Mecolaesthus multidenticulatus ( González-Sponga, 2003 )

Huber, Bernhard A. & Villarreal, Osvaldo, 2020, On Venezuelan pholcid spiders (Araneae, Pholcidae), European Journal of Taxonomy 718, pp. 1-317 : 105-108

Mecolaesthus multidenticulatus ( González-Sponga, 2003)

Figs 341–343 , 356–364 , 368 , 376–378 , 1043

Falconia multidenticulata González-Sponga, 2003: 96 , figs 3a–j (♂ ♀).

Ayomania multidenticulata – González-Sponga 2005: 108.

Venezuela multidenticulata – Koçak & Kemal 2008: 4.

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

Diagnosis

Distinguished from most congeners [except M. grandis ( González-Sponga, 2009) and M. tuberculosus ( González-Sponga, 2009) ] by armature of male chelicerae ( Figs 362–363 , 368 ; pair of large frontal processes curved downwards and set with 3–4 modified hairs each, and two small modified hairs more distally on weakly sclerotized area), by shape of main bulbal process ( Figs 359–361 ; two large sclerites visible in prolateral view), by transparent process on procursus distally bent toward retrolateral ( Fig. 357 ), and by shape of epigynum ( Fig. 376 ; short but wide plate, pair of anterior internal sclerites extending towards lateral); from the very similar M. grandis and M. tuberculosus by male cheliceral apophyses: without conspicuous projection towards median ( Fig. 368 ; in contrast to M. grandis ) and without conspicuous lateral process ( Fig. 362 ; in contrast to M. tuberculosus ). From M. tuberculosus also by larger distance between pair of rounded sclerites in female internal genitalia (arrows in Fig. 377 ).

Type material

VENEZUELA – Falcón • ♂ holotype, 1 ♀, 1 juv. paratypes, Curimagua, Sierra de San Luis (11.172° N, 69.668° W), “ 550 m s.n.m.” (see Notes below), 10 Sep. 1998 (A.R. Delgado, M.A. González-S.); not examined (the types were on loan to another researcher) .

New record VENEZUELA – Falcón • 11 ♂♂, 12 ♀♀, ZFMK (Ar 21904–05), and 3 ♂♂, 6 ♀♀ in pure ethanol,

ZFMK (Ven18-195), Sierra de San Luis , E Curimagua (11.1748° N, 69.6273° W), 960 m a.s.l., 18 Nov. 2018 (B.A. Huber, O. Villarreal M.).

Notes

The type series of this species has been on loan to another researcher and could not be examined. The newly collected material below originates from near Curimagua in the Sierra de San Luis, but it is not clear how far the new collecting site is from the actual type locality. The coordinates in the original publication are very precise and 4.5 km W of our new collecting site, but judging from other coordinates in González-Sponga’s papers they may not be accurate. The spot identified by the coordinates lies at ~ 1050 m a.s.l., not at 550 m as indicated in the original publication.

There seems to be no reasonable doubt that the new material below is correctly identified. However, contrary to González-Sponga’s (2003) statement, the male palp of this species has two trichobothria, as usual in Pholcidae , not one (the single known pholcid species with only one palpal trichobothrium is Arenita fazendinha Huber & Carvalho, 2019 ).

Several measurements in the original publication are obviously wrong (e.g., male femur 3 longer than femur 4; female femur 1 shorter than femur 2; female tibia 1 shorter than tibia 2; female metatarsus 2 shorter than tibia 2).

Redescription

Male (ZFMK Ar 21904)

MEASUREMENTS. Total body length 3.6, carapace width 1.3. Distance PME–PME 90 µm; diameter PME 110 µm; distance PME–ALE 90 µm; diameter AME 20 µm; distance AME–AME 20 µm. Leg 1: 38.0 (9.0 +0.5 +9.1+16.9 + 2.5), tibia 2: 5.8, tibia 3: 4.5, tibia 4: 5.0; tibia 1–4 diameters: 110 µm, 130 µm, 150 µm, 140 µm; tibia 1 L/d: 83.

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 indistinct 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 barely visible dark mark above pedicel opposing carapace inflation.

BODY. Habitus as in Fig. 341 . Ocular area distinctly raised. Carapace anteriorly with distinct thoracic groove, posteriorly slightly inflated. Clypeus unmodified. Sternum wider than long (0.95/0.60).Abdomen slightly elongated, pointed at spinnerets.

CHELICERAE. As in Figs 362–363 , 368 , with pair of large frontal apophyses set with 3–4 slightly hooked short hairs and ~2 straight strong hairs in addition to regular setae, with two additional short hairs on whitish area below main apophyses, and small unsclerotized ridge.

PALPS. In general as in M. grandis (cf. Figs 346–347 ); coxa with retrolateral apophysis, trochanter with 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 356–358 ) at basis with bifid dorsal process with branches of equal length, with small retrolateral apophysis, distally with pair of membranous processes: retrolateral process bent towards retrolateral, with slightly sclerotized ring-shaped element, prolateral process with pointed tip; genital bulb complex ( Figs 359– 361 ), distally mostly membranous/whitish but with distinctive distal sclerites (very similar M. grandis ).

LEGS. Without spines and curved hairs; few vertical hairs; retrolateral trichobothrium of tibia 1 at 3%; prolateral trichobothrium present on all leg tibiae; tarsus 1 with ~35 pseudosegments, mostly distinct.

Male (variation)

Tibia 1 in ten males: 7.5–9.5 (mean 8.9); most males with light to dark brown book lung covers, but anterior brown plates opposing fourth coxae absent in some males, unrelated to body size. Brown plate above pedicel also absent in some males. Sternum in some males with light brown lateral marginal bands. Rings on legs in some males barely visible.

Female

In general similar to male ( Figs 342–343 ), 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: 5.7–6.8 (mean 6.2). Epigynum ( Fig. 376 ) small, light brown, wider than long, internal sclerites partly visible in uncleared specimens (very similar M. grandis and M. tuberculosus ). Internal genitalia ( Figs 364 , 377–378 ) 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.

Distribution

Known from Sierra de San Luis only, in Venezuela , Falcón (Fig. 1043).

Natural history

This species was abundant at the bases of trees (often in close proximity to Mesabolivar eberhardi Huber, 2000 ), and in protected spaces close to the ground. The domed sheet webs were mostly very strongly curved. According to González-Sponga (2003), the type specimens were collected in crevices of rotting tree trunks.

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 356–364. Mecolaesthus multidenticulatus (González-Sponga, 2003); from Falcón, Curimagua (type locality; ZFMK Ar 21904–05). 356–358. Left palpal tarsus and procursus, prolateral, dorsal, and retrolateral views. 359–361. Left genital bulb, prolateral, dorsal, and retrolateral views. 362–363. Male chelicerae, frontal and lateral views. 364. 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).

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.