Loxosceles mahan, 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 : 50-53

LOXOSCELES MAHAN SP. NOV. ( FIGS 2 , 3 )

Loxosceles sp. FV-LZ ( Planas & Ribera, 2014)

Holotype

1♂, CRBA-LX1428 (MorphoBank: M326598−M326603), Costa Papagayo , Playa Blanca – Barranco de los Pilos, Lanzarote, Spain, 28.86038 N, 13.77626 W, 69 m a.s.l., 06.iii.2010, Opatova V. & Planas E. leg, legit.

Paratypes

2♀, CRBA-LX1430 , -LX1431 (MorphoBank: M326604−M326608), same locality and data as holotype ; 1♂, SMF-29348, Costa Papagayo, xi.1972, Schmidt leg.

Other material examined

Lanzarote: 1♂, CRBA-LX1425 , Salinas de Janubio, 28.9429 N, 13.8189 W, 28 m a.s.l., 06.iii.2010, Opatova , V. & Planas, E. leg. ; 1♂, CRBA-LX1465 , Peña Negra, Tinajo, 29.0614 N, 13.6777 W, 237 m a.s.l., 09.iii.2010, Opatova , V. & Planas, E. leg. ; 2♀, CRBA-LX1440 , -LX1441, Lomo Guantesivi, Los Valles, Teomise , 29.0791 N, 13.5249 W, 317 m a.s.l., 07.iii.2010, Opatova , V. & Planas, E. leg. ; 3♀, CRBA-LX1448 , -LX1449, -LX1450, Mirador del Río, Yé, 29.2134 N, 13.4811 W, 417 m a.s.l., 07.iii.2010, Opatova , V. & Planas, E. leg. ; 1♀, CRBA- LX1456; Fuerteventura: 1♂, ULL-DZUL-34172, Montaña de Vallebrón , 28.58542N 13.95597W, 03.iv.2004, GIET leg .; 2♀, CRBA-LX1404 , -LX1405, Cueva de Tiscamanita, Tiscamanita, 28.3350 N, 13.9953 W, 178 m a.s.l., 03.iii.2010, Opatova , V. & Planas, E. leg. ; 3♀, CRBA-LX1412 , -LX1413, -LX1414, Malpais de Villaverde, Villaverde, 28.6506 N, 13.9152 W, 174 m a.s.l., 04.iii.2010, Opatova , V. & Planas, E. leg. ; La Graciosa: 2♂ CRBA-LX2300 , -LX2301, 24.ii.1995, C. Ribera leg. ; Lobos : 2♀, CRBA-LX1037 , -LX1037-2, Cresta de la Caldera , 30.iii.2004 ; 2♀, CRBA-LX1418 , -LX1419, Playa de la Concha, 28.7439 N, 13.8254 W, 13 m, a.s.l., 05.iii.2010, Opatova , V. & Planas, E. leg.

Etymology

The specific epithet is a noun in apposition that refers to the single volcanic edifice that includes the current islands of Lanzarote and Fuerteventura, and the surrounding islets of Lobos, La Graciosa, Montaña Clara, and Alegranza.

Diagnosis

Differs clearly from L. rufescens by conspicuous dark V-mark posteriorly on pars cephalica ( Fig. 2D ), proportion of the embolus, markedly shorter in L. rufescens ( Fig. 2 ; Gertsch, 1967: plates 3, 4), and shape of seminal receptacles ( Fig. 3 ). It is also easily distinguished from Loxosceles mrazig by male palp tibia, which is distinctly oval, slightly longer than wide in L. mrazig . Males of Loxosceles mahan sp. nov. can be distinguished from the remaining Canary Island endemic species by the long, gently curved embolus that is straight at the tip ( Fig. 2A–C ). Females differ from the remaining Canary Island endemic species by having seminal receptacles with a long medium part ending in a single lobe ( Fig. 3 ). Both sexes also can be distinguished by the leg formula (Table 1) and relatively shorter legs ( Fig. 13 ). Loxosceles mahan sp. nov. can be distinguished from the remaining Canary Island endemic species and from L. rufescens by five [465 (G/A); 466 (C); 468 ( T); 774 (A); 852 ( T)] COI diagnostic nucleotide changes based on the alignment deposited in TreeBASE (accession number 15746; Fig. S1 ).

