Rumikiru, n. gen. (Scorpiones: Bothriuridae), a New Scorpion Genus from the Atacama Desert Author Ojanguren-Affilastro, Andrés A. Author Mattoni, Camilo I. Author Ochoa, José A. Author Prendini, Lorenzo text American Museum Novitates 2012 2012-02-08 2012 3731 1 44 http://www.bioone.org/doi/abs/10.1206/3731.2 journal article 2551 10.1206/3731.2 d0a0671c-03b7-4e26-b5c5-4a9087cb4991 0003-0082 5359990 7B802C26-976C-43A5-9577-18A901560BEC Rumikiru atacama , n. sp. Figures 1 , 2 , 3 , 4A, B , 5A, B , 6A , 7A , 8, 10B, F, G, H, I, 11, 12A, C, 13, 15, 16, 17, 18, 19, 24, 26B, C, D, 27A, C, 28A, C, E, G; table 1 TYPE MATERIAL: CHILE : Region III ( Atacama ): Huasco Province : Holotype ♂ ( MNHNS ), Llanos de Challe National Park : administration building , hills nearby , 28°09′39.8″S 71°03′20″W , 205 m , 25.i.2005 , C.I. Mattoni and A.A. Ojanguren-Affilastro , UV detection , full moon. Paratypes : Llanos de Challe National Park : administration building , hills nearby , 28°09′38.16″S 71°03′20.13″W , 100 m , 10.xi.2003 , L. Prendini , C.I. Mattoni , and J.A. Ochoa , UV detection on cool , breezy night , almost full moon , collecting conducted behind ridge in shadow , specimens common on scree slope and earthen banks , 4 ♂ , 9 ♀ ( AMNH ), 3 ♂ , 1 ♀ ( LBRE ), 2 ♂ , 1 ♀ ( MHNC ), 1 ♀ , 1 subad. ♀ ( AMNH [ LP 2427 ]); near administration building , 28°09′39.8″S 71°03′20″W , 205 m , 25.i.2005 , C.I. Mattoni and A.A. Ojanguren-Affilastro , UV detection , full moon , 4 ♂ , 2 ♀ ( AMNH ) , 4 ♂ , 2 ♀ ( MACN- Ar ), 1 ♂ , 1 juv. ( LBRE ), 1 ♀ ( MNHNS ); near administration, 28°10′10.8″S 71°03′40.2″W , 32 m , 17–18.viii.2009 , C. Grismado, A.A. Ojan- guren-Affilastro, J. Pizarro-Araya , and F. Alfaro- Kong , UV detection, 3 juv. (MACN-Ar); 5.5 km from administration building to Carrizal Bajo , 28°07′38.34″S 71°05′0.54″W , 88 m , 10.xi.2003 , L. Prendini , C.I. Mattoni , and J.A. Ochoa , UV detection on cool, breezy night, moon rising, steep, rocky slope, lots of scree on slope, cacti and sparsely distributed bushes, specimens common on scree and at top of ridge, 1 ♂ , 2 ♀ , 3 juv. ( LBRE ), 2 subad. ♂ , 1 subad. ♀ ( AMNH [ LP 2426]); 7.5 km from administration building to Carrizal Bajo , 28°07′05.3″S 71°05′57.3″W , 65 m , 10.xi.2003 , L. Prendini , C.I. Mattoni , and J.A. Ochoa , UV detection on cool, breezy night, moon not yet risen, on steep scree slope with cacti and bushes, 3 ♂ , 3 ♀ ( AMNH ), 1 ♀ , 1 subad. ♂ ( AMNH [ LP 2425 ]); near administration building, 28°10′10.8″S 71°03′40.2″W , 32 m , 17.viii.2009 , A.A. Ojanguren-Affilastro, C. Grismado, J. Pizarro-Araya, F. Alfaro-Kong, UV detection, 1 ♀ , 2 juv. (MACN-Ar). FIGURE 8. Rumikiru atacama , n. sp. , habitus. A, B. Holotype ♂ (MNHNS). C, D. Paratype ♀ (MACN-Ar). A, C. Dorsal aspect. B, D. Ventral aspect. Scale bars = 10 mm. FIGURE 9. Rumikiru lourencoi (Ojanguren-Affilastro, 2003) , n. comb. , habitus. A, B. Holotype ♂ (MACN- Ar). C, D. Paratype ♀ (MACN-Ar). A, C. Dorsal aspect. B, D. Ventral aspect. Scale bars = 10 mm. FIGURE 10. Rumikiru , n. gen. , sinistral hemispermatophore. A, C, D, E. Rumikiru lourencoi (Ojanguren- Affilastro, 2003), n. comb., ♂ (MACN-Ar). B, F, G, H, I. Rumikiru atacama , n. sp. , ♂ (MACN-Ar). A, B. Distal lamina, ectal aspect, under UV light. C, H. Lobe region. E, G. Sinistral hemispermatophore ectal aspect. F. Sinistral hemispermatophore ental aspect. D, I. Basal lobe, internal fold, close-up. Scale bars = 1 mm ( A, B, E–G ), 0.3 mm ( C, H ), 0.2 mm ( D, I ). FIGURE 11. Rumikiru atacama , n. sp. , sinistral chelicera, dorsal aspect. A. ♂ (MACN-Ar). B. ♀ (MACN-Ar). Scale bars = 0.3 mm. FIGURE 12. Rumikiru , n. gen. , carapace. A, C. Rumikiru atacama , n. sp. , ♂ (MACN-Ar). B, D. Rumikiru lourencoi (Ojanguren-Affilastro, 2003) , n. comb. , ♂ (MACN-Ar). A, B. Dorsal aspect. C, D. Lateral aspect. Scale bars = 1 mm. FIGURE 13. Rumikiru atacama , n. sp. , sternum, genital