Mecicobothrium baccai, Lucas, Sylvia Marlene, Indicatti, Rafael Prezzi, Brescovit, Antonio Domingos & Francisco, Rafael Carlo, 2006

Lucas, Sylvia Marlene, Indicatti, Rafael Prezzi, Brescovit, Antonio Domingos & Francisco, Rafael Carlo, 2006, First record of the Mecicobothriidae Holmberg from Brazil, with a description of a new species of Mecicobothrium (Araneae, Mygalomorphae), Zootaxa 1326, pp. 45-53 : 46-52

Mecicobothrium baccai n. sp.

( Figs. 1–14 ; 20; 22–25; 27–28; 30–31; 33–34; 36–38)

Types. Male holotype from Parque Natural Municipal Nascentes do Ribeirão Garcia (27o01’S, 49o09’W), Blumenau, Santa Catarina, Brazil, 19.X.2004, R. C. Francisco leg., deposited in IBSP 12533; male paratype, same data as holotype (IBSP 12534).

Additional material examined. Only one other male with same data as holotype, partially used for illustrations in the scanning microscope (IBSP 12535).

Etymology. The specific name is a patronym in honor of Dr. Lauro Eduardo Bacca, who has actively worked in the conservation of the Parque Natural Municipal Nascentes do Ribeirão Garcia and other areas in northern Santa Catarina, Brazil.

Diagnosis. Males differ from those of M. thorelli (for comparison, see figs. 15–19; 21; 26; 29; 32; 35; 39; Gertsch & Platnick, 1979: figs. 35–36; 40–47; 49) by the less pronounced endites ( Figs. 25 ; 31), presence of slender spines on legs, retrolateral lobe of the cymbium less developed ( Figs. 3–4 ; 10–11), and longer and straight chelicerae ( Figs. 20 ; 28; 31).

Description. Male (Holotype). Cephalothorax and legs brownish yellow. Abdomen dorsally pale yellow with grayish transverse black stripes ( Fig. 20 ), ventral surface and spinnerets pale yellow (Figs. 37–38). Total length, including chelicerae: 5.12. Cephalothorax 1.92 long, 1.50 wide, with short, longitudinal fovea ( Fig. 20 ). Chelicerae 1.05 long, porrect, with large anterior knobs (Fig. 33) distally with irregular row of 16–18 stiff black setae and two long spurs ( Figs. 6–7 ). Basal segment of chelicerae with 11–12 promarginal irregular teeth in row and no teeth on retromargin ( Fig. 8 ). Rastellum absent. Intercheliceral tumescence absent. Clypeus 0.10 wide. Eight eyes on black tubercle. Anterior eye row straight, posterior row slightly recurved. Eye diameter: AME 0.12, ALE 0.23, PLE 0.10, PME 0.08. Overall shape of eye group trapezoidal, wider than long.

Labium 0.10 long, 0.32 wide, without cuspules ( Fig. 25 ). Endites without cuspules, serrula with more than 50 teeth ( Fig. 9 ). Sternum 1.12 long, 0.87 wide, with four pairs of marginal sigilla, anterior sigilla inconspicuous. Palp measurements: femur 1.12/ patella 0.72/ tibia 0.79/ cymbium 0.75/ total 3.38; spination: femur 0-0-9. Legs: measurements: I: femur 1.52/ patella 0.85/ tibia 1.06/ metatarsus 1.00/ tarsus 0.70/ total 5.13; II: 1.37/ 0.81/ 0.85/ 0.94/ 0.72/ 4.69; III: 1.30/ 0.69/ 0.76/ 1.05/ 0.82/ 4.62; IV: 1.50/ 0.81/ 1.05/ 1.40/ 0.99/ FIGURES 27–39. Mecicobothrium spp. 27, 28, 30, 31, 33, 34, 36–38. M. baccai n. sp. 27–28, 30–31, 33. Cheliceral apophysis. 27. Frontal view; 28. Dorsal view; 30. Teeth of chelicerae, ventral view; 31. Ventral view; 33. Retrolateral view; 34. Tarsus I, retrolateral view; 36. Tergal plates, dorsal-anterior view; 37. Posterior lateral spinnerets, dorsal view; 38. Abdomen and spinnerets, retrolateral view; 29, 32, 35, 39. M. thorelli . 29, 32. Cheliceral apophysis. 29. Dorsal view; 32. Ventral view; 35. Tarsus I, retrolateral view; 39. Abdomen, retrolateral view. Scale bars = 0,5 mm. Photos: R. P. Indicatti.