Description

Male (holotype)

Specimen preparation and condition: specimen collect- ed alive and preserved in 96% ethanol. Left pedipalp removed and conserved in a vial with specimen. Coloration: carapace pale yellowish, clypeus and median groove slightly darkened. Conspicuous dark V-mark posteriorly on pars cephalica ( Fig. 2D ). 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 and thicker setae. Abdomen pale yellowish to greyish, densely coated by short setae. Cephalothorax: carapace slightly longer (2.89) than wide (2.52), truncated 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 (1.72 long, 0.8 wide). Larger 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, interspersed with shorter setae. Clypeus height 0.29. Eye sizes: ALE 0.18, ME 0.12, PLE 0.18. LE separated from ME by narrowest diameter of ME. Sternum longer (1.53) than wide (1.38). Abdomen: elongate oval (3.47 long, 2.24 wide) in dorsal view. Legs: leg formula 2 4 1 3; Leg 1 (17.37): femur 4.81/patella 1/tibia 5.32/metatarsus 5.1/tarsus 1.14; Leg 2 (20.36): 5.4/1.04/6.24/6.54/1.14; Leg 3 (15.3): 4.35/0.92/4/4.93/ 1.1; Leg 4 (17.46): 4.84/0.85/4.61/5.86/1.3. Male palp ( Fig. 2A–C, E ): femur cylindrical (1.32 long, 0.27 wide). Patella subglobular, roughly as long as wide (0.42). Tibia wider at the base (0.83 long, 0.52 wide), rounded more abruptly towards the patella than the tarsus, oval in dorsal view. Tarsus short, as large as bulb (0.43). Bulb globular, slightly compressed dorsally. Maximum bulb width four times wider than embolus base. Embolus long and steadily curved, approximately 1.8 times longer than bulb width. Long, curved setae facing apically, distributed sparsely in femur, tibia, and tarsus, denser on retrolateral side. Variation (Table 1): Leg 1 (N = 6): 13.88−18.46 (mean: 16.52); Leg 2 (N = 5): 16.07– 20.85 (mean: 18.80); Leg 3 (N = 6): 13.02–16.10 (mean:

.

Islands – 2.766) 3.576) –) – 2.881 2.783

–)) – 2.83 2.745 –)) – 3.355) 2.697 –) – 3.383

Canary CW 2.5 (2.135 2.428 2.704 (2.202 (2.504 2.61 (2.427 2.603 (2.791 2.810 (2.375 2.638 3.054 3.272 (3.314 (2.361 2.529 2.632 3.054 (

the))))))))

to

– 3.054 – 4.290 3.208

) – 3.143 3.350 – 3.118 – 3.622 – – 2.703 3.792 –

endemic (2.381 2.772 (– (2.343 (2.604 (3.224 2.578 (3.376 (2.507 ((2.887 species CL 2.767 3.162 2.73) 2.889 2.908 3.287 2.779 3.407 3.499 2.605 3.407

Loxosceles 18.22 (– 14.91

)

(12.17 24.03 –

)

* 22.34 (– 15.09 14.83 16.68 (–) 16.96 16.5 (–) – 22.09 * () 19.5) – (31.94 32 19.87 17.87 –) (– (15.71 24.82)

4

new Leg 16.84 15.75 17.68 15.76 18.96 16.73 20.81 19.69 31.97 18.87 19.69

six)

the

of

16.1)

–

20.64

)

–

)

–

20.38

)

15.38

–

) 14.86 – 20.45

)

–

)

29.31 – 18.66

)

– 21.54

measurements Leg 3 14.86) 13.02 (10.38

)

13.54 (16.46 () 13.51 13.06 (14.03) 17.46 (

)

14.7 14.54 –) 17.11 (18.82 17.75 29.24 29.17

)

(16.55 17.61

)

(17.75 13.78

)

* (

CW) – 21.77

– 25.19 28.68 – – 17.84 – 17.98 – 28.49 42.93 – 23.72 – 27.4 –

width carapace

(

2 Leg (*

16.07

19.34 16.18 (

12.27 17.01

21.14 (* *

15.45

16.36 (23.46

17.81

(17.93 26.03 () *

23.34

19.93 (

42.92

42.92 22.62 (

21.53

(

16.41

22.65). individuals

and

)

–

18.46 22.86)

–

) 24.09 16.3)

–

) 16.77

–

– 23.82) 20.61

–

– 24.58 N- 1

,

CL

)

(

13.88

(

10.69 – 14.71 (14.16 (16.08 20.18 (* * (19.51 (* 16.55 with

1

length

(

Leg 3 16.52 14.81 3 (18.3 3 15.32 3 20.63 3 16.43 3 22.04 3 18.41 3 3 34.78 20.06 3 3 21.22 calculated carapace

length

,

–

maximum) Leg Sex formula 1 N 24 = ♂ 6 6 N 1 = 24 ♀ N 4 21 = 7 ♂ = 1 24 4 ♀ N N 21 = 1 4 ♂ 2 N = 24 ♀ 1 = 21 N 4 4 ♂ = 1 24 1 N ♀ 4 21 = N ♂ 2 N = 21 2 4 ♂ 24 N = 5 1 ♀ formula mean

leg

,

minimum nov. nov.

