Mecolaesthus cordiformis ( González-Sponga, 2009 )

Huber, Bernhard A. & Villarreal, Osvaldo, 2020, On Venezuelan pholcid spiders (Araneae, Pholcidae), European Journal of Taxonomy 718, pp. 1-317 : 84-87

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.

Figures

Figs 212–219. Mecolaesthus Simon, 1893; live specimens. 212–214. M. cornutus Huber, 2000; male from Mérida, Mucuy, female with egg sac from Mérida, Escaguey. 215. M. cordiformis (González- Sponga, 2009); male from Mérida, forest near La Carbonera. 216–217. M. mucuy Huber, 2000; male and female from Mérida, Mucuy. 218–219. M. tabay Huber, 2000; male and female from Mérida, El Valle.

Figs 266–267. Mecolaesthus cordiformis (González-Sponga, 2009); holotype from Mérida, La Carbonera (MIZA 105601; MAGS 1064); left male pedipalp, prolateral and retrolateral views. Scale line: 0.5 mm.

Figs 268–270. Mecolaesthus cordiformis (González-Sponga, 2009); holotype and paratype from Mérida, La Carbonera (MIZA 105601; MAGS 1064). 268. Male ocular area, clypeus, and chelicerae, oblique frontal view. 269–270. Epigynum, ventral and lateral views. Scale lines: 0.5 mm.

Figs 271–276. Mecolaesthus Simon, 1893; epigyna, ventral views and cleared female genitalia, ventral and dorsal views. 271–273. M. tabay Huber, 2000; from Mérida, El Valle (ZFMK Ar 21888). 274– 276. M. cordiformis (González-Sponga, 2009); from Mérida, near La Carbonera (ZFMK Ar 21890).

Figs 259–265. Mecolaesthus tabay Huber, 2000; from Mérida, Mucuy (male, ZFMK Ar 21886) and from Mérida, El Valle (female, ZFMK Ar 21888). 259–261. Left palpal tarsus and procursus, prolateral, dorsal, and retrolateral views. 262–264. Left genital bulb, prolateral, dorsal, and retrolateral views (arrow: distal prolateral sclerite, shorter and with more slender tip in males from El Valle). 265. Cleared female genitalia, dorsal view. Scale lines: 0.3 mm.