Isometrus maculatus (De Geer, 1778 )

Kovařík, František, Lowe, Graeme, Ranawana, Kithsiri B., Hoferek, David & Š, V. A., 2016, Scorpions of Sri Lanka (Scorpiones Buthidae, Chaerilidae, Scorpionidae) with description of four new species of the genera Charmus Karsch, 1879 and Reddyanus Vachon, 1972, stat n, Euscorpius 220, pp. 1-133: 35-40

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Isometrus maculatus (De Geer, 1778 )


Isometrus maculatus (De Geer, 1778)  

( Figs. 13, 127–137, 196, 221–222, 237–238, 242, 252, 403–404, 555, 557, 559)

Scorpio maculatus De Geer, 1778: 346   .

Isometrus maculatus: Kraepelin, 1899: 66   .

Isometrus (Isometrus) maculatus: Vachon, 1972: 169– 180   , figs. 1–13, 15, 17, 19; Fet & Lowe, 2000: 147; Lourenço & Huber, 2002: 266; Teruel & Kovařík, 2012: 88–91, figs. 4, 27, 36–37, 46, 1 94–207, 566– 569; Kovařík & Ojanguren, 2013: 182–184, 347, 355–356, figs. 1251–1255, 1264, 1368–1375, 1376– 1383 (reference and synonymes list until 2013); Veronika & al., 2013: 75, figs. 1, 15–20, tab. 1.

TYPE LOCALITY AND TYPE REPOSITORY. “ Suriname and Pennsylvania ”   ; NHRS.

S RI LANKAN MATERIAL EXAMINED. Sri Lanka , Northern Province , Mannar District , Madhu Road, 08°48'26.3"N 080°10'26"E, 90 m a.s.l. (Locality 15 CH, Fig. 584), 24. –25.IV.2015, 1♂ 1♀, FKCP, 1♀ 2juvs., UPSL, leg GoogleMaps   .

Kovařík et al.; Northern Province, Mannar District, Marichchukkaddi env, border of Wilpattu National Park , 08°33'32.3"N 079°56'51"E, 7 m a.s.l. (Locality 15CI, Fig. 585), 25. –26.IV.2015, 1♂ 1♀ ( Figs. 129–130, 132, 134, 196, 222, 238, 404) 1 juv., FKCP, leg. Kovařík et al GoogleMaps   .; Southern Province, Matara District, Kekanadura village , 05°58'28.2"N 080°36'20.5"E, 40 m a.s.l. (Locality 15CP, Figs. 593–594), 30.IV.2015, 1♂ ( Figs. 127–128, 131, 133, 221, 237, 242, 252, 403, 555, 557, 5 59), FKCP, leg. Kovařík et al GoogleMaps   .; Eastern Province, Ampara District, Lahugala-Kitulana National Park , 06°52' 46"N 081°43'21.8"E, 40 m a.s.l. (Locality 15CR, Fig. 596), 3.–4.V.2015, photos only, leg. Kovařík et al GoogleMaps   .

DIAGNOSIS. Total length 30–75 mm. Females usually reach ca. 45 mm. Manus of pedipalp very thin, in males its width equals that of patella and femur. Pedipalps and legs yellow, with spots. Manus of pedipalps yellow with several spots, fingers dark. Mesosomal segments lightcolored. First (basal) middle lamella of female pecten quadrangular. Posterior margin of sternite V straight (females) to very slightly convex medially (males). Subaculear tooth spinoid. Pectinal teeth number 15–20 (1 7–20 in the examined Sri Lanka specimens).

COMMENTS ON DISTRIBUTION. I. maculatus   has been regarded as cosmopolitan (see Fet & Lowe, 2000: 149) and records of this species are so numerous that a complete listing would be unreasonably long. A list of specimens which the first author examined until 2003 is published in Kovařík (2003: 3). Additonal records are given in Kovařík & Ojanguren (2013: 182–184). Records peaked in the earlier era of wooden sailing ships and harbors full of wooden barracks, both ideal niches for these scorpions. For that reason between 1758 and ca. 1940 this species was reported from many countries and large harbors including Hamburg in Europe. With the transition to modern building materials and modes of travel, reports of this species have greatly diminished, and in many places have ceased altogether. Apparently, relatively few of the old invasive populations were able to persist without being resupplied by a constant influx of new individuals via human transport. The distribution of I. maculatus   in southeast Asia is not well documented, but it is possibly indigenous to India and/ or Sri Lanka because of the presence there of its most closely related species: I. thurstoni   and I. thwaitesi   . Lourenço & Huber (2002: 266) suggested that Sri Lanka was the original home of this species before cosmotropical dispersal by human activity, because Sri Lanka "is the only region in the world where I. maculatus   is found in really wild conditions inland." This was pure speculation, unsupported by any data. Firstly, their assertion implies that the authors know all species of scorpions present in every "wild condition inland" everywhere else on the globe. Secondly, their logic is flawed because although certain exotic species may fail to penetrate endemic 'wild' ecosystems of host countries, this is by no means the rule. There are many counterexamples where invasive species have become established in endemic ecosystems and displaced native fauna or flora, causing major negative impacts. However, Veronika et. al. (2013: 75) cited this speculation as fact, claimimg that I. maculatus   is an "Endemic species in Sri Lanka ". A proper test of this hypothesis may require comparative DNA studies of widespread I. maculatus   populations.


Swedish Museum of Natural History, Entomology Collections














Isometrus maculatus (De Geer, 1778 )

Kovařík, František, Lowe, Graeme, Ranawana, Kithsiri B., Hoferek, David & Š, V. A. 2016

Isometrus maculatus:

KRAEPELIN 1899: 66

Scorpio maculatus De Geer, 1778: 346

GEER 1778: 346