Research Article |
Corresponding author: Rogério Bertani ( rbert@butantan.gov.br ) Academic editor: Miquel Arnedo
© 2018 Rogério Bertani, Diego M. von Schimonsky, Jonas E. Gallão, Maria E. Bichuette.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Bertani R, von Schimonsky DM, Gallão JE, Bichuette ME (2018) Four new troglophilic species of Loxosceles Heinecken & Lowe, 1832: contributions to the knowledge of recluse spiders from Brazilian caves (Araneae, Sicariidae). ZooKeys 806: 47-72. https://doi.org/10.3897/zookeys.806.27404
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Four new species of recluse spiders from Brazilian caves are described with both males and females. Loxosceles ericsoni Bertani, von Schimonsky & Gallão, sp. n. and L. karstica Bertani, von Schimonsky & Gallão, sp. n. both occur in caves in the Peruaçu region, located in the northern area of the state of Minas Gerais; L. karstica sp. n. is additionally found in the Serra do Ramalho karst area, located in the southwestern region of the state of Bahia. These two species belong to the gaucho group. Loxosceles carinhanha Bertani, von Schimonsky & Gallão, sp. n. and L. cardosoi Bertani, von Schimonsky & Gallão, sp. n. occur exclusively in caves of the Serra do Ramalho karst area and belong to the rufescens/amazonica species group. The discovery of two additional and highly distinct species in the rufescens/amazonica group (L. carinhanha sp. n. and L. cardosoi sp. n.) increases the debate on the origin, evolution, and geographical distribution of this widely distributed group of recluse spiders in the New and Old World. The presence of three species (L. ericsoni sp. n., L. carinhanha sp. n., and L. cardosoi sp. n.) with marked differences in morphological characters in a relatively small area indicates that the region seems to be an important center for Loxosceles diversity, which remains poorly studied.
Bahia, brown spider, karst area, Minas Gerais, taxonomy
The genus Loxosceles Heinecken & Lowe, 1832, known as brown or recluse spiders, comprises 134 species (
In South America,
Loxosceles are secretive spiders found under rocks, ground litter, and loose bark; in the holes of trees, tree trunks, and natural openings in cliffs and banks; and in caves (
The aim of this paper is to describe four new Loxosceles species with a discussion about distribution and diversity of this genus in Brazilian caves.
Studied regions are in the transition zone of the Cerrado and Caatinga morphoclimatic domains (
Peruaçu region, in the northern area of the state of Minas Gerais in southeastern Brazil
The Janelão, Bonita, and Boquete Caves (Figs
Serra do Ramalho karst area, state of Bahia, northeastern Brazil
The Serra do Ramalho karst area (Figs
Habitats. 2 Caatinga vegetation at Peruaçu Caves National Park, Januária, state of Minas Gerais, Brazil 3 Janelão Cave 4 Caatinga vegetation at Serra do Ramalho karst area, Carinhanha, state of Bahia, Brazil 5 Gruna da Altina Cave 6 Gruna Água Fina Cave. Photographs by PP Rizzato (2–4), A Gambarini (5, 6).
Abbreviations:
ALE anterior lateral eye,
PLE posterior lateral eye,
PME posterior median eye.
