand, Ubon Ratchatani Province, Nam Yuen Dist., Dom Pradit St. 221 (alt. 190 m), 14.402°N, 104.215°E, 26.II.2021 R Okada leg. (THNHM); 4♂♂, 4♀♀, Thailand, Ubon Ratchathani Province, Nam Yuen District, Dom Pradit St. 240 (alt. 260 m), 14°23'22"N, 105°09'25"E, 22.V.2021, R. Okada leg. (CRO); 18 exs., Laos, Savannakhet Province, Phou Xang He NBCA, ca. 5 km SW Ban Pa Phaknau, 17°00'N, 105°38'E, alt. 250–400 m, 31.V.–6.VI. 2011, NHMB Basel, Laos 2011 Expedition, M. Brancucci, M. Geiser, D. Hauk, Z. Kraus, A. Phantala & E. Vongphachan leg. (CGW, NMB, NMP); 1♂, Laos, Champasak Province, Bolavens Plateau, waterfall ca. 2 km E Tad Katamtok, 15°08.1'N, 106°38.8'E, alt. 415 m, 10.–12.V.2010, J. Hájek leg. (NMP); 15 exs., Laos, Champasak Province, Bolavens Plateau, ca. 1 km S Ban Lak 40 [vill.] Tad Yueang waterfall, 15°10.8'N, 106°08.3'E, alt. 900–970 m, 28.IV.2010, J. Hájek leg. (CGW, CRO, NMP); 1♂, Laos, Vientiane Province, Phou Khao Khouay NBCA ca. 46 km N Vientiane (waterfall), 18°22.4'N, 102°42.4'E, alt. 270 m, 18.V.2010, J. Hájek leg. (NMP); 1♀, Laos, Vientiane Province, 90 km E Vientiane, Phou Khao Khouay NP, Nam Leuk, 1.–8.VI.1996, H. Schillhammer leg (NMW). All paratypes are provided with printed red paratype labels.

Diagnosis

Microdytes ubonensis sp. nov. is similar to M. boukali Wewalka, 1997 and M. lotteae Wewalka, 1998 in habitus, size, and pronotal coloration but differs from these species by having yellowish head and the elytral markings with distinct post-median spot near suture and finely and sparsely punctured ventral surface. M. ubonensis sp. nov. also resembles M. huangyongensis Bian et al., 2015 in habitus and coloration but it differs in size and male genitalia.

Description

Measurements. TL = 1.25–1.40 mm (1.37 mm), TL-h = 1.08–1.19 mm (1.18 mm), MW = 0.87–0.95 mm (0.95 mm), TL/MW = 1.42–1.47 (1.44). Body regularly oval, moderately convex (Fig. 6).

Coloration. Head yellowish brown. Pronotum dark brown, indistinctly yellowish brown at lateral sides. Elytron dark brown with yellowish brown markings forming a distinct transverse band at base not reaching suture, with a post-median lateral spot and a triangular spot near apex and often with a distinct longitudinal post-median spot near suture (Figs 6, 11). Ventral surface of head and prothorax yellowish brown; thorax, abdominal ventrites and elytral epipleuron reddish brown to dark brown. Legs, antennae and palpi yellowish brown.

Sculpture and structure. Head finely, sparsely, and relatively regularly punctured; almost entirely microreticulate; clypeus not bordered (Fig. 40A). Pronotum quite regularly, sparsely, and fairly strongly punctured, coarser punctures along the posterior margin; without microreticulation; lateral margins very finely bordered, regularly rounded. Elytron moderately regularly and densely punctured, progressively finer and sparser towards lateral margin; longitudinal rows of stronger punctures not distinct; highly polished and shining; without microreticulation. Ventral surface: metacoxae and metasternum finely and sparsely punctured, abdomen without punctures; without microreticulation.

Male. Median lobe of aedeagus in ventral aspect equally tapered from base to apex, with a small swelling at apex (Fig. 16A); in lateral aspect tapered from base to apex, with a small ventral hook at apex (Fig. 16B). Paramere narrow triangular in lateral aspect (Fig. 16C, D).

Figure 17. 

Microdytes balkei A median lobe in ventral aspect B median lobe in lateral aspect C left paramere in lateral aspect D right paramere in medial aspect. Scale bar: 0.25 mm.

Female. Without secondary sexual characters. Sclerotized spermatheca not found.

Variation

Variation of markings is shown in Fig. 11.

Etymology

This species is named after the popular provincial name of the type locality.

Habitat

This species was collected in a variety of habitats. At the type locality, specimens were collected from a small stream on a more or less deforested bedrock (Fig. 48). At other localities, specimens were collected in small pit holes near small forest streams with rich leaf deposits.

Distribution

Thailand: Ubon Ratchathani Province; Laos: Savannakhet, Champasak, and Vientiane provinces.

New faunistic records from Thailand, Laos, and Cambodia

Microdytes akitai Wewalka, 1997

Fig. 18

Microdytes akitai Wewalka, 1997: 17; Wewalka 2011: 37; Nilsson and Hájek 2023: 211.

Type locality

Laos, Vientiane Province, Mt. Phou Khao Khouay.

Material examined

Laos: Bolikhamsay Province. 22 exs., Nam Khading National Bio-Diversity Conservation Area, Tad Paloy campsite, 18°23.17'N, 104°09.65'E, alt. 300 m, forest stream, 8.–11.VII.2010 & 24.–28.V.2011, NHMB Basel Laos 2010 & 2011 Expeditions, M. Brancucci, M. Geiser, D. Hauk, A. Phantala & E. Vongphachan leg. (CGW, CRO, NMB, NMP) (Fig. 18).

