Metagonia triocular
Creators: name: Huber, Bernhard A.
name: Villarreal, Osvaldo
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Pholcidae
Metagonia
Metagonia triocular

description: Metagonia triocular (González-Sponga, 2011)
Figs 681–682, 687–697, 702–704, 1054
Porteña triocular González-Sponga, 2011b: 42, pl. 4, figs 1–9.
Metagonia triocular – Huber et al. 2014a: 419.
Diagnosis
Easily distinguished from known congeners by strong ventral hinged process on procursus distally sclerotized and directed toward prolateral (Figs 688, 694); also by pair of processes on male clypeus (Figs 690, 696), by modifications of male chelicerae (Fig. 696; pair of proximal lateral ridges, pair of small frontal processes, and pair of distal patches of globular hairs); and by tongue-shaped posterior sclerite of epigynum (Figs 691–692, 702) and elongate pore plates (Fig. 697).
Type material
VENEZUELA – La Guaira • ♂ holotype and 1 ♀ paratype, MIZA 105645 (MAGS 1349), Hacienda El Limón [approximately 10.475° N, 67.283°E, see Note below], 1100 m a.s.l., 25 Jan. 1992 (A.R. Delgado, M.A. González S.); examined.
New record
VENEZUELA – Aragua • 4 ♂♂, 4 ♀♀, ZFMK (Ar 22046), and 5 ♀♀ in pure ethanol, ZFMK (Ven20- 164), Henri Pittier National Park, NE El Castaño (10.3475° N, 67.5850° W), 990 m a.s.l., bamboo litter, 20 Feb. 2020 (B.A. Huber, O. Villarreal M.).
Note
The exact coordinates of the type locality are unknown to us but the coordinates given above are probably within ~ 1 km of the collecting site. González-Sponga’s (2011b) coordinates of Hacienda El Limón are ~ 20 km S, in the state of Aragua.
Redescription
Male (NE El Castaño, ZFMK Ar 22046)
MEASUREMENTS. Total body length 2.2, carapace width 0.70. Distance PME–PME 70 µm; diameter PME 80 × 100 µm; distance PME–ALE 30 µm; AME absent. Leg 1: 14.5 (3.8 +0.3+ 3.5+5.9+ 1.0), tibia 2: 2.2, tibia 3: 1.5, tibia 4: 2.2; tibia 1 L/d: 50; all femora approximately same diameter.
COLOR (in ethanol). Carapace pale ochre yellow, with brown median mark of distinctive shape including ocular area and clypeus; sternum whitish; legs ochre-yellow, patellae and tibia-metatarsus joints dark brown; abdomen pale grey, with some black marks dorsally, ventrally monochromous.
BODY. Habitus as in Fig. 681. Ocular area barely raised. Carapace without thoracic groove. Clypeus with pair of weakly sclerotized conical processes ~ 70 µm long (Fig. 696). Sternum slightly wider than long (0.50/0.46), unmodified. Abdomen with rounded conical elongation above spinnerets.
CHELICERAE. As in Fig. 696, with pair of proximal lateral ridges, pair of small frontal processes, and pair of distal patches of 9–10 globular hairs on each side.
PALPS. As in Figs 687–689; coxa unmodified, trochanter with short ventral apophysis; femur distally widened, without process; retrolateral trichobothrium on tibia in very distal position (not absent as stated in original description); procursus (Figs 693–695) with large ventral hinged process distally strongly curved toward prolateral and ending in sclerotized flap with small scales on ventral face; main branch of procursus distally bifid, one part sclerotized, other part membranous and transparent; genital bulb globular, with tubular embolus ending in spine.
LEGS. Without spines and curved hairs, few vertical hairs; retrolateral trichobothrium of tibia 1 at 13%; prolateral trichobothrium absent on tibia 1; tarsus 1 with ~20 pseudosegments, only distally fairly distinct.
Male (variation)
Tibia 1 in three other males 3.1, 3.3, 3.7. Number of modified hairs on chelicerae slightly variable.
Female
In general similar to male (Fig. 682) but clypeus unmodified and not darkened, ocular area with median and lateral marginal dark marks, otherwise light, posterior triangular mark similar to male but lighter; sternum in some females darker. Tibia 1 in nine females: 2.8–3.3 (mean 3.1). Epigynum (Figs 691–692, 702) mostly unsclerotized except posterior tongue-shaped sclerite (strongly raised in paratype), internal median receptacle and arc visible in uncleared specimens. Internal genitalia (Figs 697, 703–704) symmetric, with simple anterior arc and narrow pore plates.
Distribution
Known from two localities in the Venezuelan states La Guaira and Aragua (Fig. 1054).
Natural history
According to González-Sponga (2011b), the type specimens were collected from dead Cecropia leaves in the understory of a forest with coffee. Near El Castaño the spiders were found in dead bamboo culm sheaths on the ground. They were extremely well camouflaged and did not react to disturbance, i.e., were difficult to spot but easy to collect.
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 191-195, DOI: 10.5852/ejt.2020.718.1101, http://zenodo.org/record/4069574