Mecolaesthus chicha Huber, 2020

Huber, Bernhard A. & Villarreal, Osvaldo, 2020, On Venezuelan pholcid spiders (Araneae, Pholcidae), European Journal of Taxonomy 718, pp. 1-317 : 87-91

Mecolaesthus chicha Huber sp. nov.

urn:lsid:zoobank.org:act:F0D1196A-2958-46E1-BFA7-54F38F06063C

Figs 277–279 , 283–290 , 300–302 , 1042

Diagnosis

Easily distinguished from known congeners (including the otherwise very similar M. parchita Huber sp. nov.) by armature of male chelicerae ( Fig. 289 ; pair of pointed apophyses proximally arising from round humps and pair of blunt processes more distally) and by epigynum ( Fig. 300 ; only median area sclerotized, widening posteriorly, not divided into two median sclerites as in M. parchita Huber sp. nov.).

From most congeners (except M. parchita Huber sp. nov.) also by two dark rings on leg femora (instead of only one or none).

Etymology

The species name refers to chicha , a Latin American beverage. In Venezuela it is made of boiled rice, milk, and sugar, has the consistency of eggnog, and contains no alcohol as it is not fermented; noun in apposition.

Type material

VENEZUELA – Mérida • ♂ holotype, ZFMK (Ar 21891), between Bailadores and Pregonero (8.1701° N, 71.8990° W), 2960 m a.s.l., forest along stream, 9 Feb. 2020 (B.A. Huber, O. Villarreal M., Q. Arias C.) .

Other material examined

VENEZUELA – Mérida • 5 ♂♂, 7 ♀♀, 5 juvs, ZFMK (Ar 21892–93), and 1 ♂, 5 ♀♀, 7 juvs in pure ethanol, ZFMK (Ven20-116), same collection data as for holotype .

Description

Male (holotype)

MEASUREMENTS. Total body length 2.8, carapace width 1.2. Distance PME–PME 120 µm; diameter PME 110 µm; distance PME–ALE 90 µm; diameter AME 25 µm; distance AME–AME 20 µm. Leg 1: 25.6 (6.0 +0.5 +6.1+10.8 + 2.2), tibia 2: 3.9, tibia 3: 3.0, tibia 4: 3.5; tibia 1–4 diameters: 120 µm, 130 µm, 140 µm, 135 µm; tibia 1 L/d: 51.

COLOR (in ethanol). Carapace pale gray, lateral margins and ocular area darker brown, indistinct posterior internal triangular dark mark (in live specimens with large greenish central mark; Fig. 277 ); clypeus dark brown; sternum whitish; legs ochre-yellow, with distinct dark rings on femora (centrally and subdistally) and tibiae (subproximally and subdistally); abdomen pale greenish-gray, dorsally and laterally with dark bluish marks, ventrally with brown mark in gonopore area, light brown book lung covers, and large bluish median marks in front and behind gonopore; without dark mark above pedicel.

BODY. Habitus as in Fig. 277 . Ocular area distinctly raised. Carapace anteriorly with distinct but shallow thoracic groove; not visibly inflated. Clypeus unmodified. Sternum wider than long (0.76/0.58). Abdomen oval, pointed at spinnerets.

CHELICERAE. As in Fig. 289 , with pair of pointed apophyses proximally arising from round humps and pair of blunt processes more distally.

PALPS. In general similar to M. mucuy (cf. Huber 2000: figs 1028–1029) and M. tabay (cf. Figs 257–258 ); largely indistinguishable from M. parchita Huber sp. nov.; coxa with retrolateral apophysis, trochanter with small rounded ventral process, femur proximally with large retrolateral process, distally with short obtuse ventral process (arrow in Fig. 283 ), retrolateral trichobothrium of tibia in very distal position; procursus ( Figs 283–285 ) at basis with bifid dorsal process, with distinct retrolateral process, simple tip partly membranous; genital bulb complex ( Figs 286–288 ), distally mostly membranous/whitish but with distinctive distal sclerites (largely identical to M. parchita Huber sp. nov.; similar M. peckorum ).

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 ~40 pseudosegments, mostly distinct.

Male (variation)

Tibia 1 in six males (incl. holotype): 6.1–6.3 (mean 6.2); posterior internal mark on carapace sometimes absent.

Female

In general similar to male ( Fig. 278 ). Tibia 1 in seven females: 4.4–5.1 (mean 4.7). Epigynum ( Fig. 300 ) slightly protruding, only median area sclerotized, laterally whitish, sclerotized area widening posteriorly; posterior plate short and wide. Internal genitalia ( Figs 290 , 301–302 ) with Y-shaped sclerite connected

to median posterior sclerite, pore plates tilted into almost vertical position and converging dorsally and anteriorly; with complex system of anterior folds and arcs.

Distribution

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

Natural history

Most adult specimens were found close to the ground, by beating overhanging mosses growing on the rocks or overhanging masses of leaf litter near a small forest stream. They lived in small, relatively flat sheet webs with a diameter of ~ 10 cm. Juveniles were much lighter than adults ( Fig. 279 ) and were mostly found higher in the vegetation, on trunks of tree ferns or even on the undersides of green leaves.

Figures

Figs 277–282. Mecolaesthus Simon, 1893; live specimens. 277–279. M. chicha Huber sp. nov.; male, female, and juvenile from Mérida, between Bailadores and Pregonero. 280–282. M. parchita Huber sp. nov.; male, female, and juvenile from Mérida, between Tovar and Guaraque.

Figs 283–290. Mecolaesthus chicha Huber sp. nov.; from Mérida, between Bailadores and Pregonero (type locality; ZFMK Ar 21892–93). 283–285. Left palpal tarsus and procursus, prolateral, dorsal, and retrolateral views (arrow: ventral femur apophysis). 286–288. Left genital bulb, prolateral, dorsal, and retrolateral views. 289. Male chelicerae, frontal view. 290. Cleared female genitalia, dorsal view. Scale lines: 0.3 mm.

Figs 300–305. Mecolaesthus Simon, 1893; epigyna, ventral views and cleared female genitalia, ventral and dorsal views. 300–302. M. chicha Huber sp. nov.; from Mérida, between Bailadores and Pregonero (type locality; ZFMK Ar 21893). 303–305. M. parchita Huber sp. nov.; from Mérida, between Tovar and Guaraque (type locality; ZFMK Ar 21896).

Figs 257–258. Mecolaesthus tabay Huber, 2000; from Mérida, Mucuy (ZFMK Ar 21886); left male pedipalp, prolateral and retrolateral views. Scale line: 0.3 mm.