Heterometrus minotaurus Plíšková et al., 2016

Kawai, Kazusa, Unnahachote, Thornthan, Suttisatid, Yossaphon & Tang, Victoria, 2023, А Review of Heterometrus in Thailand (Scorpiones: Scorpionidae), Euscorpius 373, pp. 1-25 : 6-10

Heterometrus minotaurus Plíšková et al., 2016 , stat. rev.

( Figures 6–7 , 14–15 , 22–23 , 32–33 , 42–43 , 52–53 , 60–61 , 67–71 ; Table 1) http://zoobank.org/urn:lsid:zoobank.org:act:7D62EBF1-

8AAD-4D32-B68D-EB6A2EB5625D

Heterometrus spinifer spinifer: Couzijn, 1981: 89–91 (misidentification, part).

Heterometrus spinifer solitarius: Couzijn, 1981: 96 (misidentification, part).

Heterometrus minotaurus Plíšková et al., 2016: 467–474 , figs. 1–23.

Heterometrus laevigatus: Prendini & Loria, 2020: 236–237 , 240–241, 245 (part), figs. 7E, 9E, 10, 23A, B, 37A, B, 50A–D, 67D, 68D, 69D, 158, 164–168 (part), table 2 (part).

TYPE LOCALITY AND TYPE DEPOSITORY. Thailand, Surat Thani Prov., Phanom District , 8°52'N 98°36'E, 395 m a. s. l. ; FKCP.

MATERIAL EXAMINED. Thailand, Phuket Province, Phuket Island , 1 subadult, TUPC ; Surat Thani Province, Chaiya District [09.44°N 99.08°E], 1♂ (THNHM-Ar-00000007) 1♀ (THNHM-Ar-00000008), 25 August 2021, leg. T . Unnahachote, Pa We [07.84°N 98.31°E], 5♂ 5♀, TUPC .

DIAGNOSIS (modified from Plíšková et al., 2016). Total length of adults 83–102 mm (male holotype 83 mm). Base color of adults uniformly black, cuticular surface moderately lustrous ( Figs. 67–71 ). Carapace with dorsal essentially smooth and laterals heavily granulated; dorsal profile triangular (resembles isosceles trapezoid) ( Figs. 22–23 ). Tergite surface smooth with few granules in both sexes ( Fig. 67 ). PTC 14–18 in both sexes. Pedipalps relatively elongated (more slender in males, thicker and shorter in females) among congeners ( Figs. 68–71 ); ChL/W: ♂ 3.2–3.4, ♀ 2.7–3.0; FL/W: ♂ 2.6–3.0, ♀ 2.3; PL /W: ♂ 2.9, ♀ 2.4; FL/CL: ♂ 1.0–1.1, ♀ 0.8. Dorsal surface of chelal manus slightly reticulated in both sexes ( Figs. 32–33 ); prodorsal surface scattered with minute spiniform granules ( Figs. 52–53 ); fixed finger shorter than manus ( Figs. 42–43 ). Male finger relatively straight, manus narrow in vertical aspect ( Fig. 52 ). Metasoma with VSM intercarinal distance wide; DL and DSM on metasoma I–IV curved in males; telson in adults reddish black to pitch black ( Figs. 6–7 , 14–15 ) .

DISTRIBUTION. The species is distributed in southern Thailand, from Kra Isthmus to the Marui River and Nakhon Si Thammarat Mountain Range. This species has also been recorded from Myanmar (error).

COMMENTS.

Status of H. laevigatus and revalidation of H. cimrmani and H. minotaurus

Heterometrus laevigatus was originally synonymized with H. spinifer by Couzjin (1981: 93), followed by Kovařík (2004: 40); Kraepelin (1895: 34) listed both H. laevigatus and H. spinifer as synonyms of H. longimanus . This species was regarded as valid only in Keyserling (1885: 39), apart from the original description (Thorell, 1876b: 221, 222) and Prendini & Loria (2020). However, apart from the differences (reticulations on pedipalp manus, sum length of metasoma I–IV, and trichobothrial distances between V series on chela) already noted by Couzjin (1981), the prodorsal surface of the chela differs considerably from that of H. spinifer : pronounced spiniform granules are present in H. spinifer ( Figs. 38–39 ), but they are weaker in H. laevigatus ( Figs. 1–2 ). Therefore, it is not credible to synonymize H. laevigatus with H. spinifer .

The holotype (and the only type specimen) of H. laevigatus is a subadult female labeled as collected from “Nova Hollandia [ Australia], Melbourne” in 1860 ( Fig. 3 ) and was examined by Prendini & Loria (2020: 237) who considered it conspecific with H. cimrmani , as well as with H. minotaurus ( Prendini & Loria, 2020: 240–241) . However, they also argued that “… As in other scorpionid taxa, adult males are important for species identification and delimitation in Asian forest scorpions, and there are several species complexes comprising morphologically similar, range-restricted or narrowly endemic species (Prendini, 2001a) … Without series, especially adult males, the diagnostic characters (coloration, granulation, meristic variation) often presented to justify putative new species are unreliable and comparisons made with other species, the adults of which may or may not have been described, invalid …” ( Prendini & Loria, 2020: 12). The information of the holotype is not sufficient enough to justify their synonymization as it was a single subadult female with erroneous locality. However, the possibility that H. laevigatus is either H. cimrmani or H. minotaurus cannot be discarded. Comparison between subadult females could be biased; thus, H. laevigatus is hereby considered as a nomen dubium due to the ambiguity of its authentic type locality and the lack of description for adults of both sexes.

