Nueva especie de escorpión

Investigadores pastusos descubren nueva especie de escorpión para el mundo científico, siendo éste único en su tipo catalogado como endémico de Buesaco - Nariño - Colombia. A new species in the scorpion genus Troglotayosicus from forest leaf litter in Southwestern Colombia (Scorpiones, Troglotayosicidae). RICARDO BOTERO-TRUJILLO 1, JOSÉ A. OCHOA 2, OSCAR A. TOVAR 3(§) & JULIO E. SOUZA 3(*) 1Laboratorio de Entomología, Unidad de Ecología y Sistemática–UNESIS, Departamento de Biología, Pontificia Universidad Javer-iana, Bogotá, Colombia; [email protected] 2Museo de Historia Natural, Universidad Nacional de San Antonio Abad del Cusco, Local Central, Paraninfo Universitario, Plaza de Armas s/n, Cusco, Peru; [email protected] 3Departamento de Biología, Facultad de Ciencias Exactas y Naturales, Universidad de Nariño, San Juan de Pasto, Colombia; [email protected] (§), [email protected] (*) RESUMEN Se describe a Troglotayosicus hirsutus, una nueva especie de escorpión troglomórfico, en base a tres machos adultos, tres hembras adultas y ocho ejemplares juveniles capturados por detección con luz ultravioleta en hojarasca de un bosque en el municipio de Buesaco, suroccidente de Colombia. A pesar de ser similar a la otra especie Colombiana del género, Tro-glotayosicus humiculum Botero-Trujillo & Francke, 2009, T. hirsutus sp. nov. exhibe una combinación distintiva de car-acterísticas morfológicas, incluyendo una apariencia densamente setosa de la cual se deriva el nombre de la nueva especie. Con esta descripción se eleva a tres el número de especies conocidas en el género Troglotayosicus, dos de las cuales hab-itan la hojarasca de bosques en el departamento de Nariño (Colombia), mientras la especie tipo, Troglotayosicus vachoni Lourenço, 1981, sigue conociéndose únicamente de la Cueva de Los Tayos en Ecuador. Con este nuevo hallazgo, se abre la posibilidad que el género Troglotayosicus no sea tan raro después de todo, sino que su aparente rareza sea un resultado de artefactos de muestreo. Sin embargo, esta posibilidad no implica que el género sea necesariamente común, y solo el desarrollo de estudios adicionales permitirá determinar el estado de vulnerabilidad del género. Palabras clave: Escorpión, troglomorfismo, Troglotayosicus hirsutus sp. nov., taxonomía, Nariño, Colombia Introduction Troglotayosicus Lourenço, 1981, is a small genus made up of humicolous and troglobitic Neotropical scorpions, currently consisting of two described species: Troglotayosicus vachoni Lourenço, 1981, known only from Los Tayos Cave in the Amazonian Region of southern Ecuador, and Troglotayosicus humiculum Botero-Trujillo & Francke, 2009 from the mountain rainforest of southwestern Colombia. In its original description, Troglotayosicus was placed in the family Chactidae by Lourenço (1981), but later it was transferred to Superstitioniidae (as Superstitionidae) by Stockwell (1992). Lourenço (1998) subsequently created the new family Troglotayosicidae (as Troglotayosidae) to accommodate this genus and another monotypic genus endemic to the Pyrenees of France and Spain, Belisarius Simon, 1879. Even though some authors considered Troglotayosicus a superstitioniid (Soleglad & Fet, 2003; Fet & Soleglad, 2005), others currently recognize its placement in Troglotayosicidae (Prendini & Wheeler, 2005; Volschenk & Prendini, 2008; Botero-Trujillo & Francke, 2009; Ochoa et al., 2010; Prendini et al., 2010). Two species have been described for this genus: the type species Troglotayosicus vachoni was described based exclusively on the holotype female, whereas the description of T. humiculum followed 28 years later based only upon a juvenile male. The scarcity of Troglotayosicus specimens in museum collections probably was (and is still) due to the restricted and specialized habitats where these scorpions now appear to occur (caves and forest leaf litter), and also to the difficulty to detect them with traditional collecting methods [see Ochoa et al. (2010) for field observations about T. humiculum]. After finding additional specimens of T. humiculum in 2008, including adults of both sexes (Ochoa et al., 2010), the humicolous conditions where the specimens were found to occur led us to modify the ‘classical’ method for surveying scorpions, by means of disturbing the leaf litter and scanning the disturbed area with ultraviolet light. With this method, two recent expeditions yielded the collection of further specimens of Troglotayosicus in the Municipality of Buesaco, southwestern Colombia (Figs. 1, 2–3). Upon examination of this material, the specimens were determined to belong to an undescribed species, described and illustrated in the present