Brachistosternus misti, Ojanguren-Affilastro & Pizarro-Araya & Ochoa, 2018

Ojanguren-Affilastro, Andrés A., Pizarro-Araya, Jaime & Ochoa, José A., 2018, Five new scorpion species of genus Brachistosternus (Scorpiones: Bothriuridae) from the deserts of Chile and Peru, with comments about some poorly studied diagnostic characters of the genus, Zootaxa 4531 (2), pp. 151-194 : 177-182

Brachistosternus misti n. sp.

( Figs. 1 , 2D, E , 16 , 19 ; Table 2 )

Type material. Holotype male: Peru, Arequipa Department, Arequipa Province, Miraflores District , 2480 m asl, (16°23'11'' S; 71°30'40'' W), 22/XII/1996, H. Zeballos & J. A. Ochoa coll. ( MUBI) . Paratypes: (same data as holotype), 1 female ( MUBI) ; Peru, Arequipa Department, Arequipa Province, Yura District , La Pascana , ca. Ciudad de Dios , 2675 m asl (16°17.151' S; 71°39.514' W), 29/XII/2007, R. Gutiérrez, A Quiroz & J. A. Ochoa coll., 7 males ( AMNH) , 2 males ( MACN) , 5 males ( MUBI) .

Etymology. The specific name is a noun in apposition, derived from the Misti volcano (5822 m), situated near the city of Arequipa and belongs to the Volcano mountain range of southwestern Peru. This new species was collected in the vicinity of the volcano.

Diagnosis. Brachistosternus misti n. sp. is a member of the subgenus Brachistosternus because of the trichobothrial pattern and the shape of the hemispermatophore. It is most closely related to Brachistosternus turpuq Ochoa, 2002 from southern Peru. Both species can be separated because B. misti n. sp. does not bear a VM carina in metasomal segment V, whereas B. turpuq bears a well developed VM carina. Additionally, the androvestigia of B. misti are not as elongated as in B. turpuq . The ventral setae of metasomal segment V of B. turpuq are arranged in three rows of setae (2-2-2 or 4-2-2), whereas in B. misti n. sp. there are more ventral setae arranged in five or six rows (4-4-2-2-2/4-4-1-3-2-2/4-1-4-2-2-2/4-4-3-2-2/4-4-1-2-2-2). In B. turpuq the anterior half of the carapace and the tergites are always pigmented, whereas in B. misti n. sp. they are unpigmented.

Description. Based on the holotype male (MUBI) and paratypes (MACN, MUBI). Total length, males: 42.97– 62.36 mm (N=8; mean= 51.43 mm); 60.48 mm in the only studied female. Colour: general colour light yellowish, without a conspicuous pigment pattern, only median eyes, lateral ocelli, aculeus and cheliceral teeth dark brown ( Figs. 16 A–D).

Chelicerae: anterior margin of movable fingers strongly curved; movable fingers with two small subdistal teeth, basal one bigger.

Pedipalps: Femur with DI, DE and VI carinae well developed, granular, extending the entire length of the segment, with two DE macrosetae ( Fig. 17F ); anterior margin with few scattered large granules and two macrosetae; VE margin slightly granular basally; rest of the intercarinal surfaces smooth. Patella DI and VI carinae extending the entire length of the segment, but formed by few scattered granules, less abundant in female, remaining surfaces smooth, ( Figs. 17G, H ); with one DI and two VI macrosetae. Chela manus medium sized ( Figs. 17 A–E), length/width ratio, males: 3.59–4.16 (N=8; mean=3.85), 4.36 in the only female; length/height ratio, males: 2.90–3.24 (N=8; mean=3.08), 3.39 in the female; with a blunt VM accessory carina, internal surface with a slight bulge near articulation of movable finger (female) ( Fig. 17E ), or with a pronounced, subtriangular projection (males) ( Fig. 17A ); fingers elongated, with a median row of denticles, and five to seven pairs of accessory denticles, with the basal external denticle (or even the two basal external denticles) being part of the median row. Trichobothrial pattern neobothriotaxic major Type C, with one accessory trichobothrium in V series of chela; femur with 3 trichobothria (d, i, e), one macroseta (M1) between with d and i; patella with 19 trichobothria (2 d, i, 3 et, est, 2 em, 2 esb, 5 eb, 3 V), with esb 2 petite; chela with 27 trichobothria (Dt, Db, 5 Et, Est, Esb, 3 Eb, dt, dst, dsb, db, et, est, esb, eb, ib, it, 5 V), with Et 4 petite, Esb forming triangle with Eb 2 and Eb 3.

