Vachoniochactas humboldti, D, Eduardo Flórez, Botero-Trujillo, Ricardo & Acosta, Luis E., 2008

D, Eduardo Flórez, Botero-Trujillo, Ricardo & Acosta, Luis E., 2008, Description of Vachoniochactas humboldti sp. nov. from Colombia, with complementary notes on the genus (Scorpiones, Chactidae), Zootaxa 1853, pp. 31-44 : 33-37

Vachoniochactas humboldti sp. nov.

Figures 1–21 , Table 1

Type series. Holotype: COLOMBIA: Vichada Department: adult ɗ, Cumaribo, Matavén Forestry, "bosque de planicies arenosas", 260m, 04°29’13’’N 68°00’22’’W, 31 March 2007 – 02 April 2007, L.E. Franco coll., pitfall (IAvH-E 100799).

Allotype: COLOMBIA: Vichada Department: adult Ψ, Cumaribo, Matavén Forestry, "bosque de cerro rocoso", 300m, 04°36’33’’N 67°51’52’’W, 0 6 March 2007 – 08 March 2007, L.E. Franco coll., trap for dung beetles (ICN-MHN-As-651).

Paratypes: COLOMBIA: Vichada Department: one adult Ψ and two adult ɗ, Cumaribo, Matavén Forestry, "bosque de planicies arenosas", 260m, 04°29’13’’N 68°00’22’’W, 31 March 2007 – 02 April 2007, L.E. Franco coll., trap for dung beetles (IAvH-E 100796, 100798, 100801); one adult Ψ, Cumaribo, Matavén Forestry, "bosque de planicies arenosas", 260m, 04°29’13’’N 68°00’22’’W, 31 March 2007 – 02 April 2007, L.E. Franco coll., trap for dung beetles (MPUJ-SCO-378); six adult ɗ, Cumaribo, Matavén Forestry, "bosque de planicies arenosas", 260m, 04°29’13’’N 68°00’22’’W, 31 March 2007 – 02 April 2007, L.E. Franco coll., pitfall (IAvH-E 100800, 100804, 100805, 100806, 100807, 100808); one adult ɗ, Cumaribo, Matavén Forestry, "bosque de planicies arenosas", 260m, 04°29’13’’N 68°00’22’’W, 31 March 2007 – 02 April 2007, L.E. Franco coll., pitfall (MPUJ-SCO-379); one adult ɗ, Cumaribo, Matavén Forestry, "bosque de cerro rocoso", 300m, 04°36’33’’N 67°51’52’’W, 0 6 March 2007 – 08 March 2007, L.E. Franco coll., pitfall (IAvH-E 100803); two juvenile ɗ, Cumaribo, Matavén Forestry, "bosque de cerro rocoso", 300m, 04°36’33’’N 67°51’52’’W, 0 6 March 2007 – 08 March 2007, L.E. Franco coll., Winkler (IAvH-E 100793, 100794); one adult ɗ, Cumaribo, Santa Rita Municipality, El Tuparro Natural National Park, "mata de monte", 135m, 05°19’54’’N 67°53’27’’W, soil, 10 February 2004, I. Quintero & E. González coll., pitfall (ICN-MHN-As-652); one juvenile ɗ, Cumaribo, Santa Rita Municipality, El Tuparro Natural National Park, "bosque de cerro", 135m, 05º21’20’’N 68º01’28’’W, soil, 20 February 2004, I. Quintero & E. González coll., pitfall (IAvH-E 100795). Guainía Department: one adult ɗ, Santa Rosa, Santa Rosa Indigenous Community, Bocón Pipe, Inírida River, 101m, 03°43’N 68°04’W, "bosque maduro de terraza no inundable", sandy soil, November 1996, A. Lopera coll., pitfall (CDA 000.805).

Etymology. The species name is a tribute to the labor of the Instituto de Investigación de Recursos Biológicos Alexander von Humboldt (Villa de Leyva, Colombia), whose collecting programs in many Colombian areas of difficult access have led to the discovery of important novelties for the Colombian scorpion fauna.

