Brasilomma enigmatica Brescovit, Ferreira & Rheims

Brescovit, Antonio Domingos, Ferreira, Rodrigo Lopes, Silva, Marconi Souza & Rheims, Cristina Anne, 2012, Brasilomma gen. nov., a new prodidomid genus from Brazil (Araneae, Prodidomidae), Zootaxa 3572, pp. 23-32 : 25-27

Brasilomma enigmatica Brescovit, Ferreira & Rheims sp. nov.

Figs 1–22

Type material: Holotype: 13 from Gruta Moeda Sul [19° 59' 09" S 43° 50' 49" W], Nova Lima, Minas Gerais, Brazil, 2005, R.L. Ferreira leg. ( IBSP 160617). Paratypes: 1Ƥ, with same data of holotype ( IBSP 160617); 13, Gruta das Bromélias [21º42’31”S / 43º54’02”W, alt. 1050 m], Parque Estadual de Ibitipoca, Lima Duarte, Minas Gerais, Brazil, 28.VII.2005, R.L. Ferreira leg. ( IBSP 160618).

Additional material examined. BRAZIL. Minas Gerais: Matozinhos, Gruta MOC131 [19°33' S; 44°04' W], 1 Ƥ, 04−15.IV.2011, F. Pelegatti-Franco leg. ( IBSP 161700, left legs and opisthosoma used for SEM).

Etymology. The specific name is a noun in apposition and refers to the uncommon distribution of the species, since there are only remote possibilities of contiguity between the subterranean known habitats of the different populations (see discussion).

Diagnosis. See generic diagnosis.

Description. Male (IBSP 160617, holotype): Prosoma, chelicerae and legs not pigmented; opisthosoma gray in males ( Fig. 2 ), not pigmented in females and juveniles ( Fig. 1 ). Total length 2.3. Prosoma length: 1.05 long, 0.80 wide. Chelicerae with 3 denticles on promargin and a single retromarginal denticle. Leg measurements: I: femur 1.0/ patella 0.55/ tibia 0.90/ metatarsus 0.65/ tarsus 0.55/ total 3.65; II: 1.0/ 0.45/ 0.80/ 0.65/ 0.55/ 3.45; III: 0.9/ 0.5/ 0.65/ 0.6/ 0.55/ 3.2; IV: 1.05/ 0.6/ 0.75/ 1.0/ 0.7/ 4.1. Leg spination: leg I: femur p1-0-0, d1-1-2, r0; tibia p0-1- 1, r1-1-0, v3-3 -2-2-2-3-2-0; metatarsus p1-0-0, v2-2 -2-2; leg II: femur d1-1-2, tibia p1-1-1, r1-1-0, v2-3 -2-2-2-2-2- 0; metatarsus p1-0-0, v2-2 -2-2; leg III: femur d1-1-1-1, p0-0-1, r0-0-1, tibia d1-1-0, p1-1-0, r1-1-0, v1 r-2-2; metatarsus p1-0-2, r1-0-2, v2 - 0-1m; leg IV: femur d1-1-3, tibia p1-1-0, r1-1-0, v1 p-2-2; metatarsus p0-1-2, r0-1-2, v1 p- 0- 1m. Palp as in generic description ( Figs 18–19 ).

Female (IBSP 160617, paratype): Coloration as in male. Total length 3.0. Prosoma length: 1.4 long, 1.1 wide. Prosoma and eyes as in male. Chelicerae with 7 denticles in promargin and 5 denticles in retromargin. Leg measurements: I: femur 1.5/ patella 0.6/ tibia 1.3/ metatarsus 1.05/ tarsus 0.80/ total 5.31; II: 1.4/ 0.7/ 1.1/ 1.05/ 0.80/ 5.05; III: 1.3/ 0.6/ 1.05/ 1.15/ 0.75/ 4.85; IV: 1.6/ 0.6/ 1.5/ 1.6/ 1.05/ 6.35. Leg spination: leg I: femur d1-1-0, p0-0-1; tibia v2-2 -2-2-2; metatarsus v2-2 -2-2-2-2-2-2-2; leg II: femur d1-1-0; tibia v2-2 -2-2-2; metatarsus v2-3 -2- 2-2-3-2-2; legs III–IV: femur d1-1-3; tibia d1-1-0, p1-1-0, r1-1-0, v2-2 -2; metatarsus p0-1-2, r0-1-2, v2 -0-2. Epigynum as in generic description ( Figs 20–22 ).