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.

Comments

Specimens from Bolikhamsay have more distinct elytral markings and darker head color than in the specimens from the type locality but no other differences have been observed, in particular, in the male genitalia.

Distribution

Laos: Vientiane and Bolikhamsay (first record) provinces.

Microdytes balkei Wewalka, 1997

Figs 17, 19, 39D

Microdytes balkei Wewalka, 1997: 18; Wewalka 2011: 29; Nilsson and Hájek 2023: 211.

Type locality

Thailand, Rayong Province, Khao Chamao NP.

Material examined

Thailand: Mukdahan Province. 1♂, Phu Pha Thoep N.P., small pools (23), 1.I.2000, Mazzoldi leg. (CGW); Ubon Ratchathani Province. 1♂, 1♀, Nam Yuen District, Dom Pradit St. 240 (alt. 260 m), 22.V.2021, R. Okada leg. (CRO, THNHM); Saraburi Province. 1♀, Kaeng Khoi District, Ched Khot St. 122 (alt. 140 m), 30.V.2020, R. Okada leg. (CRO); Chonburi Province. 2♂♂, 1♀, Ban Bueng District, Khlong Kiu St. 261 (alt. 200 m), 6.XI.2021, R. Okada leg. (CGW, CRO) (Fig. 17); 2♂♂, 1♀, Si Racha District, Bang Phra St. 269 (alt. 90 m), 26.XII.2021, R. Okada leg. (CRO); Rayong Province. 4♂♂, Wang Chan District, Pa Yup Nai St 299 (alt. 200 m), 17.VII.2022, R. Okada leg. (CRO, THNHM).

Laos: Savannakhet Province. 203 exs., Phou Xang He NBCA, ca. 5 km SW Ban Pa Phaknau, 17°00'N, 105°38'E, alt. 250–400 m, 31.V.–6.VI. 2011, NHMB Basel, Laos 2011 Expedition, M. Brancucci, M. Geiser, D. Hauk, Z. Kraus, A. Phantala & E. Vongphachan leg. (CGW, CRO, NMB, NMP); Sekong Province. 3♀♀, ca. 51 km N Sekong (river) Ho Chi Minh trail, 15°49.6'N, 106°39.8'E, alt. 410 m, 14.–15.V.2010, J. Hájek leg. (NMP).

Cambodia: Koh Hong Province. 12 exs., 20 km SW Koh Hong, Tatai River, 11°34'N, 103°07'E, alt. 50–300 m, 3.–19.V.2005, E. Jendek & O. Šauša leg. (CGW, NMB).

Comments

Since the figure of the median lobe of this species was not depicted clearly in Wewalka (1997), we present a new figure of the aedeagus including parameres (Fig. 17).

Distribution

Thailand: Mukdahan, Rayong, Trat, Ubon Ratchathani (first record), Saraburi (first record), and Chonburi (first record) provinces, Khao Yai NP [Nakhon Ratchatsima or Nakhon Nayok Province]; Laos (first record): Savannakhet and Sekong provinces; Cambodia (first record): Koh Hong Province.

Microdytes dimorphus Wewalka, 1997

Fig. 20

Microdytes dimorphus Wewalka, 1997: 22; Wewalka 2011: 37; Nilsson and Hájek 2023: 211.

Type locality

Thailand, Nakhon Ratchasima or Nakhon Nayok Province, Khao Yai NP.

Material examined

Thailand: Chonburi Province. 1♂, Si Racha District, Bang Phra St. 269 (alt. 90 m), 26.XII.2020, R. Okada leg. (CRO) (Fig. 20).

Comments

Microdytes dimorphus was described based on a single male specimen from Khao Yai National Park and no additional records are known so far. Therefore, this is the second record of this species. Wewalka (1997) suggested M. dimorphus is more closely related to M. menopausis Wewalka, 1997 (Fig. 27) but differs by having coarser punctures on the elytra similar in size, a punctured abdomen, a more produced clypeus, and larger second segment of antennae. The specimen examined in this study corresponds with M. dimorphus due to the status of punctures on the elytra and abdomen, although the characteristics of clypeus and antenna are intermediate between M. dimorphus and M. menopausis. This species can be distinguished from M. menopausis in having a more slender body shape and indistinct elytral markings at both shoulders and post-median part (Fig. 20).

Distribution

Thailand: Khao Yai NP [Nakhon Ratchasima or Nakhon Nayok Province] and Chonburi (first record) Province.

Microdytes franzi Wewalka & Wang, 1998

Fig. 22

Microdytes franzi Wewalka & Wang, 1998: 65; Wewalka 2011: 38; Nilsson and Hájek 2023: 211.

Type locality

Laos, Vientiane Province, Mt. Phou Khao Khouay.

Material examined

Laos: Bolikhamsay Province. 20 exs., Nam Khading National Bio-Diversity Conservation Area, Tad Paloy campsite, 18°23.17'N, 104°09.65'E, alt. 300 m, forest stream, 8.–11.VII.2010 & 24.–28.V.2011, NHMB Basel Laos 2010 & 2011 Expeditions, M. Brancucci, M. Geiser, D. Hauk, A. Phantala & E. Vongphachan leg. (CGW, CRO, NMB, NMP) (Fig. 22).

Distribution

Laos: Vientiane and Bolikhamsay (first record) provinces.

