Mecolaesthus lechosa Huber 2020, sp. nov.
Creators: name: Huber, Bernhard A.
name: Villarreal, Osvaldo
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Pholcidae
Mecolaesthus
Mecolaesthus lechosa

description: Mecolaesthus lechosa Huber sp. nov.
urn:lsid:zoobank.org:act: E8FAEE68-A35E-4FA6-9EDF-65B2FD22C164
Figs 429–432, 444–452, 465–467, 1044
Diagnosis
Distinguished from congeners by armature of male chelicerae (Figs 450–451; pair of frontal lateral apophyses set with 3 modified hairs each, 1–2 modified hairs more medially, and pair of low apophyses more distally without modified hairs); also by shape of procursus (Figs 444–446; without retrolateral process; prolateral-ventral distal process sclerotized, with rounded tip), by shape of epigynum (Fig. 465; simple rectangular plate, wider than long), and by internal female genitalia (Figs 452, 466–467; large round pore plates close together); from many congeners also by long legs (male tibia 1>10.0, female tibia 1>7.0).
Etymology
The species name refers to lechosa, the Venezuelan name for papaya; noun in apposition.
Type material
VENEZUELA – Mérida • ♂ holotype, ZFMK (Ar 21929), forest above Mesa Bolívar (8.467° N, 71.614° W), 1300 m a.s.l., 12 Feb. 2020 (B.A. Huber, O. Villarreal M., Q. Arias C.).
Other material examined
VENEZUELA – Mérida • 8 ♂♂, 5 ♀♀, 2 juvs, ZFMK (Ar 21930–31), and 3 ♀♀, 1 juv. in pure ethanol, ZFMK (Ven20-132), same collection data as for holotype.
Description
Male (holotype)
MEASUREMENTS. Total body length 5.0, carapace width 1.7. Distance PME–PME 130 µm; diameter PME 130 µm; distance PME–ALE 110 µm; distance AME–AME 30 µm; diameter AME 25 µm. Leg 1: 49.6 (11.7 +0.7+11.7 + 22.4 +3.1), tibia 2: 7.1, tibia 3: 5.3, tibia 4: 6.0; tibia 1 L/d: 84.
COLOR (in ethanol). Carapace ochre-yellow with wide median dark band including ocular area and pair of wide lateral marginal dark bands, median and lateral bands not connected posteriorly; clypeus with wide median brown band; sternum yellowish to light brown; legs ochre, with indistinct darker bands on femora subdistally and tibiae proximally; abdomen pale greenish gray, dorsally and laterally with dark bluish marks, ventrally with small dark mark in gonopore area, large bluish internal median mark, dark brown book lung covers and brown plate anteriorly close to pedicel (arrows in Fig. 430), very indistinct plate above pedicel.
BODY. Habitus as in Figs 429–430. Ocular area moderately raised. Carapace inflated posteriorly, with shallow but distinct thoracic groove. Clypeus unmodified. Sternum wider than long (1.1/0.7), unmodified. Abdomen slightly elongate, pointed at spinnerets; ventral anterior plate on abdomen slightly raised, opposing sternum (corresponding area of sternum not visibly modified).
CHELICERAE. As in Figs 450–451, with pair of frontal lateral apophyses set with 3 modified hairs each, 2 modified hairs more medially, and pair of low apophyses more distally without modified hairs.
PALPS. In general very similar to other species of the M. grandis group [e.g., M. grandis (GonzálezSponga, 2009) and M. longipes Huber sp. nov.; cf. Figs 346–347, 399–400]; coxa with retrolateral apophysis, trochanter with small ventral process, femur proximally with large retrolateral apophysis, distally with ventral process, retrolateral trichobothrium of tibia in very distal position; procursus (Figs 444–446) at basis with weakly bifid dorsal process, without retrolateral apophysis, distally with pair of processes: prolateral-ventral process sclerotized, with rounded tip, retrolateral-dorsal process transparent; genital bulb complex (Figs 447–449), distally partly membranous/whitish, with distinctive sclerites.
LEGS. Without spines and curved hairs; few vertical hairs; with rows of very short hairs dorsally on tibiae (length ~ 10 µm; for comparison: short vertical hairs ~ 70 µm, regular mechanoreceptors ~ 150–200 µm, trichobothria> 300 µm); retrolateral trichobothrium of tibia 1 at 3%; prolateral trichobothrium present on all leg tibiae; tarsus 1 with ~45 pseudosegments, distally distinct. Femora proximally of similar width (proximal diameters femora 1–4: 310 µm, 330 µm, 350 µm, 320 µm), distally variably narrowing (diameters at half-length femora 1–4: 240 µm, 300 µm, 350 µm, 300 µm). Tibiae 1–4 diameters at half length: 140 µm, 190 µm, 230 µm, 210 µm. Coxa 4 not modified.
Male (variation)
Tibia 1 in eight males (incl. holotype): 10.4–11.9 (mean 11.3); anterior dark plate ventrally on abdomen strongly variable, from invisible to heavily sclerotized plate with distinct elevation; book lung covers also from not darkened to dark brown; plate above pedicel from invisible to small light brown plate; carapace inflation from absent to conspicuous; palps and chelicerae very consistent.
Female
Coloration similar to that of male (Figs 431–432), smaller with shorter abdomens, leg femora and tibiae same diameters, carapace not inflated, without ventral and dorsal anterior plates on abdomen, book lung covers consistently light brown. Tibia 1 in six females: 7.1–7.7 (mean 7.5). Epigynum (Fig. 465) simple rectangular transversal brown plate, without posterior plate. Internal genitalia (Figs 452, 466–467) with large round pore plates close together, complex anterior system of folds and small median receptacle.
Distribution
Known from type locality only, in Venezuela, Mérida (Fig. 1044).
Natural history
This species was abundant at the type locality and was found in differently shaped webs (rather flat sheet webs and strongly domed webs) at different elevations above the ground (from very close to the ground up to 2 m above the ground on rock walls).
description: Published as part of Huber, Bernhard A. & Villarreal, Osvaldo, 2020, On Venezuelan pholcid spiders (Araneae, Pholcidae), pp. 1-317 in European Journal of Taxonomy 718 on pages 127-130, DOI: 10.5852/ejt.2020.718.1101, http://zenodo.org/record/4069574