Most specimens were collected inside caves and fixed with ethanol 70%. Epigean collections were conducted in the cave surroundings. Specimens are deposited at LES – Laboratório de Estudos Subterrâneos, Universidade Federal de São Carlos, São Carlos (curator ME Bichuette); and at
Male holotype (
BRAZIL, Minas Gerais: Januária, epigean habitats near Janelão Cave (15°06'S, 44°14'W) 600 m a.s.l., 2 immatures, M.E. Bichuette, P.P. Rizzato and J.E. Gallão leg., 22.vii.2012 (
Males of Loxosceles ericsoni sp. n. resemble those of L. karstica sp. n. by the palpal tibia length being less than 2 and more than 1.4 times the palpal cymbium length. They can be distinguished from L. karstica sp. n. by the longer cymbium and slender embolus (Figs
Male holotype: Total length 6.85. Carapace 3.20 long, 3.04 wide. Eye sizes and interdistances: ALE 0.23, PME 0.21, PLE 0.22, PME-PLE 0.04, PME-ALE 0.25; clypeus 0.35. Leg formula II, I, IV, III. Leg lengths: leg I: femur 8.73, patella 1.23, tibia 10.71, metatarsus 10.68, tarsus 1.93, total 33.28; II (right leg, left missing): 11.87, 1.27, 15.01, 15.80, 1.70, 45.65; III: 8.46, 1.15, 8.65, 11.22, 1.59, 31.07; IV: 9.29, 1.23, 9.73, 12.42, 1.80, 34.47. Palp: femur 1.53 long, 0.27 wide; patella 0.45 long, 0.32 wide; tibia 0.87 long, 0.35 wide; cymbium 0.62 long, 0.33 wide. Labium 0.63 long, 0.56 wide. Sternum 1.58 long, 1.60 wide. Femur I 2.7 times as long, tibia I 3.3 times as long and leg I 10.4 as long as carapace. Palpal femur 5.6 times longer than wide, tibia 2.5 times longer than wide, cymbium longer than wide (Figs
Female paratype: Total length 9.37. Carapace 4.04 long, 3.55 wide. Eye sizes and interdistances: ALE 0.26, PME 0.21, PLE 0.24, PME-PLE 0.01, PME-ALE 0.56; clypeus 0.42. Leg formula II, I, IV, III. Leg lengths: leg I: femur 8.41, patella 1.42, tibia 10.05, metatarsus 9.41, tarsus 1.87, total 31.16; II: 9.70, 1.32, 11.66, 12.34, 1.92, 36.94; III: 7.98, 1.33, 7.58, 9.35, 1.51, 27.75; IV: 8.48, 1.34, 8.64, 10.98, 1.89, 31.33. Palp: femur 2.05 long, 0.35 wide; patella 0.58 long, 0.38 wide; tibia 1.27 long, 0.26 wide; tarsus 1.94 long, 0.20 wide. Labium 0.69 long, 0.66 wide. Sternum 2.18 long, 1.96 wide. Femur I 2.1 times as long, tibia I 2.5 times as long, and leg I 7.7 as long as carapace. Palpal femur 5.8 times longer than wide, tibia 4.9 longer than wide, tarsus not incrassate (Fig.
Loxosceles ericsoni sp. n., paratype female (
The specific name is in honor of Ericson Cernawsky Igual from Grupo Pierre Martin de Espeleologia (GPME) for his contribution to Brazilian speleology and his commitment to the conservation of caves.
Loxosceles ericsoni sp. n. females have highly modified spermathecae (Figs
Female holotype (
BRAZIL, Minas Gerais: Januária, Janelão Cave (15°06'S, 44°14'W) 600 m a.s.l., 2 immatures, M.E. Bichuette, P.P. Rizzato and J.E. Gallão leg., 22.vii.2012 (LES 14596), 1 immature, same collectors and date (LES 14713); Bahia: Carinhanha, Gruna do Cocho Cave (13°36'S, 43°46'W) 514 m a.s.l., 3 females, M.E. Bichuette, N. Hattori and J.E. Gallão leg., 02.vi.2012 (LES 14597).