Diagnosis. Vachoniochactas humboldti sp. nov. differs from the other species by (1) the presence of a ventromedian row of setae flanked by three pairs of submedian setae plus a single prolateral distal seta in telotarsi III–IV ( Figs. 9–10 ), and (2) by having the ventral surface of metasomal segments I–IV completely smooth. In contrast, in all remaining three species the tarsal setae are not arranged in rows ( González-Sponga 1978, 1991; Lourenço 1994, 2002a), and metasomal segments III–IV (and I–II in V. lasallei ) have vestigial granules on the ventral surface ( González-Sponga 1978, 1991, 1996; Lourenço 1994). The new species can also be distinguished from V. l a s a l l e i because the vesicle of telson has two to three aligned subaculear tubercles in the later (see González-Sponga 1978: fig. 65), which are absent in V. humboldti sp. nov. ( Fig. 8 ). In addition, V. humboldti sp. nov. differs from V. amazonicus and V. lasallei by the position of trichobothrium dt, basal to et on pedipalp fixed finger ( Fig. 11 ); in the two later species dt is distal to et (see González-Sponga 1978: figs. 46– 47; 1991: figs. 48–49). Finally, it can be also distinguished from V. amazonicus and V. ashleeae because esb trichobothrium is considerably more basal to eb on the fixed finger ( Fig. 12 ), contrasting with the mentioned species in which esb is located close or slightly distal to eb (see González-Sponga 1991: figs. 48–49; Lourenço 1994: fig. 6).

Description of the male holotype (IAvH-E 100799).

Total body length 23.15 mm; detailed measurements in Table 1 .

Male holotype (IAvH-E Female allotype (ICN-MHN- 100799) As-651)

Coloration. Carapace dark reddish-brown with some lighter regions, mainly in the median and posterolateral furrows; median and lateral ocular tubercles black. Tergites dark reddish-brown. Coxosternal region predominantly dark-yellow, with conspicuous brown areas on all the components. Genital operculum and pectinal basal piece yellow; pectines light-yellow, except for the basal piece of the basal lamella which is darkened near the junction with pectinal basal piece. Sternites dark-yellow, gradually becoming reddish towards sternite VII, all with inconspicuous brownish areas on the posterolateral margins. Metasomal segments reddish-brown and iridescent, with inconspicuous dark-brown mottling throughout. Telson vesicle reddish, lighter than segment V; aculeus darkened. Chelicerae predominantly yellow; manus dorsally with broad brown longitudinal reticulations and others thinner located between these, predominantly brown below junction of the movable finger; fixed finger with minute brown mottling basally and reddish teeth; movable finger with a dorsoexternal brown area located basally and reddish teeth. Pedipalps with base color red and insertion of all the trichobothria yellow; femur predominantly dark-brown dorsally and internally, yellowish-red externally and ventrally but with some brownish areas; patella variegated on dorsal and external surfaces, almost completely yellowish-red ventrally and internally; hand with longitudinal brown bands in all surfaces, suggesting the corresponding position of the carinae; fixed and movable fingers red. Legs with femur and patella predominantly brown; other segments predominantly yellow.

