Brachistosternus (Leptosternus) cepedai, 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 : 57-61

Brachistosternus (Leptosternus) cepedai n. sp.

Figs. 1–10 , 23, 24 ; Table 1

Type material: Holotype ɗ: Chile, IV Región, Elqui Province, 5 km from Punta Choros, near the route to Choros, 29°14'29.0'' S, 71°25'45.9'' W, 12 m a.s.l, 22/II/2006, A.A. Ojanguren-Affilastro, L. Compagnucci, and A.C. Cuezzo, UV sampling in dunes (MACN-Ar 12246). Paratypes: 2 ɗ, same data as holotype ( AMNH); 1 ɗ, 1 Ψ, same data as holotype ( CDA); 20 ɗ, 5 Ψ, (same data as holotype) (MACN-Ar); 4 ɗ, 7 Ψ, same date as holotype ( LEULS); 3 ɗ, 10 Ψ, 20 km from Punta Choros, 27°37´77´´ S, 67°53´126´´ W, 20 m a.s.l, 26/VIII/ 2005, D. Valdivia, UV sampling in dunes (MZUC-UCCC). 3 ɗ, 10 Ψ, 15 km from Punta Choros, 27°03´78´´ S, 67°55´851´´ W, 9/XI/2005, J. Pizarro, 2 m a.s.l, UV sampling in dunes ( MNHN).

Additional material. 2 juveniles ( AMCC [LP 5844]), same data as holotype.

Etymology. This species is named after the Chilean biologist Jorge Cepeda-Pizarro, who has carried out an extensive research on the epigean arthropods of the arid zones of northern Chile.

Diagnosis. Brachistosternus (L.) cepedai n. sp. is closely related to Brachistosternus (L.) sciosciae Ojanguren-Affilastro 2002 . These two species can be distinguished by the following characters: (1) androvestigiae are present but poorly developed in males of Br. (L.) cepedai n. sp. whereas they are absent in males of Br. (L.) sciosciae . (2) Hemispermatophores of these species are morphologically different: in Br. (L.) sciosciae the distal lamina is straight and longer than the basal portion, whereas in Br. (L.) cepedai n. sp. it is curved and of the same length as the basal portion; in Br. (L.) sciosciae the basal triangle is vestigial, whereas in Br. (L.) cepedai n. sp. it is absent or reduced to a small bulge.

Description: Measurements of a male specimen and a female specimen (paratypes) are recorded in Table 1 .

Br. (L.) cepedai Br. (L.) coquimbo

Paratype ɗ Paratype Ψ Holotype ɗ Paratype Ψ

LEULS LEULS MACN-Ar MACN-Ar Color: Light yellow, with some faint spots on the carapace and the tergites. Chelicerae: not pigmented. Carapace: median ocular tubercle and area around lateral ocelli infuscated; without pigmentation except for a slight reticular pattern around the ocular tubercle. Tergites: with three faint spots, two laterals and one median; the median spot darker than the lateral ones, (in poorly pigmented specimens the only visible spot of the tergites). Sternites: not pigmented. Metasoma: segments I–III, dorsal surfaces each with an antero-median narrow stripe, and two posterolateral dark spots, lateral and ventral surfaces not pigmented, ventral surface with a narrow VM stripe, that is absent in poorly pigmented specimens; segment IV, dorsal surface with an anteromedian narrow stripe, lateral surfaces unpigmented, ventral surfaces with a narrow VM stripe; segment V, dorsal and lateral surfaces similar to segment IV, ventral surface with a narrow VM stripe and with two narrow VL stripes, that do not join with the VM stripe. Telson: vesicle not pigmented; aculeus dark brown. Pedipalps: femur slightly pigmented on the posterior margin, and near the articulation with the patella; patella slightly pigmented on anterior and posterior margins; chela not pigmented. Legs: femur slightly pigmented near articulation with patella; remaining segments not pigmented.

