Brachistosternus (Leptosternus) coquimbo, Ojanguren-Affilastro, Andrés A., Agusto, Pablo, Pizarro-Araya, Jaime & Mattoni, Camilo I., 2007

Ojanguren-Affilastro, Andrés A., Agusto, Pablo, Pizarro-Araya, Jaime & Mattoni, Camilo I., 2007, Two new scorpion species of genus Brachistosternus (Scorpiones: Bothriuridae) from northern Chile, Zootaxa 1623, pp. 55-68 : 61-65

Brachistosternus (Leptosternus) coquimbo n. sp.

Figs. 1 , 11–22 ; Table 1

Type material: Holotype ɗ: Chile, IV Región, Coquimbo , between Juntas and Paso del Agua Negra, 30°16'14.5'' S, 69°58'27.9'' W, 3000 m a.s.l, 6/II/2006; A.A. Ojanguren, L. Compagnucci & C. Cuezzo (MACN-Ar). Paratypes: 4 ɗ, 1 juvenile; same data; 1 ɗ, Cancha Sky, El Indio mine, 29º51´00´´ S, 70º03´00´´ W, 3300 m a.s.l; 15/II/1992, H. Vásquez; 1 Ψ, Sancarrón, El Indio mine, 29º33´00´´ S, 70º14´00´´W; 5/II/ 1993; H. Vásquez (MACN-Ar).

Etymology: The name of this species refers to the Chilean region where it has been collected.

Diagnosis: Brachistosternus (L.) coquimbo n. sp. is closely related with Brachistosternus (L.) montanus Roig Alsina, 1977 . The two species can be distinguished by the following characters: (1) Br. (L.) coquimbo has a narrower pedipalp chela. In males the chela length/width ratio varies from 4.7 to 5.09 (N = 6; mean = 4.85), and in the only studied female it is 4.33, whereas in the males of Br. (L.) montanus it varies from 4.01 to 4.37 (N = 15; mean = 4.25) and in females it varies from 3.9 to 4.16 (N = 10; mean = 4.07); (2) in Br. (L.) coquimbo males the chela length/height ratio varies from 3.63 to 3.93 (N = 6; mean = 3.81) and is 3.5 in the only studied female; whereas in Br. (L.) montanus males it varies from 3.01 to 3.31 (N = 15; mean = 3.17), and in females it varies from 3.06 to 3.23 (N = 10; mean = 3.14). Brachistosternus (L.) coquimbo n. sp. lives in sympatry with Brachistosternus (L.) perettii Ojanguren-Affilastro & Mattoni 2006 . The two species are easily distinguishable: Br. (L.) perettii do not posses a VM carina of metasomal segment V whereas it is well developed and extends on the entire length of the segment in Br. (L.) coquimbo .

Description: Measurements of a male specimen and a female specimen are recorded in Table 1 . Colour. General colour dark yellow with a dense dusky pattern. Chelicerae: with a dark spot near the base of the fingers, movable finger with a dark spot on the external surface. Carapace: densely pigmented; ocular tubercle and lateral ocelli black; area around the ocular tubercle densely pigmented, with two lateral dark stripes from the lateral sulci to the lateral ocelli, and with two posterolateral dark spots; remaining tegument with reticulate pattern. Tergites I–VI: each tergite with three dark spots, two lateral and one median spot, connected by dense reticular pigmentation. Tergite VII with five dark spots, two antero-lateral, two postero-lateral, and an anteromedian spot, sometimes connected by a faint reticular pattern. Sternites: not pigmented. Metasoma: metasomal segments I–III: dorsal surface with an antero-median thin stripe, and two posterolateral dark spots; lateral surfaces depigmented; ventral surface with one thick VM and two thin VL stripes, joined distally; VM stripe barely visible in segment I, absent in some specimens, more noticeable in segment II, and well marked in segment III. Metasomal segment IV: dorsal surface with a faint small antero-median spot, and with two small posterolateral dark spots; lateral surfaces with reticulate pigment; ventral surface with one thick VM and two thin VL stripes joining in the posterior third of the segment,and connected by reticular pattern in the remaining surface. Metasomal segment V: dorsal surface with two DL faint stripes; lateral surface with slight reticular pattern; ventral surface with one thin, dark VM and two thick VL stripes that join in the posterior third of the segment; in the anterior half of the segment the VL stripes divided in four thin lines, two VL and two VSM, that join in the posterior half of the segment. Telson: vesicle with the ventral and dorsolateral surfaces densely pigmented; aculeus dark brawn. Pedipalps: femur densely pigmented near patella articulation, and in the anterior and posterior surfaces, with a dark stripe on the DE margin; patella with one DI and one DE stripe, densely pigmented near chela articulation, remaining surfaces with dense reticular pattern; chela manus with longitudinal stripes joined by a faint reticular pigment, fingers not pigmented. Legs: femur and patella densely pigmented, remaining segments not pigmented.