Males of Loxosceles karstica sp. n. resemble those of L. ericsoni sp. n. by the palpal tibia length more than 1.4 and less than 2.0 times the cymbium length. They can be distinguished from those of L. ericsoni sp. n. by the shorter cymbium and stouter embolus (Figs
Loxosceles karstica sp. n., holotype female (
Female holotype: Total length 8.60. Carapace 3.58 long, 3.16 wide. Eye sizes and interdistances: ALE 0.24, PME 0.21, PLE 0.24, PME-PLE 0.05, PME-ALE 0.20; clypeus 0.32. Leg formula II, I, IV, III. Legs length: leg I: femur 7.49, patella 1.18, tibia 8.10, metatarsus 7.79, tarsus 1.79, total 26.35; II: 8.29, 1.25, 9.01, 9.05, 1.74, 29.34; III: 6.39, 1.28, 6.32, 7.17, 1.53, 22.69; IV: 7.41, 1.31, 7.43, 8.42, 1.58, 26.15. Palp: femur 1.44 long, 0.24 wide; patella 0.52 long, 0.34 wide; tibia 1.02 long, 0.29 wide; tarsus 1.41 long, 0.24 wide. Labium 0.80 long, 0.58 wide. Sternum 1.90 long, 1.74 wide. Femur I 2.1 times as long, tibia I 2.2 times as long, and leg I 7.3 as long as carapace. Palpal femur 6 times longer than wide; tibia 3.5 longer than wide; tarsus not incrassate (Fig.
Male paratype: Total length 6.56. Carapace 3.06 long, 2.76 wide. Eye sizes and interdistances: ALE 0.26, PME 0.21, PLE 0.20, PME-PLE 0.04, PME-ALE 0.17; clypeus 0.32. Leg formula II, I, IV, III (inferred from male
The male specimen in better condition to be chosen as paratype lacks legs I and III. For this reason, another male (
The new species L. karstica sp. n. has genitalic characteristics shared with other species of the gaucho group distributed in the southern regions of Brazil and Paraguay, as L. gaucho, L. similis, L. adelaida, and L. variegata, which have palpal tibia that are short and incrassate in males (Figs
The specific name refers to karst, a word used to define terrain with distinctive hydrology and landforms that arise from a combination of high rock solubility and well-developed porosity. Loxosceles karstica sp. n. occurs in two important karst areas of Brazil (Peruaçu and Serra do Ramalho).
Male holotype (
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 (
Males of Loxosceles carinhanha sp. n. can be distinguished from those of all other Loxosceles species by the thick embolus (Figs
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
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.
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.
Loxosceles carinhanha sp. n. and L. cardosoi sp. n. males have a uniformly reddish carapace (Figs
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 (
Loxosceles carinhanha sp. n., paratype female (
Male holotype (
BRAZIL, Bahia: Carinhanha, Gruna da Altina Cave (13°33'S, 43°45'W) 496 m a.s.l., 10 immatures, M.E. Bichuette, N. Hattori and J.E. Gallão leg., 01.vi.2012 (LES 14711).
Males of Loxosceles cardosoi sp. n. resemble those of L. carinhanha sp. n. by having a group of macrosetae on the median prolateral area of femur I (Fig.
