Centruroides panamensis, Arias, Diomedes Quintero & Esposito, Lauren A., 2014

Arias, Diomedes Quintero & Esposito, Lauren A., 2014, A new species of Centruroides Marx (Scorpiones: Buthidae) from Panama and new distribution records for Centruroides bicolor (Pocock, 1898) and Centruroides granosus (Thorell, 1876), Zootaxa 3795 (3), pp. 373-382 : 374-380

Centruroides panamensis new species

( Figs. 1–4 ; Table 1 )

Material examined. PANAMA: Chiriquí Province, Volcán Barú faldas, holotype ·♂ [8°48’N, 82°37’W], 14 July 1984, Arsenio Araúz (LAV-MIUP). Allotype ♀ (gravid): Finca Lukarel (see legend of Fig. 11), Volcancito [8°47’N, 82°28W], 2 January 1984, Efraín & Lorena Bruña (LAV-MIUP). PARATYPES: 3 ♂, 3 ♀, same data as holotype (AMNH-NY); 1 immature, Finca Lukarel, Volcancito, 9 December 1984, Lorena Bruña (AMNH-NY). 1 ♀, falda Volcán Barú, camino hacia Aguacate, 1650 m, 4 Feb 2012, Arsenio Araúz (LAV-MIUP); 1 male, 1 ♀, Finca Lukarel, Boquete, 13 Feb 1985, Lorena Bruña (LAV-MIUP); 1 subadult ♀ under dried log, 2 ♀ under stones carrying on their dorsum 20 immatures (2–3 escaped) & 22 immatures, 350 to 400 m from entrance of Finca Lukarel, 1160 m; Volcancito, Boquete, 22 Feb 2012, Arsenio Araúz (AMNH-NY); 2 females under stones, Paso Ancho, Bugaba, 3 Aug, 1 Sep 2012, A. Pitty, N. Santamaría (LAV-MIUP); 1 ♀ Paso Ancho, Bugaba, inside bathroom, 5 Dec 2012, A. Miranda (LAV-MIUP); 1 ♀, Cuesta de Piedra, 6 Jul 2012, L. Espinosa (LAV-MIUP).

Etymology. The specific name refers to the type locality of the new species.

Diagnosis. Medium size scorpions, total length 54 to 65 mm, lightly colored (yellow) with infuscation on the pedipalp fingers, carapace, mesosoma , and ventral surfaces of the metasoma; metasoma V and telson brown. The new species is the only Central American Centruroides with eight oblique rows of granules on the dentate margin of the fixed finger of the pedipalp chela, and pectinal tooth counts of 17 to 21. Carapace and mesosoma densely granulated with spiniform granules; pedipalp and metasoma intercarinal surfaces smooth. Pedipalp chela with five distinct carinae: dorsomedian, dorsal secondary, ventroexternal, digital, dorsointernal. Dimorphic metasoma (elongate in ♂), telson slightly elongate and non-lobate with well-developed spinate subaculear tubercle.

