Mesabolivar tabatinga, 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 : 32-34

Mesabolivar tabatinga sp. n.

Figs 82–84 , 115–121, 133–134

Diagnosis. Easily distinguished from known congeners by armature of male chelicerae (pair of long frontal apophyses S-shaped in lateral view, Figs 117–118), by details of male palp (Figs 115–116; femur with ventro-distal protrusion, straight procursus with slender tip, bulbal process with bifid tip), by female pedipalp tibiae slightly widened, and by female external and internal genitalia (epigynum with pair of processes and anterior pocket, distinctive shape of pore-plates; Figs 119–121, 133–134).

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

Type material. BRAZIL: Amazonas: ♂ holotype, 1♀ paratype, UFMG (21507–08), 10♂ 30♀ paratypes, ZFMK (Ar 18991–92), forest near Tabatinga (4.244°S, 69.92– 69.93°W), 90 m a.s.l., 2–4.xi.2016 (B.A. Huber, L.S. Carvalho).

Other material examined. BRAZIL: Amazonas: 1♂ 2♀ in pure ethanol, ZFMK (Br16-329), same data as types.

Assigned tentatively. ECUADOR: Orellana: 2♂, ZFMK (Ar 18993–94), Yasuní Station [0.674°S, 76.398°W], botanical trail, night collecting, 4.xii.2009 (P. Michalik; PM-EC-068/069).

Description. Male (holotype)

MEASUREMENTS. Total body length 3.0, carapace width 1.35. Distance PME-PME 100 µm, diameter PME 140 µm, distance PME-ALE 90 µm, distance AME-AME 30 µm, diameter AME 40 µm. Sternum width/length: 0.95/ 0.60. Leg 1: 49.4 (11.9 + 0.5 + 11.7 + 22.5 + 2.8), tibia 2: 7.7, tibia 3: 5.6, tibia 4: 7.6; tibia 1 L/d: 98. Femora 1–4 width (at half length): 0.18, 0.19, 0.20, 0.18.

COLOR (in ethanol). Prosoma and legs ochre-orange, carapace with black median line, light brown mark behind ocular area and slightly darker lateral margins; legs with darker rings subdistally on femora and tibiae, more distinct rings proximally on tibiae, tips of femora and tibiae light; abdomen ochre-gray, with some dark internal marks dorsally on posterior half.

BODY. Habitus as in Fig. 82 ; ocular area raised; carapace with distinct median furrow; clypeus and sternum unmodified.

CHELICERAE. With pair of strongly protruding, S-shaped (in lateral view) frontal apophyses (Figs 117–118).

PALPS. As in Figs 115–116; coxa with conical retrolateral apophysis; trochanter with finger-shaped retrolateral apophysis; femur with retrolateral process proximally and rounded prolateral protrusion set with short hairs, ventro-distally with large rounded protrusion; tarsus with three dorsal processes; procursus straight, with spine-like terminal process slightly bent; genital bulb process distally divided into dorsal semitransparent flap and ventral partly sclerotized element.

LEGS. Densely covered with very short hairs (only metatarsi dorsally with hairs of usual length); without spines and curved hairs, few vertical hairs; retrolateral trichobothrium on tibia 1 at 2%; prolateral trichobothrium present on tibia 1; tarsus 1 with ~30 pseudosegments, distally fairly distinct.

Male (variation). Tibia 1 in seven other males from type locality: 9.2–11.7 (mean 10.5). Abdomen color ranges from greenish-gray (with dorsal marks) to orange (without dorsal marks). The two males from Ecuador differ slightly in the shape of the cheliceral apophyses (not bent upwards basally) and in the distal spine-like process of the procursus (slightly longer and straight). They are therefore assigned tentatively.

Female. Unusually different from male in coloration and leg length: never orange, carapace ochre-yellow, dark mark behind ocular area and dark rings on legs more distinct than in males, abdomen always greenish-gray with dorsal (and sometimes also lateral) marks ( Fig. 83 ). Tibia 1 in 30 females: 4.9–6.3 (mean 5.6). Pedipalp tibiae slightly widened. Epigynum as in Figs 119–120, 133; anterior plate with pair of low processes and deep anterior pocket (continues into heavily sclerotized tube), with dark median furrow between pocket and posterior margin; posterior plate large, medially anteriorly excavated. Internal genitalia as in Figs 121, 134, with distinctively shaped pore-plates.

Natural history. The spiders were found from ground level up to 1 m above the ground (rarely even higher). On the ground, the webs were mostly hidden under large leaves or in empty nuts where the spiders were resting; higher up in the vegetation or on trees, the webs led into dead curled leaves. When disturbed, the spiders vibrated rapidly and eventually ran away.

Distribution. Known from type locality in Amazonas state ( Brazil) and from specimens assigned tentatively from Ecuador ( Fig. 725 ).

Figures

FIGURES 78–89. Live specimens and habitus photos, Mesabolivar aurantiacus group. 78–81. M. aurantiacus (Mello-Leitão, 1930), males from Tabatinga, Manaus, and Belém, female from Belém. 82–84. M. tabatinga sp. n., male, female, and mating pair from Tabatinga. 85–87. M. eberhardi Huber, 2000, males and female from Jamari. 88–89. M. anseriformis (González- Sponga, 2011), male in dorsal and lateral views (ZFMK Ar 19012).

FIGURES 724–725. Known distribution of the Mesabolivar aurantiacus ‘group’.TL, type locality.