Loxosceles amazonica Gertsch, 1967

Fukushima, Caroline Sayuri, Andrade, Rute Maria Goncalves de & Bertani, Rogerio, 2017, Two new Brazilian species of Loxosceles Heinecken & Lowe, 1832 with remarks on amazonica and rufescens groups (Araneae, Sicariidae), ZooKeys 667, pp. 67-94 : 68-76

Loxosceles amazonica Gertsch, 1967 Figs 1-6, 7-13, 14-17, 18-21, 22-25, 26-31, 32-35, 36-39, 40-47, 48-51, 78-79

Loxosceles amazonica Gertsch, 1967: 143, pl. 4, figs 7−10, pl. 5, figs 6−7 (female holotype examined (AMNH), Brazil, state of Mato Grosso, Santa Isabel, Araguaia river, Mato Grosso side, 15-25 July 1957, B. Malkin col., receptacles not in the vial); Lucas, Cardoso and Moraes 1986: 130, figs 3−4; Duncan et al. 2010: 241, fig. 3; World Spider Catalog 2016.

Material examined

(Table 3). BRAZIL: Piauí, Serra Branca, Parque Nacional Serra da Capivara, São Raimundo Nonato [9°00'S, 42°41'W], 1 male, 1 female and 11 immatures, R. M. Gonçalves Andrade col. (MNRJ 6927); Rio Grande do Norte: Serra Negra do Norte, ESEC Seridó (6°34'S, 37°15'W), 2 females and 5 males, C. S. Fukushima, K. C. T. Riciluca and N. M. Gonçalves col., 14 March 2014, ref. Ser 8, 12, 2, 7, 9, 10, 33, respectively (MNRJ 6928); 1 female, under tree bark, during the night, C. S. Fukushima col., 14 March 2014, ref. C28 (MNRJ 6929); 1 female, C. S. Fukushima col., 14 March 2014, inside tree trunk, during the day, ref. C44 (MNRJ 6930); 1 male, C. S. Fukushima col., 14 March 2014, ref. C41 (MNRJ 7303); Açu, FLONA de Açu (5°34'S, 36°56'W), 1 female, under old house debris, during the night, L. Monteiro col., 30 October 2014, ref. L72 (MNRJ 6931); 1 female, under tree bark, during the day, C. S. Fukushima col., 30 October 2014, ref. C599 (MNRJ 6932); 1 female, near Carnaúba trees, during the day, K. C. T. Riciluca col., 26 March 2014, ref. K137 (MNRJ 6933); 1 female, in a vacated old house during the night, C. S. Fukushima col., 23 March 2014, ref. C163 (MNRJ 6934); 1 male, under roof tiles, C. S. Fukushima col., 23 March 2014, ref. C167g (MNRJ 6935); 1 male, under roof tiles, C. S. Fukushima col., 23 March 2014, ref. C167o (MNRJ 6936); 1 male, under roof tiles, C. S. Fukushima col., 30 October 2014, ref. C631 (MNRJ 6937); 1 male, in fallen Carnaúba tree, during the night, N. M. Gonçalves col., 25 March 2014, ref. N186 (MNRJ 6938); 1 male, under roof tiles, during the night, C. S. Fukushima col., 23 March 2014, ref. XXXI (MNRJ 6939); 1 female, K. C. T. Riciluca col., March 2014, ref. K133 (MNRJ 7305); Martins (6°04'S, 37°54'W), 1 female, Mirante-Casa de Pedra cave track, during the night, C. S. Fukushima col., 20 March 2014, ref. C144 (MNRJ 6940); 1 female, near Casa de Pedra cave, during the day, N. M. Gonçalves col., 19 March 2014, ref. N 81 (MNRJ 6941); 1 female, Mirante-Casa de Pedra cave track, during the day, N. M. Gonçalves col., 20 March 2014, ref. N91 (MNRJ 6942); 1 female, under fallen tree, near grange of Sr. Clesinho, during the day, A. P. L. Giupponi col., 23 October 2014, ref. A132 (MNRJ 6943), 1 female, near Casa de Pedra cave, under rock, during the night, C. S. Fukushima col., 23 October 2014, ref. C495 (MNRJ 6944); 1 male, in a ravine near Casa de Pedra cave, during the night, K. C. T. Riciluca col., 19 March 2014, ref. K59 (MNRJ 6945); 1 male, near Casa de Pedra cave, during the day, C. S. Fukushima col., 19 March 2014, ref. C103 (MNRJ 6946); 1 male, in a ravine, C. S. Fukushima col., 19 March 2014, ref. C116 (MNRJ 6947); 1 female, near Casa de Pedra cave, C. S. Fukushima col., 23 October 2014, ref. C497; 1 male, Mirante-Casa de Pedra cave track, C. S. Fukushima col., 20 March 2014, ref. C148 (MNRJ 7306); Macaíba, Escola Agrícola de Jundiaí (5°53'S, 35°21'W), 1 male (MNRJ 6948) and 1 female (MNRJ 6949), in a tree trunk during the night, C. S. Fukushima and W. Pes soa col., 13 September 2013 (ref. AV046, AV047, respectively); Ceará, Santa Quitéria (4°19'S, 40°09'W), 1 male and 1 immature male, D. R. Pedroso col., 3-12 February 2014 (MNRJ 6950); 1 male, 1 female and 9 immatures, Gruta W13, SAD’ 69, Camp 1, F. Pellegatti & D. R. Pedroso col., 3-13 February 2014 (MNRJ 6952).