opercula and pectines. A, B. Sternum and genital opercula, ventral aspect. C, D. Sinistral pecten, ventral aspect. A, C, E, G. ♂ (MACN-Ar). B, D, F, H. ♀ (MACN-Ar). E, F. Pectinal teeth, close-up. G, H. Pectinal peg sensilla, close-up. Scale bars = 1 mm ( A–D ), 0.2 mm ( E, F ), 0.02 mm ( G ), 0.01 mm ( H ). FIGURE 14. Rumikiru lourencoi (Ojanguren-Affilastro, 2003) , n. comb. A, B. Sternum and genital opercula, ventral aspect. C, D. Sinistral pecten, ventral aspect. A, C, E, G. ♂ (MACN-Ar). B, D, F, H. ♀ (MACN-Ar). E, F. Pectinal teeth, close-up. G, H. Pectinal peg sensilla, close-up. Scale bars = 1 mm ( A–D ), 0.2 mm ( E, F ), 0.02 mm ( G ), 0.01 mm ( H ). ADDITIONAL MATERIAL: CHILE : Region III ( Atacama ): Huasco Province : “Atama” [probably “ Atacama ”], x.1980 , L. Peña , 1 juv. ♂ ( AMNH ); El Tránsito to Pinte [28″53′ S 70°17′ W], 1100/ 1600 m , 25–27.x.1980 , L. Peña, 1 subad. ♂ , 2 juv. ♀ ( AMNH ) ; N of Huasco [ 28°28′08″S 71°13′11″W ], 12.x.1980 , L. Peña, 1 subad. ♂ ( AMNH ); Juntas , on Huasco River , 1600 m , 3.x.1980 , L. Peña , 1 ♀ ( AMNH ); Quebrada Maitencillo [ 28°28′23.69″S 70°49′05.80″W ], NW of Vallenar , 11.x.1980 , L. Peña , 1 subad. ♀ ( AMNH ); Quebrada Talinay [28°08″ S 71°13′11″ W], large canyon S of Huasco , 13.x.1980 , L. Peña, 2 subad. ♂ ( AMNH ); Vallenar, 2–3 km S [ 28°34′24″S 70°45′31″W ], 460 m . FIGURE 15. Rumikiru atacama , n. sp. , ♂ (MACN- Ar), sinistral telotarsi, prolateral aspect. A–D. Legs I–IV. Scale bar = 0.3 mm . ETYMOLOGY: The specific epithet, atacama , is a noun in apposition, referring to the Chilean Region III, to which this species appears to be endemic. This region forms part of the Atacama Desert, which extends from southern Peru to northern Chile . DIAGNOSIS: Rumikiru atacama , n. sp. , can be separated from the only other known species of the genus, R. lourencoi , n. comb. , by several morphological characters. The distal lamina of the hemispermatophore of R. atacama , n. sp. (fig. 10B, F, G), has a shorter apex and a longer frontal crest than that of R. lourencoi , n. comb. (fig. 10A, E); the distal crest is curved in R. atacama , n. sp. (fig. 10B, F), whereas it is almost straight in its apical two-thirds in R. lourencoi , n. comb. (fig. 10A, E); and the papillose fold of the basal lobe is less pronounced, less granular, and bears smaller papillae (spicules) in R. atacama , n. sp. (fig. 10H, I), than in R. lourencoi , n. comb. (fig. 10C, D). Metasomal segment V is less granular in R. atacama , n. sp. ( fig. 27A, C ), than in R. lourencoi , n. comb. ( fig. 27 B, D ). The telson is less granular and the vesicle of the male more globose in R. atacama , n. sp. (fig. 28A, C), than in R. lourencoi , n. comb. (fig. 28B, D). The IM carina of the pedipalp patella is often well developed along its entire length in males of R. atacama , n. sp. ( fig. 17D ), but absent or reduced to a few scattered granules in males of R. lourencoi , n. comb. ( fig. 21D ). There are also differences in the pigmentation pattern: R. atacama , n. sp. , is less pigmented, the ventral surface of the telson vesicle ( fig. 7A ) and the pedipalp chela manus largely unpigmented (fig. 6A), compared with R. lourencoi , n. comb. , in which the telson vesicle is completely covered by faint pigmentation ( fig. 7B ) and the pedipalp chela manus bears pigmentation stripes along each carina (fig. 6B). DESCRIPTION: Based on the holotype ♂ (MNHNS) and paratypes (AMNH, LBRE, MACN- Ar, MHNC, MNHNS). Total length : 24.6–39 mm ( n = 10; mean = 31.1) in ♂ ; 25.4–33.3 mm ( n = 7; mean = 29.1) in ♀ . Color : Base color yellowish, with brown reticulate pigmentation on some segments (figs. 4B, 5A, B, 6A, 7A , 8). Cheliceral manus, external surface with faint reticulate pigmentation; fingers more densely pigmented distally. Carapace, anterior margin pigmented medially; two broad, dark stripes extending from anterior margin to