Microdytes gabrielae Wewalka, 1997

Fig. 23

Microdytes gabrielae Wewalka, 1997: 24; Wewalka 2011: 29; Nilsson and Hájek 2023: 211.

Type locality

Thailand, Phetchabun Province, Huai Nam Phang.

Material examined

Thailand: Phetchabun Province. 1♂, Phu Hin Rongkla NP, small stream (7), 25.XII.1999, Mazzoldi leg. (CGW) (Fig. 23); 4♂♂, 3♀♀, Lom Kao District, Ban Noen St. 294 (alt. 1620 m), 18.VI.2022, R. Okada leg. (CGW, CRO, THNHM); Phitsanulok Province. 1♂, Nakhon Thai Distr., Phu Hin Rong Kla NP, in waterfall, 16°59'49.1"N, 101°00'34.8"E, 7.III.2016, A. Damaška leg. (NMP).

Distribution

Thailand: Phetchabun and Phitsanulok provinces.

Microdytes heineri Wewalka, 2011

Figs 24, 39A

Microdytes heineri Wewalka, 2011: 23; Nilsson and Hájek 2023: 211.

Type locality

China, Yunnan Province, Simao Prefecture.

Material examined

Thailand: Chiang Mai Province. 8 exs., Mae Taeng District, Pa Pae St. 49 (alt. 1000 m), 15.VI.2019, R. Okada leg. (CGW, CRO, THNHM); 1♂, same district, Kuet Chang St. 170 (alt. 520 m), 16.VIII.2020, R. Okada leg. (CRO) (Fig. 24).

Comments

Male specimens have distinct setae on the metacoxae (Fig. 39A).

Distribution

Thailand: Nan and Chiang Mai (first record) provinces; Laos: Luang Namtha and Luang Prabang provinces; China: Yunnan Province.

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).

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).

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.

Figures 41–43. 

41 Lectotype of Microdytes maculatus (photograph by Christophe Rivier, Muséum 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.

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.

Microdytes mariannae Wewalka, 1997

Fig. 26

Microdytes mariannae Wewalka, 1997: 28; Wewalka 2011: 30; Nilsson and Hájek 2023: 211.

Type locality

Thailand, Phetchabun Province, Nam Nao.

Material examined

Thailand: Phetchabun Province. 8♂♂, 10♀♀, Lom Kao District, Ban Noen St. 187 (alt. 1620 m), 20.IX.2020, R. Okada leg. (CGW, CRO, THNHM) (Fig. 26); 2♂♂, 2♀♀, same locality, St. 294, 18.VI.2022, R. Okada Leg. (CRO, THNHM).

Distribution

Thailand: Phetchabun and Loei provinces.

Microdytes menopausis Wewalka, 1997

Fig. 27

Microdytes menopausis Wewalka, 1997: 29; Wewalka 2011: 30; Nilsson and Hájek 2023: 211.

Type locality

Thailand, Khao Yai NP.

Material examined

Thailand: Nakhon Phanom Province. 1♂, 2♀♀, Bang Phaeng District, Phai Lom St. 203 (alt. 200 m), 27.XII.2020, R. Okada leg. (CGW, CRO); Sakon Nakhon Province. 1♀, Tao Ngoi District, Nan Tan St. 210 (alt. 310 m), 29.XII.2020, R. Okada leg. (CRO) (Fig. 27); Ubon Ratchathani Province. 1♀, Nam Yuen District, Dom Pradit St. 224 (alt. 190 m), 27.II.2021, R. Okada leg. (CGW); 1♂, Si Mueang Mai District, Nam Thaeng St. 241 (alt. 190 m), 23.V.2021, R. Okada leg. (THNHM).

Laos: Khammouan Province. 1♂, Nakai-Nam Theun NPA, Ban Navang env., 17°57–59'N, 105°13–16'E, alt. 600–750 m, 18.–21.V.2012, NHMB Basel, Laos 2012 Expedition, M. Brancucci, M. Geiser, K. Phanthavong & S. Xayalath leg. (NMB); Savannakhet Province. 3 exs., Phou Xang He NBCA, ca. 5 km SW Ban Pa Phaknau, 17°00'N, 105°38'E, alt. 250–400 m, 31.V.–6.VI. 2011, NHMB Basel, Laos 2011 Expedition, M. Brancucci, M. Geiser, D. Hauk, Z. Kraus, A. Phantala & E. Vongphachan leg. (CGW, NMB).

Distribution

Thailand: Trat, Nakhon Phanom (first record), Sakon Nakhon (first record), and Ubon Ratchathani (first record) provinces, Khao Yai NP [Nakhon Ratchasima or Nakhon Nayok Province]; Laos: Khammouan, Savannakhet (first record) and Sekong provinces.

Microdytes paoloi Wewalka, 2011

Fig. 28

Microdytes paoloi Wewalka, 2011: 24; Nilsson and Hájek 2023: 211.

Type locality

Thailand, Phetchabun Province, Phu Hin Rongkla NP.

Material examined

Thailand: Phetchabun Province. 1♂, paratypus, Phu Hin Rongkla NP, small stream, alt. 1250 m (4), 25.XII.1999, Mazzoldi leg. (CMW) (Fig. 28).

Distribution

Thailand: Phetchabun and Loei provinces.

Microdytes pasiricus (Csiki, 1938)

Fig. 29

Hydrovatus pasiricus Csiki, 1938: 126 (including var. simplicor and var. unicolor).

