Mesabolivar amazonicus,

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: 18-20

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Mesabolivar amazonicus

sp. n.

Mesabolivar amazonicus  sp. n.

Figs 7–8View FIGURES 1–12, 48–54View FIGURES 48–54, 69–71View FIGURES 69–77

Diagnosis. Males are easily distinguished from known congeners by shape of procursus ( Fig. 49View FIGURES 48–54; distinctively widened and strongly curved distal element, much smaller than in similar species, i.e. M. acrensis  , M. maraba  , M. pseudoblechroscelis  , M. huambisa  ); also by armature of male chelicerae ( Figs 50–51View FIGURES 48–54; distinctive undulating shape of apophyses in lateral view), by shape of epigynum ( Figs 52–53View FIGURES 48–54, 69–70View FIGURES 69–77; large median depression, lateral margins diverging toward anterior, bordered posteriorly by large pocket; pair of conical lateral processes; very similar to M. huambisa  but median pocket reaching further back in lateral view), and by female internal genitalia ( Figs 54View FIGURES 48–54, 71View FIGURES 69–77; similar to M. maraba  and M. huambisa  ; pore-plates larger and slightly curved towards posterior) (female of M. pseudoblechroscelis  unknown).

Etymology. The specific name is an adjective derived from the type locality.

Type material. BRAZIL: Amazonas: ♂ holotype, 1♀ paratype, UFMG (21501–02), 2♂ 2♀ paratypes, ZFMK (Ar 18952), forest near Humaitá, ‘site 1’ (7.464°S, 63.231°W), 65 m a.s.l., 20.x.2016 (B.A. Huber, L.S. Carvalho).

Other material examined. BRAZIL: Amazonas: 1♀ 2 juvs in pure ethanol, ZFMK (Br 16-283), same data as types  . 2♂ 3♀, ZFMK (Ar 18953), forest near Humaitá, ‘site 3’ (7.512°S, 63.393°W), 80 m a.s.l., 22.x.2016 (B.A. Huber, L.S. Carvalho); 2♀ in pure ethanol, ZFMK (Br 16-291), same data  .

Description. Male (holotype)

MEASUREMENTS. Total body length 2.6, carapace width 1.2. Distance PME-PME 130 µm, diameter PME 120 µm, distance PME-ALE 90 µm, distance AME-AME 30 µm, diameter AME 55 µm. Sternum width/length: 0.95/ 0.55. Leg 1: 37.2 (9.0 + 0.5 + 9.0 + 16.3 + 2.4), tibia 2: 5.9, tibia 3: 4.3, tibia 4: 6.2; tibia 1 L/d: 86. Femora 1–4 width (at half length): 0.16, 0.17, 0.19, 0.16.

COLOR (in ethanol). Carapace ochre-yellow, with large slightly darker median mark, ocular area also slightly darkened; sternum ochre-orange; legs ochre to light brown, with indistinct darker rings on femora (subdistally) and tibiae (proximally and subdistally), tips of femora and tibiae lighter; abdomen greenish-gray, with dark internal marks dorsally and laterally, small ventral mark behind gonopore.

BODY. Habitus as in Fig. 7View FIGURES 1–12; ocular area raised (higher than usual in the genus); carapace with distinct median furrow; clypeus slightly swollen and whitish, with sclerotized margin; sternum unmodified.

CHELICERAE. With pair of long cylindrical apophyses, undulating in lateral view, with strongly sclerotized hooked tips ( Figs 50–51View FIGURES 48–54).

PALPS. As in Figs 48–49View FIGURES 48–54; coxa with conical retrolateral apophysis; trochanter with retrolateral apophysis; femur very large, proximally with retrolateral apophysis and prolateral ridge set with short hairs; tarsus with small dorsal processes, with one strong and two regular hairs bent towards dorsal; procursus distally widened and strongly curved towards dorsal; bulb with distally bifid process.

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 ~30 pseudosegments, distally fairly distinct.

Male (variation). Tibia 1 in three other males: 8.8, 8.9, 9.2. Prosoma variably orange.

Female. In general similar to male ( Fig. 8View FIGURES 1–12) but carapace ochre-brown rather than yellow to orange, with larger brown median mark; ocular area slightly lower than in males; dark rings and whitish tips of femora and tibiae more distinct; clypeus less swollen and margin not sclerotized. Tibia 1 in six females: 5.5–6.0 (mean 5.8). Epigynum as in Figs 52–53View FIGURES 48–54, 69–70View FIGURES 69–77; anterior plate with large median depression bordered posteriorly by large pocket; pair of conical lateral processes directed slightly towards anterior; posterior plate large, simple. Internal genitalia as in Figs 54View FIGURES 48–54, 71View FIGURES 69–77, with elongated transversal pore-plates and distinctive median anterior structure.

Natural history. The spiders were found in small sheltered spaces in the leaf litter, under logs, or in small cavities in the ground.

Distribution. Known from type locality and a nearby site only, both in Amazonas state ( Brazil) ( Fig. 722View FIGURES 722–723).


Universidade Federal de Minas Gerais


Zoologisches Forschungsmuseum Alexander Koenig