Brachistosternus pehuenche Ojanguren-Affilastro, Alfaro, Iuri, Camousseigt-Montolivo & Pizarro-Araya, 2025, sp. nov.
Year: 2025
Type: other
Abstract: Brachistosternus pehuenche sp. nov. Figs 1, 2, 3, 4 A ‒ D, 5 A, B, D ‒ E, 6, 7, Table 1 Type material. Chile, Maule Region (VII), Maule Valley, Fundo La Escuadra: Holotype ♂ (MNHN 8651), Site 4, Open woods of Austrocedrus chilensis (35°44'21.8"S, 70°46'43.7"W), 1292 m a. s. l., 07–10/XII/2022, Pizarro-Araya, Alfaro & Calderón coll. Paratipes: Armerillo (Cabaña) manual (35°42'13.26"S, 71°6'22.16"W), 750 m a. s. l., 16–19/I/2018, Pizarro-Araya, Alfaro & Calderón coll. 1 ♀ (MACN) • Fundo La Escuadra, Site 2, L Invernada lagoon (35°43'16.1"S, 70°47'04.9"W), 1260 m a. s. l., 14–17/X/2022, Pizarro-Araya, Alfaro & Calderón coll. 2 ♀, 4 ♂ (MACN) • Fundo La Escuadra, Site 2, Herbazal Invernada Lagoon (35°43'16.1"S, 70°47'04.9"W), 1260 m a. s. l., 07–10/XII/2022, Pizarro-Araya, Alfaro & Calderón coll. 8 ♀, 3 ♂, 5 juveniles (LEULS), 5 ♀, 1 ♂, 1 juvenile (MNHN) 4 ♀, ♂, 1 juvenile (MZUC-UCCC) • Fundo La Escuadra, Site 4, Open woods of Austrocedrus chilensis (35°44'21.8"S, 70°46'43.7"W), 1292 m a. s. l., 07–10/XII/2022, Pizarro-Araya, Alfaro & Calderón coll. 3 ♀, 1 ♂, 3 juveniles (LEULS), 5 ♀, 2 juveniles (MNHN), 3 ♀ (MZUC-UCCC) • La Escuadra, Site 4, Open woods of Austrocedrus chilensis (35°44'21.8"S, 70°46'43.7"W), 1292 m a. s. l., 07–10/XII/2023, Pizarro-Araya, Alfaro & Calderón coll. 5 ♀, 9 ♂ (MACN) • La Escuadra, Site 5, Hornitos volcano (35°45'14.7"S, 70°47'32.3"W), 1154 m a. s. l., 07–10/XII/2023, Pizarro-Araya, Alfaro & Calderón coll. 1 ♀, 2 ♂ (MACN) • La Escuadra, Site 6, Woods of Quillaja saponaria and Cryptocarya alba, (35°46'04.1"S, 70°47'45.6"W), 1020 m a. s. l., 07–10/XII/2023, Pizarro-Araya, Alfaro & Calderón coll. 2 ♀, 2 ♂ (MACN) • Fundo La Escuadra, Sitie 10, Bocatoma Ojos de Agua (35°46'06.1"S, 70°47'44.4"W), 1009 m a. s. l., 14–17/X/2022, Pizarro-Araya, Alfaro & Calderón coll. 3 ♀, 1 ♂ (LEULS) • Los Cóndores valley, Paso Pehuenche, Proy. Los Cóndores, Polig. B-Y 10 (35°58'25.22"S, 70°33'35.62"W), 1182 m a. s. l., 16–19/I/2018, Pizarro-Araya, Alfaro & Calderón coll. 1 ♀, 2 ♂, 1 juvenile (MACN) • Paso Pehuenche (35°49'32.362"S, 70°45'0.849"W), 1000 m a. s. l., 18/I/2018, Ramírez, Pérez-González, Porto & Ojanguren-Affilastro coll. 2 ♂ (MACN) • Paso Pehuenche (35°51'31.968"S, 70°41'0.275"W), 1200–1250 m a. s. l., 18/I/2018, Ramírez, Pérez-González, Porto & Ojanguren-Affilastro coll. 6 ♀, 9 ♂, 9 juveniles (MACN) • Paso Pehuenche (35°57'31.608"S, 70°34'22.871"W), 1800–1900 m a. s. l., 18/I/2018, Ramírez, Pérez-González, Porto & Ojanguren-Affilastro coll. 13 ♀, 22 ♂, 21 juveniles (MACN) • Paso Pehuenche (35°54'21.97"S, 70°38'30.64"W) 1300 m a. s. l., 29/XI/2021, Pizarro-Araya, Alfaro & Ojanguren-Affilastro coll. 2 ♀, 5 ♂, 5 juveniles (MACN) • Paso Pehuenche (35°55'10.61"S, 70°37'27.12"W) 1400 m a. s. l., 18/I/2021, Pizarro-Araya, Alfaro & Ojanguren-Affilastro coll. 9 ♀, 3 ♂, 2 juveniles (MACN) • Paso Pehuenche (35°56'52.92"S, 70°35'57.97"W) 1700 m a. s. l., 18/I/2021, Pizarro-Araya, Alfaro & Ojanguren-Affilastro coll. 1 ♀, 2 ♂ (MACN) • Los Cóndores valley, Paso Pehuenche, Proy Los Cóndores, Polig. B-Y 10 (35°58'25.22"S, 70°33'35.62"W), 1182 m a. s. l., 16–19/I/2018, Pizarro-Araya, Alfaro & Calderón coll. 1 ♀, 2 ♂, 1 juvenile (MACN) • Los Cóndores valley, Paso Pehuenche, Proy. Los Cóndores, Polig. B-Y 10 S 1 R 2 (35°51'21.72"S, 