Microdytes pasiricus: Biström et al. 1997: 75; Wewalka 1997: 30; Wewalka 2011: 30; Freitag et. al. 2016: 185; Nilsson and Hájek 2023: 212.

Type locality

Indonesia, Central Java, Sarangan near Lake Pasir.

Material examined

Thailand: Chiang Rai Province. 3♂♂, Wiang Kaen District, Muang Yai St. 71 (alt. 440 m), 11.VIII.2019, R. Okada leg. (CGW, CRO) (Fig. 29); Chiang Mai Province. 2♀♀, Mae Chaem District, Tha Pha St. 166 (alt. 720 m), 15.VIII.2020, R. Okada leg. (CRO, THNHM).

Distribution

Thailand: Chiang Rai (first record), Chiang Mai (first record) and Phetchabun provinces; Philippines: Busuanga, Luzon, Mindoro, Palawan; Singapore; Indonesia: Java.

Microdytes pederzanii Wewalka, 2011

Fig. 30

Microdytes pederzanii Wewalka, 2011: 25; Nilsson and Hájek 2023: 212.

Type locality

Thailand, Phetchabun Province, Phu Hin Rongkla NP.

Material examined

Thailand: Phetchabun Province. 2♀♀, Lom Kao District, Ban Noen St. 187 (alt. 1620 m), 20.IX.2020, R. Okada leg. (CRO); Uttaradit Province. 1♂, 1♀, Nam Pad District, Phu Soi Dao NP, pine forest, 12.VII.2020, T. Jeenthong leg. (THNHM) (Fig. 30).

Distribution

Thailand: Phetchabun and Uttaradit (first record) provinces.

Microdytes rocchii Wewalka, 2011

Fig. 31

Microdytes rocchii Wewalka, 2011: 26; Nilsson and Hájek 2023: 212.

Type locality

Laos, Khammuan Province, Ban Khoun Ngeun.

Material examined

Laos: Khammouan Province. 1♀, Ban Khon Ngeun, 18°07'N, 104°29'E, alt. ca 200 m, 19.–31.V.2001, Pacholátko leg. (CGW) (Fig. 31); Savannakhet Province. 1♂, Phou Xang He NBCA, ca. 5 km SW Ban Pa Phaknau, 17°00'N, 105°38'E, alt. 250–400 m, 31.V.–6.VI. 2011, NHMB Basel, Laos 2011 Expedition, M. Brancucci, M. Geiser, D. Hauk, Z. Kraus, A. Phantala & E. Vongphachan leg. (NMB).

Distribution

Laos: Khammuan and Savannakhet (first record) provinces.

Microdytes schoedli Wewalka, 1997

Figs 32, 39B

Microdytes schoedli Wewalka, 1997: 33; Wewalka 2011: 31; Nilsson and Hájek 2023: 212.

Type locality

Thailand, Phetchabun Province, Nam Nao NP.

Material examined

Thailand: Chiang Mai Province. 2♀♀, Chiang Dao District, Ping Khong St. 226 (alt. 430 m), 20.III.2021, R. Okada leg. (CRO); Lampang Province. 1♂, 1♀, Thoen District, Mae Pa St. 197 (alt. 200 m), 15.XI.2020, R. Okada leg. (CRO); Mae Hong Son Province. 1♂, Pai District, Thung Yao St. 50 (alt. 610 m), 15.VI.2019, R. Okada leg. (CRO); 2♂♂, 2♀♀, Muang Mae Hong Son District, Pha Bong St. 250 (alt. 480 m), 13.VI.2021, R. Okada leg. (CGW, CRO) (Fig. 32); Phetchabun Province. 1♂, 2♀♀, Lom Sak District, Nam Chun St. 296 (alt. 200 m), 19.VI.2022, R. Okada leg. (CRO); Kanchanaburi Province. 2♂♂, 1♀, Si Sawat District, Khao Chot St. 27 (alt. 420 m), 12.I.2019, R. Okada leg. (CRO); 1♀, same district, Na Suan St. 28 (alt. 310 m), 12.I.2019, R. Okada leg. (CRO).

Laos: Khammouan Province. 1♂, 2♀♀, Nakai-NamTheun NPA, Ban Navang env., 17°57–59'N, 105°13–16'E, alt. 600–750 m, 18.–21.V.2012, NHMB Basel, Laos 2012 Expedition, M. Brancucci, M. Geiser, K. Phanthavong & S. Xayalath leg. (NMB); Savannakhet Province. 1♂, Phou Xang He NBCA, ca. 5 km SW Ban Pa Phaknau, 17°00'N, 105°38'E, alt. 250–400 m, 31.V.–6.VI. 2011, NHMB Basel, Laos 2011 Expedition, M. Brancucci, M. Geiser, D. Hauk, Z. Kraus, A. Phantala & E. Vongphachan leg. (NMB).

Distribution

Thailand: Chiang Mai, Lampang (first record), Mae Hong Son (first record), Phetchabun, Tak, Mukdahan, and Kanchanaburi (first record) provinces; Laos: Khammouan (first record), Savannakhet (first record) and Sekong provinces.

Microdytes schwendingeri Wewalka, 1997

Figs 34, 40B

Microdytes schwendingeri Wewalka, 1997: 36; Wewalka 2011: 37; Nilsson and Hájek 2023: 212.

Type locality

Thailand, Sakon Nakhon Province, Phu Pan NP.

Material examined

Thailand: Nakhon Phanom Province. 1♂, 1♀, Bang Phaeng District, Phai Lom St. 203 (alt. 200 m), 27.XII.2020, R. Okada leg. (CRO, THNHM) (Fig. 34).

