Mesabolivar pseudoblechroscelis González-Sponga, 1998

Huber, Bernhard A. & Villarreal, Osvaldo, 2020, On Venezuelan pholcid spiders (Araneae, Pholcidae), European Journal of Taxonomy 718, pp. 1-317 : 168-172

Mesabolivar pseudoblechroscelis González-Sponga, 1998

Figs 599–613 , 1049

Mesabolivari pseudoblechroscelis González-Sponga, 1998: 27 , figs 33–39 (♂ only) (♀, figs 40–41, not conspecific, see Notes below).

Misidentification (see Notes below)

Mesabolivar pseudoblechroscelis – Machado 2007: 88, figs 171–180.

Notes

As already noted by Machado (2011: 26), the 2 ♀♀ paratypes described by González-Sponga (1998) are not conspecific with the male holotype but are Mesabolivar eberhardi Huber, 2000 [ not M. aurantiacus (Mello-Leitṳo, 1930) as erroneously noted in Machado 2007: 88 and Huber 2018: 29].

The specimens described as M. pseudoblechroscelis in Machado (2007) originated from the type locality of M. acrensis Huber, 2018 in Brazil, Acre, and probably represent that species. In his later work, Machado (2011) no longer listed the Brazilian specimens as M. pseudoblechroscelis but correctly as an undescribed species.

We do not have precise coordinates of the type locality. In 2020, we collected at Mesa Bolívar but did not find this species. However, we only collected in a forest above the town, at ~ 1300 m a.s.l., while the types originate (according to González-Sponga 1998) from 1095 m a.s.l., i.e., the altitude of the town. We thus assume that the types were collected closer to the town, at approximately 8.474° N, 71.597° W. Our new specimens below originate from a much lower site (280 m a.s.l.) ~ 50 km NE of the type locality.

Diagnosis

Distinguished from most known congeners by general shape of procursus ( Figs 609–610 ; distinctively widened and strongly curved distal element); from two most similar known congeners ( M. acrensis Huber, 2018 ; M. maraba Huber, 2018 ) by details of procursus ( Figs 609–610 ; larger proximal dorsal process; ventral part of distal sclerite larger than in M. maraba , in prolateral view smaller than in M. acrensis ; tip wider than in M. acrensis ; subdistal dorsal process more prominent than in M. maraba ); by tip of bulbal process ( Figs 612–613 ; distal pointed sclerite longer than in M. acrensis , wider than in M. maraba ; dorsal process bifid like in M. maraba , unlike M. acrensis ); by shape of epigynum ( Figs 605–606 ; lateral processes directed towards lateral rather than ventral, in lateral view shorter than posterior median process); from both species apparently also by larger size and longer legs (male carapace width>1.5; male tibia 1 length>11.0; female tibia 1 length>6.0), and by strongly widened male femur 3 (barely wider than other femora in M. acrensis and M. maraba ).

Type material

VENEZUELA – Mérida • ♂ holotype, and 2 ♀♀ misidentified paratypes (see Notes above), MIZA 105737 ( MAGS 986 ), Mesa Bolívar [approximately 8.474° N, 71.597° W], 25 Dec. 1981 (A.R. Delgado de G., J.A. González D., M.A. González S.); examined .

New record

VENEZUELA – Mérida • 2 ♂♂, 2 ♀♀, ZFMK (Ar 21994), and 1 ♂, 3 ♀♀ in pure ethanol, ZFMK (Ven20-137), forest above Caño Azul (8.8543° N, 71.3651° W), 280 m a.s.l., 13 Feb. 2020 (B.A. Huber, O. Villarreal M., Q. Arias C.) .

Redescription of male (Caño Azul, ZFMK Ar 21994)

MEASUREMENTS. Total body length 3.4, carapace width 1.7. Distance PME–PME 150 µm, diameter PME 130 µm, distance PME–ALE 120 µm, distance AME–AME 65 µm, diameter AME 60 µm. Sternum width/length: 1.10/0.74. Leg 1: 58.9 (14.1 +0.5+14.1 + 27.1 +3.1), tibia 2: 9.9, tibia 3: 7.1, tibia 4: 9.6; tibia 1 L/d: 104. Femora 1–4 width (at half length): 0.19, 0.21, 0.34, 0.20; tibiae 1–4 width (at half length): 0.14, 0.14, 0.15, 0.15.