Morphology. Carapace: Anterior margin with a slight median bulge; tegument smooth near the ocular tubercle, lateral surfaces densely granular; ocular tubercle slightly anterior to the middle of the carapace, interocular sulcus deeply marked, median ocelli two diameters apart, with a seta behind each eye; anterior, laterals and posterior longitudinal sulci well marked, postocular furrow deeply marked. Chelicerae with two subdistal teeth. Hemispermatophore: distal lamina thick and slightly curved, approximately of the same size as the basal portion ( Figs. 11, 12 ); cylindrical apophysis well developed, longer than the laminar apophysis; basal triangle well developed, formed by 2 or 3 crests; internal spines absent; basal spines and row of spines poorly developed, and aligned along the same axis ( Fig. 13 ). Mesosoma: Tergites I–VI finely granular in the distal margin, remaining areas smooth. Tergite VII smooth in the median area, remaining areas densely granular, with two lateral carinae in the posterior half of the segment. Sternites: Sternite I smooth in the anterior half of the segment, coarsely granular in the posterior half; Sternites II–V densely granular. Spiracles narrow and well developed. Sternum type 2 ( Soleglad & Fet 2003) much wider than long, apex width almost equal to posterior width, posterior emargination quite well developed, with convex lateral lobes conspicuously separated. Pectines: pectinal teeth 29–34 in males (N = 5; median = 32), 29–30 in the only studied female. Metasoma: Metasomal segments I–III: tegument densely granular; LSM and LIM carinae present on the distal 3/4 of the segment; DL carina weakly developed, extending on the entire length of the segment. Metasomal segment IV: dorsal and lateral surfaces granular; ventral surface smooth with a large number of scattered setae; DL carinae and LSM carinae extending on the entire length of the segment, but poorly developed; LIM carina only present in the last third of the segment. Metasomal segment V: slightly wider in its median part than near the anterior and posterior margins in males ( Fig. 14 ); dorsal surface smooth; androvestigia long and well developed, occupying almost 50 % of the dorsal surface ( Fig. 15 ); lateral surface granular; LSM and DL carinae granular, extending the entire length of the segment but poorly developed; ventral surface irregularly granular, specially in the second half of the segment; VL and VM carinae extending on the entire length of the segment; four rows of ventral setae, two basal rows of four setae and two posterior rows of one or two setae each. Telson: dorsal gland in males almost triangular and well developed ( Fig. 16 ); vesicle with rounded ventral surface ( Figs. 17, 18 ), ventral surface slightly granular; aculeus slightly curved, of the same length as the vesicle. Pedipalps: Femur: internal surface slightly granular; VI, DE, and DI carinae granular, extending on the entire length of the segment, but poorly developed; remaining surfaces smooth. Patella: internal surface with scattered granules; DI and VI carinae extending on the entire length of the segment, but poorly developed; remaining surfaces of the tegument smooth. Chela: manus very narrow, with smooth tegument; ventrointernal carina poorly developed ( Fig. 19 ); prolateral apophysis well developed in males; movable finger with a median row of granules and 5 or 6 internal and external granules that do not overlap with the median row of granules. Trichobothrial pattern of subgenus Leptosternus ( Figs. 19–22 ): Neobothriotaxic Major Type C, with one accessory trichobothrium in V series of chela; femur with 3 trichobothria (1 d, 1 i and 1 e); patella with 19 trichobothria (3 V, 2 d, 1 i, 3 et, 1 est, 2 em, 2 esb, and 5 eb); chela with 27 trichobothria (1 Est, 5 Et, 5 V, 1 Esb, 3 Eb, 1 Dt, 1 Db, 1 et, 1 est, 1 esb, 1 eb, 1 dt, 1 dst, 1 dsb, 1 db, 1 ib, 1 it). Legs: Tegument finely granular in femur; telotarsi I and II with the inner unguis 5 to 10 % shorter than the external one; internal and external basitarsal spurs well developed, of the same size in all segments.

Variation: Pedipalp chela length/height ratio, male 3.63–3.93 (N = 6; mean = 3.81), female 3.5; pedipalp chela length/width ratio, male 4.7–5.09 (N = 6; mean = 4.85), female 4.33; metasomal segment V, length/ width ratio, male 1.5–1.7 (N = 6; mean = 1.61), female 1.4; metasomal segment V, ventral macroseta, 11–13 (N = 7; median = 12); metasomal segment V, ventrolateral macroseta, 8–9 (N = 7; median = 8); telotarsus III, dorsal macroseta, 10–12 (N = 7; median = 11); telotarsus III, ventrointernal macroseta, 5–8 (N = 7; median = 7); telotarsus III, ventroexternal macroseta, 6–8 (N = 7; median = 7); basitarsus III, dorsal macroseta, 5–9 (N = 7; median = 8); total length (mm), males, 49–57 (N = 6; mean = 53), female: 44.

Distribution and ecology: Brachistosternus (L.) coquimbo n. sp. has been collected in the Andean sector of Coquimbo Region, ( Chile), between 2850 to 3000 m a.s.l ( Fig. 1 ). All localities are located within the high- Andean steppe of Doña Ana botanical subregion, of the Andean desert botanical region (Cepeda-Pizarro et al. 2006; Gajardo 1993; Squeo et al. 2006a, 2006b).

Brachistosternus (L.) coquimbo n. sp. occurs in areas with fine clay substratum with scattered rocks. The vegetation of this area is composed mostly of small shrubs. This species has been collected in sympatry with Br. (L.) perettii , and with an undescribed species of Orobothriurus Maury, 1976 , closely related to O. alticola (Pocock, 1899) .

Figures

FIGURE 1. Map of Coquimbo region, Chile, with localities of Brachistosternus (L.) cepedai n. sp. and Brachistosternus (L.) coquimbo n. sp.

FIGURES 11 – 18. Brachistosternus (L.) coquimbo n. sp. 11. left hemispermatophore, ventral aspect; 12. left hemispermatophore, dorsal aspect; 13. left hemispermatophore, detail of lobe region; 14. metasomal segment V, male, dorsal aspect; 15. metasomal segment V, male, ventral aspect; 16. telson, male, dorsal aspect; 17. telson, male, lateral aspect; 18. telson, female, lateral aspect. Scale bars = 1 mm.

FIGURES 19 – 22. Brachistosternus (L.) coquimbo n. sp. 19. Left pedipalp chela, male, ventral aspect; 20. left pedipalp chela, male, internal aspect; 21. right pedipalp chela, male, external aspect; 22. right pedipalp chela, female, external aspect. Scale bars = 1 mm.