Centruroides panamensis n. sp. can be distinguished from the sympatric species Centruroides bicolor by the following characters: smaller overall size (54 to 65 mm, C. bicolor is 100 to 160 mm), lower pectinal tooth counts (17 to 21, C. bicolor with 23–28), all yellow pedipalp chela manus and patella (pedipalp chela manus and distal patella are dark brown in C. bicolor ), discontinuous ventrointernal carina on the pedipalp patella, pedipalp chela internodorsal carina absent (present and granular in C. bicolor ), eight primary rows of granules on the pedipalp fingers in C. panamensis n. sp. ( C. bicolor with nine primary rows of granules). Centruroides panamensis n. sp. appears to be most closely related to the allopatric species C. limbatus but can be distinguished by the following characters: C. panamensis n. sp. has strong granulation on the carapace and mesosoma , weak granulation on the pedipalp carinae; lack of intercarinal granulation on the internal surface of the pedipalp manus, eight primary rows of granules on the pedipalp fingers, discontinuous ventrointernal carina on the pedipalp patella (continuous in C. limbatus ), telson smooth. Centruroides panamensis n. sp., C. granosus and C. koesteri Kraepelin, 1911 have eight primary rows of granules on the pedipalp finger and chela fingers sparsely hirsute. The pedipalp chela manus is lighter than fingers in C. panamensis n. sp. and in C. koesteri . Centruroides panamensis n. sp. differs from C. granosus and C. koesteri in having smaller size (54–65 mm), C. granosus (males 95–110 mm, females 82–95 mm, unpublished measurements of 86 specimens deposited LAV-MIUP), C. koesteri (65–75 mm). Centruroides panamensis n. sp. has lower pectinal tooth counts (17–21), C. granosus (males 25–29, females 24–29, unpublished counts LAV-MIUP), C. koesteri (21–26), and a central discal depression on the pectinal plate of both sexes (absent in C. koesteri and C. granosus ). Centruroides panamensis n. sp. additionally differs from C. granosus : the pedipalp chela manus not incrassate, about same width as patella, and the pectinal plate has a discal central depression; C. granosus has pedipalp chela manus about 1.3 times wider than patella.

Description. Based on male holotype (with differences in paratype female noted) and illustrated in figures 1–5.

Coloration: Chelicerae yellow with reticulated infuscation, fingers brown with non-reticulated infuscation. Carapace yellow with heavy brown infuscation, posterior margin brown. Pedipalps yellow with infuscation on the distal femur and patella, pedipalp fingers brown. Mesosomal tergites light brown and heavily infuscate, posterior margin brown. Mesosomal sternites tan with brown infuscation, distally increasing such that sternite VII is nearly entirely infuscate. Legs yellow with weak infuscation. Metasoma tan with dark brown ventral infuscation, gradually darkening increasing distally such that metasoma V is brownish-tan and nearly entirely infuscate, carinae brown. Telson brown with a reddish tint.

Carapace ( Figure 2 ): Carapace moderately and coarsely granular with granulation medially concentrated. Anterior and posterior margins procurved with median notch, weakly granular with small granules. Lateral margins slightly widened posteriorly. Lateral ocular tubercles with three macro-ocelli each. Two pairs of fine, acuminate median ocular macrosetae. Ocular tubercle with pair of costate-granular superciliary carinae, protruding above median ocelli. Lateral ocular carinae present, weakly granular. Posterior median carinae present and costategranular. Anteromedian sulcus moderately deep, ovate; posteromedian sulcus narrow and posteriorly deep; posterolateral sulci moderately deep and slightly curved; posteromarginal sulcus shallow and wide.

Sternum: Subtriangular, median sulcus Y-shaped, shallow anteriorly and deep posteriorly.

Genital operculum: Completely divided longitudinally with marginal macrosetae ( Figure 2 ). Genital papillae present (♂), absent (♀).

Pectines: Pectines elongate, small transverse basal lobe present, fulcra prominent, ( Figure 2 ). Pectinal plate rectangular with a small anteromedian notch and a central discal depression. Pectinal tooth counts, 19 (♂), 17–21 (♀).

Pedipalps: Orthobothriotaxic, Type A, α configuration (femoral trichobothria d 1 and d 4 situated closer to dorsoexternal carina than d 3) ( Figure 3 D). Femur with five carinae: externomedian carina continuous, costate with small and irregular serrate granules; dorsoexternal, dorsointernal, and ventrointernal carinae continuous with spiniform granules; internomedian carina discontinuous, comprised of isolated large spiniform granules. Intercarinal surfaces smooth.

Patella with seven carinae: dorsointernal, dorsomedian, dorsoexternal externomedian, ventroexternal carina continuous, costate-granular; ventrointernal and internomedian carina discontinuous, comprised of irregularly spaced spiniform granules proximally, becoming smaller distally; proximal tubercle weakly developed ( Figure 3 E). Intercarinal surfaces smooth.

