Bothriurus nendai, Ojanguren-Affilastro, Andrés Alejandro & Garcia-Mauro, Ignacio, 2010

Ojanguren-Affilastro, Andrés Alejandro & Garcia-Mauro, Ignacio, 2010, A new Bothriurus (Scorpiones, Bothriuridae) from the Somuncura Plateau, with additions to the knowledge to the endemic scorpion fauna of the area, Zootaxa 2488, pp. 52-64 : 53-62

Bothriurus nendai n. sp.

figs 1–22, Table 1

Type series: Holotype male (MACN-Ar 22127): ARGENTINA: Río Negro Province, Somuncura Plateau: internal road from Chipauquil to Cona-Niyeu, 4125’20.6’’S, 6658’37.6’’W, 1465 m asl, 29 November 2008, A. Ojanguren-Affilastro, S. Nenda, and L. Compagnucci coll. Paratypes: same data as holotype, 1 female, 1 male, 5 juveniles (females) (MACN-Ar 22128).

Etymology: This species is named after the Argentinean herpetologist Santiago Nenda, from the Museo Argentino de Ciencias Naturales “Bernardino Rivadavia, who was among the collectors of the species, providing invaluable help during fieldwork.

Diagnosis: Bothriurus nendai n. sp. can be separated from the rest of the Patagonian species of genus Bothriurus because it bears six ventral trichobothria in the pedipalp chela ( Fig. 8 ), whereas the rest of the species bear five. This species seems to be more closely related to the species of the patagonicus group, because they share a similar pigmentation, a similar hemispermatophore, and a similar development of the metasomal carinae; however, Bothriurus nendai n. sp. can be separated from the species of the patagonicus group because it bears two subdistal teeth in the movable finger of chelicerae, whereas the species of this group bear only one.

Bothriurus nendai n. sp. occurs in sympatry with B. ceii , both species can be separated by several morphological differences besides those mentioned above. They can be separated because in B. ceii the ventral surface of sternite VII and metasomal segments I and II are smooth, and without carinae in both genders, whereas B. nendai females bear two VL and two VSM carinae in sternite VII, and in metasomal segments I and II; (fig. 1) and B. nendai males bear these carinae only in sternite VII (fig. 2). Both species can also be distinguished because on the ventral surface of metasoma of B. ceii there are two VL and one VM dark stripes of pigment, that are present in all segments but don’t join in any of them, whereas in B. nendai in metasomal segment I there are only two VL stripes (that don’t join), and in the rest of the segments there are two VL and a VM stripe that join in the posterior third of all segments. Bothriurus nendai is smaller than B. ceii : total length in B. nendai : 27–33 mm, total length in B. ceii 39–46 mm. The vesicle of the telson is much more globose in females of B. nendai (fig. 5) than in females of B. ceii . Telson length/height ratio is 2.19 in the only studied adult female of B. nendai , and 2.66, 2.68 and 2.77 in the three studied females of B. ceii .

Bothriurus nendai n. sp.

Bothriurus nendai has a higher number of setae in metasoma, than the rest of Patagonian species: B. nendai has 14 ventral setae in metasomal segment IV, and 20 or more in segment V; the remaining Bothriurus species from Patagonia have up to 8 ventral setae in segment IV, and up to 14 in segment V ( Mattoni, 2007). Bothriurus nendai bears 3 LSM setae in segment IV, and 6–7 in segment V; against 1 LSM setae in segment IV, and 3 in segment V in the remaining Patagonian species. DL setae on segment V are also more abundant in B. nendai being 2 or 3; whereas in the remaining Patagonian species there is always one.

