Mesabolivar huberi, Machado, Éwerton O., Brescovit, Antonio D. & Francisco, Rafael C., 2007

Machado, Éwerton O., Brescovit, Antonio D. & Francisco, Rafael C., 2007, Three new ground dweller Mesabolivar González-Sponga, 1998 (Araneae: Pholcidae) from Blumenau, Santa Catarina, Brazil, Zootaxa 1560, pp. 55-61 : 56

Mesabolivar huberi n. sp.

( Figs. 1–11 )

Types. Male holotype from Parque Natural Municipal Nascentes do Ribeirão Garcia (27o01’– 27o06’ S; 49o04’– 49o10’ W; 290–910 m), Blumenau, Santa Catarina, Brazil, 23.I.2005, R.C. Francisco col. with pitfall traps, deposited in IBSP 62441. Paratypes: 1 male and 2 females, same data as holotype, 18.IV.2004, (IBSP 62438–62440).

Etymology. The species is named in honour of the Austrian arachnologist Bernhard A. Huber from Alexander Koenig Zoological Research Museum (Bonn, Germany).

Diagnosis. The male can be distinguished from the congeners by the single pair of large and curved cheliceral apophyses ( Fig. 1 ) and the constriction on the basal segment of chelicerae ( Fig. 2 ), combined with the shape of the strong procursus ( Fig. 4 ) with a prominent membranous projection on the retrolateral side of the procursus tip ( Figs. 6–7 ). The female can be distinguished by the shape of the ventral pair of projections on the epigynal plate combined with the relatively large and shallow median pocket ( Figs. 9–10 ).

Description. Male (Holotype): Total length 1.9, carapace width 1.0; leg I: 19.8 (4.6 + 0.4 + 5.1 + 8.5 + 1.2), tibia II: 3.0, tibia III: 2.1, tibia IV: 3.7, tibia I L/d: 47. Carapace light brown; sternum light ochre. Distinct thoracic groove. Eight eyes on slightly elevated ocular area; distance PME–ALE about 70% of PME diameter. Chelicera light brown, basal segment with a median constriction in lateral view ( Fig. 2 ) and with one large frontal, very curved apophysis ( Figs. 1–3 ), approximately perpendicular to the chelicera ( Fig. 2 ). Palps as in figs. 4–8. Palpal coxa with narrow and approximately rectangular retrolateral apophysis, conical at tip ( Fig. 4 ). Palpal femur proximally with relatively small retrolateral apophysis ( Fig. 4 ). Procursus dark brown, strongly curved in the proximal region ( Fig. 4 ), with a strong proximal-prolateral hair ( Fig. 5 ). Procursus with distinct tip very sclerotised and enlarged laterally, with a distal and slightly retrolateral projection and a salient retrolateral semitransparent membranous projection ( Figs. 6–7 ). Bulb simple, embolar division slightly curved dorsally with no transparent projection ( Fig. 8 ). Legs light brown; without spines, vertical or curved hairs. Tarsus I with approximately 18 pseudosegments. Opisthosoma globular, pale green, with several lateral bluish-green spots.

Female. (Paratype IBSP 62439): Total length 2.5, carapace width 0.9; leg I: 11.8 (2.8 + 0.4 + 3.1 + 4.5 + 1.0), tibia II: 2.0, tibia III: 1.6, tibia IV: 2.7, tibia I L/d: 31. In general appearance very similar to male. Tarsus I with approximately 18 pseudosegments. Epigynum dark brown, elevated, with a medium-sized median shallow pocket, situated slightly anterior, and a pair of ventral lateral projections ( Figs. 9–10 ). Internal genitalia with two contiguous and almost square pore plates ( Fig. 11 ).

Variation. Three males: carapace width 0.9–1.0; tibia I: 4.3–5.1. Five females: carapace width 0.8–1.0.

Other material examined. Brazil: Santa Catarina: Blumenau, Parque Natural Municipal Nascentes do Ribeirão Garcia; 27o01’– 27o06’ S; 49o04’– 49o10’ W; R.C. Francisco col. with pitfall traps, 18.IV.2004, 1ɗ, 1Ψ ( IBSP 62444, 62447); 17.VII.2004, 1Ψ ( IBSP 62446); 20.X.2004, 1Ψ ( IBSP 62445).

Distribution. Known only from type locality.

Natural history. The specimens were all collected with pitfall traps, suggesting a ground level life style. The pitfall traps were installed in four sampling periods for one year (18.IV.2004; 17.VII.2004; 20.X.2004; 23.I.2005), and M. huberi n. sp. was collected in three of them (see material examined). Sampling dates suggest the presence of the species throughout the year, but too few specimens (eight) were collected to allow more assumptions.

Figures

FIGURES 1 – 11. Mesabolivar huberi n. sp. 1. Chelicerae, frontal; 2. Chelicera, lateral; 3. Chelicerae, dorsal; 4. Left palp, retrolateral; 5. Left procursus, prolateral; 6. Tip of left procursus, dorsal view; 7. Tip of left procursus, distal view; 8. Left bulb, prolateral view; 9. Epigynum, ventral view; 10. Epigynum, anterior view; 11. Epigynum, dorsal view. Scale lines: 0.5 mm, except figs. 6 – 7: 0.25 mm.