Mesabolivar tapajos, 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 : 23-24

Mesabolivar tapajos sp. n.

Figs 11–12 , 58 , 61–62, 66–68 , 75–77

Diagnosis. Males are easily distinguished from most known congeners (except M. jamari ) by extremely long distal element on procursus ( Fig. 58 ); from M. jamari by other details of tarsus and procursus (compare Figs 57 and 58 ; larger tarsal process, smaller widened part of procursus, more distal position of dorsal process of procursus); from M. jamari and other putatively close relatives also by armature of male chelicerae ( Figs 61–62 ; cylindrical apophyses relatively slender), and by shape of epigynum ( Figs 66–67 , 75–76 ; relatively small median depression with indistinct pocket; pair of conical lateral processes slender, tips slightly curved backwards).

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

Type material. BRAZIL: Pará: ♂ holotype, 1♀ paratype, UFMG (21505–06), 4♂ 6♀ paratypes, ZFMK (Ar 18957–58), Floresta Nacional de Tapajós, km 83 (3.049°S, 54.928°W), 95 m a.s.l., 14–18.x.2016 (B.A. Huber, L.S. Carvalho).

Other material examined. BRAZIL: Pará: 1 juv., together with paratypes . 2♀ in pure ethanol, ZFMK (Br 16- 258), same data as types . 1♀, ZFMK (Ar 18959), Floresta Nacional de Tapajós , km 67, ‘site 2’ (2.875°S, 54.941°W), 190 m a.s.l., 15.x.2016 (B.A. Huber, L.S. Carvalho) ; 2♀ in pure ethanol, ZFMK (Br 16-269), same data . 1♂ 3♀, ZFMK (Ar 18960), Floresta Nacional de Tapajós , km 72, ‘site 2’ (2.940°S, 54.933°W), 140 m a.s.l., 17.x.2016 (B.A. Huber, L.S. Carvalho).

Assigned tentatively. BRAZIL: Pará: 1♀, ZFMK (Ar 18961), Floresta Nacional de Tapajós , km 221 (4.046°S, 54.938°W), 80 m a.s.l., 16.x.2016 (B.A. Huber, L.S. Carvalho).

Description. Male (holotype)

MEASUREMENTS. Total body length 2.3, carapace width 1.1. Distance PME-PME 100 µm, diameter PME 110 µm, distance PME-ALE 100 µm, distance AME-AME 30 µm, diameter AME 40 µm. Sternum width/length: 0.75/ 0.55. Leg 1: 36.7 (8.6 + 0.5 + 8.8 + 16.9 + 1.9), tibia 2: 5.6, tibia 3: 3.9, tibia 4: 6.0; tibia 1 L/d: 93. Femora 1–4 width (at half length): 0.14, 0.14, 0.15, 0.14.

COLOR (in ethanol). Carapace ochre-yellow, with slightly darker lateral margins and large light brown median mark including posterior part of ocular area; clypeus not darkened; sternum medially slightly darker (orange to light brown); legs ochre, with darker rings on femora (subdistally) and tibiae (proximally and subdistally; indistinct), tips of femora and tibiae whitish; abdomen greenish-gray, with dark internal marks dorsally and laterally, small ventral mark behind gonopore.

BODY. Habitus as in Fig. 11 ; ocular area raised (higher than usual in the genus); carapace with distinct median furrow; sternum unmodified; clypeus swollen, whitish, with sclerotized rim.

CHELICERAE. With pair of long tapering apophyses with slender, slightly curved tips ( Figs 61–62 ).

PALPS. In general very similar to M. jamari (cf. Figs 55–56 ), but slightly smaller (femur length: 0.64 vs. 0.72; femur maximum width: 0.26 vs. 0.32); only tarsus and procursus clearly different ( Fig. 58 ): larger tarsal process, smaller widened part of procursus, more distal position of dorsal process of procursus.

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, indistinct.

Male (variation). Tibia 1 in three other males: 8.9, 9.2, 9.7.

Female. In general similar to male ( Fig. 12 ) but dark mark on carapace larger, clypeus unmodified, dark rings on legs more distinct, sternum in most females with distinct light brown median mark. Tibia 1 in nine females: 4.9– 5.6 (mean 5.2). Epigynum as in Figs 66–67 , 75–76 ; anterior plate with median depression bordered posteriorly by pocket; pair of conical lateral processes, tips slightly bent towards posterior; posterior plate simple. Internal genitalia as in Figs 68 , 77 , with small pore-plates and distinctive median structure (curved median tube, possibly to accommodate long processes of procursi). One female from ~ 110 km S of type locality (“km 221”) with pocket in slightly more anterior position and shorter legs (tibia 1: 4.4); assigned tentatively.

Natural history. The spiders were found close to the ground, in webs that were mostly hidden in the leaf litter, often in large rolled up leaves. Males and females were sometimes found together, hiding in the back of the shelter.

Distribution. Known from Floresta Nacional de Tapajós in Pará state ( Brazil) only ( Fig. 722 ).

Note. This species is possibly identical to “sp. 06” in Machado (2011), described from a single male specimen from Altamira (~ 300 km E Tapajos).

Figures

FIGURES 1–12. Live specimens, Mesabolivar pseudoblechroscelis group. 1–2. M. acrensis sp. n., male and female from Rio Branco. 3–4. M. maraba sp. n., male and female from Marabá. 5–6. M. huambisa Huber, 2000, male from Tabatinga, female from Belém.7–8.M.amazonicus sp. n., male and female from Humaitá.9–10.M.jamari sp. n., male and female from Jamari. 11–12. M.tapajos sp. n., male and female from Tapajós.

FIGURES 55–58. Mesabolivar jamari sp. n. (55–57, ZFMK Ar 18954) and M. tapajos sp. n. (58, ZFMK Ar 18957). 55–56. Left male palp,prolateral and retrolateral views.57–58.Left procursi, retrolateralviews (arrowspoint at putativeglands).Scale lines:0.5 (55–56), 0.3 (57–58).

FIGURES 59–68. Mesabolivar jamari sp. n. (59–60, 63–65, ZFMK Ar 18954) and M. tapajos sp. n. (61–62, 66–68, ZFMK Ar 18957–58). 59–62. Male chelicerae, frontaland lateral views.63–68.Epigyna, ventral and lateral views, and cleared female genitalia, dorsal views (arrows point at median arc-shaped ducts). Scale lines:0.3.

FIGURES 69–77. Female epigyna in ventral and lateral views and cleared female genitalia, dorsal views, Mesabolivar pseudoblechroscelis group (part 2). 69–71. M. amazonicus sp. n. (ZFMK Ar 18952). 72–74. M. jamari sp. n. (ZFMK Ar 18954).75–77.M.tapajos sp. n. (ZFMK Ar 18958).

FIGURES 722–723. Known distribution of the Mesabolivar pseudoblechroscelis group. For the dubious type locality of M. exlineae, see under description of M.jamari. TL, type locality.