Description. Colour: general colour yellowish, with brown spots (figs. 18–21). Carapace: anterior margin densely pigmented; ocular tubercle and area around the lateral ocelli dark brown; two oblique thick dark stripes extend from the base of the postocular furrow to the anterior margin; area near the lateral margins with dense reticulate pigment; with two posterolateral dark spots. The rest with reticulate pigment connecting all the spots. Chelicerae: with dorsal reticulate pigment, and with a dark spot near the articulation with the movable finger; movable finger densely pigmented. Tergites: almost completely covered with pigment, with some isolated internal unpigmented areas. Sternites, sternum, genital opercula and pectines depigmented. Metasoma: segments I–IV: dorsal surface with a median triangular spot, and with a thin line over the DL carina; lateral surface with reticulate pigment, and with a dark stripe below the LSM carina, that joins with the VL stripes in the posterior third of the segment; ventral surface: segment I with two VL stripes that don’t join in the posterior margin, segments II–IV with three wide longitudinal dark stripes, two VL and one VM, that join in the posterior third of the segments; in segments II and III the VM stripe has a median unpigmented area in the posterior two thirds; segment V: dorsal surface with two faint longitudinal paramedian dark stripes in the anterior half of the segment, and with two DL stripes that extend the entire length of the segment; lateral surface with reticulate pigment; ventral surface with a thin VM stripe and two wide VL stripes, connected in the anterior half of the segment by reticulate pigment, and joining in the posterior half of the segment forming a dark a single wide dark spot. Telson: vesicle with dark reticulate pigment all over, with four unpigmented longitudinal stripes, two laterals and two ventral; aculeus dark brown. Legs: femur densely pigmented on the prolateral surfaces and near the articulation with patella; patella densely pigmented on the lateral surfaces, trochanter, tibia and basitarsus unpigmented or slightly pigmented near their VL margins, coxa and telotarsus unpigmented. Pedipalps: trochanter slightly pigmented near the articulation with femur; femur dorsal surface densely pigmented near the articulation with patella, internal and external surfaces slightly pigmented; patella dorsal and external surfaces covered with reticulate pigment, ventral and internal surfaces unpigmented; chela, manus with seven longitudinal stripes connected by reticulate pigment, and joining in an external dark spot near the articulation with the movable finger.

