Brachistosternus, Pocock, 1893

OJANGUREN AFFILASTRO, ANDRÉS A., MATTONI, CAMILO I. & PRENDINI, LORENZO, 2007, The genus Brachistosternus (Scorpiones: Bothriuridae) in Chile, with Descriptions of Two New Species, American Museum Novitates 3564 (1), pp. 1-44 : 41-42

Brachistosternus (L.) sp. 3

figures 41 , 51 , 77

MATERIAL EXAMINED: CHILE: Region IV (Coquimbo): Elqui Province: between Juntas and Paso del Agua Negra [30 ° 14 9 S 70 ° 02 9 W], 6.iii.2006, A.A. Ojanguren Affilastro, L. Compagnucci, and A.C. Cuezzo, 3200 m, UV sampling, syntopic with B. perettii and an undescribed species of Orobothriurus , 53 (MACN-Ar); 2 km to entrance to ‘‘El Indio’’ gold mine [29 ° 54 9 S 70 ° 03 9 W], 26.ii.2004, 2850 m, UV sampling, C.I. Mattoni, J.A. Ochoa, and J. Pizarro Araya, 1 juv. (CDA); Cancha Sky, ‘‘El Indio’’ gold mine [29 ° 51 9 S 70 ° 03 9 W], ii.1992, Vasquez, 3300 m, under stones, 13 (LEULS); Sancarron, ‘‘El Indio’’ gold mine [29 ° 45 9 S 70 ° 00 9 W], ii.1993, J. Cepeda-Pizarro, 3200 m, pitfall, syntopic with B. perettii , 1 juv. (LEULS).

DIAGNOSIS: Brachistosternus sp. 3 is closely related to B. montanus , which occurs at the same latitude and in similar habitats on the eastern slopes of the Andes, in Argentina. Both species possess similar hemispermatophores, in which the distal lamina is slightly curved, medium-sized, and similar in length to the basal portion, the internal spines are absent, the basal spines and row of spines well developed, and the basal triangle weakly developed ( fig. 41 ). The two species also exhibit a welldeveloped telson gland ( fig. 51 ), similar, medium-sized androvestigia, and a VM carina extending the entire length of metasomal segment V. Both species display a similar pigmentation pattern in which the carapace is almost completely pigmented, the tergites possess a broad transverse stripe or three dark spots, connected by dense reticulate pigmentation, and a single VM and paired VL stripes on metasomal segments I–V.

The two species may be distinguished as follows. The VM stripe of metasomal segments I–IV is broad and faint, joining the VL stripes in all segments of Brachistosternus sp. 3 , but narrower, more densely pigmented, and does not join the VL stripes in segments I–III, in B. montanus . Both species may also be distinguished by the dimensions of the pedipalp chela of the male (the female of Brachistosternus sp. 3 is presently unknown). Brachistosternus sp. 3 exhibits a narrower pedipalp chela, with a length/width ratio of 4.8–5.09, whereas the chela of B. montanus is broader, varying from 4.01 to 4.37.

Brachistosternus sp. 3 is sympatric with B. perettii , which may be distinguished by the absence of a VM carina on metasomal segment V, and a telson gland divided into two separate halves ( fig. 50 ). Brachistosternus sp. 3 exhibits a well-developed VM carina, extending the entire length of metasomal segment V, and the telson gland is entire ( fig. 51 ).

DISTRIBUTION: Brachistosternus sp. 3 has been collected in the Central Andes of Coquimbo, Chile ( fig. 77 ), between 2850 and 3300 m. The localities where it has been collected fall within the Andes Mediterraneos botanical subregion of the Desierto Florido botanical region ( Gajardo, 1993) .

NOTES: A description of this species is in preparation by Jaime Pizarro, Pablo Agusto, and the first two authors.

Figures

Figs. 36–43. Diagnostic characters of Chilean Brachistosternus Pocock, 1893. 36, 42. Brachistosternus

Figs. 50–56. Diagnostic characters of Chilean Brachistosternus Pocock, 1893. 50. Brachistosternus (L.) perettii Ojanguren Affilastro and Mattoni, 2006. Telson, male, dorsal aspect. 51. Brachistosternus (L.) sp. 3. Telson, male, dorsal aspect. 52. Brachistosternus (L.) sp. 1. Telotarsus I, dextral leg, internal aspect. 53. Brachistosternus (L.) chango, n.sp. Telotarsus I, dextral leg, internal aspect. 54. Brachistosternus (L.) negrei Cekalovic, 1975. Metasoma, pigmentation pattern, ventral aspect. 55. Brachistosternus (L.) sp. 2. Metasoma, pigmentation pattern, ventral aspect. 56. Brachistosternus (L.) chilensis Kraepelin, 1911. Metasoma, pigmentation pattern, ventral aspect. Scale bars 5 1 mm.

Figs. 75–77. The known distributions of Brachistosternus Pocock, 1893 in central-northern Chile (contour interval 500 m). 75. Brachistosternus sp. 1. 76. Brachistosternus sp. 2. 77. Brachistosternus sp. 3.