Laos: Savannakhet Province, 1♀, Phou Xang He NBCA, ca. 5 km SW Ban Pa Phaknau, 17°00'N, 105°38'E, alt. 250–400 m, 31.V.–6.VI. 2011, NHMB Basel, Laos 2011 Expedition, M. Brancucci, M. Geiser, D. Hauk, Z. Kraus, A. Phantala & E. Vongphachan leg. (NMB); Champasak Province. 2♂♂, 1♀, Bolavens Plateau, waterfall ca. 2 km E Tad Katamtok, 15°08.1'N, 106°38.8'E, alt. 415 m, 10.–12.V.2010, J. Hájek leg. (CGW, NMP).

Comments

Some specimens from Laos have less distinct elytral markings but no other differences from typical specimens have been observed.

Distribution

Thailand: Nakhon Phanom (first record) and Sakon Nakhon provinces; Laos (first record): Savannakhet and Champasak provinces.

Microdytes shepardi Wewalka, 1997

Fig. 35

Microdytes shepardi Wewalka, 1997: 37; Wewalka 2011: 33; Nilsson and Hájek 2023: 212.

Type locality

Thailand, Phetchabun Province, Nam Nao NP.

Material examined

Thailand: Chiang Mai Province. 1♂, 1♀, Chiang Dao District, Ping Khong St. 226 (alt. 430 m), 20.III.2021, R. Okada leg. (CRO); Chiang Rai Province. 1♂, Wiang Kaen District, Muang Yai St. 71 (alt. 440 m), 2.VIII.2019, R. Okada leg. (CRO); Uthai Thani Province. 5♂♂, 2♀♀, Ban Rai District, Kaen Makrut St. 128 (alt. 440 m), 20.VI.2020, R. Okada leg. (CGW, CRO, THNHM) (Fig. 35).

Laos: 1♂, Luang Prabang Province, Thong Khan, 19°35'N, 101°58'E, alt. ca. 750 m, 11.–12.V.2002, V. Kubáň leg. (NMB).

Distribution

Thailand: Chiang Mai, Chiang Rai (first record), Mae Hong Son, Phetchabun, Uthai Thani (first record), Chaiyaphum and Sakon Nakhon provinces; Laos: Luang Prabang Province; China: Yunnan Province.

Microdytes shunichii Satô, 1995

Fig. 36

Microdytes shunichii Satô, 1995: 313; Wewalka 1997: 38; Wewalka 2011: 33; Nilsson and Hájek 2023: 212.

Microdytes holzmanni Wewalka & Wang, 1998: 66.

Microdytes holzmannorum: Nilsson 2007: 51 (as unjustified emendation of holzmanni).

Type locality

Vietnam, Vinh Phuc Province, Mt. Tam Dao.

Material examined

Thailand: Phetchabun Province. 1♀, Lom Kao District, Ban Noen St. 187 (alt. 1620 m), 20.IX.2020, R. Okada leg. (CRO); 3♂♂, 2♀♀, same locality, St. 294, 18.VI.2022, R. Okada leg. (CGW, CRO, THNHM).

Laos: Luang Namtha Province. 62 exs., 10 km E Muang Sing, Ban Oudomsinh / B. Nam Det / B. Nam Mai, 21°09–10'N, 101°13–15'E, 750–1400 m, 14.–20.V.2011, NHMB Basel, Laos 2011 Expedition, D. Hauk & M. Geiser (CGW, CRO, NMB, NMP) (Fig. 36); Luang Prabang Province. 1♂, 5 km W Ban Song Cha, 20°33–34'N, 102°14'E, 1200 m, 24.–30. IV.1999, V. Kubáň leg. (NMB); Khammouan Province. 2♂♂, Nakai-Nam Theun NPA, Ban Navang env., 17°57–59'N, 105°13–16'E, alt. 600–750 m, 18.–21.V.2012, NHMB Basel, Laos 2012 Expedition, M. Brancucci, M. Geiser, K. Phanthavong & S. Xayalath leg. (NMB); Savannakhet Province. 1♀, Phou Xang He NBCA, ca. 5 km SW Ban Pa Phaknau, 17°00'N, 105°38'E, alt. 250–400 m, 31.V. – 6.VI. 2011, NHMB Basel, Laos 2011 Expedition, M. Brancucci, M. Geiser, D. Hauk, Z. Kraus, A. Phantala & E. Vongphachan leg. (CGW, NMB, NMP); Attapeu Province. 1♂, 1♀, Dong Amphan National Bio-Diversity Conservation Area, Nong Fa (crater lake) env., 15°05.9'N, 107°25.6'E, alt. ca. 1160 m, 30.IV.–6.V.2010, J. Hájek leg. (NMP); 1♀, Thong Kai Ohk, Ban Kachung (Mai) env., 15°01–02'N, 107°26–27'E, 1200–1450 m, 10.–24.VI.2011, NHMB Basel Laos 2011 Expedition, M. Geiser, D. Hauk, A. Phantala & E. Vongphachan leg. (NMB).

Distribution

Thailand: Nan, Chiang Mai, and Phetchabun (first record) provinces; Laos: Phongsali (first record), Luang Namtha (first record), Oudomxai, Luang Prabang (first record), Vientiane, Khammouan, Savannakhet (first record), and Attapeu (first record) provinces; China: Yunnan Province, Hong Kong; Vietnam: Vinh Phuc Province.