Morphology. Carapace: anterior margin convex with a slight median projection; anterior longitudinal sulcus well developed; ocular tubercle well developed, situated anteromedially, interocular sulcus weakly developed, median ocelli almost two diameters apart; three pairs of lateral ocelli, considerably smaller than the median ones; anterior and posterior longitudinal sulci, lateral sulcus and postocular furrow well developed; carapace lateral surfaces slightly granular, smooth near the ocular tubercle and the anterior longitudinal sulcus. Chelicerae with two subdistal teeth. Hemispermatophore: cylindrical apophysis vestigial ( Fig. 2 ); distal lamina narrow, curved, similar in size to, or slightly longer than the basal portion ( Fig. 3 ); basal triangle absent, or reduced to a small bulge; internal spines, basal spines and row of spines absent. Mesosoma: Tergites I–VI, entirely smooth in females, they are smooth in anterior two-thirds, and slightly granular in the posterior third in males; tergite VII, surface slightly granular in the posterior two-thirds, two PL and two VL carinae apparent in the second half. Sternites: granular in males, smooth in segments I–IV and coarsely granular in segment V in females; spiracles narrow, and medium-sized. 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, 25–29 in males (N = 20; median = 27), 17–23 in females (N = 20; median = 21). Metasoma: segments I–IV each with a pair of dorsolateral macrosetae, segment V with one or two pairs of dorsal macrosetae; metasomal segments I–III: dorsal and ventral surfaces densely granular in males, smooth in females, lateral surface densely granular except the area between LSM and LIM carinae; LSM and LIM carina present only in the posterior two thirds of the segment, DL carina extending the entire length of segment, but almost indistinguishable because of the granules of the tegument; metasomal segment IV: ventral surface smooth, covered by scattered macrosetae; DL carina weakly developed, extending the entire length of segment; LIM carina poorly developed, only present in the distal quarter of the segment; LSM carina apparent only at the anterior and posterior margins of the segment; VL carina present on the entire length of the segment but poorly developed, only represented by a slight elevation of the tegument; surfaces between carinae smooth in females and slightly granular in males. Metasomal segment V: androvestigia small-sized, and very narrow, located submedially ( Fig. 4 ); dorsal and lateral surfaces slightly granular (male) or smooth (female); ventral surface sparsely granular, more densely granular in the posterior third of the segment ( Fig. 5 ); ventral macrosetae usually comprising four rows, the first row with four macrosetae, the rest with one or two macrosetae; DL carinae weakly developed; VL carinae well developed, extending the entire length of segment; VM carina absent or weakly developed, represented only by some granules in the posterior half of segment. Telson: Vesicle with rounded ventral surface, lower in males; vesicle surface sparsely granular, with four granules slightly more developed than the rest and related with 4 macrosetae; telson gland absent or not evident; aculeus slightly curved, of the same length as the vesicle ( Figs. 6, 7 ). Pedipalps: Femur: DI and VI carinae granular and well developed, DE carina only present in the proximal half of the segment, internal surface granular, remaining surfaces smooth, one macroseta (M1) associated with d and e trichobothria; patella: DI and VI carinae granular and well developed in males, less granular in females, remaining surfaces smooth; chela: smooth, VM carina weakly developed ( Fig. 8 ), internal apophysis of male well developed ( Fig. 9 ), fingers with a median row of denticles and five or six pairs of accessory denticles each, external denticles overlapping with median row near the base of the finger. Trichobothrial pattern of subgenus Leptosternus ( Figs. 8–10 ): 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: ventral surface of the femur with two longitudinal carinae, the rest of the surface smooth; telotarsi I and II: each with inner unguis ca. 15% shorter than external, and with the inner pedal spur absent or vestigial ( Figs. 23, 24 ).

Variation: Pedipalp chela length/height ratio, male 2.77–3.26 (N = 20; mean = 3.09), female 2.25–3.44 (N = 20; mean = 2.88); pedipalp chela length/width ratio, male 3.85–4.54 (N = 20; mean = 4.18), female 3.78– 4.42 (N = 15; mean = 4.11); metasomal segment V, length/width ratio, male 1.8–1.95 (N = 20; mean = 1.86), female 1.78–1.97 (N = 20; mean = 1.89); metasomal segment V, ventral macroseta 7–10 (N = 20; median = 8); metasomal segment V, ventrolateral macroseta 11–17 (N = 20; median = 14); telotarsus III, dorsal macroseta 12–15 (N = 20; median = 14); telotarsus III, ventrointernal macroseta 10–12 (N = 20; median = 11); telotarsus III, ventroexternal macroseta 5–7 (N = 20; median = 7); basitarsus III, dorsal macroseta 6–8 (N = 20; median = 7); total length (mm), male 36.5–48 (N = 20; mean = 41.5), female 39–66 (N = 18; mean = 62.3).

