Mesabolivar chapeco, 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 : 91-95

Mesabolivar chapeco sp. n.

Figs 378–379 , 390–399 , 433

Mesabolivar iguazu: Huber 2014: 139 (only specimens from Puerto Libertad and Arroyo Uruguay km 30).

Diagnosis. Distinguished from similar congeners ( M. uruguayensis , M. iguazu , M. yucuma ) by long proximal processes on male chelicerae ( Figs 392–393 ; similar in M. iguazu , where distal apophyses are more prominent in lateral view); also by male procursus ( Figs 397–399 ; with distinctive distal sclerotized and membranous elements), and by shape of epigynum ( Figs 394–395 , 433 ; anterior plate straight in lateral view, with pair of low processes and pocket on dark sclerotized process at posterior margin).

Etymology. The specific name is derived from the type locality; noun in apposition.

Type material. BRAZIL: Santa Catarina: ♂ holotype, 1♀ paratype, UFMG (21520–21), 4♂ 7♀ paratypes, ZFMK (Ar 19175), Chapecó National Forest (27.103°S, 52.779°W), 620 m a.s.l., 27.x.2014 (B.A. Huber, L.S. Carvalho).

Other material examined. BRAZIL: Santa Catarina: 3♀ in pure ethanol, ZFMK (Br14-193), same data as types.

Assigned tentatively. ARGENTINA: Misiones: 2♂ 2♀, MACN (Ar 4019), “ Pto. 17 de Octubre ” [ Puerto Libertad , 25°55’S, 54°36’W, 220 m], x.1953 (Schiapelli, De Carlo) ; 1♂, MACN (Ar 4312), same data but xi.1954 . 5♂, MACN (Ar 2889, 2984, 3262), same data, “km 30”, xi.1949 – ii.1950 (J.A. Cranwell, Partridge ). 1♂, MACN (Ar 19962), Arroyo Uruguay, km 30 [25°52’S, 54°34’W, 200 m], date unreadable, leg. Partridge.

Description. Male (holotype)

MEASUREMENTS. Total body length 3.8, carapace width 1.6. Distance PME-PME 130 µm, diameter PME 140 µm, distance PME-ALE 120 µm, distance AME-AME 40 µm, diameter AME 50 µm. Sternum width/length: 1.05/ 0.75. Leg 1: 42.3 (10.8 + 0.7 + 10.4 + 18.1 + 2.3), tibia 2: 6.8, tibia 3: 5.3, tibia 4: 6.9; tibia 1 L/d: 69. Femora 1–4 width (at half length): 0.26, 0.30, 0.30, 0.25.

COLOR (in ethanol). Carapace pale ochre-yellow with large dark median mark including ocular area and brown lateral margins; clypeus not darker; sternum pale orange; legs brown, tips of femora and tibiae lighter, without dark rings; abdomen greenish gray, with darker internal marks dorsally and laterally, ventrally with orange to light brown area in front of gonopore and indistinct plate in front of spinnerets.

BODY. Habitus as in Fig. 378 ; ocular area raised; carapace with distinct median furrow; clypeus unmodified; sternum unmodified.

CHELICERAE. With pair of small apophyses distally close to median line and pair of distinctive long processes proximally ( Figs 392–393 ).

PALPS. As in Figs 390–391 ; coxa with distinctive retrolateral apophysis; trochanter barely modified; femur with retrolateral apophysis proximally, distally strongly widening; procursus weakly curved, with distinctive sclerotized and membranous elements distally ( Figs 397-399 ); genital bulb with long process partly sclerotized.

LEGS. Without spines and curved hairs, few vertical hairs; retrolateral trichobothrium on tibia 1 at 2%; prolateral trichobothrium present on tibia 1; tarsus 1 with ~25 pseudosegments, distally fairly distinct.

Male (variation). Tibia 1 in three other males from type locality: 9.9, 10.0, 10.1. Legs sometimes lighter, with subdistal darker rings. Males from Argentina (Puerto Libertad, Arroyo Uruguay) appear indistinguishable but are assigned tentatively because the females from Puerto Libertad appear slightly different (see below); tibia 1 in two males from Puerto Libertad: 9.6, 10.5.

Female. In general similar to male ( Fig. 379 ). Tibia 1 in eight females from type locality: 7.1–7.7 (mean 7.6). Epigynum as in Figs 394–395 , 433 ; anterior plate with pair of low processes and pocket on sclerotized process at posterior margin; posterior plate barely visible, reduced to pair of light brown marks. Internal genitalia as in Fig. 396 , with pair of pore-plates in lateral position, converging anteriorly. Females from Puerto Libertad with slightly smaller epigynal humps; tibia 1: 6.0 (missing in second female).

Natural history. The spiders were abundant in sheltered spaces, usually close to the ground.

Distribution. Known from type locality in Santa Catarina state ( Brazil) and from Misiones ( Argentina) (Argentinean specimens assigned tentatively) ( Fig. 737 ).

Figures

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.

FIGURES 390–396. Mesabolivar chapeco sp. n. (ZFMK Ar 19175). 390–391. Left male palp, prolateral and retrolateral views.392–393.Male chelicerae, frontal and lateral views.394–395.Epigynum, ventral and lateral views.396.Cleared female genitalia, dorsal view.Scale lines:0.5.

FIGURES 397–407. Mesabolivar chapeco sp. n. (397–399, ZFMK Ar 19175) and M. yucuma sp. n. (400–407, ZFMK Ar 19176). 397–402. Left procursi, prolateral, dorsal, and retrolateral views (arrows point at transversal ridges). 403–404. Male chelicerae, frontal and lateral views.405–406. Epigynum, ventral and lateral views.407. Cleared female genitalia, dorsal view. Scale lines:0.2 (397–402; all procursi at same scale); 0.5 (403–407).

FIGURES 433–446. Female epigyna in ventral and lateral views and cleared female genitalia in dorsal views, Mesabolivar iguazu group. 433.M. chapeco sp. n. (ZFMK Ar 19175). 434–436. M.yucuma sp. n. (ZFMK Ar 19176). 437–438. M.iguazu Huber, 2000 (ZFMK Ar 19181). 439–440. M. charrua Machado et al., 2013 (ZFMK Ar 19184). 441–442. M. argentinensis (Mello-Leitão, 1938) (MACN Ar 20050). 443–445. M. catarinensis sp. n. (ZFMK Ar 19189). 446. M. bicuspis sp. n. (ZFMK Ar 19194).

FIGURES 736–737. Known distribution of the Mesabolivar iguazu group. TL, type locality. “?”: dubious northern records of M. uruguayensis in Machado et al. (2013) (cf. Huber 2015:60).