Morphology: Measurements of the holotype male (MACN–Ar 22127), a paratype male and a paratype female (MACN–Ar 22128), are recorded in Table 1 . Total length in the two studied males: 27.93 and 28.17 mm; in the only adult studied female: 32.98. Carapace: tegument smooth in females, finely granular in males; anterior margin slightly convex, with a poorly developed median notch, anterior longitudinal sulcus absent; with three lateral eyes on each side of the carapace; each group of lateral eyes has two eyes placed close together in the same horizontal line, and proximally, whereas the third one is placed one diameter apart, above of them and more distally, being also about a 30 % smaller; ocular tubercle well developed, median eyes small, two diameters apart; posterior longitudinal sulcus poorly developed, posterolateral sulci and postocular furrow deeply marked. Chelicerae: with two subdistal teeth. Tergites: tergites I–VI slightly granular in males; in females smooth with a slightly granular area near the posterior margin; tergite VII: slightly granular in the anterior half, densely granular in the posterior half, more densely granular in males; with two paralateral carinae in the posterior half of the segment and two paramedian carinae reduced to some scattered granules and an elevation of the tegument in the posterior quarter of the segment. Sternites: III–V with smooth tegument, spiracles small and elliptic; VI smooth in the anterior two thirds, granular in the median part and in the posterior third; spiracles small and elliptic; VII densely granular, females with four longitudinal carinae, two well developed VSM carinae that occupy the posterior half of the segment, and two poorly developed paramedian carinae restricted to some granules (fig. 1); males with two VSM carinae less developed than in females (fig. 2). Metasoma: segment I dorsal surface smooth, with some scattered granules near the posterior margin, DL carina restricted to some granules in the posterior third of the segment, with one DL setae; lateral surface: LSM and LIM carinae restricted to the posterior half of the segment, with some scattered granules between carinae, with two LSM and one LIM setae; ventral surface: females densely granular tegument, with four well developed longitudinal carinae that occupy the entire length of the segment, two VL and two VSM; males with smooth tegument, with two VSM and two VL carinae as a barely visible elevation of the tegument; with eight ventral macrosetae arranged in an anterior row of four macrosetae (two VSM and two VL) and a similar row of four setae in the posterior margin of the segment; segment II similar to segment I but less granular and with less developed carinae, ventral surface in females with poorly developed VSM and VL carinae, smooth in males; segment III: as segment II but even less granular and with less developed carinae, DL and LSM carina restricted to some blunt granules in the posterior quarter of the segment, LIM carina absent, reduced to a LIM macroseta, ventral surface smooth, the rest as in segment II; segment IV: DL carina restricted to some posterior granules and a median DL macroseta, lateral accessory carina reduced to a slight elevation of the tegument and a macroseta, LSM carina reduced to an anterior and a posterior bulge and three macrosetae, LIM carinae reduced to a macroseta, ventral surface smooth, with 14 ventral macrosetae arranged in four transversal rows, an anterior row with two VL macrosetae, two median rows with four macrosetae (2 VL and 2 VSM), and a posterior row with four macrosetae in the posterior margin of the segment; segment V: dorsal surface smooth, DL carina restricted to an anterior bulge and two or three DL macrosetae, lateral surface smooth in males with some scattered granules in females, and six or seven LSM macrosetae, ventral surface with granular tegument (figs. 3, 4), VL carinae granular, extending the entire length of the segment, with six to eight VL macrosetae, VSM carinae longitudinal in the anterior half of the segment, diverging in the posterior half of the segment and connecting with the VL carinae in the posterior quarter, with three rows of two VSM macrosetae each (in some specimens there are one or two additional setae), VM carina longitudinal, occupying almost the entire length of the segment, barely visible between the granulation; with a posterior row of four macrosetae. Telson: vesicle remarkably globose in females (fig. 5), more elongated in males (fig. 6), ventral surface granular, dorsal surface smooth, in males there is a median dorsal tegumentary depression that most probably corresponds to the telson gland; aculeus short and curved, more curved in females. Legs: smooth tegument, leg I with asymmetrical unguis and basitarsal spurs, being the prolateral spur and unguis about a 20 percent more developed than the retrolateral, in leg II spurs and unguis are almost symmetrical and in legs III and IV they are symmetrical, telotarsi with a ventral row of hyaline setae, and with well developed VL spines; spinal formula: tarsus I: 1-1; tarsus II: 2-2, tarsi III and IV: 3-3. Pectines: number of pectinal teeth in the two studied males: 12–13 and 13–14; in females: 9–11 (N = 6; mode = 10), the basal lamella is more elongated in females than in males. Pedipalps: femur: tegument smooth in females, without conspicuous carinae, granular in males, DI, DE, and VI carinae granular and extending the entire length of the segment (fig. 15); patella: tegument smooth and without carinae in females, granular in males, VI and DI carinae granular and extending the entire length of the segment (figs. 12, 13, 14); chela: robust with short fingers and smooth tegument (figs. 7–11), in females it is less robust, with longer fingers (figs. 10, 11); males with a strong conical apophysis near the articulation with the movable finger (figs. 8, 9). Internal surface of fingers with a median row of denticles and five pairs of accessory denticles (fig. 10), being the external basal denticles almost superposed to the median row. Trichobothrial pattern: neobothriotaxic major type C, with two accessory trichobothrium in the V series of chela (fig. 8); femur (fig. 15) 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), esb 2 petit (fig. 13); chela with 27 trichobothria (1 Est, 5 Et, 6 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); Esb forming a triangle with Eb 1 and Eb 2; Et 4 and Esb petit. Hemispermatophore: distal lamina narrow, similar in size to the basal portion, slightly curved in its upper third (figs. 16, 17); distal crest parallel to the posterior margin, occupying the distal half of the lamina; internal lobe with a small apophysis in its external surface (fig. 17); basal lobe laminar; frontal ridge well developed; capsular cavity well developed (fig. 16).

Distribution and habitat: Bothriurus nendai n. sp. has only been collected at the type locality, in the upper level of the Somuncura plateau. This is a tableland situated in Río Negro and Chubut provinces, in northern Argentinean Patagonia (fig. 22). The type locality is a plain, at almost 1500 m, near a temporary lake (which was full of water in spring); the soil is covered with sparse rocks of 20 to 40 cm diameter, and the vegetation is similar to the rest of the upper level of the plateau, which is a grassland of “Coirón ( Poa spp., Festuca spp. and Stipa spp.) ( Cei 1969).