5.75; spination: I: femur d1-0-0, tibia v1 r-1r-2p, without clasping spines or spurs, metatarsus v1 r-0-1r; II: femur d1-1-0, patella d2, tibia d1-1-0, v1 r-1r-1p, metatarsus d0-1- 0, v1 r-1p-2; III: femur d1-1-0, patella d4, r1, tibia d0-1-0, v1 r-1r-2, p1-1-0, r0-1-0, metatarsus v1 p-2-2, p1-1-2, r1-0-1; IV: femur d1-1-0, patella d2, r1, tibia v1 p-1p-2, p1-1- 0, r1-1-1, metatarsus v1 p-1p-2, p1-1-2, r1-1-1. Scopulae slight on all tarsi. Tarsi I–IV pseudosegmented ( Figs. 12 , 34). Superior tarsal claws I-IV with one row of 5–7 teeth and distal short conical projection next to short onychium ( Fig. 13 ). Third claw on all tarsi ( Fig. 13 ). Tarsal organ slightly elevated, with concentric ridge pattern ( Fig. 14 ). Abdomen with two tergal plates well separated, anterior with five spiniform setae; dorsal with two ( Figs. 20 ; 36). Six spinnerets (Fig. 38), anterior median APS 0.37; anterior lateral twosegmented, BAS 0.22, APS 0.36; posterior lateral three-segmented, BAS 0.37, MAS 0.50, apical segment pseudosegmented, 0.84 long, (Fig. 37). Palp without stout tibia, cymbium with distinct prolateral lobe and retrolateral invagination elongated, bulb half length of cymbium, conductor shielding corkscrew-shaped embolus basally ( Figs. 1–5 ; 10–11; 22–24).

Female. Unknown.

Variation. Three males: total length 5.12–6.00, carapace 1.92–2.10, femur I 1.52–1.55.

Natural history. All specimens were collected in pitfall traps in a protected area of northern Santa Catarina (Vale do Itajaí, Blumenau). This area is a remnant of secondary Atlantic Forest, as described by Bacca (1988). The biology of this species is probably similar to those described by Costa & Pérez-Miles (1998) for Mecicobothrium thorelli , since these two species present the same cheliceral conformation and cryptic habits.

Distribution. Known only from the type locality.

Figures

FIGURES 1 – 5. Mecicobothrium baccai n. sp., left male palpal. 1. Prolateral view; 2. Ventral view; 3. Retrolateral view; 4. Cymbium, ventral view, with bulb omitted; 5. Bulb, dorsal view. Scale bars = 0, 5 mm.

FIGURES 6 – 11. M. baccai n. sp., male. 6 – 7. Cheliceral apophysis. 6. Dorsal view; 7. Dorsalfrontal view; 8. Teeth of chelicerae, promarginal view. 9. Serrula, dorsal view; 10. Cymbium and embolus, retrolateral-dorsal view; 11. Cymbium and bulb, right border, prolateral-dorsal view. Scale bars: Figs. 6 – 9, 11 = 100 μm; Fig. 10 = 10 μm.

FIGURES 12 – 15. Mecicobothrium spp., male. 12 – 14. M. baccai n. sp. 12. Tarsus I, prolateral view; 13. Tarsal claw I, prolateral view; 14. Tarsal organ, leg III, dorsal view. 15. M. thorelli. 15. Embolus, ventral view. Scale bars: Fig. 12 = 100 μm; Figs. 13, 15 = 10 μm, Fig. 14 = 1 μm.

FIGURES 20 – 26. Mecicobothrium spp., male. 20, 22 – 25. M. baccai n. sp. 20. Male body, dorsal view; 22 – 24. Male palp. 22. Prolateral view; 23. Retrolateral view; 24. Ventral view; 25. Endites and sternum, ventral view; 21, 26. M. thorelli. 21. Male body, dorsal view; 26. Endites and sternum, ventral view. Scale bars = 0, 5 mm. Photos: R. P. Indicatti.