Loxosceles tibicena, Planas & Ribera, 2015

Planas, Enric & Ribera, Carles, 2015, Description of six new species of Loxosceles (Araneae: Sicariidae) endemic to the Canary Islands and the utility of DNA barcoding for their fast and accurate identification, Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 174 (1), pp. 47-73 : 59-61

LOXOSCELES TIBICENA SP. NOV. ( FIGS 8 , 9 )

Loxosceles sp. TF-2 ( Planas & Ribera, 2014)

Holotype

1♂, ULL-DZUL-34197 (MorphoBank: M326635− M326640), Cumbres Arico. Pista Izaña-Contador, Tenerife, 1975 m a.s.l., 05.ii.2007, GIET leg. Paratype

1♀, ULL-DZUL-34202 ( LX1164 ) (MorphoBank: M326641−M326645), same locality and data as holotype .

Other material examined

Tenerife: 3♂, ULL-DZUL-34199, -34200, -34201, Barranco del Río , Lomo Largo (Arico / Granadilla de Aboba), pitfall trap, 28.18736 N, 16.58227 W, 1700 m a.s.l., 23.iii.1985, Peraza, J.M. leg.

Etymology

The species epithet is a noun in apposition that refers to a mythological creature of the Guanches (aboriginal inhabitants of the Canary Islands) that was thought to live deep in the caves.

Diagnosis

Differs from L. rufescens and L. mrazig by the same morphological combination as L. mahan sp. nov. (see above). Males of L. tibicena sp. nov. can be distinguished from the remaining Canary Island species by the shape of the embolus, which is strongly curved after the embolus base ( Fig. 8C ), and females by the wide, straight, and directed towards the centre inner lobe of the apical part of the seminal receptacles ( Fig. 9 ). Differs from Loxosceles guayota sp. nov., also endemic to Tenerife, by the size, relatively shorter leg lengths, and longer embolus. Loxosceles tibicena sp. nov. also can be distinguished from the remaining Canary Island endemic species and from L. rufescens by 12 [6 ( T); 10 (A); 51 (G); 231 (C); 330 (A); 453 (G); 600 (C); 672 (G); 753 (A); 780 (A); 827 (G); 906 (A)] COI diagnostic nucleotide changes based on the alignment deposited in TreeBASE (accession number 15746; Fig. S1 ).

Description

Male (holotype)

Specimen preparation and condition: specimen preserved in 96% ethanol. Left pedipalp removed and conserved in a vial with specimen. Some legs removed or broken. Coloration: carapace pale yellowish, clypeus, pars cephalica and median groove slightly darkened. Conspicuous dark V-mark posteriorly on pars cephalica ( Fig. 8D ). Carapace with dispersed, short, black setae. Eye tubercles black. Chelicerae reddish brown, darkened in its distal part. Sternum bright yellowish, paler than carapace. Labium and gnathocoxae pale reddish brown. Legs pale yellowish with the apical segments slightly darkened. Sternum, labium, gnathocoxae, and legs covered by long setae interspersed with shorter, thicker setae. Abdomen pale yellowish to greyish, densely coated by short setae. Cephalothorax: carapace slightly longer (2.63) than wide (2.38), truncat- ed behind, widely rounded on sides, narrowed in front. Carapace evenly convex, with median groove moderately deep, elongated, occupying roughly the posterior third. Pars cephalica elongated (1.73 long, 0.79 wide). Large setae or bristles in a single row in the side margin of the carapace pointing anteriorly. Similar setae forming seven parallel rows in the pars cephalica and six radial rows beginning at posterior part of pars cephalica, interspersed with shorter setae. Clypeus height 0.21. Eye sizes: ALE 0.19, ME 0.13, PLE 0.12. LE separated from ME by narrowest diameter of ME. Sternum longer (1.56) than wide (1.33). Abdomen: elongate oval (3.13 long, 2.1 wide) in dorsal view. Legs: leg formula 2 1 4 3; Leg 1 (20.19): femur 5.59/patella 0.97/tibia 6.01/metatarsus 6.17/tarsus 1.45; Leg 2 (23.35): 6.3/1/6.92/7.57/1.56; Leg 3 (17.11): 5/0.86/4.58/5.51/ 1.16; Leg 4 (19.51): 5.33/1.03/5.11/6.48/1.56. Male palp ( Fig. 8A–C, E ): femur cylindrical (1.23 long, 0.29 wide). Patella subglobular, roughly as long as wide (0.38). Tibia elongated, flattened dorsally (0.8 long, 0.48 wide). Tarsus short, as large as bulb (0.43). Bulb globular, slightly compressed dorsally. Maximum bulb width slightly less than four times wider than embolus base. Embolus long approximately 1.6 times longer than bulb width. Strongly curved after embolus base, medial part slightly straight, gently curved, and slightly sinuous in its distal part. Long, curved setae facing apically, distributed sparsely on femur, tibia, and tarsus, denser on retrolateral side. Variation (Table 1): Leg 1 (N = 2): 22.1– 23.82 (mean: 22.96); Leg 2 (N = 2): 26.26–28.49 (mean: 27.38); Leg 3 (N = 2): 18.9–20.45 (mean: 19.67); Leg 4 (N = 2): 20.84–22.09 (mean: 21.47); CL (N = 3): 2.58– 3.12 (mean: 2.83); CW (N = 3): 2.72−2.75 (mean: 2.73).

