Microbuthus kristensenorum, Lowe, 2010

Lowe, Graeme, 2010, New picobuthoid scorpions (Scorpiones: Buthidae) from Oman, Euscorpius 93 (93), pp. 1-53 : 9

Microbuthus kristensenorum , sp. nov.

Figs. 23–41 , 114 , 121–124 , 134 , 141–147 , Tab. 2

Microbuthus pusillus : Finnegan, 1932: 92; Birula, 1937: 101; Vachon, 1949: 393–396, figs. 469, 471, 476; Vachon, 1951: 256; Vachon, 1952: 317, 321, 323, figs. 469, 471, 476; Vachon, 1966: 213; El-Hennawy, 1992: 102, 128 (part); Kovařík, 1998: 115 (part); Fet & Lowe, 2000: 182 (part); Lourenço, 2002: 165, 168, 169, figs. 5, 20; Fet, Soleglad & Lowe, 2005: 12 (part); Lourenço & Duhem, 2007: 444.

Figures

Figure 114: Distribution of new picobuthoid scorpions in Oman. Black circles, Microbuthus gardneri, sp. nov. Green circles, Microbuthus kristensenorum, sp. nov. Gray circles, Femtobuthus shutuae, sp. nov. Orange circles, Picobuthus wahibaensis, sp. nov. Yellow circles, Picobuthus dundoni, sp. nov.

Figures 23–26: Microbuthus kristensenorum, sp. nov., holotype female. Habitus viewed under reflected white light (23, 24) and UV fluorescence (25, 26). 23, 25. Dorsal aspect. 24, 26. Ventral aspect. Scale bar: 4 mm.

Figures 27–36: Microbuthus kristensenorum, sp. nov., holotype female. 27. Carapace, dorsal aspect. 28. Right basitarsus and telotarsus III, retrolateral aspect. 29. Right telotarsus III, ventral aspect. 30. Right pedipalp femur, dorsal aspect. 31. Right pedipalp patella, dorsal aspect. 32. Right pedipalp patella, external aspect. 33. Right pedipalp chela, dorsoexternal aspect. 34–35, right pedipalp chela movable finger terminus. 34. Dorsal aspect. 35. External aspect. 36. Right pedipalp chela, ventral aspect. Scale bar: 27, 30, 31, 32, 33, 36: 2 mm; 28, 34, 35: 1.26 mm; 29: 0.86 mm.

Figures 37–41: Microbuthus kristensenorum, sp. nov. 37–38, paratype female (Jabal Qamr); 39–41, holotype female. 37–38, right chelicera. 37. Dorsal aspect. 38. Ventral aspect. 39. Left pectine, ventral aspect. 40–41, metasoma and telson. 40. Right lateral aspect. 41. Ventral aspect. For clarity, long macrosetae of metasoma IV–V were not rendered on the lateral surfaces in Fig. 40 and the ventral surfaces in Fig. 41). Scale bar: 37, 38: 0.66 mm; 39: 1 mm; 40, 41: 2 mm.

Figures 121–124: Morphometric variation of picobuthoid scorpions in Oman (data from adults). 121. Variation in characters correlated with substratum specialization: slenderness of legs (bar plots show range of variation of leg III patella L/D), and development of basitarsal bristle combs and tibial spurs. Psammophilous species (Picobuthus spp.) have more slender legs with bristle combs, without tibial spurs; lapidicolous species (Microbuthus gardneri, M. kristensenorum) have more slender legs without bristle combs, with tibial spurs; the fossorial Femtobuthus shutuae has stout legs with bristle combs, and reduced tibial spurs. 122. Scatter plot of variation in slenderness of legs and metasoma V (leg III patella L/D vs. metasoma V L/D). Metasoma V is more slender in the psammophilous Picobuthus, and more stout in the lapidicolous Microbuthus, reflecting development of a heavily sclerotized telson sheath. 123. Scatter plot of variation in telson L/D and carapace L/W. The telson is deeper in M. gardneri and Femtobuthus, and longer in M. kristensenorum and Picobuthus, the carapace more elongated in Picobuthus, and more trapezoidal in Microbuthus and Femtobuthus. 124. Scatter plot of variation in slenderness of anterior metasoma and pedipalp (metasoma II L/W vs. pedipalp patella L/W). The anterior metasoma is more stout in Microbuthus and Femtobuthus, and more slender in Picobuthus, the pedipalp relatively more stout in Femtobuthus and Picobuthus, and more slender in Microbuthus. Data points in scatter plots represent individuals, with species membership color coded according to inset of Fig. 122.

Figures 125–134: Picobuthoid trichobothriotaxy. 125. Schematic showing trichobothrial nomenclature for right pedipalp chela (dorsoexternal aspect) of Microbuthus used by Vachon (1952, 1974). 126. Schematic showing revised trichobothrial nomenclature for right pedipalp chela fixed finger (dorsoexternal aspect) of picobuthoids, including Microbuthus, based on homologies with other buthids derived from locations of trichobothria relative to landmark carinae. Trichobothrial sockets visible on dorsal and external surfaces are shown as circles with solid outline, those hidden on internal surfaces as circles with dotted outline. 125–126, with holotype of M. gardneri as example. 127–132, stylized schematics of upper sides of right pedipalp chelae of Microbuthus and representatives of five other buthid genera, comparing placements of fixed finger trichobothria with respect to landmark carinae. Carinal terminology after Soleglad & Sissom (2001), i.e. E = external, D1 = digital, D3 = dorsal secondary, D4 = dorsal marginal, D5 = dorsal internal. Solid lines indicate strong carination, dotted lines weak carination. 127. Microbuthus gardneri, sp. nov., adult female paratype from type locality (Jabal Bani Jabir). 128. Tityus ecuadorensis Kraepelin, 1896, adult male. 129. Isometrus melanodactylus (L. Koch, 1867). 130. Lychas marmoreus (C.L. Koch, 1844). 131. Orthochirus scrobiculosus (Grube, 1873). 132. Androctonus crassicauda (Olivier, 1807). 133–134, fluorescence images of the right pedipalp patella of Microbuthus species from Oman, dorsal aspect, showing positions of dorsal trichobothria, and the tendency for placement of d3 towards external side of dorsomedian carina (for illustrative purposes, fluorescence contrast of trichobothrial sockets was enhanced). 133. Microbuthus gardneri, sp. nov., female paratype (Al Khod). 134. Microbuthus kristensenorum, sp. nov., female paratype (Jabal Qamr). Scale bars in Figs. 129–130: 0.50 mm.

Figures 135–147: Trichobothrial maps of Microbuthus species in Oman. 135–140, M. gardneri, sp. nov., right pedipalp, holotype male. 135. Base of femur, internal aspect. 136. Femur, dorsal aspect. 137. Patella, dorsal aspect. 138. Patella, external aspect. 139. Chela, external aspect. 140. Chela, ventral aspect. 141–147, M. kristensenorum, sp. nov., right pedipalp, 141, 143– 147. holotype female, 142. topoparatype female. 141–142. Base of femur, internal aspect. 143. Femur, dorsal aspect. 144. Patella, dorsal aspect. 145. Patella, external aspect. 146. Chela, external aspect. 147. Chela, ventral aspect. Trichobothrial nomenclature after Vachon (1974), except for revised nomenclature in Figs. 126–127.