70°41'0.10"W), 1184 m a. s. l., 16–19/I/2018, Pizarro-Araya, Alfaro & Calderón coll. 1 juvenil (MACN) • Los Cóndores valley, Paso Pehuenche, Proy. Los Cóndores, Polig. B-Y 10 S 1 R 1 (35°51'25.08"S, 70°40'59.61"W), 1190 m a. s. l., 16–19/I/2018, Pizarro-Araya, Alfaro & Calderón coll. 1 juvenile (MACN) • Los Cóndores valley, Paso Pehuenche, Proy. Los Cóndores, Polig. B-Y 10 S 1 R 3, (35°51'24.02"S, 70°40'55.40"W), 1191 m a. s. l., 16–19/I/2018, Pizarro-Araya, Alfaro & Calderón coll. 1 juvenil (MACN) • Los Cóndores valley, Paso Pehuenche, Proy. Los Cóndores, Polig. B-Y 9, S 2 R 2 (35°52'16.13"S, 70°40'52.62"W), 1233 m a. s. l., 16–19/I/2018, Pizarro-Araya, Alfaro & Calderón coll. 1 juvenile (MACN) • Valle de los Cóndores, Paso Pehuenche, Proy. Los Cóndores, Polig. IF Las Luces, S 7 R 2 (35°55'26.16"S, 70°37'9.75"W), 1449 m a. s. l., 16–19/I/2018, Pizarro-Araya, Alfaro & Calderón coll. 1 juvenile (MACN). Etymology. The specific epithet “ pehuenche ” is a noun in apposition referring to the Pehuenche International Pass between Argentina and Chile, in the northern Patagonia, where this and other endemic scorpion species have been collected. Pehuenche is also the name of the indigenous people of this area, belonging to the Mapuche cultural group. Diagnosis. Brachistosternus pehuenche sp. nov. is most similar to B. negrei, which is the only Brachistosternus species occurring in nearby areas of the south-central Chilean woods. Both species can be easily distinguished by several morphological characters. Brachistosternus pehuenche, on one hand, has tergites that bear two lateral spots, with pigment occupying most of the posterior lateral margins and leaving a median unpigmented stripe (Figs 4 A, C, 5 A); B. negrei, on the other hand, has five spots on each segment, one antero-median, two lateral, and two postero-submedian, in some cases connected by faint reticulate pigment (Fig. 5 E). The metasomal segments I – IV of B. pehuenche bear two VL narrow stripes and a VM wide stripe (the VM stripe can be very faint or absent in segments I – III) (Fig. 5 B), whereas in B. negrei there are two VL stripes and two VSM stripes (VSM stripes can be faint or absent in segments I – III) (Fig. 5 F). The paired dorsal glands of metasomal segment V of males, or Androvestigia, are medium-sized in B. pehuenche, occupying from a third to almost the entire posterior half of the segment (Fig. 5 C), whereas in B. negrei these glands are small, occupying between 10 to 25 percent of the dorsal surface of the segment (Fig. 5 G). Metasomal segment V is more granular ventrally in B. pehuenche than in B. negrei, with some granules even forming a slight ventro-median carinae in the former (Fig. 5 D), whereas in B. negrei there is no VM carina at all, and ventral granules are more sparse and smaller (Fig. 5 H). Description. Based on the male holotype (MNHN) and the paratypes (MACN, LEULS). Total length, males: 50–58 mm (N = 10; mean = 53.90 mm); females: 50–58 mm (N = 10; mean = 53.00 mm). (Measurements of a male and a female paratype are in Table 1). Color: Base color yellowish, with dark brown pigmentation pattern in pedipalps, carapace, tergites, metasoma, and legs; the remaining, yellowish without dark spots (Fig. 4 A ‒ C). Chelicerae with faint pigmentation on external surface of movable finger; manus with dense reticulate pigment dorsally and densely pigmented near the base of the fixed