Brachistosternus barrigai Ojanguren-Affilastro & Pizarro-Araya, 2014, n. sp.
Creators: name: Ojanguren-Affilastro, Andrés A.
name: Pizarro-Araya, Jaime
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Scorpiones
Bothriuridae
Brachistosternus
Brachistosternus barrigai

description: Brachistosternus barrigai n. sp.
(Figures 1, 3, 25–33, 35–46; Table 1)
Type material. Holotype ♂: Chile, Antofagasta Region, 8.1 km NW from the village of Paposo (24°56'22'' S, 70°29'34'' W), 114 msl, (base of the hills of the “Cordillera de La Costa”), 22-27/X/2011. A. A. Ojanguren- Affilastro, J. Pizarro-Araya, D. Valdivia, F. Alfaro Kong, J. E. Barriga Tuñón, S. Rothman Toro, J. Mondaca & M. Ramírez coll. (MNHN). Paratypes (same data as holotype): 1 ♀ (MNHN); 4 ♂, 5 ♀, 7 juv. (MACN); 4.4 km N. from the village village of Paposo (24°58'11'' S, 70°28'30'' WS24), 1 msl, (dunes in beach), (rest of the data as holotype): 1 ♂, 1 ♀ (LEULS); 3 ♂, 2 ♀, 3 juv. (MZUC); 4 ♂, 3 ♀ (MACN).
Etymology. This species is named after the Chilean entomologist Juan Enrique Barriga Tuñón, in recognition of his disinterested support during several collection campaigns.
Diagnosis. Brachistosternus barrigai n. sp. is most closely related to Brachistosternus kamanchaca, Ojanguren-Affilastro, Mattoni & Prendini 2007, with both species sharing a very similar external morphology, pigment pattern and shape of the hemispermatophore. Both species can be separated because B. barrigai n. sp. bears a wider and thicker pedipalp chela (Figs. 34–39); this difference is quite conspicuous in males, but not in females in which it overlaps with B. kamanchaca. In B. barrigai n. sp. ♂ the length/width ratio varies between 3.64–4.03 (N=10; mean=3.86) whereas in B. kamanchaca ♂ it varies between 4.12–5.03; in B. barrigai n. sp. ♀ the length/width ratio varies between 4 – 4.73, whereas in B. kamanchaca ♀ it varies between 4.07– 5. In B. barrigai n. sp. ♂ the length/height ratio varies between 2.93–3.30 (N=10; mean=3.08) whereas in B. kamanchaca ♂ it varies between 3.34–3.61; in B. barrigai n. sp. ♀ the length/height ratio varies between 3.33–3.55, whereas in B. kamanchaca ♀ it varies between 3.19–3.71. Metasomal segment V tends to be wider in the distal margin in B. kamanchaca (Fig. 24), than in B. barrigai n. sp. (Fig. 25), so that the segment seems to be wider in B. barrigai n. sp., however the total length/width ratio is similar in both species. Lateral surfaces of metasomal segment V and telson of males of B. barrigai n. sp. are more granular than in males of B. kamanchaca being the granules of B. barrigai n. sp. more conspicuously marked and more abundant.
Description. Based on the holotype ♂ (MNHN) and paratypes (MACN, LEULS, MZUC). Total length: 43– 53.5 mm in ♂ (N=10; mean= 47.2 mm); 42–49 mm in ♀ (N=10; mean= 46.7 mm). Colour: Base colour dark yellowish, with dark brown pattern (Figs. 43–46). Chelicerae with faint reticulate pigmentation on external surface of manus, densely pigmented in the base of the fixed finger, and in the external surface of movable finger. Carapace, with a triangular unpigmented area from the anterior margin of the ocular tubercle, to the anterior margin of the lateral ocelli; with two broad, dark stripes, extending from the lateral ocelli to the posterior longitudinal sulcus, surrounding the ocular tubercle and the unpigmented anterior triangle; median ocular tubercle and area around lateral ocelli dark brown; with two posterolateral dark spots covering most of posterior margin, leaving a median unpigmented area; rest of the carapace with reticular pigment pattern. Tergites I–VI each with a single transversal stripe; tergite VII with three spots, one median anterior and two posterolateral. Sternites, sternum, genital opercula and pectines unpigmented. Metasomal segment I: dorsal surface with two posterolateral dark spots and an anterior median spot, lateral margins pigmented only in the area between LSM and LIM carinae; ventral surface with VL stripes, slightly diffuse that are broader and more marked in their posterior third, VM stripe absent or reduced to some faint pigment in the posterior margin of the segment. Metasomal segment II: dorsal and lateral surfaces as in segment I, ventrally with VL stripes well developed and getting broader distally, VM stripe wide and slightly faint, in some specimens in its median area it is not completely pigmented forming two VSM stripes. Segment III as segment II but more densely pigmented. Segment IV, dorsal surface as segment III, lateral surfaces with a small pigmented area near the posterior margin; ventral surface with well-developed VL and VM stripes, getting broader posteriorly, connected by reticulate pattern in the anterior half, and fusing completely in the posterior margin. Metasomal segment, V dorsal surface as in the rest of the segment (except males with paired median unpigmented glands), lateral surfaces unpigmented, ventral surface with VL and VSM stripes that join in the anterior third of the segment to form a wide VL stripe, and with a thin VM stripe, that fuses with the VL stripes in the posterior half of the segment. Telson, vesicle