Loxosceles carinhanha Bertani, von Schimonsky & Gallao

Bertani, Rogerio, Schimonsky, Diego M. von, Gallao, Jonas E. & Bichuette, Maria E., 2018, Four new troglophilic species of Loxosceles Heinecken & Lowe, 1832: contributions to the knowledge of recluse spiders from Brazilian caves (Araneae, Sicariidae), ZooKeys 806, pp. 47-72 : 47

Loxosceles carinhanha Bertani, von Schimonsky & Gallao sp. n. Figs 1, 28-33, 34-36, 37-41

Material examined.

Male holotype (MZUSP 74436) and female paratype (MZUSP 74437), 1 female paratype (MZUSP 74438), 1 female paratype (LES 14709), BRAZIL: Bahia, Carinhanha, Gruna Água Fina cave (13°41'S, 43°48'W) 484 m a.s.l., M.E. Bichuette, N. Hattori and J.E. Gallão leg., 29.v.2012.

Other material examined.

BRAZIL, Bahia: Carinhanha, Gruna Água Fina Cave (13°41'S, 43°48'W) 484 m a.s.l., 1 female and 2 immatures, M.E. Bichuette, N. Hattori and J.E. Gallão leg., 29.v.2012 (MZUSP 74439).

Diagnosis.

Males of Loxosceles carinhanha sp. n. can be distinguished from those of all other Loxosceles species by the thick embolus (Figs 29-31), a strong curvature on basal metatarsus I, and a constriction on distal tibia I (Figs 34, 35). Females of L. carinhanha sp. n. resemble females of L. cardosoi sp. n. by having spermathecae as a large, weakly sclerotized pouch with two large receptacles on its distal portion. Females of L. carinhanha sp. n. can be distinguished from those of L. cardosoi sp. n. by the spermathecae lacking a sclerotized transverse plate and dorsal parts of bursa copulatrix having only a small sclerotized triangular area (Figs 39-41).

Description.

Male holotype: Total length 7.32. Carapace 3.63 long, 3.39 wide. Eye sizes and interdistances: ALE 0.22, PME 0.22, PLE 0.21, PME-PLE 0.05, PME-ALE 0.27; clypeus 0.38. Leg formula II, IV, III, I. Leg lengths: leg I: femur 7.18, patella 1.44, tibia 6.68, metatarsus 9.29, tarsus 2.18, total 26.77; II femur 9.69, patella 1.51, tibia 10.87, metatarsus 13.34, tarsus 2.23, total 37.64; III: 7.56, 1.33, 7.88, 9.97, 1.70, 28.44; IV: 8.37, 1.41, 8.54, 11.92, 2.16, 32.40. Palp: femur 1.92 long, 0.34 wide; patella 0.54 long, 0.41 wide; tibia 1.12 long, 0.57 wide; cymbium 0.61 long, 0.45 wide. Labium 0.89 long, 0.49 wide. Sternum 1.87 long, 1.74 wide. Femur I 1.9 times as long, tibia I 1.8 times as long and leg I 7.4 as long as carapace. Palpal femur 5.6 times longer than wide; tibia 2.0 times longer than wide; cymbium oval (Figs 32, 33). Bulb suboval and slightly larger than cymbium. Embolus thick and straight, with a curvature on apex, approximately 1.3 times longer than bulb length in retrolateral view, without carina (Figs 29-31). Femur I prolateral median area with a series of enlarged setae (Figs 34, 36). Metatarsus I strongly curved on its basal portion. Distal tibia I abruptly narrow, with a series of strong macrosetae before the constriction (Figs 34, 35). Cephalic region of carapace, fovea, and thoracic striae with long, greyish setae (Fig. 28). Carapace and chelicerae uniformly reddish (Fig. 28). Abdomen, legs, and palp light brown, covered by short, greyish setae. Coxae and sternum light brown; labium and endites slightly darker.

Female paratype: Total length 9.30. Carapace 3.99 long, 3.25 wide. Eye sizes and interdistances: ALE 0.20, PME 0.20, PLE 0.22, PME-PLE 0.05, PME-ALE 0.34; clypeus 0.41. Leg formula II, I, IV, III. Leg lengths: leg I: femur 6.79, patella 1.30, tibia 7.12, metatarsus 7.47, tarsus 1.82, total 24.50; II: 7.97, 1.40, 8.69, 9.30, 1.98, 29.34; III: 6.69, 1.29, 6.42, 7.48, 1.69, 23.57; IV: 7.23, 1.35, 7.20, 9.21, 1.69, 26.68. Palp: femur 1.61 long, 0.28 wide; patella 0.54 long, 0.34 wide; tibia 1.07 long, 0.26 wide; tarsus 1.67 long, 0.23 wide. Labium 0.67 long, 0.54 wide. Sternum 1.98 long, 1.68 wide. Femur I 1.7 times as long, tibia I 1.8 times as long and leg I 6.1 as long as carapace. Palpal femur 5.7 times longer than wide, tibia 4.1 longer than wide, tarsus not incrassate (Fig. 38). Spermathecae are a large, weakly sclerotized pouch with two large receptacles on its distal portion. Dorsal parts of bursa copulatrix have a small, sclerotized triangular area (Figs 39-41). Carapace with some sparse, long, greyish setae (Fig. 37). Carapace light brown, cephalic area, fovea, and border darker (Fig. 37). Chelicerae reddish brown. Abdomen greyish, legs light brown, both covered by short greyish setae. Palp femur and patella light brown, tibia and tarsus reddish brown (Fig. 38). Coxae and sternum light brown, labium and endites brown.

