Eusarcus cavernicola, Hara & Pinto-Da-Rocha, 2010

Hara, Marcos Ryotaro & Pinto-Da-Rocha, Ricardo, 2010, Systematic review and cladistic analysis of the genus Eusarcus Perty 1833 (Arachnida, Opiliones, Gonyleptidae) 2698, Zootaxa 2698, pp. 1-136 : 45-51

Eusarcus cavernicola sp. n.

( Figs. 10, 11, 40E,F, 50B)

Type material: BRAZIL. Goiás: São Domingos (Parque Estadual Terra Ronca, Lapa do Passa Três ), C.A. Rheims leg., ma holotype & 1 fe paratype ( MZSP 19170 ). Paratypes : BRAZIL. Bahia: Santana (Gruta do Padre), P. Gnaspini et al. leg., 16.ix.2001, 1 ma ( MZSP 28652 ); idem, 1 fe ( MZSP 28651 ). Goiás: Anápolis (Fazenda Formiga, Gruta Jaboticaba), Gregeo leg., 30.iv.1989, 1 ma & 2 fe ( MHNC 6552 ); São Domingos ( Lapa do Bezerra ), L. Horta leg., 3.viii.1993, 2 fe ( MZSP 14024 ); idem (Gruta complexo São Mateus Imbuia, galeria Matilde III), F. Chaimowicz leg., vii.1985, 1 ma & 1 im ( HEMS 880 ); idem, 1 ma & 2 fe ( HEMS 883 ); idem (Gruta São Vicente), 1 ma ( HEMS 882 ); idem (Parque Estadual Terra Ronca, Lapa do Angélica ), C.A. Rheims leg., 6.ix.2000, 1 fe ( MZSP 19174 ); idem, 1 ma & 1 fe ( IBSP 1288 ); idem, F.P. Franco leg., 1 fe ( IBSP 1289 ); idem, C.A. Rheims leg., 7.ix.2000, 2 ma ( IBSP 1286 ); idem, 9.ix.2000, 1 ma & 1 fe ( MZSP 19172 ); idem, ( MZSP 19173 ); idem, 2 ma & fe ( IBSP 1298 ); idem, 1 ma & 3 fe ( IBSP 1299 ); idem (Parque Estadual Terra Ronca, Lapa do Passa Três ), E. Trajano leg., 27.vi.1988, 1 ma ( MHNC 6269 ); idem, ix.1999, 1 fe ( MZSP 28653 ); idem, F.P. Franco leg., 3.ix.2000, 1 fe (IB1295); idem, 4.ix.2000, 2 ma ( MZSP 19175 ); idem, 1 ma ( IBSP 1293 ); idem, 1 ma ( IBSP 1296 ); idem, 1 ma ( IBSP 1297 ); idem, 1 ma & 2 fe ( IBSP 1301 ); idem, C.A. Rheims leg., 2 ma ( MZSP 19171 ); idem, 1 ma & 1 fe ( MZSP 19176 ); idem, 3 ma & 1 fe ( IBSP 1300 ); idem, 4 ma ( IBSP 1302 ); idem, F.P. Franco leg., 5.ix.2000, 1 fe ( IBSP 1287 ); idem, 1 ma ( IBSP 1290 ); idem, F. Borges et al. leg., 1 fe ( IBSP 1294 ). Minas Gerais: Gruta Vaca Voadora, F. Chaimowicz leg., vii.1984, 1 fe ( HEMS 879 ); Itacarambi, A. Giupponi leg., 3.ix.2002, 1 ma & 1 fe ( MNRJ 11368 ); idem (Gruta Olhos D'Água), Amazonas & Silvia leg., 26.vi.2001, 2 ma & 3 fe ( MNRJ 11363 ); idem, P. Gnaspini et al. leg., 14.ix.2001, 1 fe ( MZSP 28654 ); Montes Claros (Gruta Curralinho), F. Chaimowicz leg., xii.1984, 1 ma ( HEMS 881 ); Unaí (Gruta Tamboril), Gregeo leg., without date, 1 ma & 1 fe ( MHNC 6553 ); idem, 21.v.1989, 1 ma & 2 fe ( MHNC 6739 ) .

Diagnosis: E. cavernicola resembles E. aduncus , E. berlae , E. elinae , E. fulvus , E. signatus , E. sooretamae , E. mirabilis and E. sergipanus because of the conical prolateral median apophysis on the male trochanter IV, and can be distinguished by: The presence of PAM; ocularium with similar-sized tubercles; median spine of scutal area III of medium size; basitarsus I elongated; posterior margin of prolateral apical apophysis of coxa IV without projections on retrolateral margin; femur IV longer than 1.5 times dorsal scutum length.

Etymology: The name is a noun in apposition and refers to the habitat of this species, caves.

Description: Male (holotype): Dorsum ( Fig. 10A,B): Measurements: SL 3.69; SMW 3.65; femur I 3.50; II 7.30; III 5.00; IV 6.85. Median paracheliceral projection larger than PAM. Ocularium far from anterior scutal margin; with 6 tubercles. Carapace with 71 scattered tubercles. Scutal area I with 30–33 scattered tubercles on each side; II with 73; III with 71 and a median spine of medium size, curved backwards, not surpassing posterior margin of dorsal scutum; IV with 46 tubercles. Posterior margin of dorsal scutum and free tergites I, III with rows of 11 and 26, 5 and 22, 10 and 14 tubercles, respectively; II with an irregular row of 21 tubercles. Anal operculum with 58 tubercles.

Venter: Coxa I with 26–32 tubercles, median and distal ones largest; II with 52, distal ones largest; III–IV irregularly tuberculate.

Chelicera: Segment I with 5–6 tubercles.