.

nov. nov.

.

. nov

.

sp nov

.. leg the

formula means (sp mahan . tazarte . sp sp bentejui tibicena sp sp guayota

Leg

1

. are Loxosceles Loxosceles Loxosceles Loxosceles Loxosceles

hupalupa

Loxosceles

underlining in

. 1 Table Values Species The n− *

14.86); Leg 4 (N = 6): 14.91–18.22 (mean: 16.84); CL (N = 6): 2.38−3.05 (mean: 2.77); CW (N = 6): 2.14– 2.77 (mean: 2.5). General coloration ranges from paleyellow to darker yellow-orange, depending on the time since the last moult. The shape of the dark V-mark also presents some variation in intensity and extent.

Female (paratype, CRBA-LX1431 )

Specimen preparation and condition: specimen collect- ed alive and preserved in 96% ethanol. Genitalia removed and conserved in a vial with specimen. Legs 3 right and 1 and 4 left removed. Coloration: similar to male but slightly darker. Carapace yellow-orange, with pars cephalica slightly darkened. Palps and chelicerae reddish. Cephalothorax: carapace longer (2.97) than wide (2.43), truncated behind, widely rounded on sides, less narrowed in front than males. Carapace evenly convex, with median groove moderately deep, elongated, occupying roughly the posterior third. Pars cephalica elongated (1.87 long, 0.9 wide) and wider than in males. Clypeus height 0.36. Eye sizes: ALE 0.18, ME 0.13, PLE 0.18. LE separated from ME by 0.16. Sternum longer (1.54) than wide (1.16). Abdomen: elongate oval (4.06 long, 2.42 wide) in dorsal view. Legs: leg formula 2 4 1 3; Leg 1 (12.97): femur 3.76/patella 0.93/tibia 3.72/ metatarsus 3.56/tarsus 1; Leg 2 (14.06): 4.01/0.98/4.07/ 4.11/0.89; Leg 3 (12): 3.59/0.93/3.03/3.52/0.93; Leg 4 (13.94): 4/0.97/3.64/4.27/1.06. Female genitalia ( Fig. 3 ): atriobursal orifices situated in two large, rounded, and 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 long, cylindrical, and gently directed towards the centre. Apical part strongly curved, pointing dorsally. Seminal receptacles not touching each other, separated at their closest point by a distance of roughly the diameter of the apical part. Variation (Table 1): Leg 1 (N = 6): 10.69−22.86 (mean: 14.81); Leg 2 (N = 6): 12.27−25.19 (mean: 16.18); Leg 3 (N = 6): 10.38−20.64 (mean: 13.61); Leg 4 (N = 6): 12.17–24.03 (mean: 15.75); CL (N = 5): 2.87−4.29 (mean: 3.24); CW (N = 5): 2.43−3.58 (mean: 2.76). Similar range of general coloration variation as in males. Genital morphology presents little variability in females, with some differences in the direction of the apical curvature of sperm receptacles, pointing dorsally.

Distribution and natural history

Loxosceles mahan sp. nov. is endemic and exclusive to the easternmost Canary Islands of Lanzarote and Fuerteventura, and the islets of Lobos, La Graciosa, and Montaña Clara ( Fig. 1 ). Found in a variety of habitats, from humid localities, such as in Mirador del Río (Lanzarote), to xeric areas such as Península Jandía (Fuerteventura). Common under big stones, usually lying above a dense whitish-blue web.

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 2. ♂ Loxosceles mahan sp. nov. A, palp, prolateral view; B, palp, retrolateral view; C, bulb and embolus; D, cephalothorax, dorsal view; E, palp, dorsal view. Abbreviation: eb, embolus base. Scale bars: A, B, C, E = 0.5 mm; D = 1 mm.

Figure 3. ♀ Loxosceles mahan sp. nov. vulva: A, ventral view; B, dorsal view; C, anterior view; D, posterior view. Abbreviations: a, apical part of seminal receptacle; b, base of seminal receptacle; m, medium part of seminal receptacle. Scale bars = 0.2 mm.

Figure 13. Graphical representation of the leg length/carapace length ratio variation for Leg 1 to Leg 4 in Loxosceles. Females are coloured in green and males in red. Continuous line corresponds to the linear regression for each sex and leg, with the 95% confidence interval in grey. (Colour version of figure available online.)