Mecolaesthus bienmesabe Huber, 2020

Huber, Bernhard A. & Villarreal, Osvaldo, 2020, On Venezuelan pholcid spiders (Araneae, Pholcidae), European Journal of Taxonomy 718, pp. 1-317 : 121-124

Mecolaesthus bienmesabe Huber sp. nov.

urn:lsid:zoobank.org:act:E2F910BC-0121-43EB-A536-5BE7625F5EF2

Figs 386–387 , 410–417 , 424–426 , 1043

Diagnosis

Distinguished from congeners by combination of: armature of male chelicerae ( Fig. 416 ; pair of large, rounded frontal processes set with many hairs, 5–7 of them slightly stronger, and 2–3 small modified hairs more distally on weakly sclerotized area; very similar to M. longipes Huber sp. nov.); by shape of procursus ( Figs 410–412 ; very indistinct retrolateral process; distinctive pair of membranous distal processes, more slender than in M. longipes Huber sp. nov. and straight), by shapes of distal bulbal sclerites (relatively long and slender median sclerite; arrow in Fig. 413 ); by epigynum ( Fig. 424 ; wider than long trapezoidal to semicircular brown plate), and by internal female genitalia ( Figs 417 , 425–426 ; Y-shaped sclerite connected to median posterior sclerite, pore plates on strong sclerite tilted into vertical position, wing-like anterior sclerites).

Etymology

The species name refers to bienmesabe (Spanish: it tastes good to me), a sweet Venezuelan dessert prepared with honey, egg yolk, and coconut; noun in apposition.

Type material

VENEZUELA – Lara • ♂ holotype, ZFMK (Ar 21922), ~ 5 km SW of Guarico, between Barquisimeto and Boconó (9.5906° N, 69.8343° W), 1370 m a.s.l., 20 Nov. 2018 (B.A. Huber, O. Villarreal M.) .

Other material examined

VENEZUELA – Lara • 7 ♂♂, 8 ♀♀, ZFMK (Ar 21923–24), and 1 ♂, 3 ♀♀ in pure ethanol, ZFMK (Ven18-204), same collection data as for holotype • 1 ♂, ZFMK (Ar 21925), Yacambú National Park, Sendero Ecológico (9.708° N, 69.583° W), ~ 1550 m a.s.l., 15–16 Dec. 2002 (B.A. Huber, A. Pérez González, O. Villarreal M., B. Striffler, A. Giupponi) .

Description

Male (holotype)

MEASUREMENTS. Total body length 3.6, carapace width 1.25. Distance PME–PME 80 µm; diameter PME 130 µm; distance PME–ALE 100 µm; diameter AME 25 µm; distance AME–AME 25 µm. Leg 1: 44.1 (10.3+0.5+10.7 + 20.1 +2.5), tibia 2: 6.3, tibia 3: 4.7, tibia 4: 5.7; tibia 1–4 diameters: 100 µm, 120 µm, 130 µm, 140 µm; tibia 1 L/d: 107.

COLOR (in ethanol). Carapace pale ochre-gray with wide median and lateral marginal dark bands, ocular area medially not darkened, clypeus with wide dark brown mark; sternum pale ochre-yellow; legs ochre to light brown, without darker rings; 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; without dark mark above pedicel.

BODY. Habitus as in Fig. 386 . Ocular area distinctly raised. Carapace anteriorly with distinct thoracic groove, posteriorly slightly inflated. Clypeus unmodified. Sternum wider than long (0.80/0.60).Abdomen elongated, pointed at spinnerets.

CHELICERAE. As in Fig. 416 , lateral view as in M. longipes Huber sp. nov. (cf. Fig. 408 ), rounded frontal processes set with many hairs, five of them slightly stronger, and two small modified hairs more distally on weakly sclerotized area.