Pedipalpus: Trochanter dorsally inflated, with 5–7 tubercles. Femur dorsally with a prolateral row of 7–9 tubercles, a median row with 7–11, a retrolateral row with 5; ventrally with 1 large basal tubercle, 5–6 small aligned tubercles. Patella with scattered tubercles. Tibial setation: Prolateral IiiIi, retrolateral IiiIii. Tarsal setation: Prolateral IIi, retrolateral IiIi.

Legs ( Fig. 10C–G): Coxa IV densely tuberculate, surpassing dorsal scutum in dorsal view only apically, with 1 oblique prolateral apical apophysis, this conical, short, curved posteriad and slightly ventrad. Trochanters I–IV with scattered tubercles; I–II with 1 large ventro-basal tubercle; IV with 1 prolateral median apophysis, this conical, long, curved dorsad. Femora I–III with reduced PDS, RDS; III slightly sinuous; IV slightly sinuous, with medium PDS, small RDS. Metatarsus I with 2 ventro-apical setae. Basitarsus I elongated. Tarsal segmentation: 6, 10–11, 6, 6.

Penis (MZSP 19176; Fig. 40E,F): Stylus smooth, apex slightly swollen; with angular medio-ventral projection. Ventral process of glans curved, with apex blunt, thin. Ventral plate with slightly convex sides; with 3–4 pairs of distal setae curved apicad (basalmost pair far from the remaining distal ones); 2 pairs of short, straight, median setae; 4 pairs of slightly curved basal setae.

Coloration: Light orange-brown; dark brown on carapace, posterior margin of dorsal scutum, free tergites, and apophyses of coxa IV. Light brown on metatarsi and tarsi.

Female (paratype; MZSP 19170): Dorsum: Measurements: SL 3.96; SMW 3.80; femur I 3.40; II 7.20; III 5.10; IV 6.39. Median paracheliceral projection of similar-size as PAM. Scutal area III with median spine of medium size, curved backwards, not surpassing groove V. Legs: Coxa IV densely tuberculate, with 1 oblique prolateral apical apophysis, this conical, short, curved posteriad and slightly dorsad, smaller than in male. Trochanter III with scattered tubercles, with 1 large ventro-basal tubercle; IV with scattered tubercles, with 1 large high, blunt retrolateral apical tubercle. Femur III with small PDS, RDS; IV with medium PDS, small RDS. Tarsal segmentation: 6, 10–11, 6, 6. Coloration: Light brown; dark brown on edges of dorsal scutum, trochanters and coxae.

Variation in males (n=6): Measurements: SL 3.60–4.30; SMW 3.20–4.00; femur I 3.10–4.05; II 6.50– 8,50; III 3.90–6.00; IV 5.80–7.65. Pedipalpus: Tibial setation: Prolateral IiIi/IiiIi, retrolateral IiiIii/iiIi. Femur III with reduced or small PDS, RDS; IV with small or medium PDS. Tarsal segmentation: 6, 9–11, 6, 6.

Variation in females (n=6): Measurements: SL 3.60–4.50; SMW 2.90–3.80; femur I 2.80–3.85; II 6.20– 7.90; III 4.20–5.60; IV 6.00–7.20. Pedipalpus: Tibial setation: Prolateral IiiIi/IiIi, retrolateral IiiIii/IiiIi/IiIi. Femur II with reduced or small PDS; IV with small or medium PDS. Tarsal segmentation: 6, 8–11, 6, 6.

Taxonomical notes: This species is similar to E. aduncus , differing from the latter by the relatively longer legs IV, besides being collected only inside caves. To evaluate whether these two species can be distinguished morphometrically, we used three statistical analyses. The data used are given in table 4 and results in table 5.

Cluster analysis: Only a single specimen collected in a cave was grouped in group 1 (" E. aduncus "). This can be due to the specimen being a beta male and not showing the characteristic proportions of alpha males. Alternatively, we can imagine that this is an “anomalous” specimen whose proportions do not reflect the group to which it belongs. Performing the same statistical analysis without this specimen, the same groupings were obtained. We also used “box-plot” graphics ( Fig. 11) to describe the quartile, maximum and minimum values of the variables by grouping.

MANOVA and Student´s t test: MANOVA indicates that the means of all used measures are significantly different between the two species (Wilk´s Lambda=0.116, F 6, 54 =68.85, p<0.0001) and this is corroborated by the Student´s t test. Therefore, we concluded that E. aduncus and E. cavernicola sp. n. are two species (see table 5) which are recognizable and morphometrically different, i.e. E. cavernicola sp. n. has relatively longer legs.

Wilk´s Lambda=0.116, F6,54=68.85, p<0.0001; n E.aduncus =28; n E. cavernicola =33

Although E. cavernicola sp. n. exhibits hypertely of legs and pedipalps we cannot classify it as a troglobitic harvestman species because it inhabits karstic areas with independent geological histories ( Gnaspini & Hoenen 1999). In this case, it is possible that what we know as E. cavernicola sp. n. is actually an assembly of species that cannot be recognized by external and genitalic features. Therefore two hypotheses need to be tested in the future: (i) E. cavernicola sp. n. is really a single species or (ii) E. cavernicola sp. n. is an assembly of troglobite species that can only be recognized by other techniques (such as molecular analysis). Only after testing these hypotheses one will be able to decide if the hypertely of the legs and pedipalps is a preadaptation or the result of a cave adaptation process.

Type locality: Brazil, Goiás, São Domingos, Parque Estadual de Terra Ronca, Lapa do Passa Três .

Geographical distribution ( Fig. 50B): Caves in central Brazil. Bahia, Goiás , and Minas Gerais.