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 : 39-41

Brachistosternus (L.) sp. 1

figures 39 , 52 , 75

MATERIAL EXAMINED: CHILE: Region IV (Coquimbo): Elqui Province: 5 km from Punta Choros, near the road to Choros, 29 ° 14 9 29.0 0 S 71 ° 25 9 45.9 0 W, 22.ii.2006, A.A. Ojanguren Affilastro, L. Compagnucci, and A.C. Cuezzo, 12 m, UV sampling, in dunes, syntopic with B. roigalsinai , 253, 5♀, 4 juv. (MACN-Ar); Choros, 29 ° 17 9 10.3 0 S 71 ° 19 9 7.2 0 W, 22.ii.2006, A.A. Ojanguren Affilastro, L. Compagnucci, and A.C. Cuezzo, UV sampling, in dunes with some shrubs, syntopic with B. roigalsinai , and B. coriaceus , 13 (MACN-Ar).

DIAGNOSIS: Brachistosternus sp. 1 is closely related to B. sciosciae . Both species are small in size (less than 40 mm on average) and almost completely unpigmented. The inner unguis of telotarsi I and II is approximately 15% longer than the external unguis, and the internal pedal spur of telotarsi I and II is vestigial or absent in both species ( fig. 52 ). The pedipalpal and metasomal carinae are weakly developed in these species, and the telson slightly compressed dorsoventrally (especially in males). Furthermore, the internal spines, basal spines, and row of spines of the hemispermatophore are absent, and the basal triangle vestigial, reduced to a small smooth bulge without crests or spines, in both species.

The two species may be distinguished by the presence, in Brachistosternus sp. 1 , of small androvestigia, which are absent in B. sciosciae . Both species may also be distinguished according to the following characters. In Brachistosternus sp. 1 , the distal lamina of the hemispermatophore is curved medially ( fig. 39 ), whereas in B. sciosciae , it is almost straight and only slightly curved distally ( fig. 38 ). The VM carina of metasomal segment V extends the entire length of the segment in Brachistosternus sp. 1 , but is restricted to the second half of the segment in B. sciosciae .

DISTRIBUTION: Brachistosternus sp. 1 has only been collected in coastal dunes near Punta Choros in Coquimbo region, Chile ( fig. 75 ). These localities fall within the Desierto Costero del Huasco botanical subregion of the Desierto 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.