Variation. Live specimen with brownish yellow prosoma.

Distribution. Known from three caves in the state of Minas Gerais, Brazil (for details, see discussion).

Natural history. Specimens of Brasilomma enigmatica sp. nov. were collected in three different caves in the state of Minas Gerais. One adult male was collected in the Gruta das Bromélias ( Fig. 24 ), Parque Estadual de Ibitipoca, Conceição de Ibitipoca. This cave, with approximately 2,750 meters, is considered one of the largest quartzitic caves in the world. The single male ( Fig. 2 ) was observed walking on the top of a moist quartzite block in a completely dark area located approximately 200 meters from the nearest entrance. It was moving slowly, using its front legs to investigate the cave substrates. The Gruta das Bromélias has been prospected many times in other biospeleological surveys (data unpublished), but no other specimens were collected, which demonstrates its rarity. The male holotype and the female paratype were collected in ferruginous caves ( Fig. 23 ) in the municipality of Nova Lima, in the region known as the “quadrilátero ferrífero”. One of the main characteristics of these underground systems is the existence of a large number of sub-surface canaliculi that make up a network of interstitial spaces (micro and mesocaves) connected to the macrocaves ( Simmons 1963, Ferreira 2005, Piló & Auler 2005). A third adult female was recently collected in the Gruta MOC131, in Matozinhos, in a calcareous cave with vertical entrance approximately 30m below surface level, forming a precipice ending at an aphotic zone (unpublished data).

Figures

FIGURE 1. Brasilomma enigmatica sp. nov. Immature, latero-dorsal habitus, collected in Moeda Sul cave (iron ore cave). Photo: R. L. Ferreira.

FIGURE 2. Brasilomma enigmatica sp. nov. Male, dorsal habitus, colleted in Bromélias cave (quartzite cave). Photo: R. L. Ferreira.

FIGURES 3 – 8. Brasilomma enigmatica sp. nov., female: 3 Tarsus I, lateral view; 4 Trichobothria, dorsal view; 5 Tarsal organ, dorsal view; 6 – 7 Tarsus I, lateral view, showing specialized claw teeth (arrow); 8 Tarsus IV, lateral view, with same claw teeth (arrow). Scale lines: 0.25 mm.

FIGURES 9 – 12. Brasilomma enigmatica sp. nov., female: 9 – 10 Anterior lateral spinnerets, distal view (thick arrows pointing to piriform gland spigots and thin arrows to plumose setae); 11 – 12 Posterior lateral spinnerets, distal view. Scale lines: 0.25 mm.

FIGURES 13 – 17. Brasilomma enigmatica sp. nov., female: 13 – 15 Spinnerets, distal view; 16 – 17 tarsus, lateral view (16 tarsus I, 17 tarsus IV).

FIGURES 18 – 22. Brasilomma enigmatica sp. nov.: 18 – 19 male, left palp (18 ventral view, 19 retrolateral view); 20 – 22 female, epigynum (20 ventral view, 21 dorsal view, 22 posterior view). Scale lines: 0.25 mm.

FIGURES 23 – 24. 23. Moeda Sul cave (iron ore), Nova Lima, Minas Gerais, Brazil; 24 Bromélias cave (quartzite), Parque Estadual de Ibitipoca, Lima Duarte, Minas Gerais, Brazil. Photos: R. L. Ferreira.