Carapace: anterior margin almost straight, with four setae and a medium sized median projection. Surface: slightly granular in the median area near the ocular tubercle; lateral and posterior margins more densely granular, more so in males. Anterior longitudinal sulcus, posterior longitudinal sulcus, and lateral sulci well developed. Median ocular tubercle well developed, in the middle of the carapace, interocular sulcus well developed and slightly granular, median ocelli well developed, facing towards the lateral margins, ca two diameters apart; with one seta behind each eye. Lateral ocelli pattern type 3A; with three small lateral ocelli on each side of carapace, two of them placed anteriorly, anterior one placed slightly above posterior one, third ocellus similar in size to the other two, and placed slightly above the others.

Legs: Surfaces smooth, except for the external surface of femora which are slightly granular. Basitarsi each with two pedal spurs, retrolateral one between 30 and 50% shorter than external one in legs I and II, symmetrical in legs III and IV. Telotarsi elongated, ventrolaterally compressed, dorsally with a row of setae, ventrally each with a ventromedian row of hyaline setae, and paired rows of ventrosubmedian setae. Counts of setae on telotarsus of leg III: Dorsal setae: 11–13 (N=9; median=12); ventrosubmedian prolateral setae: 7–9 (N=9; median=8); ventrosubmedian retrolateral setae: 6 in all studied specimens (N=9). Ungues shallowly curved and elongated; asymmetrical in legs I and II, with the retrolateral one smaller; equal in length in legs III and IV. Ungues of leg IV more elongated and less curved than the rest.

Pectines: well developed. Tooth count, males: 35–41 (N=8); 29-30 in the only female.

Sternum: With two conspicuous subtriangular lateral lobes, each with a medium sized macroseta with an acute apex.

Genital opercula: Sclerites subtriangular, slightly more concave posterolaterally in males than in females.

Tergites: I–VI: with two anterior dorsosubmedian setae, surface smooth, only slightly granular in the posterior half of the segment. Tergite VII: with two anterior dorsosubmedian setae, median area finely granular, rest of the segment densely granular; with two barely visible dorsosubmedian carinae in the posterior half of the segment, and two well developed lateral carinae extending the posterior two thirds of the segment.

Sternites: Surface smooth in female, granular in males; sternites III–VI with large and elongated spiracles, and medium sized deep ventrosubmedian furrows.

Metasoma: Metasomal segment I, dorsal surface densely granular, except for a smooth area next to the median sulcus; DL carinae granular, extending the entire length of the segment, with one median DL macroseta; lateral surfaces granular between DL and LM carinae, smooth below LM carinae; LM carinae extending the entire length of the segment; LIM carinae in the posterior two thirds of the segment; with one LM seta in the middle of the segment and one LIM macroseta in the posterior third of the segment, ventrally granular in males, smooth in female, with 2-2 VL setae and two posterior VSM setae, VSM and VL carinae absent. Metasomal segments II and III similar to segment I but less granular, with diffuse LM and LIM carinae. Metasomal segment IV, dorsal surface smooth in its median area, dorsolateral margin slightly granular, DL carina poorly developed, reduced to some scattered granules but extending the entire length of the segment, with one DL macroseta; lateral margins with scarce blunt granules above LM carinae, LM carinae reduced to some scattered granules with two or three LM macrosetae; accessory carinae poorly developed, LIM carinae absent; VL carinae represented by a slight elevation of the tegument in males, absent in female; ventral surface smooth, with 16-20 scattered setae, and 5 macrosetae in the posterior margin. Metasomal segment V elongated; length/width ratio, males: 1.78–2.45 (N=8; mean=1.90); 1.95 in the female; dorsal surface smooth, males with two medium sized glands ( Fig. 18E ), or androvestigia, occupying the anterior half of the segment; DL carinae represented by some scattered granules extending the entire length of the segment, more marked in males; lateral margins, males densely granular above LM carinae, with scarce granulation below LM carinae; female with scarce blunt granules above LM carinae, smooth below LM carinae; LM carinae extending the entire length of the segment, reduced to some scattered granules and 6–8 macrosetae; LIM carinae absent ( Figs. 18C, D ), VL carinae well developed and extending the entire length of the segment, with 8–10 VL macrosetae; ventral surface smooth in the anterior half of the segment, with scattered granules in the posterior half of the segment; VM carina weakly developed in the posterior third, with scarce granules and obscured by granulation of ventral surface. ( Fig. 18F ); with abundant ventral macrosetae usually arranged in five transverse rows, two near the anterior margin of four macrosetae each, and three rows of two macrosetae each (variability: 4-4-2-2-2/4-4-1-3-2-2/4-1-4-2-2-2/4-4-3-2-2/4-4-1-2-2-2).

