Mecolaesthus cordiformis
Creators: name: Huber, Bernhard A.
name: Villarreal, Osvaldo
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Pholcidae
Mecolaesthus
Mecolaesthus cordiformis

description: Mecolaesthus cordiformis (González-Sponga, 2009)
Figs 215, 266–270, 274–276, 1042
Carbonaria cordiformis González-Sponga, 2009: 2, figs 1a–j (♂ ♀).
Mecolaesthus cordiformis – Huber et al. 2014a: 417.
Notes
The types of this species seem to originate from the same locality as those of the very similar M. azulita Huber, 2000. We do not have precise coordinates of this locality, but we assume that the actual collecting spots of the types of both nominal species are within ~ 1 km from the coordinates given for
the M. cordiformis type specimens below; the coordinates given in the original description are certainly wrong (~ 370 km N).
The newly collected material listed below is from very close to the type locality, presumably less than 1 km SW, at almost the same altitude. Nevertheless, there seem to be small morphological differences between these new specimens and the types of both M. cordiformis and M. azulita as well as between the two described species. The two described species are known from very small samples (2 ♂♂ and 1 ♂, 1 ♀, respectively), and we were not able to directly compare the specimens under the microscope. As a result, we consider the available data insufficient to decide on the species status of the two described species and the newly collected specimens. We chose a conservative approach in leaving both described species as valid and tentatively assign the newly collected specimens to M. cordiformis. Future collecting should cover several forest patches in the area and combine morphological and molecular data to reevaluate this unsolved complex.
Diagnosis
Distinguished from very similar M. azulita by male chelicerae (indistinct humps below main apophyses rather than small but distinct apophyses; median distal area without distinct sclerotized plates), by genital bulb distal dorsal part straight (curved toward dorsal in M. azulita), and by larger procursus (distal part beyond ventral ‘knee’ longer); female of M. azulita unknown.
Type material
VENEZUELA – Mérida • ♂ holotype, 1 ♀ paratype, MIZA 105601 (MAGS 1064), La Carbonera (“frente a el Hato La Carbonara, carretera Mérida-Jaji”) [approximately 8.633° N, 71.366° W], 19 Jun. 1987 (A.R. Delgado, M.A. González S.); examined.
New record/material assigned tentatively
VENEZUELA – Mérida • 5 ♂♂, 3 ♀♀, ZFMK (Ar 21890), and 1 ♀ in pure ethanol, ZFMK (Ven20- 111), forest near La Carbonera (8.6276° N, 71.3688° W), 2380 m a.s.l., 8 Feb. 2020 (B.A. Huber, O. Villarreal M., Q. Arias C.).
Notes on newly collected specimens
As indicated above, the newly collected specimens do neither fit perfectly M. cordiformis nor M. azulita. Complicating the situation further, they also resemble M. tabay in certain aspects. In particular, the male chelicerae seem indistinguishable from those of M. tabay (cf. Huber 2000: fig. 1040). The procursus also resembles M. tabay (cf. Figs 259–261) but there is only a single dorsal process proximally at the transition between tarsus and procursus. The genital bulb lacks the curved dorsal sclerite of M. azulita and it lacks the distinctive prolateral sclerite of M. tabay. The epigynum appears identical to that of the paratype of M. cordiformis (compare Figs 269 and 274), i.e., it is not triangular like that of M. tabay but rather evenly curved posteriorly; the internal female genitalia resemble those of M. tabay but the lateral sclerites are not strongly bent at their lateral extremes (compare Figs 273 and 276). Tibia 1 in five males: 4.6–5.1 (mean 4.8); in three females: 3.1, 3.3, 3.5.
Distribution
Known from type locality only, in Venezuela, Mérida (Fig. 1042).
Natural history
According to González-Sponga (2009) the type specimens were collected in rotten tree trunks. Most newly collected specimens were taken from the trunks of (alive) tree ferns.
description: Published as part of Huber, Bernhard A. & Villarreal, Osvaldo, 2020, On Venezuelan pholcid spiders (Araneae, Pholcidae), pp. 1-317 in European Journal of Taxonomy 718 on pages 84-87, DOI: 10.5852/ejt.2020.718.1101, http://zenodo.org/record/4069574