contribution, thus raising to three the number of known species in the genus. Methods Material herein described was collected during field expeditions carried out by the authors. Specimens were hand-captured at night by ultraviolet light detection (Stahnke, 1972). The type locality was georeferenced in the field with a portable Garmin e Trex Vista 24 MP GPS Navigation System. Material is deposited in the following collections: Museo Javeriano de Historia Natural ‘‘Lorenzo Uribe S. J.,’’ Pontificia Universidad Javeriana, Bogotá, Colombia (MPUJ); Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia (ICN); Colección Aracnológica Regional de Nariño, San Juan de Pasto, Colombia (CARN, housed by O.A.T and J.E.S.). Style and terminology used for the species description follows that used by Ochoa et al. (2010) in the redescription of T. humiculum, to ease comparisons, as detailed below. Morphological terminology follows Vachon (1952) and Prendini (2000) for pedipalp carinae, abbreviated as follows: internomedian (IM), digital (D), dorsointernal (DI), dorsomedian (DM), dorsoexternal (DE), dorsomarginal (DMA), dorsal secondary (DS), external (E), externomedian (EM), ventroexternal (VE), ventromedian (VM), ventrointernal (VI), dorsal patellar process (DPP), ventral patellar process (VPP); a modified version of Prendini (2004) for tergal, sternal, and metasomal carinae, abbreviated as follows: dorsosubmedian (DSM), dorsolateral (DL), lateral supramedian (LSM), median lateral (ML), lateral inframedian (LIM), ventrolateral (VL), ventrosubmedian (VSM), ventromedian (VM); and Stahnke (1970) for other characters. Trichobothrial notation follows Vachon (1974), but we adopt the reinterpretation of Typhlochactas trichobothrial patterns proposed by Prendini & Wheeler (2005) and Vignoli & Prendini (2009). Cheliceral dentition notations follow Vachon (1963). Photographs of preserved specimens were taken under ultraviolet and sun light using an Olympus D-590 ZOOM digital camera. Specimens were studied and illustrated under an Advanced Optical JSZ-6S Zoom stereomicroscope and a Zeiss Stemi SV 6 stereomicroscope, the latter equipped with camera lucida. Measurements (L = length, W = width, H = height) are presented in millimeters and were obtained following the methodology of Sissom et al. (1990) using an ocular micrometer fitted to the calibrated Advanced Optical stereomicroscope. The distribution map was produced using DIVA-GIS Version 5.4 (http://www.diva-gis.org/) by superimposing georeferenced point locality records on a digital elevation dataset from the CGIAR Consortium for Spatial Information (CGIAR-CSI) available at http://srtm.csi.cgiar.org. Family Troglotayosicidae Lourenço, 1998 Troglotayosicus Lourenço, 1981 Troglotayosicus hirsutus sp. nov. Figures 1–28; Table 1 Type material. Holotype male (adult): COLOMBIA: Nariño department, Buesaco, 0.1º22’39.2’’ N 0.77º0.9’29’’ W (error margin ~22 m), 1959 m, UV light at night, O. A. Tovar & J. E. Souza, March 2011 (MPUJ-SCO-401). Allotype female (adult): COLOMBIA: same data of holotype (MPUJ-SCO-402). Paratypes: COLOMBIA: 1 adult male (dissected for hemispermatophore extraction), 2 juvenile females, same data of holotype (ICN-As-835); 1 adult male (dissected for hemispermatophore extraction), 2 adult females, 3 juvenile females, same locality of holotype, J. A. Ochoa, O. A. Tovar & J. E. Souza, 01–02 December 2011 (CARN); 3 juvenile females, same locality of holotype, J. A. Ochoa, O. A. Tovar & J. E. Souza, 01–02 December 2011 (MPUJ-SCO-405). All specimens preserved in 70% ethanol. FIGURE 1. Map plotting known locality records of Troglotayosicus Lourenço, 1981 species in Colombia and Ecuador. Troglotayosicus humiculum Botero-Trujillo & Francke, 2009, circles. Troglotayosicus vachoni Lourenço, 1981, squares. Troglotayosicus hirsutus sp. nov., star. Etymology. Epithet is derived from the latin word hirsutus, meaning hairy and referring to the hirsuteness of the whole body of males and females of the new species, one of its most distinctive features. Diagnosis (male and female). Troglotayosicus hirsutus sp. nov. differs from T. humiculum in the following respects: i) entire body densely hirsute (Figs. 8–11, 12–13), ii) pedipalp hand and fingers without granulations, or hand infrequently barely granular distally on DMA and DI carinae, iii) carapace with pronounced anterior epistome (Fig. 12), iv) metasomal segments III and IV predominantly smooth ventrally, without VSM or VL carinae and with no granulations (or with only very few irregularly-arranged granules in segment IV ventrally), and v) LIM carinae less developed in segments I through III and absent in IV where replaced by disaggregated