Diplocentrus formosus Armas and Martín-Frías, 2003

Santibäñez-López, Carlos E., Francke, Oscar F. & Prendini, Lorenzo, 2013, Systematics of the keyserlingii group of Diplocentrus Peters, 1861 (Scorpiones: Diplocentridae), with descriptions of three new species from Oaxaca, Mexico, American Museum Novitates 2013 (3777), pp. 1-48 : 12-18

Diplocentrus formosus Armas and Martín-Frías, 2003

Figures 7A , 8A , 9A , 10A , 11A , 12 , 13 ; tables 1, 2

Diplocentrus formosus Armas and Martín-Frías, 2003: 72–75 , figs. 1–7, tables I, II.

Diplocentrus tehuano: Armas, 2006: 10 (in part, incorrect synonymy).

TYPE MATERIAL: MEXICO: OAXACA: DISTRITO DE TEHUANTEPEC: Municipio de Santo Domingo Tehuantepec : Holotype ♂ ( IES), 3 ♂, 29 ♀ paratypes ( EMF), 1 ♂, 2 ♀ paratypes ( CNAN) [lost?], 8 ♀ paratypes ( IES), Colonia Emiliano Zapata, 5 km WSW Tehuantepec [16°19.655′N 95°17.283′W], 11.vi.2002, H. Cabrera [not examined].

ADDITIONAL MATERIAL: MEXICO: OAXACA: DISTRITO DE TEHUANTEPEC: Municipio de Asunción Ixtaltepec: Chivela [16°42.813′N 94°59.827′W], 210 m, 30.v.1962, J. Martinez, 1 ♂, 1 ♀ ( CNAN); Nizanda, 16°39.4902′N 95°00.6342′W, 99 m, 15.ix.2009, R . Paredes, C. Santibáñez, and A. Valdez, deciduous forest, in burrow entrance, UV light detection, 9 ♀ ( CNAN), 1 ♀ [leg] ( AMCC [ LP 10979 ]); Santo Domingo Tehuantepec [16°19.650′N 95°17.273′W], 80 m, 9.vii.2004, P. Berea, 4 ♂, 11 ♀ ( CNAN) .

DIAGNOSIS: The following character combination, updated from Armas and Martín-Frías (2003), is diagnostic for D. formosus . Total length (adult), 47–65 mm. Base coloration (adult) pale yellow to brown. Carapace anteromedian notch V-shaped (fig. 7A); frontal lobes and interocular surface granular. Pedipalp femur, dorsal surface sparsely granular, comprising larger granules medially (fig. 9A). Pedipalp patella, dorsomedian carina well developed, slightly granular (♂); dorsoexternal carina moderately developed, slightly granular (♂); externomedian carina weakly developed, granular (♂; fig. 11A); ventromedian carina obsolete (♂, ♀). Pedipalp chela manus, dorsal and external surfaces densely granular (♂, ♀); dorsal marginal carina well developed, comprising large granules; digital carina weakly developed, granular, obscured by granulation on dorsal and external surfaces; fingers gently curved (fig. 12). Legs I–IV telotarsi, counts of spiniform macrosetae in pro- and retroventral rows, 5/6:5–6/6:6/6:6–7/7 (variation in table 2). Pectinal tooth count, 12–16, mode = 15 (♂; fig. 8A) or 10–14, mode = 12 (♀) (variation in table 1).

Diplocentrus formosus resembles D. hoffmanni in the similar counts of spiniform macrosetae on the telotarsi of leg IV, but can be separated from the latter as follows. The dorsal and external surfaces of the pedipalp chela manus (♂) are granular in D. formosus but reticulate in D. hoffmanni . The pedipalp chela digital carina is weakly developed (♂) in D. formosus , but moderately to weakly developed (♂) in D. hoffmanni . The pectinal tooth count is higher in D. formosus (♂: 12–16; ♀: 10–14) than in D. hoffmanni (♂: 9–11; ♀: 7–9). The margin of the median lobe of the hemispermatophore is entire in D. formosus , but crenulate in D. hoffmanni (see Sissom, 1994: fig. 22).

SUPPLEMENTARY DESCRIPTION: Based on additional ♂♂ (fig. 13A, B) and ♀♀ (fig. 13C, D) specimens.

Coloration: Carapace brown to brownish orange; moderately infuscate throughout, uniformly so around median ocelli, variegated elsewhere. Coxosternum pale orange. Pedipalps orange to reddish brown, carina weakly infuscate. Legs uniformly pale orange. Mesosoma brown to dark brown, tergites brown (♂, ♀), densely infuscate, sternites pale orange. Metasoma pale brown to orange; carinae weakly infuscate. Telson orange to reddish, uniformly infuscate.

Carapace: Anterior margin moderately setose; anteromedian notch moderately deep, V-shaped (fig. 7A). Frontal lobes, surface densely granular; other surfaces sparsely granular or shagreened. Three pairs of subequal lateral ocelli.