Morphology. Carapace: Uniformly covered with dense thin granulation, except for the carapace furrows which exhibit weaker granulation; granules are stronger between the lateral ocular tubercles; median and lateral ocular tubercles smooth; anterior and posterior margins of carapace almost straight, lateral margins not parallel ( Fig. 2 ); anteromedian furrow vestigial, reduced to a slight depression; posterotransverse and posteromedian furrows pronounced; lateral ocular and central lateral carinae represented by slight elevations, from which the carapace is declined until the lateral margins; other carinae absent; median ocular tubercle rhomboidal, located in the anterior half of the carapace ( Fig. 2 ); lateral ocular tubercles each with two equally sized eyes and two small ocelli behind them. Tergites: With similar granulation to that of the carapace; without median or dorsolateral carinae; each tergite with a clearly defined pretergite; tergite VII with vestigial and incomplete lateral carinae which are absent on the preceding tergites. Coxosternal region: Sternum wider than long, slit-like ( Fig. 6 ); all the components of the coxosternal region smooth, almost without granules but with numerous setae. Genital operculum and pectines: Genital operculum divided longitudinally, composed of two subtriangular plates; pectinal basal piece wider than long, with anteromedian notch ( Fig. 6 ); pectines long, surpassing the lateral margins of sternite III, without fulcra and with 8 thick teeth each, of which the distal one is rounded ( Fig. 6 ); basal and middle lamellae with abundant setae. Sternites: Densely covered with minute granulation uniformly distributed, and with few setae especially on the lateral margins; without lateral or submedian carinae; spiracles small and round. Metasoma: Metasomal segments with abundant setae of different sizes ( Fig. 8 ); lateral margins parallel; dorsal surface of all segments deeply depressed; segments I–IV with an anterotransverse suture; segments I–IV with granulose dorsal carinae, evident and complete, and dorsolateral carinae represented by a large anterior tubercle and another posterior; segment V with only dorsolateral carinae ( Fig. 8 ); segment I with few granules located between both dorsal carinae, other segments smooth dorsally; segments I–II with few granules laterally, III–IV almost completely smooth except for some granules occurring in the dorsolateral surfaces ( Fig. 8 ); ventral surface of segments I–IV completely smooth and shiny; segment V with abundant and strong granulation in ventral and lateral surfaces, except basally where the granules are scarce ( Fig. 8 ). Telson with an elongated vesicle and a short and curved aculeus; vesicle smooth dorsally, with dense granulation ventrally and laterally similar to that on segment V but rather stronger; with abundant setae ventrally and laterally, especially under the aculeus ( Fig. 8 ); dorsal aspect of vesicle with a slight basal expansion on each side, under which a smooth longitudinal furrow is present. Chelicerae: With abundant setae on the internal and ventral surfaces; cheliceral dentition characteristic of the family Chactidae ( Vachon 1963) . Movable finger external surface with one small basal tooth, one sub-basal pronounced tooth, one (right chelicera) or two (left chelicera) small subdistal teeth, and one distal tooth; internal surface of movable finger without teeth and with well developed serrula. Fixed finger external surface with one basal and one median tooth mounted onto a bicuspid, one subdistal pronounced tooth, and one distal tooth; internal surface of fixed finger without teeth. Pedipalps: Femur with four granulose carinae (dorsoexternal, dorsointernal, internal median and ventrointernal; ventroexternal carinae absent); patella with four smooth, slightly elevated carinae (ventrolateral, ventrointernal, dorsal and median dorsal carinae; others absent); chela acarinate. Femur with abundant large granules dorsally ( Fig. 15 ), with thin granulation internally, smooth ventrally and externally; patella smooth in all surfaces, with an internal well developed tubercle; chela smooth; fixed and movable fingers short and thick ( Figs. 11–14 ), each with six rows of granules flanked by one external and one internal larger granule. Trichobothriotaxy ( Figs. 11–18 ): Type C ( Vachon 1973) with 54 trichobothria (major neobothriotaxy); femur with three trichobothria; patella with 25 of which 17 are external; chela with 26. Legs: Telotarsi III–IV with a ventromedian row of setae flanked by three alternated pairs of submedian setae plus a single prolateral distal seta ( Figs. 9–10 ).

Hemispermatophore. Lamelliform ( Figs. 19–21 ). Lamina straight and slender, with no distal ridge; capsular lobes small and simple; internal lobe with two to four sclerotized spur-like external projections.

Female allotype (ICN-MHN-As-651) and sexual dimorphism.

Total body length 24.31 mm; detailed measurements in Table 1 .

Coloration and morphology similar to the male holotype, except for that the sternites are lighter and the pectines have 7:8 teeth. The following differences were also identified and, through the examination of the available sample, are attributed to sexual dimorphism: (1) the tergites, sternites and medially the carapace are almost completely smooth and shiny, with very weak granulation ( Figs. 4–5 ); (2) the pectines are short and with smaller and more slender teeth ( Fig. 7 ); (3) the sternum is almost as long as wide in the female ( Fig. 7 ); and (4) the pectinal basal piece is straight anteriorly lacking median notch ( Fig. 7 ). Sexual dimorphism in the total body size, with males being smaller than females, is also suggested by the available materials (no male reaches the size of the female allotype, 24.31 mm). These differences may occur too in the other species of the genus but this still remains to be proven (in most of them males are unknown).

