Mesabolivar bicuspis, 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 : 102-105

Mesabolivar bicuspis sp. n.

Figs 388–389 , 427–432 , 446

Diagnosis. Easily distinguished from known congeners by male procursus ( Fig. 428 ; pair of unique distal processes); also by armature of male chelicerae ( Figs 429–430 ; two pairs of frontal processes; similar to M. yucuma ) and shape of epigynum ( Fig. 431 ; roundish, with posterior pocket separated from sclerotized part by whitish area).

Etymology. The specific name refers to the distinctive pair of blade-like processes of the procursus (Latin cuspis = blade, spear, sting); noun in apposition.

Type material. BRAZIL: Paraná: ♂ holotype, 1♀ paratype, UFMG (21526–27), 4♂ 8♀ paratypes, ZFMK (Ar 19194), Saint-Hilaire/Lange National Park, forest along river above Fazenda Niteroi (25.657°S, 48.601°W), ~ 100 m a.s.l., 11.x.2014 (B.A. Huber, L.S. Carvalho).

Other material examined. BRAZIL: Paraná: 1♀ in pure ethanol, ZFMK (Br 14-132), same data as types . 2♂ 1♀, ZFMK (Ar 19195), same data but night collecting ; 2♀ in pure ethanol, ZFMK (Br 14-138), same data . 3♀, ZFMK (Ar 19196), Saint-Hilaire/Lange National Park, forest above Hotel Mata Atlântica (25.670°S, 48.600°W), ~ 200–300 m a.s.l., night collecting, 12.x.2014 (B.A. Huber, L.S. Carvalho)

Description. Male (holotype)

MEASUREMENTS. Total body length 4.3, carapace width 2.0. Distance PME-PME 180 µm, diameter PME 180 µm, distance PME-ALE 130 µm, distance AME-AME 45 µm, diameter AME 60 µm. Sternum width/length: 1.30/ 0.85. Leg 1: 72.2 (18.0 + 0.9 + 17.5 + 32.7 + 3.1), tibia 2: 11.5, tibia 3: 8.7, tibia 4: 11.1; tibia 1 L/d: 95. Femora 1– 4 width (at half length): 0.28, 0.33, 0.33, 0.28.

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

BODY. Habitus as in Fig. 388 ; ocular area raised; carapace with deep median furrow; clypeus unmodified; sternum unmodified.

CHELICERAE. With two pairs of frontal apophyses: one pair weakly sclerotized proximally, one pair strongly sclerotized distally, close to median line ( Figs 429–430 ).

PALPS. As in Figs 427–428 ; coxa with large retrolateral apophysis; trochanter barely modified; femur with retrolateral apophysis proximally, distally strongly widening; tarsus with two dorsal conical processes; procursus proximally simple, with two distinctive distal processes; genital bulb with large process partly sclerotized. LEGS. Densely covered with short hairs, with spine-like short hairs dorsally on all tibiae and metatarsi; without curved hairs, few vertical hairs; retrolateral trichobothrium on tibia 1 at 1.5%; prolateral trichobothrium present on tibia 1; tarsus 1 with ~45 pseudosegments, distally fairly distinct.

Male (variation). Tibia 1 in five other males: 15.7–18.3 (mean 17.0).

Female. In general similar to male but without spine-like hairs on legs. Tibia 1 in 13 females: 11.6–14.5 (mean 12.9). Epigynum as in Fig. 431 ; simple and relatively small anterior plate weakly curved, without processes, with posterior pocket separted from anterior sclerotized area by whitish cuticle; posterior plate short and wide. Internal genitalia as in Figs 432 , 446 , with pair of pore-plates in lateral position, converging anteriorly.

Natural history. The spiders were found in large sheltered spaces among rocks and logs, and in hollow logs. At Saint-Hilaire/Lange National Park they shared the microhabitat with M. kaingang .

Distribution. Known from two neighboring sites in Saint-Hilaire/Lange National Park, Paraná state ( Brazil) only ( Fig. 737 ). The single male specimen from Santa Catarina, Porto Belo, Bombas [27.15°S, 48.52°W; ~ 170 km S of Saint-Hilaire/Lange National Park], described in Machado (2011) as “sp. 14” may belong to this species.

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 427–432. Mesabolivar bicuspis sp. n. (ZFMK Ar 19194). 427–428. Left male palp, prolateral and retrolateral views. 429–430. Male chelicerae, lateral and frontal views.431. Epigynum, ventral view.432.Cleared female genitalia, dorsal view.Scale lines:0.5 (427–430), 0.3 (431–432).

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).