Etymology.

The specific name refers to the type locality of the species, Carinhanha, a municipality in the southwestern section of the state of Bahia, Brazil. The region possesses several cave systems with high diversity and a fragile subterranean fauna.

Remarks.

Loxosceles carinhanha sp. n. and L. cardosoi sp. n. males have a uniformly reddish carapace (Figs 28, 42) instead of the brown marked carapace characteristic of the groups gaucho and rufescens / amazonica , and femur I has macrosetae on its prolateral median area (Figs 36, 48), which is exclusive of the two species. They occur in closer areas and are probably sister species. The inclusion of the two species in one of the groups defined by Gertsch (1967) for South American Loxosceles is not simple question. They could fit in either gaucho or rufescens / amazonica groups. Males of gaucho group have the cymbium and tibia subequal in length ( Gertsch 1967). However, two species described more recently has slightly longer and slender tibia ( L. chapadensis and L. niedeguidonae ). Even though the tibia is not incrassate in these species, the cymbium is larger than the bulb, projecting forward. Considering the variation of tibia length and width in this group, we consider the cymbium size a better character to diagnose males of gaucho group. Males of the rufescens / amazonica group have the cymbium considerably shorter than tibia. More important, however, is they are never much more larger than the bulb. Based in this criterion, both L. carinhanha sp. n. and L. cardosoi sp. n. can be included in the rufescens / amazonica group (Figs 32, 33, and 46, 47). Concerning females, those of the gaucho group are readily recognizable by "the seminal receptacles attached to immovable, sclerotized, transverse plate" ( Gertsch 1967). We noted that in species of gaucho group the receptacles are always slender and strongly sclerotized, except the apex and can be another diagnostic character. Those of the rufescens / amazonica group have the "seminal receptacles with a cluster of small, globular lobes at apex" ( Gertsch 1967). More recently, at least two species were known to have a single large lobe at apex, L. mahan Planas & Ribera, 2015 from Canary Islands and L. willianilsoni , from Brazil ( Fukushima et al. 2017). We consider that the main characters shared by females of rufescens / amazonica group is the spermathecae triangular shape, two free receptacles (not attached to a transverse sclerotized plate) with large basal transverse openings with or without sclerotized edges and two dark sclerotized lateral bands with distinct levels of sclerotization depending on the species (see Planas and Ribera 2015 and Fukushima et al. 2017 for spermathecae variation). Loxosceles cardosoi sp. n. females have a transverse sclerotized plate (compatible with those species of gaucho group) and the receptacles are short (contrary to rufescens / amazonica group) and broad (as in the rufescens / amazonica group). A single dark sclerotized band is present (another characteristic of rufescens / amazonica group). The bursa copulatrix is strongly sclerotized. The putative sister species, L. carinhanha sp. n. has spermathecae weakly sclerotized lacking a transverse sclerotized plate and the receptacles are free. The bursa copulatrix is weakly sclerotized, except for a central triangular area. In favor of the inclusion of L. cardosoi sp. n. and L. carinhanha sp. n. in rufescens / amazonica group are the short cymbium in males and the broad and no sclerotized receptacles in females. Additionaly, L. carinhanha sp. n. spermathecae have a single dark sclerotized band. There is no supporting character for the inclusion of males in the gaucho group. In females, L. cardosoi sp. n. has the characters transverse sclerotized plate and short receptacles, which are lacking in L. carinhanha sp. n. Therefore, it seems more parsimonious to include the two species in the rufescens / amazonica group, elevating to five the number of species of this group in South America. These two species are very distinctive of the other species of the group both in the New and the Old World.

It has been proposed the origin of Loxosceles rufescens group in the Old World with a posterior introduction of L. amazonica during portuguese colonization of Brazil beginning in 1500 ( Duncan et al. 2010). One of the evidences for the introduction hypothesis was the lack of other related species in South America ( Duncan et al. 2010). Recently, Fukushima et al. (2017) described two species related with L. amazonica and L. rufescens from Brazil and argued contrary to this possibility for the short time (500 years) for speciation taking place. The discovery of two additional and very distinctive species reinforces the proposal of Fukushima et al. (2017). As the Loxosceles diversity in South America is still largely unknown, it is necessary more efforts to collect and describe species from more remote areas of Brazil, mainly those in the northeastern and central western regions, as the areas under study here, which seems to be a hot spot for Loxosceles diversity.