Telson: Vesicle globose, slightly more globose in female; length/height ratio, males: 2.85–3.19 (N=8; mean=3.04); 3.25 in the female; ventral and lateral surfaces densely granular in males, with blunt granules in female; lateral margin with a shallow furrow; dorsal surface smooth and shallow, in males there is a glandular subtriangular surface. Aculeus similar in size to the vesicle, shallowly curved ( Figs. 18A, B ), less so in females.

Hemispermatophore: Basal portion well developed. Distal Lamina well developed, only slightly curved medially ( Fig. 19A ), similar in length to the basal portion but much narrower; distal lobe (distal posterior flexure) medium sized, occupying less than a quarter of the distal lamina, distal crest medium sized occupying the apical third of the distal lamina, with some tiny transverse crests. Left hemispermatophore: cylindrical apophysis of the basal lobe well developed, and slightly longer than the laminar apophysis, similar in thickness in all its length, and with an acute tip barely reaching the base of the distal lobe ( Fig. 19B ); laminar apophysis bilobed, with a median internal longitudinal flexure that divides it into two lobes; row of spines and basal spines medium sized and joining in a continuous line, internal spines represented by some granules placed laterally to the basal triangle; basal triangle medium sized formed by a lobe with some sparse granules and two or three chitinous crests. Right hemispermatophore without a cylindrical apophysis ( Fig. 19C ), ILA very well developed, with well developed spines in all its extension, with the apical spines usually, forming a chitinous crest in the dorsointernal angle; the rest as left hemispermatophore.

Distribution. Brachistosternus misti n. sp. inhabits in the slopes of the Misti volcano near the city of Arequipa, at 2480–2675 m asl ( Fig. 1 ), in the Arequipa Department, southern Peru. Ecology. This species was collected in Serrania Esteparia Ecoregion, characterized by herbaceous vegetation, cacti, shrubs, and few small trees ( Ochoa, 2005). Brachistosternus misti n.sp. occurs in sympatry with other bothriurid scorpions: Brachistosternus ehrenbergii (Gervais, 1841) and Orobothriurus curvidigitus (Kraepelin, 1911) .

Figures

FIGURE 1. Distribution map of Brachistosternus gayi n. sp., Brachistosternus philippii n. sp., Brachistosternus contisuyu n. sp., Brachistosternus misti n. sp. and Brachistosternus anandrovestigia n. sp.

FIGURES 2A–F. Type locality of Brachistosternus species herein described. A. Brachistosternus gayi n. sp.; B. Brachistosternus philippii n. sp.; C. Brachistosternus contisuyu n. sp.; D, E. Brachistosternus misti n. sp.; F. Brachistosternus anandrovestigia n. sp.

FIGURES 16A–D. Brachistosternus misti n. sp., habitus. A. Male, dorsal aspect; B. Male, ventral aspect; C. Female, dorsal aspect; D. Female, ventral aspect. Scale bars: 1 cm.

FIGURES 17A–H. Brachistosternus misti n. sp. A. Left pedipalp chela, male, internal aspect; B. Left pedipalp chela, male, ventral aspect; C. Left pedipalp chela, male, external aspect; D. Left pedipalp chela, male, dorsal aspect; E. Left pedipalp chela, female, ventral aspect; F. Left pedipalp femur, male, dorsal aspect. G. Left pedipalp patella, male, external aspect; H. Left pedipalp patella, male, ventral aspect. Scale bars: 1mm.

FIGURES 18A–F. Brachistosternus misti n. sp. A. Telson, male, lateral aspect; B. Telson, female, lateral aspect; C. Metasomal segment V, male, lateral aspect; D. Metasomal segment V, female, lateral aspect; E. Metasomal segment V, male, dorsal aspect; F. Metasomal segment V, male, ventral aspect. Scale bars: 1mm.

FIGURES 19A–C. Brachistosternus misti n. sp. A. Left hemispermatophore, external aspect. B. Left hemispermatophore, detail of the lobe region; C. Right hemispermatophore, detail of the lobe region. Scale bars: 1mm.