Chela manus not incrassate ( Figure 3 F) about same width as the patella. Chela with five distinct carinae: dorsomedian, dorsal secondary, and ventroexternal carinae continuous smooth keel (costate-granular in ♀); digital carina nearly obsolete, consisting of a few small proximal granules; dorsointernal carina nearly obsolete, consisting of a wide, smooth keel (scattered spiniform granules in ♀); other carinae absent. Intercarinal surfaces smooth. Movable finger with small lobe (eminence) proximally; movable finger length 32–36% (♂) or 61–77% (♀) greater than length along ventroexternal carina ( Table 1 ); dentate margins of fixed fingers with eight oblique primary rows of denticles (basal rows fused in moveable finger). In addition to the eight main rows, the movable finger has a short apical row of three-four denticles. Each denticular row terminates in a large denticle at proximal and distal ends; internal and external supernumerary denticles present; fingers each with an enlarged terminal denticle.

Legs: Basitarsi with paired rows of fine, acuminate macrosetae on pro- and retrolateral surfaces. Telotarsi with dense brush of acuminate macrosetae; laterodistal lobes truncated; median dorsal lobes extending to moderately long, narrow, slightly curved ungues.

Mesosoma: Tergites I –VI pretergites smooth, post-tergites coarsely granular, each with a granular dorsomedian carina. Tergite VII with costate-granular dorsomedian, dorsosubmedian, and dorsolateral carinae; intercarinal spaces finely granular. Sternites III–VI smooth, acarinate, each with pair of narrow, slit-like respiratory spiracles; V with prominent pale surface posteromedially in adult ♂. Sternite VII with pair of ventrosubmedian and ventrolateral keeled carinae.

Metasoma: Segments I–V progressively increasing in length, with ♂ having a more elongate metasoma (metasoma V length/width 2.8–3.0) than ♀ (metasoma V length/width 2.2–2.3). Intercarinal surfaces smooth (minutely granular in ♀). Segments I–IV, paired dorsosubmedian, dorsolateral, ventrolateral, ventrosubmedian, and median lateral carinae continuous, serrate to costate-granular. Segment V, dorsosubmedian carinae absent; dorsolateral carinae obsolete, granular, reduced to anterior third of segment; ventrolateral carinae continuous, weakly granular; ventrosubmedian carinae obsolete, reduced to several anterior granules; ventromedian carina continuous, weakly granular ( Figure 4 ). Number of ventrolateral macrosetae on metasomal segments 2 to 4 is 2.

Telson: Slightly elongate, non-lobate, length: width ratio of 1.7–1.8, smooth (minutely granular in ♀), carinae absent (obsolete ventromedian carinae in ♀) ( Figure 4 ). Subaculear tubercle well-developed, spinate, the tip oriented towards the tip of the aculeus. Aculeus strongly curved ventrally.

Variation. Sexual Dimorphism: In addition to previously discussed characters, adult males are proportionally longer than adult females; metasomal segments sum to 61–62% of the total length of males, but to 51–58% of the total length of females. Adult males are slightly more slender than adult females: sternite VII width is 12–13% greater than its width in males and 41–51% greater in females ( Table 1 ).