with faint reticular pattern, except for paired, narrow VSM and VL unpigmented stripes, with a well marked dark VM stripe; males with an unpigmented gland in the median area of dorsal surface; aculeus basally unpigmented, apex dark brown. Pedipalps, trochanter unpigmented; femur with well developed stripes along DI, DE, E, and VE margins, joining in a big dark spot in the articulation with patella. Patella, with dorso-internal, external and ventro-external stripes, connected to each other by reticulate pattern; internal and ventral surfaces unpigmented. Chela with seven dark stripes along DI, DM, DS, D, E, V and VM carinae, these stripes are connected by a dense reticulate pattern, specially in the external surface; area near articulation of fixed and movable fingers, and base of fingers with faint pigmentation. Legs: coxae and trochanters unpigmented; femur pigmented near articulation with patella and along external margin; patella pigmented near articulations and along dorsal and external margins; tibia, basitarsi, and telotarsi unpigmented. Chelicerae: with two vestigial subdistal teeth. Carapace: anterior margin convex and with a weak median projection (Fig. 29). Surface slightly granular in the area anterior from the median eyes; lateral and posterior surfaces more densely granular. Anterior longitudinal sulcus, posterior longitudinal sulcus present but not very deep; lateral sulci very well developed. Median ocular tubercle pronounced placed slightly ahead the middle of the carapace, interocular sulcus present, median ocelli medium sized, ca. two diameters apart; with one seta behind each eye. Three small lateral ocelli on each side of carapace, being the median anterior ocellus 30 percent smaller than the rest of the ocelli; anterior and posterior situated in the same horizontal axis, median ocellus situated one diameter below the rest. Tergites: Surfaces, I–VI: finely granular, more densely in males; VII with paired submedian and lateral carinae; lateral carinae restricted to posterior two-thirds of segment, submedian carinae restricted to the posterior half of the segment, intercarinal surfaces with scattered medium-sized granules, rest of surface finely granular. Sternites: Surface coarsely granular, more densely so in posterior and lateral margins, III–VI with large and elongated spiracles. Metasoma: Metasomal segment I, dorsal surface densely granular, except for the median area that is smooth; DL carinae poorly developed, granular, with no elevation of the tegument, extending entire length of segment, barely visible between the granulation, being in some specimens indiscernible, in some specimens with a DL macrosetae; LSM as DL carinae but even less developed and without macrosetae; lateral surface granular, except for the area between LM and LIM carinae, almost completely smooth, LM and LIM carinae well developed and discernible, occupying the posterior half of the segment and joining medially, LM carina with one macroseta in its anterior margin, LIM carina with one macroseta in its median part; ventral surface densely granular in males, smooth in females, VL carinae absent or reduced to a barely visible elevation of the tegument, each with two macrosetae; with no VSM nor VM carinae, with two pairs of VSM macrosetae, one pair in the anterior half and the other on the distal margin, in some specimens the anterior pair is absent. Metasomal segment II: as segment I, but almost in all specimens with a DL macrosetae, with LM and LIM carinae reduced to less than the posterior half of the segment, and with an additional pair of VSM macrosetae; Segment III: as segment II but with more reduced carinae and with an additional pair of VSM macrosetae. Metasomal segment IV: dorsal surface granular, except for the median area, DL carinae obsolete, with one or two macrosetae each; LSM carinae absent, only represented by a macroseta; lateral surface granular in males, with scattered granules in females, LM carinae obsolete, only discernible by two macrosetae and by surrounding a smooth lateral area below it extending the entire length of the segment; LIM carinae obsolete, reduced to two macrosetae; ventral surface smooth in females, slightly granular in males, with abundant scattered setae, in most granular males VM and VL carinae are barely discernible by some granules. Segment V elongated (Figs. 25, 26); length/width ratio varies between 1.60–1.83 in ♂, and between 1.73–1.95 in ♀; dorsal surface smooth, males with two glands or androvestigia (Cekalovic 1973) medium sized, of about half of the length of the segment, DL carinae extending the entire length of the segment but reduced to some scattered granules and 5 or 6 macrosetae; lateral surface granular in males, smooth in females, LSM carinae not visible, LM carinae obsolete, represented by five or six macrosetae, and a similar number of microsetae; ventral surface sparsely granular, more so in the posterior third of the segment, usually with five transversal rows of macrosetae, two in the anterior half of four to six macrosetae each, and three of 1 to three macrosetae each (more usually two), being the