Diagnosis.

Males of L. amazonica resemble those of Loxosceles rufescens , Loxosceles bentejui Planas & Ribera, 2015, Loxosceles foutadjalloni Millot, 1941, Loxosceles guayota Planas & Ribera, 2015, Loxosceles hupalupa Planas & Ribera, 2015, Loxosceles lacta Wang, 1994, Loxosceles mahan Planas & Ribera, 2015, Loxosceles tazarte Planas & Ribera, 2015, Loxosceles tibicena Planas & Ribera, 2015, Loxosceles willianilsoni sp. n., and Loxosceles muriciensis sp. n. by incrassated palpal tibia, longer than cymbium (Figs 1-2). They differ from those of L. hupalupa , L. mahan and L. tazarte by having shorter embolus (Figs 1-2), and entire pars cephalica as well as carapace border dark brown (Fig. 14), best seen in live specimens. From those of L. rufescens , L. bentejui , L. foutadjalloni , L. guayota , L. lacta , L. tibicena , L. willianilsoni sp. n. and L. muriciensis sp. n., they can be distinguished by having embolus with a mild retrolateral curvature along its length (Fig. 11). Females of L. amazonica resemble those of L. rufescens , L. bentejui , L. foutadjalloni , L. hupalupa , L. lacta , L. mahan , L. tazarte , L. tibicena , L. willianilsoni sp. n. and L. muriciensis sp. n. by having spermathecae with large seminal receptacles and dark sclerotized lateral bands (Fig. 26). Females of L. amazonica can be distinguished from all these species by a cluster of globular lobes on apex of seminal receptacles (Figs 26-31). Additionally, L. amazonica males and females can be distinguished from L. mahan , L. tazarte , L. bentejui , L. guayota , L. tibicena and L. hupalupa by lacking a conspicuous dark V-mark posteriorly on pars cephalica.

Natural history.

Despite its specific epithet, L. amazonica specimens were found in areas covered by caatinga (Figs 36-47), a semi-arid vegetation found in northeastern Brazil (Fig. 78). At FLONA de Açu, specimens were found under rocks and tree bark, and also under or inside fallen trees, especially carnaúbas ( Copernicia prunifera Miller) (Figs 36-39). They were also found at vacant old houses inside an area of conservation unit, and under house debris near the FLONA’s base.

The ESEC Seridó is located on a sui generis region of the state of Rio Grande do Norte characterized by a hyper-xerophilous, arboreal-shrubby caatinga, with irregular precipitation of 500 to 800 mm/year ( Varella-Freire 2002). Specimens of L. amazonica were found throughout different landscapes of the ESEC (Figs 40-43). They were found under rocks and tree bark in shaded areas (Fig. 44), inside termite nests (Fig. 47) or cracks of rocky outcrops (Fig. 45), under fallen trees (Fig. 46) or under house debris near ESEC’s base.

Specimens of L. amazonica were also found in Martins, state of Rio Grande do Norte, "a brejo de altitude" region, i.e. an area covered by humid forest surrounded by arid caatinga ( Pereira Filho and Montingelli 2011), usually over mountains and hillsides with an elevation of more than 500 m ( Ruiz-Esparza 2009) and that receives more than 1,200 mm of orographic rains (Prado 2003, in Ruiz-Esparza 2009). We found specimens of L. amazonica in ravines near the town (Fig. 48), in a trail on the top on the hill (Fig. 49) and under old house debris close to more humid and higher areas (about 700 m a.s.l.) (Fig. 50), as well as under rocks and tree bark near Casa de Pedra cave, in a lower region with caatinga vegetation (about 300 m a.s.l.) (Fig. 51). No specimens were found inside Casa de Pedra cave.

Spermatheca variation

(see Fig. 79). Specimens vary in number and size of globular lobes on spermatheca apex and seminal receptacles proportions. Specimens from Martins and Macaíba in the State of Rio Grande do Norte (Figs 26 and 31, respectively), São Raimundo Nonato, state of Piauí (Fig. 27) and Santa Quitéria, state of Ceará (Fig. 30) have three to six lobes in each spermatheca, more or less similar in size. The seminal receptacles of specimens of these areas are slightly short and trapezoid. On the other hand, specimens of ESEC Seridó and FLONA de Açu, both in the state of Rio Grande do Norte (Figs 28 and 29, respectively) have four to five lobes, usually one of them larger than the others. The seminal receptacles are slightly longer, with a triangular shape.

It is not clear how these genitalic traits vary along the distribution of L. amazonica or if these variations reflect a higher diversity in amazonica lineage. Variation in the morphology of palps and spermatheca of other Loxosceles species has already been noted, such as in L. rufescens ( Brignoli 1969). However, Duncan et al. (2010) recovered a monophyletic group of specimens that morphologically resemble L. rufescens , within which there are divergent clusters of specimens and populations, but with genetic distances high enough to be considered as cryptic species. In the same way, the slight morphological variations in L. amazonica could correspond to separated species, only detectable through a molecular approach, which was beyond the scope of this study.