Heterometrus Ehrenberg, 1828

Prendini, Lorenzo & Loria, Stephanie F., 2020, Systematic Revision Of The Asian Forest Scorpions (Heterometrinae Simon, 1879), Revised Suprageneric Classification Of Scorpionidae Latreille, 1802, And Revalidation Of Rugodentidae Bastawade Et Al., 2005, Bulletin of the American Museum of Natural History 2020 (442), pp. 1-480 : 216-225

Heterometrus Ehrenberg, 1828

Figures 5 , 7E, F, 8F, 9E, 10, 22–24, 36–38, 50–52, 53A–D, 67C–E, 68C–E, 69C–E, 70A–D, 71A–D, 72A–D, 157–192, table 2

Buthus (Heterometrus) Ehrenberg in Hemprich and Ehrenberg, 1828, pl. I, figs. 1, 2 (part), type species by subsequent designation ( Karsch, 1879a: 20): Buthus

(Heterometrus) spinifer Ehrenberg, 1828

[= Heterometrus spinifer (Ehrenberg, 1828) ]; Hemprich and Ehrenberg, 1829: 351, 352; 1831 [pages unnumbered].

Buthus (Heterometros) : Hemprich and Ehrenberg, 1829: 351.

Centrurus Ehrenberg in Hemprich and Ehrenberg, 1829: 350, type species by subsequent monotypy: Centrurus galbineus C.L. Koch, 1838 [= Heterometrus longimanus ( Herbst, 1800) ] (synonymized by Kraepelin, 1894: 34).

Palamnaeus Thorell, 1876a: 13 , type species by original designation: Palamnaeus petersii Thorell, 1876 ; 1876b: 84; Pocock, 1892: 38 (part); 1893b: 307 (part); Laurie, 1896a: 193; 1896b: 128; Pocock, 1896a: 77; 1900a: 84; Tikader, 1973: 263; Couzijn, 1981: 5, 75, 86.

Caucon Karsch, 1879a: 14 , type species by original designation: Centrurus galbineus C.L. Koch, 1838 [= Heterometrus longimanus ( Herbst, 1800) ] (synonymized by Kraepelin, 1894: 34).

Heterometrus: Karsch, 1879a: 20 ; Ausser, 1880: 466; Laurie, 1896a: 193; 1896b: 128; Kraepelin, 1899: 106, 107; 1904: 198, 199; 1905: 344; 1913: 165; Birula, 1917a: 161; 1917b: 59; Kopstein, 1921: 128, 129; 1927: 107; Fage, 1933: 27, 28; Werner, 1934: 277; Fage, 1936: 179, 180; Kästner, 1941: 233; Vachon, 1953 c: 9, fig. 1; 1963: 162, fig. 4; Bücherl, 1964: 59; Couzijn, 1978: 327, 331; Daling- water, 1980: 286; Couzijn, 1981: 3–6, 8, 26, 32, 47, 48, 50, 52, 60, 64, 65, 69, 73, 74, 81, 101, 130, 133, 145, 167, 178, 179, 181, 183– 189, 191, tables 7, 8, 9, figs. 66a, 68, 70, 71; Tikader and Bastawade, 1983: 2, 6, 7, 518, 519; Biswas, 1984: 320; Francke, 1985: 8, 18; Lourenço, 1989: 174; Mahsberg, 1990: 269, 271; Sissom, 1990 a: 136; Nenilin and Fet, 1992: 19, 20; Braunwalder and Fet, 1998: 31; Kovařík, 1998: 136; Fet, 2000: 431; Lourenço, 2000: 25; Prendini, 2000a: 2, 4, 27, 28 34, 35 44, 50, 53, 57, 61, 62, 70, tables 1, 2, 10; Indra, 2001: 55; Bastawade, 2002: 95, 295; Lourenço and Huber, 2002: 273; Prendini et al., 2003: 185–191, 194, 199, 200, 202–206, 208–210, 212–214, 217, 218, 220, 222, 223, 226, 229, 230, 234, 235, 237, 250–

