Bayana labordai, Pérez-Miles & Costa & Oca, 2014

Pérez-Miles, Fernando, Costa, Fernando G. & Oca, Laura Montes de, 2014, Bayana labordai, new genus and species of Nemesiidae (Araneae: Mygalomorphae) from Northern Uruguay and Southern Brazil, Journal of Natural History (J. Nat. Hist.) 48 (31 - 32), pp. 1937-1946 : 1940-1944

Bayana labordai sp. nov

( Figures 1 – 7 )

Type specimens

Male Holotype from Cerro Miriñaque, Rivera, Uruguay (31°32'04 ″ S 55°37'56 ″ W), Oct. 22 2012. L. Montes de Oca, F.G. Costa, F. Pérez-Miles coll., (adult moult in the laboratory on Dec 25 2012) deposited in FCE-MY:1029. Paratypes: male (FCE- MY:1030), four females ( FCE-MY:1031-1034) from the same site, date and collectors; male ( MCTP: 14494) from Potreiro Velho (currently, Centro de Pesquisas e Conservação da Natureza Pró-Mata), São Francisco de Paula, Rio Grande do Sul, Brazil (29°28'21 ″ S 50°09'25 ″ W), Jul 19 – 22 1999, A.A. Lise coll.

Etymology

The specific name is a patronym in honour of Alvaro Laborda, a Uruguayan arachnologist who first collected the new species in Uruguay.

Male holotype ( Figure 3a ). Colouration (alive): Cephalotorax, legs and abdomen dark brown with longer reddish setae on the lateral faces of legs, edge of the carapace and on the abdomen. Dense body pubescence. Total length, excluding chelicerae and spinnerets 18.70. Cephalothorax 9.70 long, 8.40 wide. Fovea 1.30 wide, slightly procurved. Clypeus 0.26. Anterior eye row procurved, posterior straight to slightly recurve. AME 0.29, ALE 0.38, PME 0.10, PLE 0.41. Eye group subrectangular, 0.8 length, 1.3 wide. Chelicerae with 3 large – 2 small – 3 large teeth on the promargin and 8 small in a line on the retromargin. Rastellum formed by thin setae. Intercheliceral tumescence pale, round, covered by few thin reddish setae. Labium 0.60 long, 1.40 wide, with four cuspules. Palpal coxae with 40 and 34 cuspules disposed in a triangle in the angle between basal and prolateral edges. Serrula present. Sternum 4.10 long, 3.80 wide. Posterior sternal sigillae subtriangular, marginal; anterior and median sigillae present round and marginal ( Figure 3b ). Palp measurements: femur 4.4, patella 2.6, tibia 2.6, cymbium 1.4. Palp spination: femur 0, patella 0, tibia 2p, cymbium 0. Leg measurements: I femur 7.9, patella 5.0, tibia 5.5, metatarsus 5.6, tarsus 3.7; II 7.5, 4.2, 5.1, 5.5, 4.2; III 6.7, 4.1, 4.4, 6.4, 4.3; IV 8.8, 4.2, 6.6, 9.0, 4.8. Leg spination: I femur 1p, patella 0, tibia 5v2p, metatarsus 1p1v (with an elevated base), tarsus 0; II femur 0, patella 1p, tibia 5v2p3r, metatarsus 2v2p, tarsus 0; III femur 0, patella 1p, tibia 5v2p3r, metatarsus 2v2p, tarsus 0; IV femur 0, patella 0, tibia 2v1p3r, metatarsus 3v4p5r2d, tarsus 0. Tibia I thickened with subapical spine. Scopulae present on all tarsi; I – III entire, IV divided by a row of longer setae. Scopula present on 2/3 of metatarsi I – II, absent on III – IV. Tarsi I-IV flexible ( Figure 3c ). STC with a double row of 6 teeth on all tarsi, ITC absent on all tarsi. Four spinnerets, apical segment of PLS short and domed. Palp with incrassate tibia ( Figure 2a ), palpal bulb piriform, abruptly tapered to embolous; 12 small, short parallel keels on the basis of the embolous ( Figures 4a, b ). Palpal bulb which rests on a large and deep tibial excavation ( Figure 2a ).

Female paratype (FCE-MY: 1031) ( Figure 1 ). Colouration (alive): as in male but with reddish setae more extended on abdomen, dense body pubescence. Total length excluding chelicerae 30.5. Cephalothorax 11.3 long, 8.6 wide. Fovea 2.2 wide, straight. Clypeus narrow 0.4. Anterior eye row procurved, posterior slightly recurved. AME 0.31, ALE 0.41, PME 0.16, PLE 0.27. Eye group subrectangular, 0.79 long, 1.27 wide. Chelicerae with 7 large teeth on the promargin and 20 small on the retromargin, disposed in three lines. Rastellum formed by thin setae. Intercheliceral tumescence absent. Labium 1.1 long, 1.8 wide, with five cuspules. Palpal coxae with 40 and 47 cuspules disposed in a triangle in the angle between basal and prolateral edges. Serrula absent. Sternum 5.5 long, 5.3 wide. Posterior sternal sigillae subtriangular, marginal; anterior and median sigillae present round and marginal ( Figure 5a ). Palp measurements: femur 5.6, patella 3.2, tibia 3.2, tarsus 2.4. Palp spination: femur 0, patella 0, tibia 3v2p1r, tarsus 0. Palpal femur strongly curved ( Figure 5b ). Leg measurements: I femur 8.5, patella 5.5, tibia 5.3, metatarsus 4.8, tarsus 3.3; II 7.5, 5.1, 4.2, 4.4, 3.6; III 6.9, 4.0, 4.1, 4.7, 3.7; IV 7.7, 5.3, 6.5, 9.3, 4.4. Leg spination: I femur 0, patella 0, tibia 0, metatarsus 0, tarsus 0; II femur 0, patella 0, tibia 2v, metatarsus 2v1p, tarsus 0; III femur 0, patella 3p, tibia 3v, metatarsus 3v3p3r, tarsus 0; IV femur 0, patella 0, tibia 2v2r, metatarsus 1v2r2p, tarsus 0. Scopulae present on all tarsi, I – III entire, IV less dense and divided by a row of longer setae. Scopula complete on metatarsi I – II, III 1/5 apical, IV absent. Tarsi I-IV flexible. STC with a double row of 6 teeth; ITC absent on all tarsi. Four spinnerets, PLS with apical segment short and domed. Spermathecae formed by two subcylindrical receptacles, supraspermathecal chamber less developed ( Figure 6 ).