anterior part of posteromedian longitudinal sulcus, surrounding median ocular tubercle; lateral margins densely pigmented; median ocular tubercle and area around lateral ocelli dark brown to black; posterior third with reticulate pigmentation and two faint spots posterolaterally; posterior margin with dark narrow stripe. Tergites I–VI each with faint, paired spots laterally, posterior margin with dark narrow stripe, more developed on anterior than posterior segments; VII with faint brown spot posteromedially. Sternum, sternites, genital opercula, and pectines unpigmented. Metasomal segment I, dorsal surface with faint triangular spots medially and at posterior margin; DL carinae with pigmented granules; lateral margins with faint triangular spot between LM and LIM carinae; faint vestigial VL and VM stripes, reduced to dark pigmentation at posterior margin of segment. Metasomal segments II and III as for I, except more densely pigmented; dorsal surface with dark triangular spot medially, posterior margin with dark spot medially; DL, LM and LIM carinae with pigmented granules; lateral margins with triangular spot between LM and LIM carinae; VL and VM stripes well developed, extending entire length of segment, contiguous at posterior margin, VL stripes narrow, reduced to lateral margins, VM stripe broad, occupying most of surface. Metasomal segment IV, dorsal surface with elongated spot medially, not reaching posterior margin of segment; DL carinae pigmented; lateral margins with elongated dark spot; ventral surface as for segment III. Metasomal segment V, dorsal surface unpigmented medially; DL margins densely pigmented; lateral margins with reticulate pigmentation; VM and paired VL stripes contiguous at posterior margin of segment, VL stripes broad, occupying most of surface, VM stripe very narrow, restricted to carina. Telson vesicle conspicuous light yellow color, lateral surfaces with faint vestigial pigment; aculeus unpigmented basally, apex dark brown ( fig. 7A ). Pedipalps, coxa unpigmented; trochanter faintly pigmented at articulation with femur; femur with well-developed stripe at posterior margin and faint reticulate pigmentation near articulation with patella; patella with four complete stripes along DI, EM, VI, and VE carinae, dorsal margin with reticulate pigmentation; chela almost unpigmented (fig. 6A), faintly pigmented along E carinae and near external articulation with patella and movable finger. Legs, coxa, and trochanter unpigmented; femur, internal surface densely pigmented, external surface densely pigmented near articulation with patella; patella, internal surface densely pigmented, external surface pigmented near articulations and along ventral margin; tibia, internal surface pigmented at articulation with patella; basitarsi and telotarsi unpigmented. Carapace : Carapace dorsoventrally compressed (fig. 12C); anterior margin almost straight (fig. 12A). Surface finely granular medially, more densely granular laterally, less so in ♀ . Anteromedian longitudinal and interocular sulci absent or obsolete; posteromedian longitudinal and posterolateral sulci well developed. Median ocular tubercle shallow, ocelli situated in depression, only median part of ocular tubercle protruding above carapace in lateral profile (fig. 12C); median ocelli small, approximately two diameters apart, with two pairs of longitudinally aligned microsetae anteriorly and one pair of macrosetae posteriorly (fig. 12A, C). Three pairs of small lateral ocelli on each side of carapace (fig. 12A), anterior ocellus noticeably larger than other ocelli; anterior and median ocelli situated very close together, in same horizontal axis, posterior ocellus smaller and situated slightly dorsal to others. Chelicerae : Movable finger, distal internal tooth well developed, strongly curved, forming angle of almost 90° with rest of finger in ♂ (fig. 11A), less