259, tables 1, 2, 6, 8, 9, figs. 1, 3, appendices 1, 2 (part); Soleglad and Fet, 2003a: 58, 88, 113, 115, 116, table 9; Bastawade et al., 2004: 47; Kovařík, 2004: 1, 2, 4, 7, 49, 51, 53 tables 2, 3 (part); Bastawade et al., 2005: 77;

Prendini and Wheeler, 2005: 460, 477, 482; Bastawade, 2006a: 134; Booncham et al., 2007: 43 (part); Shultz, 2007: 78, 84, 86–91, table 1, figs. 2–5; Bastawade, 2008: 133, 136; Bastawade and Borkar, 2008: 212; Bastawade, 2009: 215; Kovařík, 2009: 1–3, 14–16, 28, 33, 34, 46, 49, 99–101 (part); Mirza and Sanap, 2009: 486 (part); Javed et al., 2010a: 143; Mirza et al., 2012: 1, 2 (part); Di et al., 2013: 86, 88, 94, 96; Tahir and Prendini, 2014: 1–5, 11, 20, 21, fig. 1 (part); Kovařík et al., 2016: 96, 100; Plíšková et al., 2016: 467–469, 474; Rossi, 2016a: 6–9, 15, 19, 20, 25 (part); Aswathi and Sureshan, 2017: 9847; Esposito et al., 2017: 4, 14; Pham et al., 2017: 133, 136; Esposito et al., 2018: 89, 90, 110, 115, appendix 1.

Scorpio (Buthus) (nec Leach, 1815): Lankester, 1885: 379.

Scorpio (nec Linnaeus, 1758): Laurie, 1896a: 193; Lönnberg, 1897a: 197 (part).

Heterometrus (Heterometrus) : Couzijn, 1978: 330; 1981: 80, 83, 86, 121, 161, 173–177, 180, 182–184, 186–188, 191, table 14, figs. 62–65, 66b, 69, 70; Tikader and Bastawade, 1983: 519, 520 (part); Biswas, 1984: 320; Francke, 1985: 8, 18; Fet, 2000: 431, 432; Prendini, 2000a: 44; Prendini et al., 2003: 222, 252, appendix 1; Bastawade et al., 2004: 47; Bastawade and Borkar, 2008: 212, 218.

Herometrus: Bastawade and Borkar, 2008: 218.

Haterometrus: Bastawade, 2009: 218.

