Mesobuthus gibbosus (Brullé, 1832)

Teruel, Rolando, Fet, Victor & de Armas, Luis F., 2004, A note on the scorpions from the Pirin Mountains, south- western Bulgaria (Scorpiones: Buthidae, Euscorpiidae), Euscorpius 14 (14), pp. 1-11 : 2-3

Mesobuthus gibbosus (Brullé, 1832)

Figs. 2–15

Material examined. BULGARIA: Pirin Mountains ; under stones in open areas, 1,200-1,300 m asl, July 1972 (coll. Gallia), 1 juvenile ♀ ( IES) .

Morphology. Body light yellowish orange, prosoma densely spotted with blackish brown coloration (mainly over all carinae and furrows), tergites with five blackish longitudinal stripes, legs almost entirely dark to blackish brown, chelicerae, pedipalps and metasoma with some small blackish spots. Carapace with central median and posterior median carinae joined, forming a continuous linear series of granules to posterior margin; anterior margin with 12 short, stout setae. Tergites with three strong longitudinal carinae moderately projecting beyond posterior margin, but not as spiniform processes. Metasomal segments I–IV with 10 carinae, ventrolateral carinae of segment V with posterior granules conspicuously enlarged and lobated. Chelicerae ventrally with two well-pigmented denticles in both fingers. Pedipalps with trichobothrial pattern A-β, fixed finger of chela with trichobothrium db basal to est; fingers with 12 principal rows of granules; tip of movable finger with four accessory granules just proximal to terminal denticle. Legs III–IV with a strong tibial spur; tarsi and basitarsi of all legs with two submedian rows of short, spiniform setae. Pectinal tooth count 24–22.

Comments. The Bulgarian specimen is a small juvenile less than 35 mm long, possibly a third or fourth instar. Its color pattern is identical to other examined specimens of the same species from Lesvos Island (Aegean Sea, Greece) and Kirklareli (European Turkey), all in RTO collection, and its pectinal tooth count is diagnostic for females (Crucitti & Marini, 1987; Crucitti & Cicuzza, 2000). The structure of the prosomal carinae in this specimen does not match the definition of the genus Mesobuthus Vachon, 1950 as given by Sissom (1990), but it is otherwise typical for M. gibbosus (R. Teruel, unpublished data).

This represents the first precise record of M. gibbosus from Bulgaria. Its occurrence here is not surprising, as the altitude and habitat where it was collected are typical of this species (Crucitti & Marini, 1987; Crucitti & Cicuzza, 2000), and it is known to occur at the same latitude in neighboring Macedonia (Kovařík, 1998, 1999) and European Turkey (R. Teruel, unpublished data). It is very possible M. gibbosus could reach Pirin Mountains directly from the south via the Struma or Mesta river basins, These two biogeographic routes are common avenues of penetration of sub-Mediterranean elements into Bulgaria (Fet, 2000). The similar dispersal strategy was mentioned for two other species of the same genus, M. caucasicus (Nordmann, 1840) and M. eupeus (C.L. Koch, 1839) in the Caucasus (Birula, 1917). Such a dispersal could be a recent postglacial event, or alternatively could happen during the Pleistocene interglacial periods.

The species M. gibbosus was described from the Peloponnesus, Greece; is found in Albania, Bulgaria, Greece, Macedonia, Montenegro, and Turkey (both European and Asian). Its formerly reported (Fet & Lowe, 2000: 177) populations from Cyprus, Israel, Lebanon, and Syria belong to different species: M. cyprius Gantenbein & Kropf, 2000 on Cyprus (Gantenbein et al. 2000b) and M. nigrocinctus Ehrenberg, 1828 in Israel, Lebanon, and Syria (Fet et al., 2000). The genus Mesobuthus has an Asian center of diversity, and most likely the Asian origin, and M. gibbosus is its westernmost species (Gantenbein et al., 2003).

Figures

Figure 2: Juvenile female Mesobuthus gibbosus from Pirin Mountains.

Figures 3-10: Same specimen as in Fig. 2. 3. Right pedipalp femur, dorsal view. 4. Internal view. 5. Right pedipalp patella, dorsal view. 6. External view. 7. Right pedipalp chela, ventral view. 8. External view. 9. Right movable finger, dorsal view. 10. Close-up of tip of movable finger.

Figures 11-15: Same specimen as in Fig. 2. 11. Anterior half of carapace. 12. Sternopectinal region. 13. Leg IV tibia, basitarsus and tarsus, external view. 14. Ventral view. 15. Right chelicera, ventral view.