COLOR (in ethanol). Carapace ochre-yellow to orange, with darker median mark, ocular area posteriorly also darkened; clypeus only at rim dark brown; sternum orange; legs ochre to light brown, with indistinct darker rings on femora (subdistally) and tibiae (proximally; subdistal rings barely visible), tips of femora and tibiae lighter; abdomen greenish-gray, densely covered with many black and few white internal marks dorsally and laterally, without ventral mark.

BODY. Habitus as in Figs 601–602 ; ocular area distinctly raised (higher than usual in genus); carapace with distinct median furrow; clypeus slightly swollen, with sclerotized margin; sternum unmodified. Abdomen slightly longer than high, pointed at spinnerets.

CHELICERAE. Shape as in M. acrensis and M. maraba (cf. Huber 2018: figs 18–19) but larger than in M. acrensis (maximum width 0.67, versus 0.53 in M. acrensis ); with pair of long, slender apophyses, straight in lateral view.

PALPS. As in Figs 599–600 , in general very similar to M. acrensis and M. maraba (cf. Huber 2018: figs 13–14) but larger (femur length: 1.20, versus 1.14 in M. maraba and 0.86 in M. acrensis ); coxa with conical retrolateral apophysis; trochanter with retrolateral apophysis; femur very large, proximally with retrolateral apophysis and prolateral hump set with short hairs; tarsus with one small and one large dorsal processes, with some hairs bent towards dorsal; procursus ( Figs 609–610 ) distally widened and strongly curved towards dorsal, with large ventro-distal sclerite separated from proximal part by whitish area; bulbal process with distinctive distal structures ( Figs 612–613 ).

LEGS. Without spines and curved hairs, few vertical hairs; retrolateral trichobothrium on tibia 1 at 2%; prolateral trichobothrium present on tibia 1; tarsus 1 with ~30 pseudosegments, mostly distinct.

VARIATION. Tibia 1 in other male: 11.7 (first legs missing in third male). Femora 1–4 width (at half length) in this male: 0.18, 0.19, 0.28, 0.19.

Description of female

In general similar to male ( Figs 603–604 ) but carapace ochre-brown rather than yellow to orange, with larger brown median mark; ocular area slightly lower than in males; dark rings and whitish tips of femora and tibiae slightly more distinct; clypeus not swollen and margin not sclerotized. Tibia 1 in six females: 6.4–7.5 (mean 7.1). Epigynum ( Figs 605–606 ) anterior plate with large median depression ending posteriorly in large pocket; pair of conical lateral processes directed towards lateral and posterior; posterior plate large, simple. Internal genitalia ( Figs 607–608 , 611 ) with small elongated pore-plates in transversal position, distinctive median dark anterior structure.

Distribution

Known from two localities in the Venezuelan state Mérida (Fig. 1049).

Natural history

At Caño Azul, the spiders were collected in a forest remnant along a small stream. This species shared the microhabitat (low vegetation and sheltered spaces near the ground) with the similar but larger (and more abundant) M. eberhardi ; the webs of M. pseudoblechroscelis were smaller (~ 20–30 cm diameter) and closer to the ground. González-Sponga (1998) collected the types in a cloud forest with coffee, among the buttress roots of trees.

Figures

Figs 599–608. Mesabolivar pseudoblechroscelis González-Sponga, 1998. 599–600. Right pedipalp of male holotype (MIZA 105737; MAGS 986), retrolateral and prolateral views. 601–604. Live male and female from Mérida, Caño Azul. 605–608. Epigynum, lateral and ventral views, and cleared female genitalia, ventral and dorsal views, female from Mérida, Caño Azul (ZFMK Ar 21994). Abbreviations: lp= lateral process; mp =median process.

Figs 609–613. Mesabolivar pseudoblechroscelis González-Sponga, 1998; from Mérida, Caño Azul (ZFMK Ar 21994). 609–610. Left male palpal tarsus and procursus, prolateral and retrolateral views. 611. Cleared female genitalia, dorsal view. 612–613. Process of left genital bulb, prolateral and retrolateral views. 1 =proximal dorsal process; 2=ventral part of distal sclerite; 3=subdistal dorsal process. Scale lines: 0.5 mm.