finger. Carapace, with a heavily pigmented anterior triangular area from the postocular furrow to the lateral ocelli, leaving a slightly less pigmented area anterior to the ocular tubercle (in some specimens, as the type material, it can be densely pigmented, but in others it is unpigmented); median ocular tubercle dark brown; with two small posterolateral dark spots, leaving a posterior median unpigmented area. Pedipalps, coxae, and trochanter unpigmented; femur, dorsally heavily pigmented in the distal third, ventro-posterior margin with a faint stripe, the rest unpigmented. Patella, with a wide dorso-internal stripe, dorso-external margin with reticulate pigment, and the rest unpigmented. Chela with six dark stripes along DI, DM, DS, D, E, and V carinae; the external stripes are in some cases connected by a faint reticulate pattern. Legs: coxae and trochanter unpigmented; femur pigmented in its apical third, near articulation with patella; patella pigmented on the ventro-external and dorso-internal margins; tibia, basitarsi, and telotarsi unpigmented. Tergites I – VI heavily pigmented, each with two subtriangular lateral spots leaving an unpigmented median stripe (Fig. 5 A); in some specimens, there is a median faint small anterior spot; tergite VII with the lateral spots limited to the posterior third of the segment. Sternites, sternum, genital opercula, and pectines unpigmented. Metasomal segment I: dorsal surface with two posterolateral dark spots and an anterior median thin small faint spot, lateral margins unpigmented; ventral surface with three stripes; two thin, well-developed VL and a faint wide VM; in less pigmented specimens the VM stripe can be absent. Metasomal segment II-III similar to segment I (Fig. 5 B), but the dorsal median spot is more extended and marked, the lateral margins bear tiny spots near the base of LSM and LIM setae, and the VM stripe is usually more densely marked (yet it can be absent in some specimens). Metasomal segment IV similar to segment III, but the lateral margins have a single LSM stripe along the segment, and the VSM stripe is always present and well-marked. Metasomal segment, V dorsal surface with faint pigment on each side, Androvestigia of males light yellow, with thin DL stripes along the whole segment, widening distally; lateral margin with thin complete LSM stripe, ventral surface with two VL stripes and a VM stripe along the whole segment, all of them being thin and well-marked. Telson, vesicle ventrally with three faint longitudinal stripes, lateral margins with a thin stripe, dorsally with dorso-lateral spots; glands of males poorly marked with tegument with similar color to the rest of the dorsal surface; aculeus basally unpigmented, apex dark brown. Chelicerae: Anterior margin of movable finger curved, with two small subdistal teeth. Pedipalps: Femur (Fig. 7 G) with DI, DE, and VI carinae granular, extending the entire length of the segment in males, less marked in females; DE carina with two macrosetae, DI carina with one median macroseta, VE carina absent; anterior margin with some scattered coarse granules and three macrosetae; rest of the intercarinal surfaces smooth. Patella with DI and VI carinae slightly granular (Fig. 7 F), more so in males, extending the entire length of segme
Language: English
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W6893418126
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