curved in ♀ (fig. 11B); distal external tooth well developed, protruding dorsally from surface of finger; two vestigial subdistal teeth, barely visible in some specimens. Pedipalps : Femur, dorsal, internal and ventral surfaces densely granular ( fig. 16 ), especially along internal margin, with external surface less granular ( ♂ ), or dorsal and external surfaces with scattered granules only, internal and ventral surfaces smooth ( ♀ ); DE and VI carinae well developed, extending entire length of segment; DI carina reduced to scattered granules along margin of segment; IM carina barely discernible among coarse surface granulation ( ♂ ; fig. 16D ) or comprising scattered granules ( ♀ ). Patella, intercarinal surfaces densely granular ( ♂ ) or smooth ( ♀ ); DI, VI, and VE carinae granular, extending entire length of segment, DI carina especially pronounced and coarsely granular ( ♂ ; figs. 17A, D ) or obsolete, reduced to few scattered granules ( ♀ ); external margin undulated ( fig. 17C ), DE and EM carinae obsolete, reduced to few granules ( ♂ ; fig. 17A, B ) or DE carina absent, EM carina obsolete, reduced to slight curvature of surface along entire length of segment ( ♀ ); IM carina granular, well developed along entire length in some ♂ ( fig. 17D ) but reduced to scattered granules in others, and absent in ♀ . Chela manus prism shaped, more robust in ♂ (figs. 18, 19, 24), length/width ratio 2.35–2.78 in ♂ ( n = 10; median = 2.55), 2.83–3.18 in ♀ ( n = 7; median = 3.01); length/height ratio 2.16–2.45 in ♂ ( n = 10; median = 2.3), 2.53–2.92 in ♀ ( n = 7; median = 2.69); internal surface with small conical apophysis, situated almost medially, in ♂ (figs. 18C, D, 24A, B), absent in ♀ (figs. 19C, D, 24C, D); carinae of ♀ absent, except for DS and VI carinae each evident as subtle lobe near articulation with patella; carinae of ♂ as follows: DM carina finely granular, obsolete, extending entire length of segment (fig. 18A); DS and D carinae each finely granular, obsolete, reduced to slight curvature of surface and lobe near articulation with patella (fig. 18B); E carina obsolete, reduced to scattered macrosetae; VE, VM, and VI carinae obsolete, reduced to slight curvature of surface along entire length of manus; IM carina obsolete, reduced to well-developed lobe reaching conical apophysis; fixed and movable fingers short and stout, each with single median denticle row and five pairs of internal and external accessory denticles; basal denticle of median denticle row on movable finger approximately three times larger than and replacing first five or six median denticles (figs. 18A, B, D, 19A, D, 24A, C); distal third of fingers twisted, abruptly altering orientation of median denticle row (more conspicuously on movable finger), in ♂ (fig. 18A). Trichobothrial pattern neobothriotaxic major Type C, with one accessory trichobothrium in V series of chela (figs. 18, 19, 24); femur ( fig. 16 ) with three trichobothria ( d , i, and e ), one macroseta (M 1 ) associated with d and i , e situated in same axis as or slightly proximal to M 1 ( fig. 16A ); patella ( fig. 17 ) with 19 trichobothria (2 d , i , 3 et , est , 2 em , 2 esb , 5 eb , 3 v ); chela (figs. 18, 19, 24) 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 . FIGURE 16. Rumikiru atacama , n. sp. , ♂ (MACN-Ar), dextral pedipalp femur. A. Dorsal aspect. B. External aspect. C. Ventral aspect. D. Internal aspect. Scale bar = 1 mm. FIGURE 17. Rumikiru atacama , n. sp. , ♂ (MACN-Ar), dextral pedipalp patella. A. Dorsal aspect. B. External aspect. C. Ven- tral aspect. D. Internal aspect. Scale bar = 1 mm . FIGURE 18. Rumikiru atacama , n. sp. , ♂ (MACN-Ar), dextral pedipalp chela. A. Dorsal aspect. B. External aspect. C. Ventral aspect. D. Internal aspect. Scale bar = 1 mm. FIGURE 19. Rumikiru atacama , n. sp. , ♀ (MACN-Ar), dextral pedipalp chela. A. Dorsal aspect. B. External