PALPS. In general similar to M. longipes Huber sp. nov. (cf. Figs 399–400 ); coxa with retrolateral apophysis, trochanter with small ventral process, femur proximally with large retrolateral process, distally with prominent rounded ventral process (shorter than in M. longipes Huber sp. nov.), retrolateral trichobothrium of tibia in very distal position; procursus ( Figs 410–412 ) at basis with bifid dorsal process with branches of unequal length, with very indistinct retrolateral process, distally with membranous dorsal process and proximally slightly sclerotized, distally pointed ventral process; genital bulb complex ( Figs 413–415 ), distally mostly membranous/whitish but with distinctive distal sclerites.

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 ~40 pseudosegments, mostly distinct.

Male (variation)

Tibia 1 in seven males (incl. holotype): 9.6–10.7 (mean 10.1); most males with light to dark brown book lung covers, but anterior brown plates opposing fourth coxae absent in some males. Number of modified hairs on chelicerae slightly variable (5–7 on large rounded processes; 2–3 distally).

Female

In general similar to male ( Fig. 387 ), also with variably dark book lung covers but never with brown plates opposing fourth coxae. Tibia 1 in five females: 6.3–7.4 (mean 6.9). Epigynum ( Fig. 424 ) wider than long, trapezoidal to semicircular brown plate, internal structures and posterior median dark sclerite variably visible in uncleared specimens. Internal genitalia ( Figs 417 , 425–426 ) with Y-shaped sclerite connected to median posterior sclerite, pore plates on strong sclerite tilted into vertical position, and wing-like anterior sclerites.

Distribution

Known from two localities in the Venezuelan state Lara (Fig. 1043).

Natural history

At the type locality the spiders built their strongly curved dome-shaped webs close to the ground in a forest fragment along a small stream.

Figures

Figs 382–387. Mecolaesthus Simon, 1893; live specimens. 382–383. M. niquitanus (González-Sponga, 2011); male and female with egg sac from Trujillo, Laguna Negra. 384–385. M. longipes Huber sp. nov.; male and female from Mérida, Mucuy. 386–387. M. bienmesabe Huber sp. nov.; male and female from Lara, between Barquisimeto and Boconó.

Figs 410–417. Mecolaesthus bienmesabe Huber sp. nov.; from Lara, between Barquisimeto and Boconó (type locality; ZFMK Ar 21923–24). 410–412. Left palpal tarsus and procursus, prolateral, dorsal, and retrolateral views. 413–415. Left genital bulb, prolateral, dorsal, and retrolateral views (arrow: median sclerite on bulbal process). 416. Male chelicerae, frontal view. 417. Cleared female genitalia, dorsal view. Scale lines: 0.3 mm.

Figs 418–426. Mecolaesthus Simon, 1893; epigyna, ventral views and cleared female genitalia, ventral and dorsal views. 418–420. M. niquitanus (González-Sponga, 2011); from Trujillo, Laguna Negra (ZFMK Ar 21912). 421–423. M. longipes Huber sp. nov.; from Mérida, Mucuy (type locality; ZFMK Ar 21916). 424–426. M. bienmesabe Huber sp. nov.; from Lara, between Barquisimeto and Boconó (type locality; ZFMK Ar 21924).

Figs 401–409. Mecolaesthus longipes Huber sp. nov.; from Mérida, Mucuy (type locality; ZFMK Ar 21916). 401–403. Left palpal tarsus and procursus, prolateral, dorsal, and retrolateral views. 404– 406. Left genital bulb, prolateral, dorsal, and retrolateral views (arrow: median sclerite on bulbal process). 407–408. Male chelicerae, frontal and lateral views. 409. Cleared female genitalia, dorsal view (arrow: frame-like sclerite). Scale lines: 0.3 mm.

Figs 399–400. Mecolaesthus longipes Huber sp. nov.; from Mérida, Mucuy (type locality; ZFMK Ar 21916); left male pedipalp, prolateral and retrolateral views. Scale line: 0.5 mm.