DIAGNOSIS: Species of Heterometrus may be separated from other Asian scorpionid genera as follows. The carapace is vaulted, the lateral surfaces sloping steeply (figs. 22–24) in Heterometrus , but slightly to markedly dorsoventrally compressed, the lateral surfaces sloping gently, in all except two species of Deccanometrus , D. latimanus and D. xanthopus , all except two species of Sahyadrimetrus , S. mathewi and S. scaber , all except three species of Chersonesometrus , C. fulvipes , C. madraspatensis , and C. shivashankari , and three species of Srilankametrus , S. indus , S. pococki , and S. serratus . The carapace anterior margin is concave, with the frontal lobes uneven and sloping medially in Heterometrus , whereas the anterior margin is straight, with the frontal lobes evenly rounded or truncate in Gigantome- trus, Srilankametrus , two species of Deccanometrus , D. latimanus and D. xanthopus , and some species of Chersonesometrus . The carapace anterolateral margins converge gradually anteriorly in Heterometrus but are subparallel anteriorly in Javanimetrus and Srilankametrus ; the mediolateral margins converge markedly posteriorly (at the posterolateral sulci) in Heterometrus but diverge or converge slightly posteriorly (at the posterolateral sulci) in all other genera, and three species of Sahyadrimetrus , S. barberi , S. rugosus , and S. tikaderi . The carapace rostrolateral margin is distinctly incised adjacent to the posterior lateral ocelli in Heterometrus but entire in all the other genera. Anterocular extensions of the superciliary carinae are present in Heterometrus but absent in Srilankametrus . The median ocelli are relatively large, the distance between them less than the width of an ocellus in Heterometrus but relatively small, the distance between them equal to or greater than the width of an ocellus in the other genera; the median ocular tubercle is situated anteromedially to medially, the distance from carapace anterior margin: carapace length (CAM:CL) 0.40–0.50 in Heterometrus , but posteromedially, CAM:CL 0.51–0.62 in Chersonesometrus . The interocular suture is absent in Heterometrus but present in Chersonesometrus , Gigantometrus , and all except one species of Deccanometrus , and two species of Srilankametrus . The carapace posterior sutures are present, extending to the median ocular tubercle, and connected by a short cross-suture anterior to the postocular depression in Heterometrus ; present, extending past the median ocular tubercle, and connected anteriorly to the posterior bifurcations of the interocular suture or disconnected in Chersonesometrus , Deccanometrus , Gigantometrus , and most species of Srilankametrus ; and absent in Javanimetrus , Sahyadrimetrus , and two species of Srilankametrus . The cheliceral movable finger prodistal (DI) and retrodistal (DE) teeth are subequal, with the DE tooth only slightly smaller than the DI tooth, and opposable, i.e., forming a bicusp in Heterometrus but unequal, with the DE tooth considerably smaller than the DI tooth, aligned longitudinally and not opposable in Gigantometrus , Javanimetrus , Sahyadrimetrus , Srilankametrus , most Deccanometrus , and some Chersonesometrus . The pedipalp patella dorsomedian carina of the female is absent or obsolete (figs. 161, 190) in Heterometrus , but predominantly granular or costate in Chersonesometrus , Gigantometrus , and all except three species of Deccanometrus , D. latimanus , D. liurus , and D. ubicki . The patella retromedian carinae of the female are absent or obsolete in Heterometrus , but granular or costate in Chersonesometrus , three species of Deccanometrus , D. bengalensis , D. obscurus , and D. phipsoni , three species of Sahyadrimetrus , S. barberi , S. rugosus , and S. tikaderi , and two species of Srilankametrus , S. gravimanus and S. yaleensis . The prominent spiniform granule of the patella proventral carina is present (figs. 161, 166, 171, 176, 181, 186, 190) in Heterometrus but absent in all the other genera. The patella dorsal, retrodorsal, and retroventral intercarinal surfaces of the female are smooth or nearly so (figs. 161, 190) in Heterometrus but granular in all species of Chersonesometrus except C. nathanorum . The pedipalp chela of the adult male is sparsely setose (figs. 162, 167B, 168, 172, 177B–D, 182B, 183, 187B, 188, 191A) in Heterometrus but moderately to densely setose in Sahyadrimetrus , all species of Deccanometrus except D. xanthopus , one species of Srilankametrus , and some species of Chersonesometrus . The distance between the chela manus dorsomedian and promedian carinae or setal rows (DMC–PMC) is similar to the distance between the promedian and proventral carinae or setal rows (PMC–PVC) in Heterometrus whereas the DMC–PMC is slightly to markedly greater than the PMC–PVC in all other genera. The dorsomedian carina becomes obsolete proximally in Heterometrus but is continuous to the proximal edge of the manus in Chersonesometrus , Gigantometrus , and two species of Deccanometrus , D. obscurus and D. phipsoni . The chela manus dorsal secondary, subdigital, and digital carinae (setal rows) are well separated along their entire length in Heterometrus whereas the proximal half of the dorsal secondary carina, distal half of the subdigital carina and distal third of the digital carina are closely adjacent in Chersonesometrus and Gigantomentrus. The dorsal secondary and subdigital carinae of the male are absent or obsolete in Heterometrus but present and entirely to predominantly granular or costate in Gigantometrus , all species of Chersonesometrus except C. bastawadei and C. fulvipes , and all species of Srilankametrus except S. indus and S. pococki . The chela manus digital and retromedian carinae are similarly developed (figs. 162, 163, 167, 172, 173, 177, 182, 187, 191) in Heterometrus whereas the retromedian carina is more pronounced than the digital carina in Chersonesometrus . The retromedian carina of the male is absent or obsolete in Heterometrus but entirely to predominantly granular in Gigantometrus , Srilankametrus caesar , and S. serratus , and entirely to predominantly costate in Chersonesometrus , Srilankametrus couzijni , S. gravimanus , and S. yaleensis . The depression in the dorsal surface of the chela manus, proximal to the fixed finger of the adult male, is present and distinct (figs. 162, 167B, 172, 177B–D, 182B, 187B, 191A) in Heterometrus but absent or obsolete in all the other genera. The chela manus dorsal surface is without reticulation (figs. 172, 173, 177, 182, 187) in all except three species of Heterometrus , H. glaucus , H. laevigatus , and H. thorellii , in which the dorsal surface is shallowly reticulate (figs. 162, 163, 167, 191) as in Javanimetrus , Sahyadrimetrus , and all except two species of Deccanometrus , D. obscurus and D. phipsoni ; the dorsal surface is smooth in Heterometrus but finely to coarsely granular in Chersonesometrus , Gigantometrus , Srilankametrus , all species of Deccanometrus except D. ubicki , and all except two species of Sahyadrimetrus , S. kanarensis and S. tikaderi . The chela manus retrolateral intercarinal surfaces are smooth or nearly so in Heterometrus but granular in Chersonesometrus , Gigantometrus , Srilankametrus , all species of Deccanometrus except D. ubicki , and some species of Sahyadrimetrus . The chela manus ventral surface is flat, with the axes of the retroventral and ventromedian carinae in approximately the same plane in Heterometrus

