Mecolaesthus discrepantis ( González-Sponga, 2003 ) Huber & Villarreal, 2020

Huber, Bernhard A. & Villarreal, Osvaldo, 2020, On Venezuelan pholcid spiders (Araneae, Pholcidae), European Journal of Taxonomy 718, pp. 1-317 : 97-101

Mecolaesthus discrepantis ( González-Sponga, 2003) comb. nov.

Figs 309–311 , 321–330 , 334–337 , 1042

Queliceria discrepantis González-Sponga, 2003: 98 , figs 4a–j (♂ ♀).

Diagnosis

Easily distinguished from known congeners by armature of male chelicerae ( Fig. 329 ; pair of large frontal processes, each with subdistal ventral branch) and epigynum with pair of large pointed posterior processes ( Figs 334–337 ); also by two distinctive elements distally on procursus ( Figs 323–325 ) and genital bulb with distinctive prolateral distal apophysis and membranous distal elements ( Figs 326–328 ).

Type material

VENEZUELA – Trujillo • 3 ♂♂, 4 ♀♀, and 3 juvs (+ 3 ♀♀, misidentified) types (see Notes below), MIZA 105754 ( MAGS 1383 ), Boconó, Laguna Negra [approximately 9.305° N, 70.177° W], 28 Feb. 1993 (A.R. Delgado, M.A. González S.); examined .

New record

VENEZUELA – Trujillo • 2 ♂♂, 2 ♀♀, ZFMK (Ar 21898), and 3 ♀♀ in pure ethanol, ZFMK (Ven18- 206), near Boconó, Laguna Negra (9.3054° N, 70.1752° W), 1870 m a.s.l., 21 Nov. 2018 (B.A. Huber, O. Villarreal M.) .

Notes

The original description mentions 1 ♂ holotype ( MAGS 1383a) and 1 ♀, 6 juvs paratypes ( MAGS 1383b), i.e., eight specimens. However, the MIZA has only one vial numbered “1383” (i.e., the holotype is not separated) and the vial contains 13 specimens: 3 ♂♂, 7 ♀♀, 3 juvs. Since there is no doubt about the identity of this species there is no need for a lectotype, and the type specimens are treated as ‘types’. Three females in the type vial are misidentified Canaima loca Huber sp. nov.

The coordinates in the original description are wrong, i.e., ~ 15 km SW of Laguna Negra. Figures 4 i–j in the original publication show the female abdomen (contrary to the legend of this figure).

Redescription

Male (ZFMK Ar 21898)

MEASUREMENTS. Total body length 2.9, carapace width 1.3. Distance PME–PME 120 µm; diameter PME 115 µm; distance PME–ALE 100 µm; diameter AME 30 µm; distance AME–AME 15 µm. Leg 1: 23.2 (5.2 +0.4 +5.5+10.1 + 2.0), tibia 2: 3.3, tibia 3: 2.5, tibia 4: 3.1; tibia 1–4 diameters: 135 µm, 150 µm, 165 µm, 160 µm; tibia 1 L/d: 41.

COLOR (in ethanol). Carapace ochre, darker brown frontally including ocular area and clypeus; sternum dark brown; legs ochre to light brown, with 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, and bluish mark behind gonopore.

BODY. Habitus as in Figs 309–310 . Ocular area distinctly raised. Carapace anteriorly with shallow but distinct thoracic groove, posteriorly slightly inflated. Clypeus unmodified. Sternum wider than long (0.88/0.60). Abdomen slightly elongated and pointed at spinnerets.

CHELICERAE. As in Fig. 329 , with pair of large frontal apophyses, each with subdistal ventral branch; processes dark on dorsal side, whitish on ventral side.

PALPS. As in Figs 321–322 ; coxa with strong retrolateral apophysis, trochanter with rounded ventral process, femur proximally with retrolateral process, distally with prominent rounded ventral process, retrolateral trichobothrium of tibia in very distal position; procursus ( Figs 323–325 ) proximally very simple, distally with two distinctive elements; genital bulb ( Figs 326–328 ) large, with distinctive prolateral distal apophysis and membranous distal elements.

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 ~30 pseudosegments, mostly distinct.

Male (variation)

Tibia 1 in one other measured male: 5.5.

Female

In general similar to male ( Fig. 311 ). Tibia 1 in two females (newly collected specimens): 3.9, 4.1. Epigynum large, heavily sclerotized, with pair of large pointed posterior processes; angle between processes slightly variable (compare Figs 334 and 336 ). Internal genitalia ( Figs 330 , 336–337 ) with pair of anterior sclerites extending towards lateral, median receptacle, pair of large pore plates converging anteriorly and tilted into almost vertical position, and narrow median sclerite connecting anterior structures with posterior processes.

Distribution

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

Natural history

In the original description, González-Sponga (2003) mentions the underside of petioles of dead palm leaves as microhabitat of this species. We found only one female in this microhabitat.All other specimens were collected from small webs at the bases of sedges ( Cyperaceae ) in the forest, very close to the ground.

Figures

Figs 306–311. Mecolaesthus Simon, 1893; live specimens. 306–308. M. piedras Huber sp. nov.; male and female with egg sac from Mérida, Las Piedras. 309–311. M. discrepantis (González-Sponga, 2003); male and female from Trujillo, Laguna Negra.

Figs 321–322. Mecolaesthus discrepantis (González-Sponga, 2003); type from Trujillo, Laguna Negra (MIZA 105754; MAGS 1383); left male pedipalp, prolateral and retrolateral views. Scale line: 0.5 mm.

Figs 323–330. Mecolaesthus discrepantis (González-Sponga, 2003); from Trujillo, Laguna Negra (type locality; ZFMK Ar 21898). 323–325. Left palpal tarsus and procursus, prolateral, dorsal, and retrolateral views. 326–328. Left genital bulb, prolateral, dorsal, and retrolateral views. 329. Male prosoma, lateral view. 330. Cleared female genitalia, dorsal view. Scale lines: 323–328, 330=0.3 mm; 329=0.5 mm.

Figs 331–337. Mecolaesthus Simon, 1893; epigyna, ventral views and cleared female genitalia, ventral and dorsal views. 331–333. M. piedras Huber sp. nov.; from Mérida, Las Piedras (type locality; ZFMK Ar 21897). 334–337. M. discrepantis (González-Sponga, 2003); from Trujillo, Laguna Negra (type locality; epigyna: MIZA 105754 / MAGS 1383; cleared female genitalia: ZFMK Ar 21898).

Figs 1–4. Live specimens. 1–2. Anopsicus ana Huber sp. nov.; male from Falcón, Cueva del Guano and female from Cerro Santa Ana. 3–4. Blancoa piacoa Huber, 2000; male and female with egg sac from Bolívar, Ciudad Guayana.