Distribution and ecology. Brachistosternus (L.) cepedai n. sp. inhabits in the Coquimbo Region of northern Chile; all specimens have been collected in coastal dunes and in the coastal steppe near the localities of Choros and Punta Choros ( Fig. 1 ). The localities where this species has been collected fall within the coastal desert of Huasco, pertaining to the transitional coastal desert of Chile ( Gajardo 1993, Cepeda-Pizarro 1995).

Brachistosternus (L.) cepedai n. sp. inhabits in sandy areas with scarce vegetation, usually Crystaria glaucophyla Cav. ( Malvaceae ) and Tetragonia maritima Barn. (Aizoaceae) . This species lives in sympatry with the bothriurids Bothriurus coriaceus Pocock 1893 , Brachistosternus (L.) roigalsinai Ojanguren-Affilastro 2002 , and an undescribed Brachistosternus species, and the iurid Caraboctonus keyserlingi Pocock 1893 , being the later absent from the coastal dunes.

Figures

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

FIGURES 2 – 10. Brachistosternus (L.) cepedai n. sp. 2. left hemispermatophore, ventral aspect; 3. left hemispermatophore, dorsal aspect; 4. metasomal segment V, male, dorsal aspect; 5. metasomal segment V, male, ventral aspect; 6. telson, male, lateral aspect; 7. telson, female, lateral aspect; 8. right pedipalp chela, male, ventral aspect; 9. right pedipalp chela, male, internal aspect; 10. left pedipalp chela, female, external aspect. Scale bars = 1 mm.

FIGURES 23 – 30. Prolateral view of right leg telotarsi I and II of four Brachistosternus species. 23 – 24. Brachistosternus cepedai n. sp., 23. telotarsus I; 24. telotarsus II. 25 – 26 Brachistosternus sciosciae. 25. telotarsus I; 26. telotarsus II. 27 – 28 Brachistosternus roigalsinai. 27. telotarsus I; 28. telotarsus II. 29 – 30 Brachistosternus montanus. 29. telotarsus I; 30. telotarsus II. Scale bars 1 mm.

Tables

TABLE 1. Measurements of Brachistosternus (Leptosternus) cepedai n. sp. (Paratypes) and Brachistosternus (Leptosternus) coquimbo n. sp. (Holotype and Paratype). (In mm.).

Total length 42.2	40.52	49.23	39.67
Carapace, length 5.25	4.85	5.98	5.49
Carapace, anterior width 3.15	3.23	4.04	4.04
Carapace, posterior width 4.93	5.09	5.98	6.87
Mesosoma, total length 12.38	14.67	12.23	9.78
Metasoma, total length 19.47	16.15	24.15	18.74
Metasomal segment I, length 3.31	2.83	4.04	2.99
Metasomal segment I, width 3.23	2.75	3.79	3.34
Metasomal segment I, height 2.50	2.18	2.99	2.75
Metasomal segment II, length 3.64	2.99	4.53	3.23
Metasomal segment II, width 3.07	2.74	3.47	3.07
Metasomal segment II, height 2.51	2.18	2.91	2.67
Metasomal segment III, length 3.71	3.15	4.68	3.47
Metasomal segment III, width 2.91	2.42	3.31	2.91
Metasomal segment III, height 2.50	2.02	2.83	2.66
Metasomal segment IV, length 4.04	3.39	5.25	4.04
Metasomal segment IV, width 2.58	2.26	2.99	2.70
Metasomal segment IV, height 2.18	1.77	2.67	2.42
Metasomal segment V, length 4.77	3.79	5.65	5.01
Metasomal segment V, width 2.67	2.26	3.07	2.70
Metasomal segment V, height 2.02	1.61	2.50	2.26
Telson, length 5.01	4.85	6.87	5.66
Vesicle, length 2.42	2.26	4.04	2.99
Vesicle, width 1.77	1.69	2.30	2.10
Vesicle, height 1.61	1.54	2.18	1.78
Aculeus, length 2.58	2.58	2.83	2.66
Femur, length 3.64	3.07	5.33	4.00
Femur, width 1.13	1.21	1.29	1.37
Patella, length 3.23	3.23	4.60	3.88
Patella, width 1.45	1.37	1.69	1.65
Chela, length 6.2	5.74	8.16	14.8
Chela, width 1.65	1.54	1.61	3.42