Mecolaesthus grandis ( González-Sponga, 2009 )

Huber, Bernhard A. & Villarreal, Osvaldo, 2020, On Venezuelan pholcid spiders (Araneae, Pholcidae), European Journal of Taxonomy 718, pp. 1-317 : 101-105

Mecolaesthus grandis ( González-Sponga, 2009)

Figs 338–340 , 346–355 , 367 , 373–375 , 1043

Nasuta grandis González-Sponga, 2009: 6 , figs 3a–j (♂ ♀).

Mecolaesthus grandis – Huber et al. 2014a: 417.

Diagnosis

Distinguished from most congeners [except M. multidenticulatus ( González-Sponga, 2003) and M. tuberculosus ( González-Sponga, 2009) ] by armature of male chelicerae ( Fig. 354 ; pair of large frontal processes curved downwards and set with ~5 modified hairs each, and two small modified hairs more distally on weakly sclerotized area), by shape of main bulbal process ( Figs 351–353 ; two large sclerites visible in prolateral view), by transparent process on procursus distally bent toward retrolateral ( Fig. 349 ), and by shape of epigynum ( Fig. 373 ; short but wide plate, pair of anterior internal sclerites extending towards lateral); from the very similar M. multidenticulatus and M. tuberculosus by male cheliceral apophysis with conspicuous projection towards median (arrow in Fig. 367 ); from M. tuberculosus also by absence of conspicuous lateral process on male cheliceral apophysis and by larger distance between pair of rounded sclerites in female internal genitalia (arrows in Fig. 374 ).

Type material

VENEZUELA – La Guaira • ♂ holotype, 4 ♀♀, 7 juvs (see Notes below), MIZA 105663 ( MAGS 1215 ), Hacienda El Limón (10.475° N, 67.283° W), 1200 m a.s.l. (see Notes below), 27 Oct. 1990 (A.R. Delgado de G., M.A. González-S.); examined .

New records

VENEZUELA – La Guaira • 3 ♂♂, 5 ♀♀, ZFMK (Ar 21899–21900), and 3 ♀♀, 2 juvs in pure ethanol, ZFMK (Ven18-155), El Limón , above road Colonia Tovar-Puerto Cruz (10.4566° N, 67.2548° W), 1535 m a.s.l., 9 Nov. 2018 (B.A. Huber, O. Villarreal M.) • 2 ♂♂, ZFMK (Ar 21901), and 1 ♀ in pure ethanol, ZFMK (Ven20-173), 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.). – Aragua • 2 ♂♂, 2 ♀♀, ZFMK (Ar 21902), and 2 ♂♂, 2 juvs in pure ethanol, ZFMK (Ven02/100-32), Henri Pittier National Park , “site 2” (10.350° N, 67.692° W), ~ 1000 m a.s.l., 11 Dec. 2002 (B.A. Huber) • 1 ♂, 1 ♀, ZFMK (Ar 21903), Henri Pittier National Park , “site 3” (10.360° N, 67.720° W), ~ 730 m a.s.l., 11 Dec. 2002 (B.A. Huber) .

Notes

The original description mentions 11 specimens: 1 ♂ holotype, 1 ♀ paratype, eight (non-type) females, and 1 juvenile. The 12 specimens listed under ‘Type material’ above are all joined in one vial, so it is no longer possible to distinguish the female paratype from the other females.

The original coordinates are probably accurate or close to accurate. We were not able to exactly identify the original collecting site. Our 2020 collecting site above (“El Limón, site 2”) is within 300 m from the coordinates in the original publication.

Redescription

Male (ZFMK Ar 21899)

MEASUREMENTS. Total body length 4.3, carapace width 1.5. Distance PME–PME 100 µm; diameter PME 120 µm; distance PME–ALE 100 µm; diameter AME 30 µm; distance AME–AME 20 µm. Leg 1: 37.9 (9.0 +0.6 +9.3+16.6 + 2.4), tibia 2: 5.8, tibia 3: 4.7, tibia 4: 5.1; tibia 1–4 diameters: 120 µm, 155 µm, 180 µm, 160 µm; tibia 1 L/d: 78.

COLOR (in ethanol). Carapace pale ochre-gray with wide median and lateral marginal dark bands, ocular area mostly not darkened, clypeus with wide dark brown mark; sternum pale ochre-grey; legs ochre to light brown, with barely visible 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 brown mark in gonopore area, brown book lung covers, pair of lateral anterior brown plates opposing fourth coxae, and large bluish marks in front and behind gonopore; with light brown plate above pedicel opposing carapace inflation (arrow in Fig. 338 ).

BODY. Habitus as in Figs 338–339 . Ocular area distinctly raised. Carapace anteriorly with distinct thoracic groove, posteriorly slightly inflated. Clypeus unmodified. Sternum wider than long (0.95/0.75). Abdomen slightly elongated, pointed at spinnerets.

