Mecolaesthus yerbatero Huber, 2020

Huber, Bernhard A. & Villarreal, Osvaldo, 2020, On Venezuelan pholcid spiders (Araneae, Pholcidae), European Journal of Taxonomy 718, pp. 1-317 : 153-155

Mecolaesthus yerbatero Huber sp. nov.

urn:lsid:zoobank.org:act:69C90207-D2BA-4DA2-9F06-54A7AC298AF4

Figs 554–555 , 560–568 , 576–578 , 1045

Diagnosis

Easily distinguished from similar pale leaf-dwelling Venezuelan pholcids ( Mecolaesthus fallax Huber sp. nov.; Systenita prasina Simon, 1893 ; Metagonia spp.) by presence of AME, by distinctive pair of apophyses distally on male chelicerae ( Figs 566–567 ; directed towards median), by shape of simple procursus with bifid tip ( Figs 560–562 ), and by epigynum and female internal genitalia ( Figs 568 , 576– 578 ): slightly longer than wide weakly sclerotized plate; tube-like internal structure ending at posterior margin of plate (arrow in Fig. 568 ); distinctive position of pore plates.

Etymology

Named for “Yerbatero” of Colombian singer-songwriter Juanes, in which the protagonist has remedies to offer for almost any suffering; noun in apposition.

Type material VENEZUELA – Mérida • ♂ holotype, ZFMK (Ar 21949), between Mérida and Barinas, ‘site 2’

(8.8645° N, 70.6182° W), 1650 m a.s.l., 27 Nov. 2018 (B.A. Huber, O. Villarreal M.).

Other material

VENEZUELA – Mérida • 2 ♂♂, 1 ♀, 3 juvs, ZFMK (Ar 21950), and 1 ♀, 6 juvs in pure ethanol, ZFMK (Ven18-235), same collection data as for holotype .

Description

Male (holotype)

MEASUREMENTS. Total body length 2.6, carapace width 1.0. Distance PME–PME 130 µm; diameter PME 80 µm; distance PME–ALE 70 µm; distance AME–AME 35 µm; diameter AME 20 µm. Leg 1: 37.2 (8.9 +0.5 +8.9+16.0 + 2.9), tibia 2: 5.3, tibia 3: 3.9, tibia 4: 4.8; tibia 1 L/d: 89.

COLOR (in ethanol). Carapace pale ochre-gray (with greenish internal mark in live specimens), with thin dark median line; ocular area with light brown V-mark; clypeus light brown; sternum whitish; palps ochre-yellow (reddish in live specimens); legs ochre-yellow, with dark rings on tibiae proximally and subdistally, femur 1 proximally darkened; abdomen pale greenish gray, with few darker bluish marks dorsally, monochromous ventrally.

BODY. Habitus as in Fig. 554 . Ocular area slightly raised. Carapace very weakly inflated posteriorly, with shallow thoracic groove in anterior part. Clypeus unmodified. Sternum wider than long (0.80/0.55), unmodified. Abdomen slightly elongated, widest in posterior third, pointed at spinnerets.

CHELICERAE. As in Figs 566–567 , with pair of proximal anterior humps provided distally with transversal ridges, and distinctive pair of distal apophyses directed towards median.

PALPS. In general similar to M. guasacaca Huber sp. nov. (cf. Figs 534–535 ) but trochanter with larger ventral process and femur proximally with lower retrolateral process; procursus ( Figs 560–562 ) simple, proximally with indistinct dorsal process, distally with bifid tip; genital bulb ( Figs 563–565 ) with large distal process mostly membranous.

LEGS. Without spines and curved hairs; few vertical hairs; retrolateral trichobothrium of tibia 1 at 2.5%; prolateral trichobothrium present on all leg tibiae; tarsus 1 with ~45 pseudosegments, mostly distinct.

Male (variation)

Tibia 1 in two other males: 9.0, 9.2.

Female

In general similar to male ( Fig. 555 ) but paler (recently molted?), entire prosoma whitish, femur 1 proximally not darkened. Tibia 1 in two females: 5.4, 6.0. Epigynum ( Fig. 576 ) weakly sclerotized, slightly longer than wide, posteriorly weakly bulging, internal structures partly visible in uncleared specimens. Internal genitalia ( Figs 568 , 577–578 ) with tube-like structure ending at posterior margin of epigynal plate (arrow in Fig. 568 ); distinctive position of pore plates; anterior ‘valve’ with median receptacle.

Distribution

Known from type locality only, in Venezuela , Mérida (Fig. 1045).

Natural history

The spiders were found in a forest along a mountain stream. Their slightly domed sheet webs were attached to the undersides of leaves ~ 0.5–1.5 m above the ground, with the spider resting in the apex of the dome directly under the leaf. Most specimens were found in a ‘regular’ position, i.e., ventral side of abdomen facing upwards; one specimen was found in an inverted resting position (abdomen dorsal side upwards).

Figures

Figs 554–559. Mecolaesthus Simon, 1893; live specimens. 554–555. M. yerbatero Huber sp. nov.; male and female from Mérida, between Mérida and Barinas. 556–559. M. fallax Huber sp. nov.; males from Mérida, Mucuy and females from Trujillo, Laguna Negra.

Figs 560–568. Mecolaesthus yerbatero Huber sp. nov.; from Mérida, between Mérida and Barinas (type locality; ZFMK Ar 21950). 560–562. Left palpal tarsus and procursus, prolateral, dorsal, and retrolateral views. 563–565. Left genital bulb, prolateral, dorsal, and retrolateral views. 566–567. Male chelicerae, frontal and lateral views. 568. Cleared female genitalia, dorsal view (arrow: tube-like internal structure). Scale lines: 0.3 mm.

Figs 576–581. Mecolaesthus Simon, 1893; epigyna, ventral views and cleared female genitalia, ventral and dorsal views. 576–578. M. yerbatero Huber sp. nov.; from Mérida, between Mérida and Barinas (type locality; ZFMK Ar 21950). 579–581. M. fallax Huber sp. nov.; from Trujillo, Laguna Negra (type locality; ZFMK Ar 21953).

Figs 532–535. Mecolaesthus guasacaca Huber sp. nov.; male holotype from Falcón, Curimagua (ZFMK Ar 21947). 532. Habitus, dorsal view. 533. Coxae 4 and anterior part of abdomen, ventral view (arrow: median ventral process on coxa 4). 534–535. Left pedipalp, prolateral and retrolateral views. Scale line: 0.5 mm.