Pedipalps: Orthobothriotaxic, type C. Femur height greater than width (fig. 10A); dorsal intercarinal surface markedly convex, coarsely and sparsely granular; external intercarinal surface smooth; ventral intercarinal surface flat, smooth; internal intercarinal surface finely and sparsely granular; dorsointernal carina moderately developed, granular, becoming obsolete posteriorly; dorsoexternal carina weakly developed, granular; ventroexternal carina obsolete; ventrointernal carina weakly to moderately developed, granular. Patella, dorsal intercarinal surfaces smooth to slightly granular (♂) or smooth (♀); external and ventral intercarinal surfaces granular (♂, fig. 11A) or smooth (♀); internal intercarinal surface finely granular; proximal tubercle moderately developed, bifurcate; dorsointeral carina weakly developed to obsolete; dorsomedian carina strongly developed, granular (♂) or moderately developed, granular (♀); dorsoexternal carina moderately to weakly developed, granular (♂) or weakly developed, finely granular (♀); externomedian carina weakly developed, granular; ventroexternal carinae moderately developed, granular to crenulate (♂), or weakly developed, smooth to crenulate (♀); ventromedian carina weakly to moderately developed, granular; ventrointernal carina weakly to moderately developed, comprising large granules (♂), or weakly developed, granular to smooth (♀). Chela manus, rounded, height greater than width (♂, ♀), densely (♂) or sparsely (♀) setose; dorsal intercarinal surface granular (♂, fig. 12A) or finely granular (♀, fig. 12B); external intercarinal surface granular (♂) or finely granular (♀); dorsal marginal carina moderately developed, coarsely granular; digital carina weakly developed, granular (♂) or weakly developed to obsolete, granular (♀); dorsal secondary and external secondary carinae weakly developed (♂) or obsolete to weakly developed (♀), granular; ventroexternal carina weakly developed, granular, becoming obsolete proximally; ventromedian carina strongly developed, crenulate proximally, granular medially, becoming obsolete distally, directed toward midpoint of movable finger articulation; ventrointernal carina weakly developed, granular; internodorsal, internomedian and internoventral carinae weakly developed, granular; internal surface with shallow longitudinal depression where chela rests against patella. Chela fixed finger curved; length equal (♂) or subequal (♀) to femur length; dorsal surface smooth and densely setose proximally; external surface flat; internal surface shallowly concave.

Legs: Legs I–IV femora and tibiae, prolateral surfaces shagreened; telotarsi, counts of spiniform macrosetae in pro- and retroventral rows (dextral/sinistral), 5/6 5/6: 5/6 5/6: 6/6 6/6: 6/7 6/7.

Pectines: Tooth count: 15–15 (♂; fig. 8A); 13–13 (♀).

Mesosoma: Tergites I –VI, pretergites smooth, posttergites shagreened. Sternites smooth; VII, dorsosubmedian and dorsolateral carinae weakly developed to obsolete, granular.

Metasoma: Metasomal segments I–V, dorsal intercarinal surfaces smooth; lateral intercarinal surfaces finely granular to smooth; ventral intercarinal surfaces smooth. Segments I–IV, dorsolateral carinae weakly developed, granular; lateral supramedian carinae weakly to moderately developed, granular; lateral inframedian carinae weakly developed, granular on I–III; weakly developed to obsolete, granular on IV; ventrolateral carinae strongly developed, granular on I and II; moderately to weakly developed, granular on III and IV; ventrosubmedian carinae strongly developed, granular on I and II; moderately developed, granular on III and IV. Segment V length: pedipalp femur length ratio, 1.26 (♂), 1.18 (♀); dorsolateral carina moderately developed, granular to serrate (♂), or weakly developed, granular (♀); lateral inframedian carina weakly developed to obsolete, granular to smooth; ventrolateral carinae moderately developed, granular to serrate; ventromedian carina strongly developed, granular with subspiniform granules; ventral transverse carina strongly developed, comprising eight subspiniform granules; anal arch semicircular; anal subterminal carina strongly developed, comprising 13 subspiniform granules; anal terminal carina moderately developed, granular.

Telson: Telson , width: length ratio, 0.53 (♂), 0.67 (♀). Vesicle, lateral surfaces smooth; ventral surface granular anteriorly. Subaculear tubercle stout, subconical. Aculeus, 1.4 length of subaculear tubercle, strongly curved.

Hemispermatophore: Lamelliform, weakly sclerotized (fig. 9A); total length, 6.5 mm; distal lamella, length, 3.4 mm; capsular region, width, 1.4 mm; median lobe narrow, margin entire.