Female (paratype, ULL-DZUL-34202)

Specimen preparation and condition: specimen preserved in 96% ethanol. Genitalia removed and conserved in a vial with specimen. Right Legs 3 and 4 removed for molecular study. Coloration: darker than in male, with chelicerae and pedipalps brownish-red. Cephalothorax: carapace slightly longer (3.35) than wide (3). Pars cephalica elongated (2.14 long, 1 wide). Clypeus height: 0.37. Eye sizes: ALE 0.23, ME 0.14, PLE 0.23. LE separated from ME by diameter of ME. Sternum longer (1.93) than wide (1.55). Labium 0.78 long, 0.64 wide at its base. Abdomen: elongate oval (4.16 long, 2.56 wide) in dorsal view. Legs: leg formula 2 4 1 3; Leg 1 (18.43): femur 5.34/patella 1.11/tibia 5.38/ metatarsus 5.34/tarsus 1.26; Leg 2 (19.92): 5.76/1.17/ 5.48/6.12/1.39; Leg 3 (16.59): 5.01/1.18/4.26/5.01/1.13; Leg 4 (18.6): 5.23/1.03/4.95/5.96/1.43. Female genitalia ( Fig. 9 ): atriobursal orifices situated in two large, rounded, almost contiguous pouches, slightly sclerotized around the edges. Base of seminal receptacles conical and wide, reinforced laterally with a curved, dark, sclerotized band. Medium part short, cylindrical, and strongly curved towards the centre. Subtle lobe protruding on its external side. Inner lobe wide, straight, directed towards the centre. Seminal receptacles not touching each other, separated at their closest point by roughly the apical diameter of the inner lobes. Variation (Table 1): female known only from the paratype specimen.

Distribution and natural history

Endemic to Tenerife. Known from two localities in central-east Tenerife. Extensive direct sampling effort was conducted near these localities without finding further specimens.

Figures

Figure 1. A, geographical position of the Canary Islands, indicated by the inset box. B, phylogenetic relationships amongst the Canary Islands endemic Loxosceles species; lineages with more than one individual are collapsed (see Planas and Ribera, 2014 for further information). C, sampling localities of the Canary Islands endemic Loxosceles; colours correspond to B.

Figure 8. ♂ Loxosceles tibicena sp. nov. A, palp, prolateral view; B, palp, retrolateral view; C, bulb and embolus; D, cephalothorax, dorsal view; E, palp, dorsal view. Scale bars: A, B, C, E = 0.5 mm; D = 1 mm.

Figure 9. ♀ Loxosceles tibicena sp. nov. vulva: A, ventral view; B, dorsal view; C, anterior view; D, posterior view. Scale bars = 0.2 mm.