Mecolaesthus limon Huber, 2020

Huber, Bernhard A. & Villarreal, Osvaldo, 2020, On Venezuelan pholcid spiders (Araneae, Pholcidae), European Journal of Taxonomy 718, pp. 1-317 : 160-161

Mecolaesthus limon Huber sp. nov.

urn:lsid:zoobank.org:act:216D316A-3547-4553-9CA0-DCB4D24F5F7C

Figs 582–593 , 1046

Diagnosis

Easily distinguished from known congeners by details of male pedipalp ( Figs 589–590 ; procursus slender and simple; genital bulb with prolateral process and complex embolar division), by armature of male chelicerae ( Figs 591–592 ; two pairs of frontal apophyses), by presence of spines ventrally on male femur 1, and by unique shape of epigynum ( Fig. 586 ; very short but wide anterior plate, large posterior plate slightly protruding and with whitish median area anteriorly).

Etymology

The species name refers to the type locality; noun in apposition.

Type material

VENEZUELA – La Guaira • ♂ holotype, ZFMK (Ar 21961), El Limón , ‘site 2’ (10.4774° N, 67.2819° W), 1235 m a.s.l., forest along stream, 21 Feb. 2020 (B.A. Huber, O. Villarreal M.) .

Other material examined

VENEZUELA – La Guaira • 5 ♂♂, 5 ♀♀, ZFMK (Ar 21962–63), and 1 ♂, 1 ♀ in pure ethanol, ZFMK (Ven20-174), same collection data as for holotype .

Description

Male (holotype)

MEASUREMENTS. Total body length 2.7, carapace width 1.05. Distance PME–PME 90 µm; diameter PME 120 µm; distance PME–ALE 80 µm; AME absent (distinct dark mark but no lenses). Leg 1: 35.7 (8.4 +0.5 +8.1+15.6 + 3.1), tibia 2: 5.0, tibia 3: 3.6, tibia 4: 4.7; tibia 1 L/d: 81.

COLOR (in ethanol). Carapace pale gray, with wide dark brown lateral marginal bands connected posteriorly with wide dark brown median mark widened behind ocular area; ocular area and clypeus light reddish-brown; sternum light ochre-yellow, with dark brown margins; legs brown, with black rings on femora (subdistally) and tibiae (proximally, subdistally), tips of femora, tibiae, and metatarsi light; abdomen greenish gray, dorsally and laterally with dark bluish marks, ventrally with light brown mark

in gonopore area and dark bluish median band behind gonopore; book lung covers not darkened; without dark plate above pedicel.

BODY. Habitus as in Figs 582–583 . Ocular area moderately raised. Carapace anteriorly with shallow but distinct thoracic groove, posteriorly strongly inflated. Clypeus unmodified. Sternum wider than long (0.86/0.60), unmodified. Abdomen slightly elongated, pointed at spinnerets.

CHELICERAE. As in Figs 591–592 , with two pairs of pointed frontal apophyses, distal pair overhanging fangs.

PALPS. As in Figs 589–590 ; coxa with strong retrolateral-ventral apophysis, trochanter barely modified, femur proximally with large retrolateral-ventral process, dorsally with low hump, distally with long and tapering ventral process and with prolateral protrusion; procursus slender and very simple; genital bulb with prolateral process densely set with small tubercles, complex embolar division apparently forming furrow for procursus.

LEGS. With single row of ~18–20 very short spines on femur 1, restricted to proximal third of femur, with elevated sockets; without curved hairs; few vertical hairs; coxa 4 unmodified; retrolateral trichobothrium of tibia 1 at 2%; prolateral trichobothrium present on all leg tibiae; tarsus 1 with ~55–60 pseudosegments, distally distinct.

Male (variation)

Tibia 1 in six males (including holotype): 7.7–9.0 (mean 8.4). Smallest male with fewer spines on femur 1 (~7 on each side), carapace barely inflated, without lateral dark marks (as in females). Some males with tiny AME lenses.

Female

Unusually different from male ( Figs 584–585 ), considerably smaller and with shorter legs (tibia 1 in five females: 5.2–5.6; mean 5.4), carapace not inflated and without lateral dark bands, ocular area dark brown, clypeus pale gray, femur 1 without spines, AME present in all females. Epigynum ( Fig. 586 ) consisting of short but wide anterior plate and large posterior plate slightly protruding and with whitish median area anteriorly. Internal genitalia ( Figs 587–588 , 593 ) small relative to epigynum, oval pore plates close together on central sclerite.

Distribution

Known from type locality only, in Venezuela, La Guaira (Fig. 1046).

Natural history

The spiders were collected in a well preserved humid forest near a small stream. The weakly domed sheet webs had a diameter of ~ 30 cm and were built ~ 20–50 cm above the ground, in sheltered spaces provided by rocks or logs.

Figures

Figs 582–588. Mecolaesthus limon Huber sp. nov.; from La Guaira, El Limón (type locality). 582– 585. Live male and female with egg sac. 586–588. Epigynum, ventral view and cleared female genitalia, ventral and dorsal views (ZFMK Ar 21963).

Figs 589–593. Mecolaesthus limon Huber sp. nov.; from La Guaira, El Limón (type locality; ZFMK Ar 21962–63). 589–590. Left male pedipalp, prolateral and retrolateral views. 591–592. Male chelicerae, lateral and frontal views. 593. Cleared female genitalia, dorsal view. Scale lines: 0.3 mm.