Microdytes wewalkai Bian & Ji, 2009

Microdytes wewalkai Bian & Ji, 2009: 37; Wewalka 2011: 36; Nilsson and Hájek 2023: 212.

Type locality

China, Hainan, Lingtou (Ledong) County, Jianfengling NR.

Material examined

Laos: Attapeu Province. 3♂♂, 2♀♀, Dong Amphan National Bio-Diversity Conservation Area, Nong Fa (crater lake) env., 15°05.9'N, 107°25.6'E, alt. ca. 1160 m, 30.IV.–6.V.2010, J. Hájek leg. (CGW, NMP).

Comments

Specimens from Laos have two transverse yellowish red markings on both sides of the middle of pronotum while in specimens from China (Hainan) it is completely black, but no other differences have been observed.

Distribution

Laos (first record): Attapeu Province; China: Hainan Province.

Microdytes zetteli Wewalka, 1997

Fig. 37

Microdytes zetteli Wewalka, 1997: 41; Wewalka 2011: 34; Nilsson and Hájek 2023: 212.

Type locality

Thailand, Chiang Mai Province, Doi Suthep.

Material examined

Thailand: Chiang Mai Province. 12 exs., Mae Taeng District, Pa Pae St. 49 (alt. 1000 m), 15.VI.2019, R. Okada leg. (CGW, CRO, THNHM); 2♂♂, Mae Chaem District, Tha Pha St. 136 (alt. 720 m), 4.VII.2020, R. Okada leg. (CGW, CRO); 1♂, same locality St. 166 (alt. 720 m), 15.VIII.2020, R. Okada leg. (THNHM) (Fig. 37); Chiang Rai Province. 1♀, Wiang Kaen District, Muang Yai St. 71 (alt. 440 m), 2.VIII.2019, R. Okada leg. (CRO).

Laos: 4 exs., Luang Prabang Province, 5 km W Ban Song Cha, 20°33–4'N, 102°14'E, alt. ca. 1200 m, 1.–16.V.1999, V. Kubáň leg. (CGW, NMB).

Distribution

Myanmar: Shan State; Thailand: Chiang Mai, Chiang Rai (first record) and Mae Hong Son provinces; Laos: Luang Prabang Province.

Additional species known from Thailand, Laos, or Cambodia

Microdytes schoenmanni Wewalka, 1997

Fig. 33

Microdytes schoenmanni Wewalka, 1997: 34; Miller and Wewalka 2010: 35; Wewalka 2011: 31; Nilsson and Hájek 2023: 212.

Type locality

Thailand, Trat Province, Koh Chang Island, Klong Prao.

Material examined

Myanmar: 1♂, Shan State, N Aungban, halfway between Pindaya and Ye’ngan, 20°58.271'N, 96°32.488'E, ca. alt. 1241 m, stream, 10.VI.2004, Shaverdo leg. (CGW) (Fig. 33).

Distribution

India: Darjeeling; Nepal; Myanmar: Chin and Shan states, Saganing and Tanintharyi divisions; Thailand: Trat Province, Khao Yai NP [Nakhon Ratchasima or Nakhon Nayok Province]; Laos: Attapeu Province; China: Yunnan Province.

Checklist of the species of Microdytes from Thailand, Laos, and Cambodia

Microdytes akitai Wewalka, 1997 Laos

Microdytes balkei Wewalka, 1997 Thailand, Laos, Cambodia

Microdytes dimorphus Wewalka, 1997 Thailand

Microdytes eliasi Wewalka & Okada, sp. nov. Thailand, Cambodia

Microdytes franzi Wewalka & Wang, 1998 Laos

Microdytes gabrielae Wewalka, 1997 Thailand

Microdytes heineri Wewalka, 2011 Thailand, Laos, China

Microdytes jeenthongi Okada & Wewalka, sp. nov. Thailand

Microdytes maculatus (Motschulsky, 1860) India, Myanmar, Thailand, Laos, China

Microdytes mariannae Wewalka, 1997 Thailand

Microdytes maximiliani Wewalka & Okada, sp. nov. Laos, China

Microdytes menopausis Wewalka, 1997 Thailand, Laos

Microdytes paoloi Wewalka, 2011 Thailand

Microdytes pasiricus (Csiki, 1938) Thailand, Philippines, Singapore, Indonesia

Microdytes pederzanii Wewalka, 2011 Thailand

Microdytes rocchii Wewalka, 2011 Laos

Microdytes schoedli Wewalka, 1997 Thailand, Laos

Microdytes schoenmanni Wewalka, 1997 India, Nepal, Myanmar, Thailand, Laos, China