Distribution. The new species is currently known only from the Cordillera Central of Chiriquí province, Panama, an uninterrupted mountainous chain above sea level until at least Miocene times ( Montes et al. 2012) ( Figure 5 ). The evolutionary origin of C. panamensis has been shaped by climatic and montane forest changes in the Cordillera de Talamanca of Costa Rica and Panama brought by the last ice age that began in late Pliocene, and by past Pleistocene eruptive episodes of Volcán Barú (see Sherrod et al. 2008). Centruroides panamensis has not shown signs of recent demographic expansion, a limitation that we interpret might have been caused by a more widespread and successful, highly polymorphic species, Centruroides limbatus (Pocock 1898) , that ranges from Nicaragua to Costa Rica ( Francke & Stockwell 1987, Armas & Trujillo 2010) and Panama (Bocas del Toro Archipelago, Montoya & Armas 2002). We have numerous new additional inland collections of C. limbatus from Bocas del Toro (LAV-MIUP) and our data from Chiriquí Province represents a new distribution record for a second species: Centruroides bicolor (Pocock, 1898) (collecting data listed apart, Appendix 1). We have found individuals of the dark morph of C. bicolor present in Volcancito and Boquete, Chiriquí Province, in close vicinity and sympatric with C. panamensis in Finca Lukarel, Volcancito. C. bicolor is the only species found in sporadic collections of scorpions carried out by Arsenio Araúz from the years 2008 until 2012 in the fields surroundings the town of Balita de Dolega, Dolega District, southeast from Volcán Barú ( Figure 5 ).

Ecology. The holotype male and 7 paratypes of the new species were found in the foothills of Volcán Barú, at 1650–1700 m, in an open, treeless habitat ( Figure 6 ), under rocks, and inside shallow earth ground fissures, near the border of dirt paths. Two paratype females carrying immatures (20 collected, 2–3 escaped; 22 younger immatures) were found under stones (one was close to the dirt road margin, the other, about 2 m away from the road), at 350 to 390 m from the entrance to Finca Lukarel, Boquete, at an elevation of 1160 m, on 22 February 2012. On the same date, one subadult female was found under a dried log, 400 m from the entrance to Finca Lukarel. This area has numerous coffee plantations and rows of Pinus caribaea trees are planted on one side of the dirt road. The ground was covered with dried grasses, pine needles, and under the stones diplopods, centipedes, roaches and crickets were found.

Separation of species in Centruroides based heavily on coloration patterns and morphometric characters, known to have high intraspecific variation, has led to a proliferation of names and misidentifications. Using a combination of molecular and morphological data, the genus Centruroides is currently being revised by coauthor LAE. Mexico and the southwestern USA have some Centruroides species with venoms highly toxic to humans, however none of the presently known species of Centruroides from Panama cause medically significant envenomations in humans ( Borges et al. 2012). This new species, with a distribution limited only to the uppermost limit of the highest mountain range in Panama, provides evidence for arachnid endemism in this unique region and has important implications for conservation.

Figures

FIGURE 1. Habitus of Centruroides panamensis new species: A—male paratype, dorsal aspect; B—male paratype, ventral aspect; C—female paratype, dorsal aspect; D—female paratype, ventral aspect. Scale bar represents 10 mm.

FIGURE 2. Centruroides panamensis new species: A—male paratype dorsal carapace; B—female paratype dorsal carapace; C—female paratype pectines; D—male paratype pectines. Scale bar represents 1 mm.

FIGURE 3. Centruroides panamensis new species, pedipalps. Female Paratype: A—dorsal aspect of femur; B—dorsal aspect of patella; C—dorsoexternal aspect of chela. Male Paratype: D—dorsal aspect of femur; E—dorsal aspect of patella; F—dorsoexternal aspect of chela. Scale bar represents 1 mm.

FIGURE 4. Centruroides panamensis new species, metasoma. From top to bottom: lateral aspect of paratype male, ventral aspect of paratype male, lateral aspect of paratype female. Scale bar represents 2 mm.

FIGURE 5. Panama, Chiriquí Province. Distribution of Centruroides panamensis new species. Grey circle (collected C. panamensis sp. n.): dirt road to town Aguacate on SW slopes of Volcán Barú. Black circle (collected both C. panamensis sp. n. and C. bicolor): Finca Lukarel, Volcancito (Finca Lukarel, is located between towns of Volcancito Arriba and Bajo Volcancito.