During the same trip in which we collected B. nendai , we also collected scorpions in other plains on the upper level of the Somuncura Plateau, with a slightly drier soil (not near a lake), and almost without rocks; however no specimens of B. nendai were found in these areas.

The Somuncura Plateau is connected to the foothills of the Andes by areas of intermediate altitudes (about 1000 m). We have made some collections in these areas, in early spring, in two different years (2007 and 2008) and could not collect any specimens of B. nendai . We also had access to several pitfall traps from ecological studies performed during the spring and summer of 2005–2007, in several different environments from this intermediate area, and from the foothills of the Andes. However, no specimens of B. nendai were captured in these traps. We therefore assume that B. nendai is endemic to the upper level of the Somuncura Plateau, and probably restricted to the more humid areas of the plateau.

Natural history: All known specimens of Bothriurus nendai n. sp. were collected in early spring. Despite several previous summer field trips to the Somuncura Plateau, no other specimens of this species appear to have been collected. It is possible that this species has a different activity period, being active during early spring instead of in summer as the rest of the known Bothriurus from Patagonia. However, we cannot affirm conclusively that this is the case, without long term ecological studies in the area.

Only a few species of Bothriuridae are known to have a spring surface activity period. These are the species of Urophonius Pocock 1893 of the granulatus group (three known species), Brachistosternus telteca Ojanguren Affilastro 2000 ( Ojanguren Affilastro 2000, 2005; Ojanguren Affilastro & Ramirez 2009), and some species of Orobothriurus (Ochoa pers. comm.). All these species are syntopic with larger and more abundant species of Bothriurus and Brachistosternus Pocock 1893 that have a summer surface activity period. Perhaps the spring activity period evolved to avoid direct competition or predation with larger, more abundant species. In the same area where B. nendai was collected occurs B. ceii , a larger species that is very abundant in summer ( Acosta 2003; Ojanguren-Affilastro 2007).

Bothriurus nendai is syntopic with U. somuncura , both species being active in the same period of the year. However, even if both species have been collected together, U. somuncura is more abundant in rocky habitats, where B. nendai is absent.

Figures

FIGURES 7 – 11. Bothriurus nendai n. sp. 7: left pedipalp chela, male, external aspect; 8: left pedipalp chela, male, ventral aspect; 9: left pedipalp chela, male, external aspect; 10: left pedipalp chela, female, dorsal aspect; 11: right pedipalp chela, female, external aspect.

Tables

TABLE 1. Bothriurus nendai n. sp. Measurements in mm of the male holotype (MACN-Ar 22127) and a female paratype (MACN-Ar 22128).

Measurementes in mm	Male holotype	Male paratype	Female paratype
Total length	28.17	27.93	32.98
Carapace, length	3.26	3.40	4.33
Carapace, anterior width	2.27	2.27	2.80
Carapace, posterior width	3.47	3.53	4.23
Mesosoma, total length	9.31	9.18	12.64
Metasoma, total length	11.97	11.62	12.28
Metasomal segment I, length/width/height	1.78/2.27/1.77	1.90/2.17/1.70	1.94/2.42/1.94
Metasomal segment II, length/width/height	2.10/2,10/1.80	2.27/2.03/1.70	2.25/2.37/1.94
Metasomal segment III, length/width/height	2.18/2.06/1.80	2.27/2.02/1.73	2.22/2.26/1.94
Metasomal segment IV, length/width/height	2.58/1.94/1.72	2.41/1.93/1.70	2.45/2.20/1.86
Metasomal segment V, length/width/height	3.33/1.94/1.52	2.77/1.93/1.50	3.42/2.18/1.66
Telson, length	3.63	3.73	3.73
Vesicle, length/width/height	2.67/1.60/1.33	2.73/1.47/1.24	2.73/2.07/1.7
Aculeus, length	0.97	0.99	1.00
Pedipalp, total length	8.74	9.3	9.88
Femur, length/width	2.17/0.97	2.40/1.01	2.47/1.20
Patella, length/width	2.24/1.2	2.37/1.00	2.48/1.23
Chela, length/width/height	4.33/1.47/1.87	4.53/1.53/1.93	4.93/1.56/1.93
Movable finger, length	2.27	2.20	2.73