CHELICERAE. As in Figs 354 and 367 , with pair of large frontal apophyses set with ~5 slightly hooked short hairs, with two additional short hairs on whitish area below main apophysis, and small unsclerotized ridge.

PALPS. As in Figs 346–347 ; coxa with retrolateral apophysis, trochanter with very small ventral process, femur proximally with large retrolateral process, distally with prominent rounded ventral process, retrolateral trichobothrium of tibia in very distal position; procursus ( Figs 348–350 ) at basis with bifid dorsal process with branches of unequal length, with small retrolateral apophysis, distally with pair of membranous processes: retrolateral process distally bent towards retrolateral, prolateral process with pointed tip; genital bulb complex ( Figs 351–353 ), distally mostly membranous/whitish but with distinctive distal sclerites (very similar M. multidenticulatus ).

LEGS. Without spines and curved hairs; few vertical hairs; retrolateral trichobothrium of tibia 1 at 3.5%; prolateral trichobothrium present on all leg tibiae; tarsus 1 with ~35 pseudosegments, mostly distinct.

Male (variation)

Tibia 1 in nine males: 8.7–10.5 (mean 9.5); most males with light to dark brown book lung covers, but anterior brown plates opposing fourth coxae indistinct or absent in some males, unrelated to body size. Brown plate above pedicel also absent in some males.

Female

In general similar to male ( Fig. 340 ), also with variably dark book lung covers but never with brown plates opposing fourth coxae and never with brown plate above pedicel. Tibia 1 in nine females: 5.7–6.6 (mean 6.3). Epigynum ( Fig. 373 ) small, light brown, wider than long, internal sclerites partly visible in uncleared specimens (possibly indistinguishable from M. multidenticulatus and M. tuberculosus ). Internal genitalia ( Figs 355 , 374–375 ) with pair of anterior sclerites extending towards lateral, median receptacle, pair of pore plates tilted into almost vertical position, and pair of round ventral sclerites (arrows in Fig. 374 ).

Distribution

Known from several localities in the Venezuelan states La Guaira and Aragua (Fig. 1043).

Natural history

González-Sponga (2009) found the species under decaying logs. The new specimens from El Limón were collected in a forest fragment from strongly curved webs close to the ground. When disturbed, the spiders ran away rather than shaking or vibrating their bodies.

Figures

Figs 338–345. Mecolaesthus Simon, 1893; live specimens. 338–340. M. grandis (González-Sponga, 2009); male and female with egg sac from La Guaira, El Limón (arrow: brown plate above pedicel opposing carapace inflation). 341–343. M. multidenticulatus (González-Sponga, 2003); male and female with egg sac from Falcón, Curimagua. 344–345. M. tuberculosus (González-Sponga, 2003); male and female with egg sac from Yaracuy, Yurubi National Park.

Figs 346–347. Mecolaesthus grandis (González-Sponga, 2009); holotype from La Guaira, Hacienda El Limón (MIZA 105663; MAGS 1215); left male pedipalp, prolateral and retrolateral views. Scale line: 0.3 mm.

Figs 348–355. Mecolaesthus grandis (González-Sponga, 2009); from La Guaira, El Limón (type locality; ZFMK Ar 21899–21900). 348–350. Left palpal tarsus and procursus, prolateral, dorsal, and retrolateral views. 351–353. Left genital bulb, prolateral, dorsal, and retrolateral views. 354. Male chelicerae, frontal view. 355. Cleared female genitalia, dorsal view. Scale lines: 0.3 mm.

Figs 367–372. Mecolaesthus Simon, 1893; male chelicerae, distal, frontal and lateral views; cleared female genitalia, dorsal view. 367. M. grandis (González-Sponga, 2009); from La Guaira, El Limón (type locality; ZFMK Ar 21899) (arrow: distinctive projection towards median). 368. M. multidenticulatus (González-Sponga, 2003); from Falcón, Curimagua (type locality; ZFMK Ar 21904). 369– 372. M. tuberculosus (González-Sponga, 2003); from Yaracuy, Yurubi National Park (ZFMK Ar 21906– 07) (arrow: distinctive lateral process). Scale lines: 0.3 mm (all chelicerae at same scale).

Figs 373–381. Mecolaesthus Simon, 1893; epigyna, ventral views and cleared female genitalia, ventral and dorsal views (arrows: internal rounded sclerites). 373–375. M. grandis (González-Sponga, 2009); from La Guaira, El Limón (type locality; ZFMK Ar 21900). 376–378. M. multidenticulatus (González- Sponga, 2003); from Falcón, Curimagua (type locality; ZFMK Ar 21905). 379–381. M. tuberculosus (González-Sponga, 2003); from Yaracuy, Yurubi National Park (ZFMK Ar 21907).