Variability. Body size: Total body length 19.30–24.02 mm in adult males (n = 13; mean 22.56 mm), 23.15–24.31 mm in females (n = 3; mean 23.67 mm). Pectinal teeth count: 7 to 9 in males (mode 8:8; n = 16); 7 to 8 in females (mode 8:8; n = 3). External trichobothria of the patella: In most specimens the external trichobothria of the patella are arranged as in figure 18; however, two males (CDA 0 0 0.805, IAvH-E 100795) exhibit a different position of the esb trichobothria, being the resulting line connecting these trichobothria parallel to the em group. Hemispermatophore: Total length 3.05–4.25 mm (n = 14; mean 3.78 mm). Both hemispermatophores were extracted from seven adult males. In two specimens the number of spur-like projections in the capsule (expressed for left/right hemispermatophores respectively) is 4/3 (IAvH-E 100806, 100808), in one it is 3/4 (IAvH-E 100804), in one it is 2/3 (CDA 000.805), in one it is 3/2 (IAvH-E 100807), in one it is 2/2 (IAvH-E 100805), and in one it is 3/3 (IAvH-E 100803). This indicates that the number of spurlike projections in the capsule is variable not only between individuals but also between hemispermatophores from the same specimen.

Distribution and habitat. According to the biogeographic units proposed by Hernández-Camacho et al. (1992) the area where V. humboldti sp. nov. was collected is enclaved in the Vaupes complex of the Guayana Biogeographic Province, adjacent to the Amazonian region. This region comprises swampy forests and noninundable terraces surrounded by rivers where the gallery forests are formed. The northernmost known locality of the new species is inhabited by the Santa Rosa Indigenous Community, and includes mature forests with non-inundable terrace growing in rocky hills and sandy floors. It is somewhat disturbed due to small cultivations and animal hunting by the indigenous community for their survival.

The fact that most specimens were collected by pitfall and Winkler traps suggests that this species is a leaf litter dweller, a microhabitat where the specimen of Vachoniochactas sp. from Venezuela and deposited in the California Academy of Science was also captured (M.E. Soleglad, pers. comm.).

Figures

FIGURE 1. Distribution of the genus Vachoniochactas: V. amazonicus (); V. ashleeae (); V. humboldti sp. nov. (); V. lasallei ().

FIGURES 2 – 5. Vachoniochactas humboldti sp. nov. 2 – 3. Male holotype (IAvH-E 100799), dorsal and ventral views. 4 – 5. Female allotype (ICN-MHN-As- 651), dorsal and ventral views. Scale bars = 5 mm.

FIGURES 6 – 10. Vachoniochactas humboldti sp. nov. 6 – 7. Coxosternal region, genital operculum, and pectines. 6. Male holotype (IAvH-E 100799). 7. Female allotype (ICN-MHN-As- 651). 8. Metasomal segments IV – V and telson of male holotype, lateral view. 9 – 10. Telotarsus IV of male holotype. 9. Prolateral view. 10. Ventral view. Scale bars = 1 mm (Figs. 6 – 7), 2 mm (Fig. 8), 0.5 mm (Figs. 9 – 10).

FIGURES 11 – 18. Vachoniochactas humboldti sp. nov., distribution of the trichobothria in male holotype (IAvH-E 100799) 11. Chela, dorsal view. 12. Chela, external view. 13. Chela, ventral view. 14. Chela, internal view. 15. Femur, dorsointernal view. 16. Patella, dorsointernal view. 17. Patella, ventral view. 18. Patella, external view. Scale bars = 1 mm.

FIGURES 19 – 21. Vachoniochactas humboldti sp. nov., left hemispermatophore of a male paratype (IAvH-E 100808). 19. External view. 20. Rear view. 21. Internal view. Scale bars = 0.5 mm.

Tables

TABLE 1. Vachoniochactas humboldti sp. nov., measurements (in mm). L = length, W = width, D = depth.

Total body L (includ- ing telson) Carapace Length	23.15 3.25	24.31 3.55
Anterior W	1.90	2.27
Posterior W Mesosoma Total L	3.40 6.65	3.73 7.83
Metasoma Total L (including telson)	13.25	12.93
Segment I L Segment I W	0.95 2.25	1.06 2.47
Segment II L	1.40	1.40
Segment II W Segment III L	2.20 1.50	2.28 1.55
Segment III W	2.26	2.30
Segment IV L Segment IV W	2.15 2.30	2.12 2.36
Segment V L	3.50	3.25
Segment V W Telson L	2.33 3.75	2.44 3.55
Aculeus L	0.9	0.8
Vesicle L Vesicle W	2.85 1.94	2.75 1.75
Vesicle D	1.30	1.20
Pedipalps Total L Femur L	8.60 2.00	9.23 2.28
Femur W	0.95	1.07
Patella L Patella W	2.50 1.02	2.52 1.05
Chela L	4.10	4.43
Chela W Chela D	1.77 1.41	2.05 1.77
Movable finger L	2.07	2.16