Validity of both H. cimrmani and H. minotaurus is confirmed also by DNA analysis implemented by Charles University in Prague (paper in preparation; F. Kovařík, pers. comm.).

Figures

Figures 4–11: Comparison of Heterometrus spp. in Thailand, metasoma and telson in dorsal aspect. Figures 4–5. H. cimrmani, male from Trang (4) and female from Nakhon Si Thammarat (5), THNHM. Figures 6–7. H. minotaurus, male (6) and female from Surat Thani (7), THNHM. Figures 8–9. H. silenus, male from Chanthaburi (8) and female from Chonburi (9), TUPC. Figures 10–11. H. laoticus, male (10) and female from Lamphun (11), TUPC.

Figures 12–19: Comparison of Heterometrus spp. in Thailand, metasoma and telson in ventral aspect. Figures 12–13. H. cimrmani, male from Trang (12) and female from Nakhon Si Thammarat (13), THNHM. Figures 14–15. H. minotaurus, male (14) and female from Surat Thani (15), THNHM. Figures 16–17. H. silenus, male from Chanthaburi (16) and female from Chonburi (17), TUPC. Figures 18–19. H. laoticus, male (18) and female from Lamphun (19), TUPC.

Figures 20–29: Comparison of Heterometrus spp. in Thailand, prosoma in dorsal aspect. Figures 20–21. H. cimrmani, male from Trang (20) and female from Nakhon Si Thammarat (21), THNHM. Figures 22–23. H. minotaurus, male (22) and female from Surat Thani (23), THNHM. Figures 24–25. H. silenus, male from Chanthaburi (24) and female from Chonburi (25), TUPC. Figures 26–27. H. laoticus, male (26) and female from Lamphun (27), TUPC. Figures 28–29. H. spinifer, males from Yala (28) and Narathiwat (29), TUPC.

Figures 30–39: Comparison of Heterometrus spp. in Thailand, chela in dorsal aspect (trichobothria indicated by red circles). Figures 30–31. H. cimrmani, male from Trang (30) and female from Nakhon Si Thammarat (31), THNHM. Figures 32–33. H. minotaurus, male (32) and female from Surat Thani (33), THNHM. Figures 34–35. H. silenus, male from Chanthaburi (34) and female from Chonburi (35), TUPC. Figures 36–37. H. laoticus, male (36) and female from Lamphun (37), TUPC. Figures 28–29. H. spinifer, males from Yala (38) and Narathiwat (39), TUPC.

Figures 40–49: Comparison of Heterometrus spp. in Thailand, chela in external aspect (trichobothria indicated by red circles). Figures 40–41. H. cimrmani, male from Trang (40) and female from Nakhon Si Thammarat (41), THNHM. Figures 42–43. H. minotaurus, male (42) and female from Surat Thani (43), THNHM. Figures 44–45. H. silenus, male from Chanthaburi (44) and female from Chonburi (45), TUPC. Figures 46–47. H. laoticus, male (46) and female from Lamphun (47), TUPC. Figures 48–49. H. spinifer, males from Yala (48) and Narathiwat (49), TUPC.

Figures 50–57: Comparison of Heterometrus spp. in Thailand, chela in ventral aspect (trichobothria indicated by red circles). Figures 50–51. H. cimrmani, male from Trang (50) and female from Nakhon Si Thammarat (51), THNHM. Figures 52–53. H. minotaurus, male (52) and female from Surat Thani (53), THNHM. Figures 54–55. H. silenus, male from Chanthaburi (54) and female from Chonburi (55), TUPC. Figures 56–57. H. laoticus, male (56) and female from Lamphun (57), TUPC.

Figures 58–61: Heterometrus spp., post-mating spermatophores in bilateral aspects. Figures 58–59. H. cimrmani from Trang. Figures 60–61. H. minotaurus from Surat Thani.

Figures 66–67: Courtship in Heterometrus spp., between males (left) and females (right). Figure 66. H. cimrmani from Trang. Figure 67. H. minotaurus from Surat Thani.

Figures 68–71: Heterometrus minotaurus, in dorsal (68, 70) and ventral (69, 71) aspects; scale bar = 10 mm. Figures 68–69. Male from Surat Thani, THNHM. Figures 70–71. Female from Surat Thani, THNHM.

Figures 1–3: Heterometrus laevigatus, holotype subadult female (NMG 90); scale bar = 10mm. Figure 1. Dorsal aspect. Figure 2. Ventral aspect. Figure 3. Label.