Mesabolivar borgesi, Huber, 2018

Huber, Bernhard A., 2018, The South American spider genera Mesabolivar and Carapoia (Araneae, Pholcidae): new species and a framework for redrawing generic limits, Zootaxa 4395 (1), pp. 1-178 : 123-125

Mesabolivar borgesi sp. n.

Figs 545–551

Mesabolivar “MACN 197”: Huber 2014: 139.

Diagnosis. Easily distinguished from known congeners by tip of procursus (strongly S-shaped; Fig. 546 ), by armature of male chelicerae (three pairs of frontal apophyses; Figs 547–548 ), and shape of epigynum (posterior margin trilobed, without pocket; Fig. 549 ).

Etymology. Named for Argentine writer Jose Luis Borges (1899–1986).

Type material. ARGENTINA: Buenos Aires: ♂ holotype, MACN ( Ar 38625) , 2♂ paratypes, MACN (Ar 20003), Vuelta de Obligado, Caverna La Salamanca [33°35.4’S, 59°49.2’W, 5 m], 29.vii.1972 (C. Cesar) .

Other material examined. ARGENTINA: Buenos Aires: 1♂, MACN (20065), Vuelta da Rocha [34°38.4’S, 58°21.8’W, 15 m] xii.1972 (Cesar). 1♀, MACN (19970), Ciudad Buenos Aires, Palermo [34°35’S, 58°26’W, 15 m], i.1931 (J.B. Daguerre). 2♀, MACN (12278), Reserva Natual Otamendi, Sección "Los Guardianes de la Barranca" (34°14.7’S, 58°53.7’W), 16 m, forest, 10.iii.2007 (C. Grismado et al.). 1 juv., MACN (12336), Reserva Natual Otamendi, “senderos varios”, 25.iii.2007 (C. Grismado).

Chaco: 1♂, MACN (72), Resistencia [27°27’S, 58°59’W, 50 m], without date, leg. J.B. Daguerre.

Description. Male (holotype)

MEASUREMENTS. Total body length 3.2, carapace width 1.3. Distance PME-PME 120 µm, diameter PME 110 µm, distance PME-ALE 80 µm, distance AME-AME 30 µm, diameter AME 40 µm. Sternum width/length: 0.9/ 0.55. Leg 1: 38.7 (10.1 + 0.5 + 9.7 + 16.3 + 2.1), tibia 2: 6.3, tibia 3: 4.6, tibia 4: 6.1; tibia 1 L/d: 81. Femora 1–4 width (at half length): 0.19, 0.20, 0.20, 0.18.

COLOR (in ethanol; specimen strongly bleached). Prosoma and legs pale ochre-orange, carapace with brown median band, ocular area light brown; clypeus not darkened; legs without dark rings; abdomen pale gray, with purple internal marks dorsally and laterally.

BODY. Habitus similar to members of the iguazu group (cf. Figs 378, 380 ); ocular area raised; carapace with distinct median furrow; clypeus and sternum unmodified.

CHELICERAE. With three pairs of frontal apophyses and rounded unsclerotized protrusion proximally near median line ( Figs 547–548 ).

PALPS. As in Figs 545–546 ; coxa with retrolateral apophysis; trochanter with small apophysis; femur with weakly sclerotized retrolateral process proximally, strongly widened distally; procursus strongly S-shaped, with distinctive tip; genital bulb process mostly unsclerotized.

LEGS. Without spines and curved hairs, few vertical hairs; retrolateral trichobothrium on tibia 1 at 3%; prolateral trichobothrium present on tibia 1; tarsus 1 with ~20 pseudosegments, barely visible in dissecting microscope.

Male (variation). Tibia 1 in four other males: 6.7, 8.7, 9.2, 9.6.

Female. In general similar to male. Tibia 1 in two females: 5.9, 6.4. Abdominal marks variably distinct, in one female absent. Epigynum as in Figs 549–550 ; posterior margin trilobed, without pocket, with series of anterior transversal sclerotized furrows; without posterior plate. Internal genitalia as in Fig. 551 , with pore-plates in vertical lateral position and distinctive median structure.

Distribution. Known from Buenos Aires and Chaco provinces ( Argentina) ( Fig. 740 ).

Figures

FIGURE 740. Known distributions of Mesabolivar species not assigned to any species group.Not shown: M. yuruani (Huber, 2000) (Venezuela).

FIGURES 545–551. Mesabolivar borgesi sp. n. (MACN Ar 20003). 545–546. Left male palp, prolateral and retrolateral views.547–548.Male chelicerae, frontal and lateral views.549–550.Epigynum, ventral and lateral views.551.Cleared female genitalia, dorsal view.Scale lines:0.5.

FIGURES378–389. Live specimens,Mesabolivar iguazugroup.378–379.M.chapeco sp. n., male and female from Chapecó. 380–381. M. yucuma sp. n., male and female from Turvo. 382–383. M. iguazu Huber, 2000, males from Iguaçú. 384–385. M. charruaMachado etal., 2013, male andfemale from Serra Geral. 386–387.M.catarinensis sp. n., male and female from Serra Geral.388–389. M. bicuspis sp. n., male and female from St. Hilaire/Lange.