granules (Figs. 23–24). In contrast, in T. humiculum i) the body does not have abundant setae, ii) at least the DS, DMA and DI carinae on hand are conspicuously granular, iii) the anterior margin of carapace is sublinear with weak epistome, iv) metasomal segments III and IV are ventrally granulose with presence of VSM (often absent in segment III of females) and VL carinae, and v) LIM carinae are well-developed in segments I to IV. Besides, the shape of the male pedipalp hand is different between both species, being bulkier in T. hirsutus sp. nov. (L:W = 2,74–2,11:1; L:H = 2,84–2,99:1) as compared to T. humiculum (L:W = 3,06:1; L:H = 2,80:1). Troglotayosicus hirsutus sp. nov. differs from T. vachoni in the following respects: i) ventral setae in the telotarsus of all legs regularly arranged into a pair of parallel rows, ii) lateral ocular areas each with three ocelli (median ocellus present but greatly reduced), iii) pedipalp chela with D, DS, DMA, DI, E, VI and VE carinae identified by subtle differences in angles between adjacent surfaces, and iv) metasomal segments I and II without VL carinae. In contrast, in T. vachoni the ventral setae of telotarsi are not regularly arranged into rows, the lateral ocular areas bear two ocelli each, the pedipalp hand lacks carinae, and metasomal segments I and II have VL carinae. The hemispermatophore morphology provides additional diagnostic features to further separate T. humiculum from T. hirsutus sp. nov.: the lamina is broader medially and inclined towards the ventrointernal surface in T. humiculum, but is slightly more elongated and almost straight in T. hirsutus sp. nov.; the external lobe ends in small dorsal process in T. humiculum, but is vestigial without process in T. hirsutus sp. nov. (Figs. 25–28). The hemispermatophore of T. vachoni remains unknown. Description. Based on three adult males, three adult females and eight juveniles. Measurements in Table 1. Color. Description from preserved specimens. Base color, chelicerae and legs yellowish to light chestnut; carapace, tergites, metasoma, and pedipalps yellowish to pale orange (juveniles) or carapace, tergites and pedipalps orange to dark chestnut, becoming darker on metasomal segments (adults); sternites and coxosternal region yellowish (juveniles) or light chestnut (adults); pectines whitish (Figs. 4–7). Carapace (more evident in juveniles), pedipalps (more in adults) and coxosternal region with slight pigmentation, lighter than base color, remaining areas unpigmented. Anterior and posterior pairs of lateral ocelli surrounded by black pigment. Chelicerae. Manus, dorsal and external surfaces smooth, sparsely setose; ventral and internal surfaces densely setose. Fixed finger, dorsal margin with four teeth (distal, subdistal, median, and basal); median and basal teeth separate, not fused into bicusp. Movable finger, internal distal and external distal teeth not opposable, internal distal tooth at most partially overlapping external distal tooth in dorsal view; dorsal margin with five or infrequently six teeth [distal, two (or three on one of each chelicerae of two adult females and one juvenile) small subdistal, median, and basal]; ventral surface with long, well-developed serrula and a vestigial internal basal teeth by the position of the basal beginning of serrula. FIGURES 4–7. Troglotayosicus hirsutus sp. nov. under sun light. 4–5. Holotype male, dorsal and ventral aspects (MPUJ-SCO-401). 6–7. Allotype female, dorsal and ventral aspects (MPUJ-SCO-402). Scale bars = 5 mm. Carapace. Anterior margin with pronounced epistome medially projected and a variable number of pairs of macrosetae (more in number in males); posterior margin sublinear, with few setae (Fig. 12). Median ocelli absent; three pairs of lateral ocelli present, anterior pair largest, median pair greatly reduced, posterior pair slightly smaller than anterior pair. Median longitudinal sulcus well developed; posterolateral and posterior transverse sulci obsolete. Surfaces acarinate, smooth, and hairy Discussion The finding of a third species in the genus Troglotayosicus makes plausible that this genus is not rare after all. The occurrence of different species in southeastern Ecuador and southern Colombia may be evidence of a patchy distribution, with species inhabiting restricted and isolated areas, but also it may well suggest that the genus Troglotayosicus is widely distributed in this region of northwestern South America. These possibilities need to be studied in the future, by conducting additional field expeditions to different territories in Ecuador. Acknowledgements The authors are grateful to Erich S. 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