Male holotype: Total length 7.54. Carapace 3.70 long, 3.54 wide. Eye sizes and interdistances: ALE 0.23, PME 0.20, PLE 0.19, PME-PLE 0.02, PME-ALE 0.23; clypeus 0.30. Leg formula II, IV, III, I. Leg lengths: leg I: femur 7.39, patella 1.38, tibia 8.25, metatarsus 9.26, tarsus 1.77, total 28.05; II: 10.12, 1.43, 12.41, 13.65, 2.06, 39.67; III: 8.05, 1.36, 8.04, 9.82, 1.52, 28.79; IV: 8.67, 1.38, 9.04, 11.74, 2.03, 32.86. Palp: femur 2.10 long, 0.47 wide; patella 0.57 long, 0.51 wide; tibia 1.27 long, 0.67 wide; cymbium 0.72 long, 0.52 wide. Labium 0.89 long, 0.52 wide. Sternum 1.85 long, 1.82 wide. Femur I 2.0 times as long, tibia I 2.2 times as long, and leg I 7.6 as long as carapace. Palpal femur 4.5 times longer than wide, tibia 1.9 times longer than wide, cymbium oval (Figs
Female paratype: Total length 9.15. Carapace 4.05 long, 3.49 wide. Eye sizes and interdistances: ALE 0.26, PME 0.24, PLE 0.22, PME-PLE 0.04, PME-ALE 0.36; clypeus 0.49. Leg formula II, IV, I, III. Leg lengths (left): leg I: femur 7.45, patella 1.42, tibia 8.24, metatarsus 8.30, tarsus 1.69, total 27.10; II: 8.87, 1.48, 9.87, 10.22, 1.80, 32.24; III: 7.30, 1.48, 7.00, 8.17, 1.48, 25.43; IV: 8.10, 1.48, 8.20, 9.91, 1.73, 29.42. Palp: femur 1.36 long, 0.31 wide; patella 0.36 long, 0.41 wide; tibia 1.18 long, 0.29 wide; tarsus 1.78 long, 0.22 wide. Labium 0.66 long, 0.64 wide. Sternum 2.13 long, 1.79 wide. Femur I 1.8 times as long, tibia I 2.0 times as long, and leg I 6.7 as long as carapace. Palpal femur 4.4 times longer than wide, tibia 4.0 longer than wide, tarsus not incrassate (Fig.
Loxosceles cardosoi sp. n., paratype female (
The specific name is in honor of Dr. João Luiz Costa Cardoso, a physician who worked for several years at the Hospital Vital Brazil, Instituto Butantan, São Paulo, Brazil, treating bites and stings of venomous animals and publishing several related articles.
See remarks under L. carinhanha sp. n.
Living specimens in their habitats. 55 Loxosceles ericsoni sp. n. female, Bonita Cave, Peruaçu Caves National Park, Januária, state of Minas Gerais, Brazil 56, 57 Loxosceles cardosoi, Gruna da Altina Cave, Serra do Ramalho karst area, Carinhanha, state of Bahia, Brazil. 56 Female 57 Male. Photographs by PP Rizzato (55), ME Bichuette (56, 57).
According to
Autapomorphic states, known as troglomorphisms in troglobitic species, evolving because the subterranean habitats (by natural selection, neutral mutation or even pleyotropy) are relevant clues to state if a species are obligatory and exclusive cave-dwelling, however, this method is only valid when used in a comparative method.
Loxosceles karstica sp. n., L. carinhanha sp. n. and L. cardosoi sp. n., only found inside caves, do not show any troglomorphisms, at least morphological, such as elongated appendices, reduction of visual organs, sclerotization degree or pigmentation, when compared with other Loxosceles species, as observed in L. troglobia, the only troglobitic representative of Loxosceles in Brazil (
The presence of three new species (L. ericsoni sp. n., L. carinhanha sp. n., and L. cardosoi sp. n.) with very distinct morphological characteristics in a relatively small area (Fig.
The karst areas of Peruaçu and Serra do Ramalho have different conservation statuses. Peruaçu’s caves are under legal protection as part of a National Park (Peruaçu Caves National Park-PCNP), and part of its cave fauna is included in the Brazilian RedList (at present, four species); by contrast, the Serra do Ramalho karst area has no legal protection, and the main strategy to protect its karst, caves, and cave fauna is to use the Brazilian RedList, since six of the 14 troglobites are included on this list (
We are grateful to Vandeir B. de Jesus (“Branco”) and Reinaldo dos Santos for help with field trips in the Peruaçu region and to the Peruaçu Caves National Park administrators for their support. We are grateful to the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) 2012/01093-0 and 2015/19976-3 for RB, 2010/08459-4 for MEB; to the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) research fellow 307704/2017-3 for RB, research fellow 303715/2011-1 and 308557/2014-0 for MEB, and PhD scholarship 142276/2013-8 for JEG; to Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for PhD scholarship for DMVS and master scholarship for JEG. We also thank the Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio) for collection permits (20165 and 28992), Ricardo Pinto-da-Rocha (