Variation. Carapace length, males: 8.12 – 9.70; females: 9.13 – 12.25 (X = 10.61 ± 1.45SD). Length of palp and legs, males: palp 9.14 – 11.00, I 24.26 – 27.70, II 21.72 – 26.50, III 20.51 – 25.9, IV 29.64 – 33.40; females palp 13.01 – 15.51(14.25 ± 1.05), I 23.13 – 27.77 (26.91 ± 1.67), II 21.75 – 25.14 (24.14 ± 1.60), III 19.51 – 24.01(22.48 – 2.02), IV 28.01 – 33.38 (32.08 ± 2.73). Labial cuspules, males 4 – 5; females: 3 – 11; cuspules on palpal coxae, males: 34 – 42, females: 30 – 53. Colouration dark to very dark brown with reddish longer setae on the lateral face of legs, edge of the carapace and on the abdomen.

Natural history

Females and juveniles inhabit tubular basket-like burrows with a portion dug in the soil (about 15 cm deep) and an aerial portion (10 cm) constructed with silk and surrounding vegetation, mainly the Gramineae Elyonurus muticus (Spreng.) ( Figure 7 ). The burrow has homogeneous diameter of 1.5 – 2.0 cm. Burrows were found on the southern slope and top of Miriñaque hill. Miriñaque is a flat hill of 282 m height, considered a relict as product of the erosive action on the basaltic shield. On the sandstone soil, a dense meadow matrix predominates with more than 80 species of grasses registered, most of them aestival. Also there are some patches of arborescent vegetation including Myrrhinum lorantoides (Hook. and Arn.), Blepharocalix angustifolius O.Berg in Mart., Daphnopsis racemosa Griseb., Shinus lentiscifolius March., Shinus engleri Barkley and Litraea brasiliensis (L.) March. The dwarf palm Butia paraguayensis (Barb.Rodr.) is a rare species present in this hill ( Evia and Gudynas 2000). Other mygalomorph spiders present in this site are the theraphosids Plesiopelma longisternale (Schiapelli and Gerschman, 1942) and Grammostola anthracina (C.L. Koch, 1842) .

The specimen from Brazil was collected by pit-fall trap in a different habitat: Mixed Ombrophilous Forest dominated by Araucaria angustifolia (Bertol.) Kuntze , with savannas at altitudes of about 900 m (see Indicatti et al. 2008b, p. 31); also occurring there are the theraphosid Magulla brescoviti Indicatti et al. 2008 , the nemesiids Stenoterommata arnolisei Indicatti et al. 2008 , S. curyi Indicatti et al. 2008 , S. grimpa Indicatti et al. 2008 , S. palmar Goloboff, 1995 , Acanthogonatus ericae Indicatti et al. 2008 and the microstigmatid Xenonemesia araucaria Indicatti et al. 2008 ( Indicatti et al. 2008a).

Sexual behaviour

Both males moulted to adults in the laboratory on the 25 December 2012 (holotype and paratype FCE-MY 1030 ) and the female on 14 – 16 December 2012 (paratype FCE-MY 1031 ). The male holotype copulated the female paratype FCE-MY 1031 in the laboratory. Male initiated courtship after contacting the female silk tube, performing body vibrations. After touching the female, male placed his forelegs between the retrolateral face of female chelicerae and palps. The distal end of the first tibia of male was retained between the bases of female chelicerae and palp. The second pair of male legs surrounds the female between the second and third pair of legs. Forelegs push and the second pair of legs pulls the female, raising her and adopting the typical mygalomorph mating position (Type I, Foelix 2011). Probably the curved palpal femur of the female facilitates the passage of the male first leg. Fifteen alternate palpal insertions were observed during copulation. Mating duration was 44 minutes and took place in the entrance of the tubular burrow. After copulation the male walked away; we did not observe any attacks .

Figures

Figure 1. Bayana labordai sp. nov., habitus of the female.

Figure 2. (A–D) Bayana labordai sp. nov., (A) male palp showing thin setae on cymbium, ventral view; (B) female patella IV, showing the absence of spines, prolateral view; (C) female ocular area; (D) male tibia I showing the absence of tibial apophysis or megaspines, ventral view.

Figure 3. (A–C) Bayana labordai sp. nov., (A) male body, dorsal view; (B) male sternum, labium and endites, ventral view; (C) male tarsus IV flexible (lateral view).

Figure 4. (A–B) Bayana labordai sp. nov., left male palpal bulb; (A) dorsal view; (B) ventral view (Scale 1 mm).

Figure 5. (A–B) Bayana labordai sp. nov., (A) female sternum, ventral view; (B) female palpal femur strongly curved, dorsal view.

Figure 6. Bayana labordai sp. nov., female spermathecae, dorsal view (Scale 1 mm).

Figure 7. Bayana labordai sp. nov., female at the burrow entrance.