REMARKS: The original description of D. formosus was based on 4 adult males, 38 adult females, 3 immature males and 1 immature female from Tehuantepec, Oaxaca. Armas and Martín-Frías (2003) compared D. formosus with D. hoffmanni , D. keyserlingii , D. mitlae , and D. rectimanus and placed it in the penultimate couplet of Francke’s (1977) key, i.e., in the keyserlingii group, comprising species with the pedipalp femur higher than wide. Armas (2006) synonymized D. formosus with Diplocentrus tehuano Francke, 1977 , a species of the mexicanus group in which the pedipalp femur is wider than high, without any formal justification. Based on the original descriptions and an examination of the paratypes of D. tehuano , the two species are distinct and may be separated as follows. The pedipalp femur is higher than wide, its dorsal surface convex in D. formosus , whereas the femur is wider than high, its dorsal surface flat in D. tehuano , as in the other members of the mexicanus group. As the description of D. tehuano was based on 13 adult males and 15 adult females, the variation in spiniform macrosetal counts on the leg telotarsi can be satisfactorily assessed for the two species (4/5:5/5:5/6:6/ 6 in D. tehuano compared with 5/6:5–6/6:6/6:6–7/7 for D. formosus ) lending further support for their differentiation. Based on the evidence, D. formosus is hereby reinstated as a valid species.

DISTRIBUTION: Diplocentrus formosus is known from the Tehuantepec district in the Isthmus of Tehuantepec, southern Oaxaca (fig. 3A).

ECOLOGY: According to Armas and Martín-Frías (2003), the type series of D. formosus was collected mostly from burrows in a lowland area of thorny forest mixed with tropical deciduous vegetation. The personally collected material reported here was excavated from burrows in riparian vegetation. Burrows, constructed almost horizontally in sandy soil, were ca. 40 cm long, and mostly straight, except when turning around stones in the soil matrix. Centruroides nigrimanus ( Pocock, 1898) and an undetermined species of Vaejovis C.L. Koch, 1831 , related to Vaejovis occidentalis Hoffmann, 1931 , were collected in sympatry. The habitat and habitus of D. formosus are consistent with the pelophilous ecomorphotype ( Prendini, 2001).

Figures

FIGURE 7. Diplocentrus keyserlingii group, carapace, dorsal aspect. A. Diplocentrus formosus Armas and Martín-Frías, 2003, ♂ (CNAN). B. Diplocentrus kraepelini, n. sp., paratype ♂ (AMNH). C. Diplocentrus sagittipalpus, n. sp., paratype ♂ (AMNH). D. Diplocentrus sissomi, n. sp., paratype ♂ (AMNH). Scale bars = 1 mm.

FIGURE 8. Diplocentrus keyserlingii group, sternum, genital operculum, and pectines, ventral aspect. A. Diplocentrus formosus Armas and Martín-Frías, 2003, ♂ (CNAN). B. Diplocentrus kraepelini, n. sp., paratype ♂ (AMNH). C. Diplocentrus sagittipalpus, n. sp., paratype ♂ (AMNH). D. Diplocentrus sissomi, n. sp., paratype ♂ (AMNH). Scale bars = 1 mm.

FIGURE 9. Diplocentrus keyserlingii group, sinistral hemispermatophore, dorsal aspect. A. Diplocentrus formosus Armas and Martín-Frías, 2003, ♂ (CNAN). B. Diplocentrus kraepelini, n. sp., paratype ♂ (AMNH). C. Diplocentrus sagittipalpus, n. sp., paratype ♂ (AMNH).D. Diplocentrus sissomi, n. sp., paratype ♂ (AMNH). Scale bars = 1 mm.

FIGURE 10. Diplocentrus keyserlingii group, dextral pedipalp femur, dorsal aspect. A. Diplocentrus formosus Armas and Martín-Frías, 2003, ♂ (CNAN). B. Diplocentrus kraepelini, n. sp., paratype ♂ (AMNH). C. Diplocentrus sagittipalpus, n. sp., paratype ♂ (AMNH). D. Diplocentrus sissomi, n. sp., paratype ♂ (AMNH). Scale bars = 1 mm.

FIGURE 11. Diplocentrus keyserlingii group, dextral pedipalp patella, external aspect. A. Diplocentrus formosus Armas and Martín-Frías, 2003, ♂ (CNAN). B. Diplocentrus kraepelini, n. sp., paratype ♂ (AMNH). C. Diplocentrus sagittipalpus, n. sp., paratype ♂ (AMNH). D. Diplocentrus sissomi, n. sp., paratype ♂ (AMNH). Scale bars = 1 mm.

FIGURE 12. Diplocentrus formosus Armas and Martín-Frías, 2003, dextral pedipalp chela, dorsoexternal aspect. A. ♂ (CNAN). B. ♀ (CNAN). Scale bar = 1 mm.

FIGURE 13. Diplocentrus formosus Armas and Martín-Frías, 2003, habitus, dorsal (A, C) and ventral (B, D) aspect. A, B. ♂ (CNAN). C, D. ♀ (CNAN). Scale bars = 10 mm.