aspect. C. Ventral aspect. D. Internal aspect. Scale bar = 1 mm. Legs : Femur and patella, surfaces slightly granular, other segments smooth. Basitarsi each with two well-developed, equal-length pedal spurs ( fig. 15 ). Telotarsi elongated, shallow, each with ventromedian row of small spinules, and pro- and retroventral rows of short, stout spiniform macrosetae, with following counts on leg I: 1/1, II: 2/2, III and IV: 3/3 ( fig. 15 ). Ungues curved, equal in length. Sternum : Shape markedly compressed anteriorly to posteriorly, but not divided into two separated plates (figs. 13A, B). Genital opercula : Sclerites subtriangular, more elongated in ♂ (fig. 13A, B). Pectines : Single row of median lamellae; first median lamella more elongated in ♀ (figs. 13C, D). Fulcra present, small (fig. 13C, D). Pectinal teeth small, triangular; tooth count: 16–18 in ♂ ( n = 24; median = 16), 13–16 in ♀ ( n = 18; median = 14); retrolateral margins covered posteriorly with peg sensilla, sensilla field more extensive (fig. 13E, F) with sensilla apparently more acute basally (fig. 13. G, H), in ♂ . Tergites : Tergites I–VI, surfaces smooth to finely granular ( ♀ ) or entirely finely granular, more coarsely so near posterior and lateral margins ( ♂ ); VII with paired submedian carinae, restricted to posterior third of segment, and lateral carinae, restricted to posterior half, intercarinal surfaces with scattered medium-sized granules, finely granular elsewhere. Sternites : Sternites III–VII, surfaces entirely smooth ( ♀ ) or smooth to finely granular ( ♂ ); III–VI each with small, elliptical spiracles. Metasoma : Metasomal segment I, dorsal surface finely granular; DL and LM carinae granular, extending entire length of segment, LM carinae weakly developed medially; one pair of LM macrosetae posteriorly; LSM and LIM carinae granular, restricted to posterior half of segment (fig. 26B); one pair of LIM macrosetae anteriorly; surfaces between LSM and LIM carinae sparsely granular; lateral margins and ventral surfaces smooth, acarinate; two pairs of VL and VSM macrosetae. Segment II as for I, but carinae less granular; LIM carinae absent or reduced to few granules at posterior margin of segment (fig. 26B). Segment III as for II but less granular, carinae less developed; LSM carina reduced to few granules near posterior margin of segment; LIM carinae absent (fig. 26C). Segment IV slightly more elongated than preceding segments; DL carinae granular, extending entire length of segment (fig. 26C); one pair of DL macrosetae medially; LM carinae restricted to anterior and posterior thirds of segment, almost smooth medially; one pair of LM macrosetae in posterior third of segment; LIM carinae absent, represented only by pair of LIM macrosetae (fig. 26C); ventral surface smooth, acarinate; two pairs of VSM and VL macrosetae. Segment V elongated; dorsal and lateral surfaces smooth or finely granular (fig. 26D); DL carina finely granular, extending entire length of segment; one pair of DL macrosetae; lateral surfaces acarinate, smooth or sparsely granular; LM carinae represented only by two pairs of LM macrosetae in posterior third of segment, LIM carinae by one pair of LIM macrosetae in anterior third (fig. 26D); VL carinae granular, extending almost entire length of segment, comprising larger granules near posterior margin ( fig. 27A, C ); VSM carinae subparallel to VL carinae, restricted to posterior two-thirds of segment, contiguous with VL carinae at margins; VM carina granular, extending entire length of segment, with two accessory granules separated from it in anterior part of posterior third ( fig. 27A, C ); other surfaces sparsely granular, slightly more densely granular in ♂ ; three pairs of VL macrosetae and four pairs of VSM macrosetae, one pair of each at posterior margin of segment. FIGURE 20. Rumikiru lourencoi (Ojanguren- Affilastro, 2003), n. comb., ♂ (MACN-Ar), dextral pedipalp femur. A. Dorsal aspect. B. External aspect. C. Ventral aspect. D. Internal aspect. Scale bar = 1 mm. FIGURE 21. Rumikiru lourencoi (Ojanguren- Affilastro, 2003), n. comb., ♂ (MACN-Ar), dextral pedipalp patella. A. Dorsal aspect. B. External aspect. C. Ventral aspect. D. Internal aspect. Scale bar = 1 mm. Telson : Vesicle shallow in ♂ (fig. 28C), more globose in ♀ (fig. 28A); length/height ratio 3.2–3.84 in ♂ ( n = 9; median = 3.43), 2.68–3.04 in ♀ ( n = 7; median = 2.93); dorsal surface smooth, telson gland not apparent, but with small depression, containing abundant pores in cuticle, at posterodorsal margin (fig. 28G); ventral surface granular, especially in ♂ , with conspicuous granule medially at posterior margin (fig. 28E); three pairs of VL and VSM macrosetae. Aculeus elongated, shallowly curved (fig. 28A, C). FIGURE 22. Rumikiru lourencoi (Ojanguren-Affilastro, 2003) , n. comb. , ♂ (MACN-Ar), dextral pedipalp chela. A. Dorsal aspect. B. External aspect. C. Ventral aspect. D. Internal aspect. Scale bar = 1 mm. FIGURE 23. Rumikiru lourencoi (Ojanguren-Affilastro, 2003) , n. comb. , ♀ (MACN-Ar), dextral pedipalp chela. A. Dorsal aspect. B. External aspect. C. Ventral aspect. D. Internal aspect. Scale bar = 1 mm. FIGURE 24. Rumikiru atacama , n. sp. , dextral pedipalp chela. A, B. ♂ (MACN-Ar). C, D. ♀ (MACN-Ar). A, C. Internal aspect. B, D. Ventral aspect. Scale bar = 1 mm. FIGURE 25. Rumikiru lourencoi (Ojanguren-Affilastro, 2003) , n. comb. , dextral pedipalp chela. A, B. ♂ (MACN-Ar). C, D. ♀ (MACN-Ar). A, C. Internal aspect. B, D. Ventral aspect. Scale bar = 1 mm. FIGURE 26. Rumikiru , n. gen. , sternite VII and metasomal segments. A. Rumikiru lourencoi (Ojanguren-Affilastro, 2003) , n. comb. , ♀ (MACN-Ar), sternite VII and metasomal segments I and II, ventral aspect. B–D. Rumikiru atacama , n. sp. , ♂ (MACN-Ar). B. Metasomal segments I and II, lateral aspect. C. Metasomal segments III and IV, lateral aspect. D. Metasomal segment V, lateral aspect. Annotations: DL: dorsolateral carina; LSM: lateral supramedian carina; LM: lateral median carina; LIM: lateral inframedian carina. Scale bar = 1 mm. Hemispermatophore : Basal portion well developed (fig. 10F, G). Distal lamina well developed, similar in length to basal portion (fig. 10B, F, G); apical half forming well-developed apex; distal crest slightly undulated in distal third, convex in basal two-thirds (fig. 10B, F, G); frontal crest (distal posterior flexure) well developed, almost straight, occupying basal half of distal lamina. Lobe region well developed (fig. 10H); basal lobe well developed, with small projection, internal fold covered by tiny, scattered papillae (spicules) (fig. 10I). DISTRIBUTION: All known records of R. atacama , n. sp. , occur within a small part of Huasco Province, in the southern part of Region III ( Atacama ), northern Chile (figs. 2, 3), to which this species is probably endemic. ECOLOGY: The area in which this species was collected falls within the “Desierto Costero del Huasco” subregion of the “Desierto” botanical region ( Gajardo, 1993 ). This area is extremely arid, with sparse shrubs and cacti, except in areas with greater exposure to sea fog, where a “Lomas” habitat, comprising more abundant vegetation, occurs. Rumikiru atacama , n. sp. , has been collected close the seashore but not in “Lomas” habitat. Most personally collected specimens were taken from scree slopes, cliff faces, and exposed rocky outcrops, in areas with little or no vegetation (fig. 4A). This species occurs in sympatry with the iurid Caraboctonus keyserlingi Pocock, 1893 , and three other bothriurids, Bothriurus dumayi Cekalovic, 1974 , Brachistosternus kamanchaca Ojanguren-Affilastro et al., 2007 , and Brachistosternus roigalsinai Ojanguren-Affilastro, 2002 . None of these species shares the same microhabitat as R. atacama , n. sp. , however.