FIGURE 6. Habitat of C. panamensis new species: A—Collection site of male holotype and 7 paratypes; the southwest flank of Volcán Barú looms in the background. B—Dirt road between towns of Volcancito Arriba and Bajo Volcancito; Coffee plantation across the road with row of Pinus caribae trees. C—Under these dried logs one subadult female was collected. D—Bank road where one female carrying 20 immatures was collected (under rock).

Tables

TABLE 1. Measurements of Centruroides panamensis new species, in mm.

	♂ Holotype	♀ Paratype	♂ Paratype	♀ Paratype	♀ Paratype	♂ Paratype	♀ Paratype	♀ Paratype
Carapace length	5.3	5.8	5.3	6.1	5.2	5.5	6.2	6.8
Anterior width	2.8	3.2	2	2.5	2.3	2.1	2.3	2.7
Posterior width	5.3	5.8	4.98	6.2	5.4	5.2	6.0	6.7
Metasoma length	34.5	31.0	34.6	26.9	27.3	35.7	27.5	31.8
Segment I length (width)	5.2 (2.8)	3.9 (3.1)	5.1 (2.6)	4.2 (3.3)	4.3 (3.2)	5.3 (2.7)	4.4 (3.0)	5.2 (3.6)
Segment II length (width)	6.1 (2.5)	4.7 (3.1)	6.6 (2.5)	5.0 (3.1)	5.1 (3.0)	6.6 (2.5)	5.3 (2.9)	6.1 (3.5)
Segment III length (width)	6.8 (2.6)	5.5 (2.7)	7.5 (2.4)	5.4 (3.02)	5.5 (2.9)	7.7 (2.5)	5.4 (2.9)	6.4 (3.3)
Segment IV length (width)	7.3 (2.6)	5.6 (3.1)	7.6 (2.3)	5.7 (3.1)	6.0 (2.9)	7.8 (2.5)	5.8 (2.9)	6.6 (3.5)
Segment V length (width)	7.9 (2.6)	6.2 (3.1)	7.8 (2.7)	6.6 (3.0)	6.5 (2.8)	8.2 (3.0)	6.6 (2.9)	7.5 (3.4)
Telson vesicle length	3	3.1	3.8	3.8	3.3	4.5	3.8	4.6
Aculeus length	2.7	1.9	2.6	2.7	2.5	2.4	2.5	2.6
Vesicle width (depth)	2.3 (1.7)	2.4 (1.9)	2.4 (1.9)	2.3 (1.7)	2.1 (1.5)	2.5 (1.9)	2.1 (1.5)	2.5 (2.0)
Pedipalp length	21.2	23	21.3	21.1	19.4	22.4	21.5	24.2
Femur length (width)	5.4 (1.2)	4.7 (1.3)	5.4 (1.4)	5.2 (1.6)	4.9 (1.4)	5.7 (1.4)	5.3 (1.7)	6.0 (1.9)
Patella length (width)	6.2 (1.6)	6.1 (1.6)	6.2 (1.9)	6.1 (2.1)	5.7 (1.9)	6.2 (1.9)	6.1 (2.0)	6.8 (2.4)
Chela external carina length (width)	4.2 (2.3)	3.8 (2.3)	4.2 (2.4)	3.8 (2.4)	3.4 (2.0)	4.4 (2.5)	3.6 (2.3)	4.2 (2.3)
Movable finger length	6.1	6.2	5.6	6.0	5.5	6.0	6.5	7.2
Pectines (length along denticle margin)			3.9	3.4	3.8	4.4	4.5	4.4
Pectinal teeth L/R	17/17	18/18	17/17	17/17	19/19	19/19	20/20	20/19
Mesosoma I-VI length	12.1	12.9	12.2	15.6	11.4	12.4	11.8	13.2
Mesosoma VII length	4.2	4.0	4.2	4.1	4.1	4.0	4.3	5.2
Mesosoma VII anterior width	4.8	6.0	4.8	6.2	5.7	4.4	6.2	7.4
Total length	65.4	64.1	60.6	58.6	52.9	62.5	55.5	63.7
Discussion