Microdytes schwendingeri Wewalka, 1997 Thailand, Laos

Microdytes sekaensis Okada & Wewalka, sp. nov. Thailand, Laos

Microdytes shepardi Wewalka, 1997 Thailand, Laos, China

Microdytes shunichii Satô, 1995 Thailand, Laos, China, Vietnam

Microdytes ubonensis Okada & Wewalka, sp. nov. Thailand, Laos

Microdytes wewalkai Bian & Ji, 2009 Laos, China

Microdytes zetteli Wewalka, 1997 Myanmar, Thailand, Laos

Key to the species of Microdytes from Thailand, Laos, and Cambodia

1 Elytron with a distinct impression on lateral side in anterior third (Fig. 38); TL: 1.60–2.00 mm M. maximiliani sp. nov.
– Elytron without impression on lateral side 2
2 Punctures on metacoxae very coarse (Fig. 39B) to moderately coarse (Fig. 39C) 3
– Punctures on metacoxae fine (Fig. 39D) or very fine (Fig. 39E) 18
3 Elytra with two postmedian longitudinal bands (Fig. 28); TL: 1.90–2.00 mm M. paoloi
– Elytra without longitudinal band 4
4 Pronotum dark brown to black with a transverse reddish-brown band on each side. TL: 1.90–2.10 mm M. wewalkai
– Pronotum without transverse band 5
5 Body oval or rhomboid (Figs 20, 24, 27, 29, 35); medium to large species TL: 1.40–2.10 mm 6
– Body oval; small species TL: 1.30–1.40 mm 11
6 Elytra without a post-median spot near suture 7
– Elytra with a post-median spot near suture 13
7 Pronotum predominantly reddish brown to dark brown; metacoxae of male with distinct setae (Fig. 39A); TL: 1.85–1.95 mm M. heineri
– Pronotum predominantly yellowish brown; metacoxae without setae 8
8 Body regularly oval; cypeus not bordered; TL: 1.70–2.00 mm M. shepardi
– Body rhomboid; clypeus bordered at least in the middle 9
9 Elytra predominantly yellowish brown; clypeus rounded and finely bordered; TL: 1.40–1.60 mm M. pasiricus
– Elytra predominantly dark brown; clypeus straightened and slightly bordered in the middle (Fig. 40C) 10
10 Apical three sternites distinctly punctured; the coarser punctures on the elytra similar in size; TL: 1.75–1.85 mm M. dimorphus
– Apical three sternites almost without punctures; the coarser punctures on the elytra distinctly of two kinds; TL: 1.40–1.70 mm M. menopausis
11 Body oblong oval; pronotum predominantly dark brown; TL: 1.25–1.40 mm M. ubonensis sp. nov.
– Body broadly oval; pronotum predominantly yellowish brown 12
12 Elytral markings with distinct transversal band at the base and without a post-median spot near the suture; TL: 1.30–1.40 mm M. schwendingeri
– Elytral markings with two indistinct spots at the base and with a post-median spot near the suture; TL: 1.34–1.36 mm M. sekaensis sp. nov.
13 Elytral punctures consisting of one kind 14
– Elytral punctures consisting of two kinds (e.g., Fig. 32) 15
14 Body regularly oval; the two parts of the median lobe obtuse to right apical medial angles but not expanded laterally at apex; the tips of paramere narrow to rounded but not constricted; TL: 1.60–1.90 mm M. maculatus
– Body more regularly oval; the two parts of the median lobe expanded laterally at apex; the tips of paramere constricted; TL: 1.64–1.85 mm M. eliasi sp. nov.
15 Body oblong oval; TL: 1.90–2.15 mm M. schoedli
– Body regularly oval
16 Elytral marking near the base indistinct; bigger punctures on elytra coarser; TL: 1.60–1.75 mm M. pederzanii
– Elytral marking near the base distinct; bigger punctures on elytra less coarse 17
17 Post-median spot near the suture rounded; TL: 1.80–1.85 mm M. rocchii
– Post-median spot near the suture longitudinal; TL: 2.10–2.25 mm M. mariannae
18 Body oblong oval; TL: 1.70–1.80 mm M. balkei
– Body regularly oval 19
19 Elytral marking near the base indistinct and small spot; TL: 1.45–1.55 M. gabrielae
– Elytral marking near the base distinct 20
20 Elytral marking dilated or waved at the shoulder; TL: 1.40–1.65 mm 21
– Elytral marking broad transverse band at the shoulder; TL: 1.60–1.90 mm 22
21 Head dark brown; pronotum dark brown; TL: 1.40–1.60 mm M. franzi
– Head yellowish brown; pronotum reddish brown; 1.40–1.65 mm M. schoenmanni
22 Pronotal punctures coarser; elytral punctures stronger; TL: 1.60–1.70 mm M. akitai
– Pronotal punctures spacer; elytral punctures finer 23
23 Pronotum predominantly yellowish brown; elytral punctures fine but distinct; TL: 1.65–1.90 mm M. shunichii
– Pronotum predominantly reddish brown; elytral punctures very fine and very sparse 24
24 Head moderately finely and sparsely punctured; TL: 1.55–1.70 mm M. zetteli
– Head finely and sparsely punctured; TL: 1.79–1.82 mm M. jeenthongi sp. nov.

Discussion

Distribution patterns

The discovery of five new species with three first country records and 40 first regional records from Thailand, Laos, and Cambodia shows how poorly the Dytiscidae fauna of these countries is known. The data on species diversity of Microdytes species are summarized in Table 1 and Fig. 44. A total of 25 Microdytes species were recorded from these three countries. Among the recorded species, 20 are known from Thailand, 17 from Laos, and two from Cambodia; 16 species (64%) are known to occur only from those three countries, whereas nine species (36%) are also recorded in adjacent countries. This result makes Thailand and Laos the most and second-most fauna-rich countries for this genus.

Table 1.
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Summary of distribution types of Microdytes species in main ecoregions in Thailand, Laos, and Cambodia. T Thailand L Laos C Cambodia KAY Kayah-Karen montane rain forest NIN northern Indochina subtropical forests LUA Luang Prabang montane rain forests NAN northern Annamites rain forests NKH northern Khorat Plateau moist deciduous forests SEI southeastern Indochina dry evergreen forests CIN central Indochina dry forests CAR Cardamom Mountains rain forests CHA Chao Phraya lowland moist deciduous forests.