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FIGURE but angled, with the axis of the retroventral carina ventral to the axis of the ventromedian carina in Javanimetrus , four species of Chersonesometrus , C. beccaloniae , C. hendersoni , C. pelekomanus , and C. tristis , and two species of Srilankametrus , S. indus and S. pococki . The pro- and retrolateral surfaces of the tibiae of legs I and II each bear scattered, setiform macrosetae, not arranged in a definite row, in Heterometrus and a row of two or three spiniform macrosetae in all the other genera. Macroseta st on the retroventral surface of the basitarsus of leg I is usually setiform (figs. 50–52, 53A–D) in Heterometrus but spiniform in all the other genera, and sb on the retroventral surface of the basitarsus of leg III is often setiform in Heterometrus but spiniform in Javanimetrus and Sahyadrimetrus . The pseudonychium (dactyl) of the telotarsi of legs I–IV is prominent and acuminate in Heterometrus but usually reduced and rounded in the other genera. The pectinal first proximal median lamella (scape) of the female is distinctly angular,> 90° but <180° (figs. 36–38) in Heterometrus but straight or shallowly curved in Srilankametrus . The mesial surfaces of mesosomal tergites I–VI of the male are smooth in Heterometrus , but granular in Gigantometrus , one species of Deccanometrus , D. xanthopus , two species of Sahyadrimetrus , S. mathewi and S. scaber , and some species of Chersonesometrus . The lengths of metasomal segments I and II are approximately equal to or less than their respective widths (figs. 67C–E, 69C–E, 70A–D, 72A–D) in Heterometrus but markedly greater than their respective widths in Gigantometrus . The ventrosubmedian and ventrolateral carinae are granular or costate-granular on metasomal segment IV only and costate on segments I–III (figs. 68C–E, 69C–E, 71B, D, 72B, D) in all except two species of Heterometrus , H. laoticus and H. silenus , in which the carinae are granular on segments I–IV, II–IV (costate on I), or III and IV (costate on I and II) (figs. 71A, C, 72A, C), as in Gigantometrus . The ventral intercarinal surfaces of metasomal segment IV are usually smooth (figs. 69C–E, 72A–D) in Heterometrus but sparsely granular in Javanimetrus . The dorsosubmedian carinae of metasomal segment V are absent (figs. 67C–E, 70A–D) in Heterometrus but vestigial or partial in all other genera. The dorsal intercarinal surface of segment V is smooth in Heterometrus but granular in Gigantometrus , and some species of Chersonesometrus and Srilankametrus . The width of the telson vesicle is approximately equal to or less than the width of metasomal segment V in the female of Heterometrus but greater than the width of segment V in the female of Gigantometrus and the vesicle is elongate in Heterometrus but globose in Chersonesometrus , Deccanometrus , Gigantometrus , and three species of Srilankametrus , S. indus , S. pococki , and S. serratus .

