Tutaibo sam Cajade, 2024

Cajade, Manuel, Rodrigues, Everton N. L., Hagopián, Damián, Laborda, Álvaro & Simó, Miguel, 2024, The spider genus Tutaibo (Araneae, Linyphiidae) in Uruguay: two new species and new records, Zootaxa 5537 (2), pp. 195-210 : 200-206

Tutaibo sam Cajade new species

Figs 3, 4, 7, 9A, C

Type material. Holotype. URUGUAY: Cerro Largo, Protected Landscape Paso Centurión and Sierra de Ríos ( National System of Protected Areas ), in hillside forest, 32°10’44.35”S, 53°51’35.99”W, 5.xi.2017, collected with G-VAC, D. Hagopián leg., 1M (FCE-Ar 15587) . Paratypes. URUGUAY: Same data, 1F, 1M (FCE-Ar 8564) ; same data, Á. Laborda leg., 2FF, 1M (FCE-Ar 8613) .

Etymology. The species epithet is a noun in apposition from the Charrua language “sam ” that means “two”, in reference to the bifid tip of the distal tegular sclerite, according to the nomenclature of Silva in Pebet et al. (1969).

Diagnosis. Males of Tutaibo sam sp. nov. can be distinguished from other Tutaibo species by having the distal tegular sclerite with the tip bifid, in opposition to the other congeners which have an undivided tip ( Figs 3A, 7A). Females differ from other Tutaibo species except T. debilipes Chamberlin, 1916 ( Millidge 1991: fig. 670) and T. pullus Millidge, 1991 ( Millidge 1991: fig. 672) by having an approximately isodiametric anterior lobe, but differs from these ones by lacking a conical projection in the anterior process ( Figs 4A, 7C).

Description. Male holotype (FCE-Ar 15587). Total length: 1.80. Carapace length: 0.74, width: 0.59. Clypeus height: 0.19. Sternum length: 0.47, width: 0.42. Chelicerae length: 0.37. Abdomen length: 1.10, width: 0.64, height: 0.65. Leg formula: I/IV/II/III. Leg lengths (I/II/III/IV): femora: 0.78/0.69/0.55/0.78; patellae: 0.19/0.18/0.19/0.20; tibiae: 0.87/0.78/0.57/0.86; metatarsi: 0.80/0.72/0.57/0.78; tarsi: 0.61/0.55/0.43/0.51; total: 3.25/2.92/2.31/3.13. Palp (femur, patella, tibia, cymbium): 0.30/0.12/0.19/0.39. Metatarsal trichobothria I‒III present, IV absent. TmI: 0.29. Eye diameters and interdistances: AME: 0.04, ALE: 0.05, PME: 0.04 and PLE: 0.06; AME-ALE: 0.05, PME-PLE: 0.07, AME-AME: 0.04, PME-PME: 0.09. Ocular region raised, eyes with black margins. Setae present at ocular area, with three groups: two groups of three minor setae anterior to PMA and one group of two majors, stiff and not contiguous setae between to the PMA ( Figs 3C, E). Setae present in ocular area. Clypeus glabrous. Carapace brownish orange, grayish at ocular area and continuing in a longitudinal line up to the fovea, narrowed anteriorly, longer than wide ( Figs 3D, E). Chelicerae light brown; chelicerae paturon with scattered promarginal setae. Chelicerae promargin with five teeth (four grouped and one isolated) and retromargin with four tiny teeth. Endites yellowish brown, darker in serrula area, with setae. Labium dark brown. Sternum orange with dispersed setae. Palps brown. Legs long and slender, yellow. Abdomen elliptical, longer than wide, dorsally pale orange in the anterior part, becoming darker to the posterior part, laterally and ventrally ( Figs 3D, E). Spinnerets brown. Colulus present, ovoid, brown, with setae. Palpal patella with one retrolateral macroseta. Palpal tibia with one retrolateral and one dorsal trichobothrium, a claw-shaped retrolateral tibial apophysis and a truncated prolateral tibial apophysis ( Figs 3A, 7A). Paracymbium L(turned)-shaped, with broad base and long hooked apex, with four setae ( Figs 3A, 7A). Distal tegular sclerite with the tip bifid ( Figs 3A, 7A). Distal suprategular apophysis long and narrow, with rounded apex ( Figs 3B, 7B). Retrolateral tibial apophysis and anterior radical process pointed ( Figs 3A, B, 7B). Embolus coiled, long and distally narrow ( Figs 3A, B, 7A, B).

Female paratype (FCE-Ar 8564). Total length: 2.25. Carapace length: 0.79, width: 0.64. Clypeus height: 0.19. Sternum length: 0.48, width: 0.46. Chelicerae length: 0.39. Abdomen length: 1.52, width: 1.16, height: 1.23. Leg formula: I/IV/II/III. Leg lengths (I/II/III/IV): femora: 0.96/0.89/0.74/0.96; patellae: 0.23/0.23/0.22/0.22; tibiae: 0.78/0.73/0.53/0.78; metatarsi: 0.72/0.67/0.55/0.70; tarsi: 0.56/0.52/0.40/0.46; total: 3.25/3.04/2.44/3.12. Palp (femur, patella, tibia, tarsus): 0.24/0.11/0.19/0.29. Metatarsal trichobothria I‒III present, IV absent. TmI: 0.32. Eye diameters and interdistances: AME: 0.05, ALE: 0.06, PME: 0.05 and PLE: 0.06; AME-ALE: 0.05, PME-PLE: 0.06, AME-AME: 0.04, PME-PME: 0.08. Eyes with black margins. Setae present at ocular area. Clypeus glabrous. Carapace brown, narrowed anteriorly, longer than wide; ocular area dark brown, raised ( Figs 4C, D). Chelicerae dark pale brown. Chelicerae promargin with five teeth (four grouped and one isolated) and retromargin with five tiny teeth. Endites dark pale brown, lighter in serrula area, with setae. Labium dark pale brown. Sternum brown, with dispersed setae. Palps yellowish brown. Legs long and slender, yellow orange. Abdomen elliptic, longer than wide, dorsally and laterally pale beige ( Fig. 4C, D), ventrally pale brown. Spinnerets dark brown. Colulus present, ovoid, dark pale brown. Palpal patella with one dorsal macroseta; palpal tibia with one retrolateral and one dorsal trichobothrium, one dorsal and one prolateral macrosetae; palpal tarsus with three prolateral macrosetae. Epigynum with round spermathecae ( Fig. 4B). Copulatory ducts moderately sclerotized, arising ectally from the spermathecae and following a sinuous path to the anterior part of the anterior lobe of the dorsal plate ( Fig. 4B). Fertilization ducts originate in the posterior part of spermatheca and are directed inwards to the dorsal plate ( Fig. 4B). Anterior process of ventral plate slightly sclerotized ( Fig. 4A). Dorsal plate posterior lobe oblong, longer than the anterior lobe ( Figs 4A, 7C); dorsal plate anterior lobe approximately isodiametric ( Figs 4A, 7C).

Variation: Males (n=3). Total length 1.80‒1.88; carapace length 0.74-0.83, carapace width 0.59‒0.64; femur I 0.78‒0.94. Females (n=3). Total length 1.99‒2.25; carapace length 0.76‒0.85, carapace width 0.63‒0.66; femur I 0.92‒0.96.

Distribution: Known only for Uruguay (Cerro Largo Department) ( Fig. 9A).

Natural history: Tutaibo sam sp. nov. was found in hillside forests ( Fig. 9C). Both males and females were collected with G-Vac.