Distribution pattern Microdytes species Distribution records Limited to Main ecoregions in Thailand, Laos, and Cambodia N Ratio
Thailand Laos Cambodia three countries KAY NIN LUA NAN NKH SEI CIN CAR CHA
Widespread maculatus + + T T T/L L T T T 5 20%
pasiricus + T T T
schoedli + + + T T T/L L T/L
schuichii + + T L L L L L
schoenmanni + + T L T
N Thailand and Laos heineri + + T T/L 9 36%
jeenthongi sp. nov. + + T
maximiliani sp. nov. + L
shepardi + + T T T/L
zetteli + + T T L
(limited to N Thailand) gabrielae + + T
mariannae + + T
paoloi + + T
pederzanii + + T
NE Thailand to S Laos akitai + + L L 6 24%
franzi + + L L
rocchii + + L
schwendingeri + + + T L T
sekaensis sp. nov. + + + L T
ubonensis sp. nov. + + + L L L T
NE and E Thailand to S Laos balkei + + + + L T L T/C T 5 20%
dimorphus + + T T
eliasi sp. nov. + + + T T/C T
menopausis + + + L T T T T
wewalkai + L
Total recorded species 20 17 2 16 8 8 13 10 6 8 8 4 3 25 100%
Ratio 64% 32% 32% 52% 40% 24% 32% 32% 16% 12%

Notes. Ecoregions where only 1 or 2 Microdytes species were recorded are excluded in the list (i.e., northern Thailand-Laos moist deciduous forests, southern Annamites montane rain forests, and Chao Phraya lowland moist deciduous forests).
Figure 44. 

Distribution map of Microdytes species in Thailand, Laos, and Cambodia.

In view of species diversity by ecoregions, LUA has the highest number of species (13 species, 52% of total fauna). This region comprises four species which occur only in one ecoregion. NAN has the second highest number of species (10 species, 40%), including the two new species M. sekaensis sp. nov. and M. ubonensis sp. nov. KAY, NIN, SEI, and CIN also have high numbers of species (8 species, 32%), including M. jeenthongi sp. nov., M. maximiliani sp. nov., M. ubonensis sp. nov., and M. eliasi sp. nov., respectively.

The distribution pattern of Microdytes species recorded from the three countries represents four types: 1) widespread type, occurring throughout continental Southeast Asia to adjacent countries (5 species, 20%); 2) northern type, distributed mainly from northern Thailand and Laos to adjacent countries (9 species, 36%); 3) central type, recorded only from northeastern Thailand to southern Laos (6 species, 24%); 4) eastern type, occurring in northeastern and eastern Thailand and southern Laos (5 species, 20%). The conclusions made above are not definitive because there are still many unexplored areas.

Most of the Microdytes specimens examined in this study were collected at lotic habitats associated with running water flowing under primary or secondary forests, and many species were sympatric. At one locality of Tha Pha, northern Thailand, located at Kayah-Karen montane rain forests, four species were collected from the same small stream (Fig. 46). In this stream, M. maculatus, which shows a wide distribution, was found at several sites: at the edge of a water body, among roots of trees in the gaps between stone and gravel. The other species, however, were collected only in restricted areas: M. jeenthongi sp. nov. from a shallow, relatively fast-flowing area where tree roots were exposed at bottom of the river, M. zetteli from calm pool areas associated with slowly running water, and M. pasiricus among gravel under big stones in fast streams. Although our field surveys were conducted only two times at this site, it is worth noting that M. jeenthongi sp. nov. and M. zetteli, which morphologically resemble each other, were collected each time at the same places which are only one meter from each other. This result suggests that microhabitat preferences for some Microdytes species are very strict, and it may lead to the discovery of the richest fauna in this area.

Figures 45–48. 

Collecting localities of Microdytes species in Thailand 45 Ban Kaeng, Sa Kaeo Province, one of the localities of M. eliasi sp. nov. 46 Tha Pha, Chiang Mai Province, type locality of M. jeenthongi sp. nov. 47 Ban Tong, Bueng Kan Province, type locality of M. sekaensis sp. nov. 48 Nam Thaeng, Ubon Ratchathani Province, type locality of M. ubonensis sp. nov.

Unlike the northern region of Thailand, where diving beetle surveys have been carried out relatively many times (e.g., by Dr. William D. Shepard, Dr. Manfred A. Jäch, Dr. Herbert Zettel; pers. comm.), a large part of this country remained poorly explored, especially Isan (northeastern region) and the eastern regions. Our study detected three new Microdytes species from these unexplored areas. From the southern region no Microdytes species have been reported so far, although two species (Microdytes elgae Hendrich, Balke & Wewalka, 1995 and M. pasiricus) were recorded from Singapore, situated at the southern end of the Malay Peninsula (Wewalka 1997; Hendrich et al. 2004). Further new species can be expected from Thailand, particularly by collecting in unexplored provinces and repeated sampling at the microhabitat levels.

Acknowledgements

We thank Jiří Hájek (Prague, Czech Republic), Isabelle Zürcher-Pfander (Basel, Switzerland), Manfred A. Jäch (Vienna, Austria), and Tadsanai Jeenthong (Pathum Thani, Thailand) for providing study material. Sincere gratitude to Antoine Mantilleri (Paris, France) for checking type material. Thanks also go to Michael Cota (Pathum Thani, Thailand) for correcting the English of this manuscript. We also offer thanks to Helena Shaverdo (Vienna, Austria) and Veera Vilasri (Pathum Thani, Thailand) for their supporting loan material.

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