more common distribution 5-4-2-2-2; VL carinae granular, straight, and extending the entire length of the segment with 7 to 10 VL macrosetae (N=10; mean=9), VM carina granular, extending the entire length of the segment, and diverging in the posterior third. Telson: Vesicle, globose, more so in females; lateral and ventral margins granular in males, smooth in females; dorsally with a VM and two VSM carinae, laterally with two longitudinal carinae on each side; dorso-lateral surface granular in males, with barely visible DL carinae that is obsolete in females, dorsal surface smooth and shallow, males with a glandular area medially formed by two separated glands, that in some specimens seem to be fused. Aculeus longer than the vesicle, shallowly curved; more so in females (Figs. 27, 28). Pedipalps: Femur (Fig. 40) with DI, DE, and VI carinae granular, extending entire length of segment; VE carina only present in the basal half of the segment; anterior margin with coarse granules and three macrosetae, one basal and two placed medially; rest of the intercarinal surfaces smooth. Patella with DI and VI carinae slightly granular, more so in males, extending entire length of segment (Figs. 41, 42); rest of the segment smooth. Chela manus medium sized (Figs. 35–39), slightly more robust in ♂, length/width ratio varies between 3.64–4.03 (N=10; mean=3.86) in ♂, and in ♀ it varies between 4.07–5 (N=10; mean=4.29), the length/ height ratio varies between 3.64–4.03 (N=10; mean=3.86) in ♂, and in ♀ it varies between 3.33–3.55 (N=10; mean=3.41); with a blunt VM accessory carina, internal surface with slight bulge near articulation of movable finger (♀), or with a pronounced, subtriangular projection (♂); fingers elongated, with a median row of denticles, and with five or six pairs of accessory denticles. 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) associated with d and i, e situated in same axis as, or slightly proximal to M; patella, with 19 trichobothria (2 d, i, 3 et, est, 2 em, 2 esb, 5 eb, 3 V); chela with 27 trichobothria (Dt, Db, 5 Et, Est, Esb, 3 Eb, dt, dst, dsb, db, et, est, esb, eb, ib, it, 5 V), Esb forming triangle with Eb 1 and Eb 2. Pectines: Tooth count: 28–33 in ♀ (N=10; median=30); 31–36 in ♂ (N=10; median=35). Legs: Surfaces smooth, except for the femur of legs II-IV which is dorsally and ventrally granular. Basitarsi each with two well developed, equal length pedal spurs. Telotarsi elongated and ventrolaterally compressed, dorsally with a row of setae, ventrally each with a ventromedian row of poorly developed hyaline setae, and paired rows of ventrosubmedian setae; telotarsus III (Fig. 30) with following counts of setae: dorsal setae: 9–11 (N=10; median=9); ventro internal setae: 5–7 (N=10; median=6); ventroexternal setae: 4–6 (N=10; median=5). Ungues slightly curved, equal in length, except in telotarsus I in which the ventroexternal ungues is slightly shorter than the ventrointernal. Hemispermatophore: right and left hemispermatophores asymmetrical as in the rest of the species of the genus (Figs. 31−33). Left hemispermatophore: Basal portion well developed. Distal lamina well developed, ca. similar in length to the basal portion; distal lobe (distal posterior flexure) medium sized, occupying the basal third of the distal lamina; cylindrical apophysis of the basal lobe well developed, longer than the laminar apophysis; row of spines and basal spines well developed and in the same line, internal spines absent; basal triangle well developed formed by three or four chitinous crests. Right hemispermatophore without a cylindrical apophysis, instead there is secondary laminar apophysis, 50 % longer than the laminar apophysis; the rest as left hemispermatophore.
Distribution. This species has only been collected in its type locality and in a close locality, both in the area around the village of Paposo, in the coast of Southern Antofagasta region (Fig. 1).
Ecology. The area where this species has been collected belongs to the “Desierto Costero de Taltal”, of the “Desierto Costero” Botanical region. This species has been collected in coastal areas, and in the foothills of the mountains of the “Cordillera de la Costa”. It occurs in areas with fine clay substratum with scattered rocks. Brachistosternus barrigai n. sp. was collected in a coastal plain environment, associated to the following plant species Copiapoa cinerea (Phil.) Britton & Rose, Polyachyrus fuscus Meyen & Walp, Tetragonia maritima Barnéoud, Perityle emoryi Torr, Heliotropium pycnophyllum Phil., Nolana divaricata (Lindl.) I.M. Johnst. and Nolana aplocaryoides (Gaudich.) I.M. Johnst (Fig. 3).
Brachistosternus barrigai n. sp. lives in sympatry with the bothriurids Bothriurus dumayi and Brachistosternus paposo n. sp. and the caraboctonid Caraboctonus keyserlingi.
description: Published as part of Ojanguren-Affilastro, Andrés A. & Pizarro-Araya, Jaime, 2014, Two new scorpion species from Paposo, in the Coastal desert of Taltal, Chile (Scorpiones, Bothriuridae, Brachistosternus), pp. 400-418 in Zootaxa 3785 (3) on pages 410-415, DOI: 10.11646/zootaxa.3785.3.4, http://zenodo.org/record/226634