Mecolaesthus piedras Huber, 2020

Huber, Bernhard A. & Villarreal, Osvaldo, 2020, On Venezuelan pholcid spiders (Araneae, Pholcidae), European Journal of Taxonomy 718, pp. 1-317 : 94-97

Mecolaesthus piedras Huber sp. nov.

urn:lsid:zoobank.org:act:CF40549A-34A3-4C69-834A-17B965CE9216

Figs 306–308 , 312–320 , 331–333 , 1042

Diagnosis

Distinguished from known congeners by armature of male chelicerae ( Figs 318–319 ; pair of strong pointed frontal processes), by two distinctive flat elements distally on procursus ( Figs 312–314 ), by genital bulb with distinctive ventral and dorsal sclerites on embolar division (arrows in Fig. 315 ), by long epigynum widening anteriorly ( Fig. 331 ), and by internal female genitalia ( Figs 320 , 332–333 ; strong median sclerite, pore plates on distinctively curved sclerite).

Etymology

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

Type material

VENEZUELA – Mérida • ♂ holotype, ZFMK (Ar 21897), Las Piedras , ‘site 1’ (8.8939° N, 70.6448° W), 1710 m a.s.l., forest remnant, 7 Feb. 2020 (B.A. Huber, O. Villarreal M., Q. Arias C.) .

Other material

VENEZUELA – Mérida • 1 ♀ in pure ethanol, ZFMK (Ven20-106), same collection data as for holotype; abdomen moved to holotype .

Description

Male (holotype)

MEASUREMENTS. Total body length 3.0, carapace width 1.25. Distance PME–PME 130 µm; diameter PME 100 µm; distance PME–ALE 110 µm; diameter AME 25 µm; distance AME–AME 25 µm. Leg 1: 24.6 (5.7+ 0.6+5.7+ 10.3 +2.3), tibia 2: 3.6, tibia 3: 2.7, tibia 4: 3.3; tibia 1–4 diameters: 170 µm, 185 µm, 190 µm, 190 µm; tibia 1 L/d: 34.

COLOR (in ethanol). Carapace pale gray, darker brown frontally including ocular area and clypeus, lateral dark bands in anterior part only, median dark mark with radiating lines; sternum dark brown; legs light brown, with darker rings on femora subdistally and on tibiae proximally and subdistally, femora and tibiae with light tips; abdomen pale bluish-gray, dorsally and laterally densely covered with dark bluish marks, ventrally with large brown mark in gonopore area, brown book lung covers, and bluish marks in front of and behind gonopore; without ventral or dorsal anterior brown plates.

BODY. Habitus as in Figs 306–307 . Ocular area distinctly raised. Carapace anteriorly with shallow but distinct thoracic groove, posteriorly without groove, not inflated. Clypeus unmodified. Sternum wider than long (0.84/0.68). Abdomen slightly elongated and pointed at spinnerets.

CHELICERAE. As in Figs 318–319 , with pair of strong pointed frontal processes, tips slightly diverging.

PALPS. Proximal segments as in M. discrepantis ( González-Sponga, 2003) comb. nov. (cf. Figs 321– 322 ); coxa with strong retrolateral apophysis, trochanter with rounded ventral process, femur proximally with retrolateral process, distally with prominent rounded ventral process, retrolateral trichobothrium of tibia in very distal position; procursus ( Figs 312–314 ) proximally simple, without retrolateral process, small dorsal processes, distally with two distinctive flat elements; genital bulb ( Figs 315–317 ) with distinctive ventral and dorsal sclerites on embolar division, with slender prolateral pointed process.

LEGS. Without spines and curved hairs; few vertical hairs; retrolateral trichobothrium of tibia 1 at 5%; prolateral trichobothrium present on all leg tibiae; tarsus 1 with ~35 pseudosegments, mostly distinct. Coxa 4 not modified.

Female

In general similar to male ( Fig. 308 ). Tibia 1 missing. Epigynum ( Fig. 331 ) longer than wide, widening anteriorly, posterior margin strongly sclerotized, internal sclerites partly visible in uncleared specimens. Internal genitalia ( Figs 320 , 332–333 ) with strong median sclerite on ventral wall of uterus externus

( not on epigynal plate), pore plates on distinctively curved sclerite, with small round anterior median receptacle.

Distribution

Known from type locality only, in Venezuela , Mérida (Fig. 1042).

Natural history

The two specimens were collected from holes in the ground near an almost dried up stream in a small forest remnant.

Figures

Figs 306–311. Mecolaesthus Simon, 1893; live specimens. 306–308. M. piedras Huber sp. nov.; male and female with egg sac from Mérida, Las Piedras. 309–311. M. discrepantis (González-Sponga, 2003); male and female from Trujillo, Laguna Negra.

Figs 312–320. Mecolaesthus piedras Huber sp. nov.; from Mérida, Las Piedras (type locality; ZFMK Ar 21897). 312–314. Left palpal tarsus and procursus, prolateral, dorsal, and retrolateral views. 315– 317. Left genital bulb, prolateral, dorsal, and retrolateral views (arrows: distinctive ventral and dorsal sclerites on embolar division of genital bulb). 318–319. Male chelicerae, frontal and lateral views. 320. Cleared female genitalia, dorsal view. Scale lines: 0.3 mm.

Figs 331–337. Mecolaesthus Simon, 1893; epigyna, ventral views and cleared female genitalia, ventral and dorsal views. 331–333. M. piedras Huber sp. nov.; from Mérida, Las Piedras (type locality; ZFMK Ar 21897). 334–337. M. discrepantis (González-Sponga, 2003); from Trujillo, Laguna Negra (type locality; epigyna: MIZA 105754 / MAGS 1383; cleared female genitalia: ZFMK Ar 21898).

Figs 321–322. Mecolaesthus discrepantis (González-Sponga, 2003); type from Trujillo, Laguna Negra (MIZA 105754; MAGS 1383); left male pedipalp, prolateral and retrolateral views. Scale line: 0.5 mm.