INCLUDED SPECIES: As redefined in the present contribution, Heterometrus accommodates eight species formerly assigned to the nominotypical subgenus by various authors ( Couzijn, 1981; Tikader and Bastawade, 1983; Fet, 2000), that were recovered as a monophyletic group by phylogenetic analysis of morphological characters and DNA sequences from the nuclear and mitochondrial genomes (fig. 10): Heterometrus glaucus (Thorell, 1876) , comb. nov. et stat. rev.; Heterometrus laevigatus (Thorell, 1876) , comb. nov. et stat. rev.; Heterometrus laoticus Couzijn, 1981 ; Heterometrus longimanus ( Herbst, 1800) ; Heterometrus petersii (Thorell, 1876) ; Heterometrus silenus (Simon, 1884) , comb. nov. et stat. rev.; Heterometrus spinifer (Ehrenberg, 1828) ; Heterometrus thorellii ( Pocock, 1892) .

DISTRIBUTION: The genus Heterometrus is distributed throughout Southeast Asia (figs. 5, 157, 158), from the Andaman and Nicobar Islands, throughout Indochina, the Thai-Malay Peninsula and offshore islands (Ko Chang, Ko Lanta, Ko Muk, Ko Samui, Langkawi, the Myeik archipelago, Penang, the Phi Phi Islands, Phuket, Phú Quoc Island, Tioman, Tinggi and Singapore), the Riau archipelago, Sumatra, Weh, Simeulue, Babi, Nias, the Batu archipelago, Siberut, the Mentawai archipelago, Bangka, Belitung, Java, Madura, Bali, Borneo, Miang-Besar, and the Philippine islands of Balabac, Mindanao, Luzon, Palawan, Panay, and Tawi Tawi in the Sulu archipelago, to Wallace’s Line (table 2). Reports of Heterometrus from the Indonesian islands of Sulawesi and Halmahera ( Meise, 1932: 662; Takashima, 1945: 90), to the east of Wallace’s Line, have never been confirmed (Couziijn, 1981: 175). The genus has been recorded from the following countries: Brunei, Cambodia, India, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam. Its distribution overlaps with that of Javanimetrus in Borneo, Luzon, Nias, the Nicobar Islands, Sumatra, and Thailand.

ECOLOGY: Heterometrus species occur in primary and secondary evergreen rainforests, deciduous and semideciduous forests, plantations, agricultural fields, and backyards, from sea level to 1315 m elevation. Most species of the genus are fossorial and pelophilous, although some appear to be lapidicolous or corticolous ( Prendini, 2001b). Whereas some Heterometrus were collected under stones or logs during daytime, most were collected with UV detection or flashlights at night, doorkeeping at or near burrow entrances, or walking on the ground after rains. Many Heterometrus appear to vacate their burrows during the monsoon season.

In several species of Heterometrus , e.g., H. longimanus and H. spinifer , mixed age groups of related and unrelated individuals cohabit with minimal aggression or cannibalism in laboratory terraria ( Harrison, 1954; Polis and Lourenço, 1986) and, according to some evidence, this also occurs in the wild ( Schultze, 1927).

CONSERVATION STATUS: Several species of Heterometrus are extensively harvested for the commercial trade in exotic pets. The most commonly traded species are H. silenus , apparently exported from Vietnam and, to a lesser extent, H. spinifer , exported from Malaysia, and H. petersii , exported from Malaysia and Singapore. Heterometrus spinifer is now protected in Malaysia. Heterometrus laevigatus and H. laoticus are occasionally available, apparently exported from Thailand, where H. laoticus is also harvested for consumption ( Menzel and D’Aluisio, 1998).

Figures

FIGURE 5. Map of Southeast Asia, plotting known locality records of all species of Heterometrus Ehrenberg, 1828, based on material examined, and verified records from virtual museums and the literature.