Mesabolivar argentinensis
Creators: name: Huber, Bernhard A.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Pholcidae
Mesabolivar
Mesabolivar argentinensis

description: Mesabolivar argentinensis (Mello-Leitão, 1938)
Figs 411–418, 441–442
Litoporus argentinensis Mello-Leitão, 1938: 92, fig. 3 (♀, Argentina: Buenos Aires Province).
Mesabolivar argentinensis (Mello-Leitão): Huber 2000: 215, figs 840–842 (♀). Huber 2014: 139 (except specimen from P.N. El Palmar and part of specimens from Santa Maria; see Notes below).
Blechroscelis globulosus (Nicolet, 1849): Mello-Leitão 1941: 108, figs 5–6 (misidentification; see Notes below). Mesabolivar globulosus (Nicolet, 1849): Huber 2014: 139 (misidentification; see Notes below).
Notes. In a recent summary on the Pholcidae of Argentina (Huber 2014), I followed Mello-Leitão’s (1941) assignment of the widespread Argentinean Mesabolivar to M. globulosus (Nicolet). A more detailed study of the available specimens and of Nicolet’s (1849) original description suggests that this was wrong. Nicolet’s (lost) specimen(s) had a globular abdomen and a monochromous carapace; the Argentinean specimens (in Huber 2014 and below) have a slightly elongated abdomen (similar to M. iguazu, M. chapeco, etc.; cf. Figs 378–385) and a pale carapace with distinct brown median mark.
At the same time, the female type specimen of M. argentinensis shares with the specimens listed below two characters that distinguish this species from similar relatives: the absence of paired humps on the anterior epigynal plate (Figs 417–418, 441–442) and the absence of lateral dark marks on the carapace. It seems thus justified to assign all the Argentinean specimens below to M. argentinensis, even though none of them is even close to the type locality, Monte Veloz in Buenos Aires Province. New material from Buenos Aires Province is needed to test this assignment.
Two specimens assigned to M. argentinensis in Huber (2014) (one male from P.N. El Palmar and one of two males from Santa Maria) are in fact M. uruguayensis Machado et al., 2013.
Mello-Leitão’s (1941) drawing of the palp of “ Blechroscelis globulosus ” (his fig. 5) clearly shows the distal spine-like process of the procursus distinctive for what is here considered to be M. argentinensis (cf. Figs 411– 414). His drawing of the epigynum appears different (compare Mello-Leitão 1941: fig. 6 with Fig. 417 herein) but this is due to different angles of view: his drawing is in ventro-posterior view, the drawing herein is in ventral view.
The identity of Mesabolivar globulosus (Nicolet, 1849) (type locality: Chile, Valdivia) remains a mystery.
Diagnosis. (amendments; see Huber 2000). Distinguished from similar congeners (M. iguazu, M. uruguayensis, M. chapeco) by absence of dark lateral marks on carapace, by absence of paired humps on anterior epigynal plate (Figs 417–418, 441–442), by male cheliceral armature (Figs 415–416; proximal processes short, rounded, and directed towards lateral; distal apophyses barely visible in lateral view), by details of male palp (tarsus with low but distinct retrolateral hump, procursus with distinctive distal spine-like process and prolaterodorsal sclerite; Figs 411–414), and by first leg femora wider than other leg femora.
Type material. ARGENTINA: Buenos Aires: ♀ holotype, MLP (14031), Monte Veloz [35.45°S, 57.28°W], without date, leg. C. Bruch, examined (Huber 2000).
Other material examined. ARGENTINA: Misiones: 1♀, MACN (part of Ar 4350), Parque Nacional Iguazú, Área Cataratas [25°40.7’S, 54°26.9’W], xi.1954 (R.D. Schiapelli, J.A. De Carlo, J.M. Viana, M.E. Galiano). 1♂, MACN (part of Ar 4879), Santa María [27.89°S, 55.35°W, 150 m a.s.l.], x.1956 (M.J. Viana).
Catamarca: 2♂ 1♀ several juvs, MACN (Ar 19940, 20050), Mutquin [28.317°S, 66.117°W], 2000 m a.s.l., i.1996 (O. de Ferrariis). 1♀ 2 juvs, MACN (Ar 20015), El Rodeo [28.217°S, 65.867°W, 1100 m a.s.l.], i.1957 (M.E. Galiano).
Santiago del Estero: 1♂, MACN (Ar 4319), Weisburd [27.33°S, 62.60°W, 160 m a.s.l.], 23.ix.1947 (W. Partridge).
Mendoza: 1♀, MACN (Ar 19958), [Dpto. Las Heras: 32°51’S, 68°49’W], Papagallos, vii.1975 (A. Roig). 1♀, MACN (Ar 22139), Ruta Provincial 52, camino a Villavicencio (32°32.8’S, 68°57.4’W) 1250 m a.s.l., 30.viii.2008 (C. Grismado, M. Izquierdo, A. Ojanguren, Martínez).
Tucuman: 1♀, MACN (Ar 20076), Amaichá del Valle [26.60°S, 65.92°W, 1900 m a.s.l.], 17.viii.1995 (M.J. Ramírez, P.A. Goloboff).
La Rioja: 1♀ 1 juv., MACN (Ar 20109), Chilecito [29.17°S, 67.5°W, 1100 m a.s.l.], 27–30.i.1956 (M.E. Galiano). 1♀, MACN (Ar 20064), Ruta 40 camino a Famatina [~ 28.92°S, 67.52°W, 1700 m a.s.l.], ix.1981 (A. González). 1♀, MACN (part of Ar 20023), La Rioja, no further locality data, xi.1959 (J.M. Viana).
Salta: 1♀, MACN (Ar 20115), La Salamanca, 7 km S Alemanía [~ 25.67°S, 65.60°W, 1300 m a.s.l.], 18.vii.1995 (P.A. Goloboff, M.J. Ramírez). 1♂ in pure ethanol, MACN (Ar 32453), Alemanía, Ruta Provincial 68, km 80 [25.62°S, 65.61°W], 3.xi.2004 (C.J. Grismado, L.A. Compagnucci).
San Juan: 1♂ 2♀ 3 juvs, MACN (Ar 20036), 50 km N Marayes [~ 31.0°S, 67.25°W, 700 m a.s.l.], 12.iv.1979 (A. Roig).
Cordoba: 1♀ several juvs, MACN (Ar 13530), 2 km E Nono (31°48’S, 64°59’W), 900 m a.s.l., 3–9.ii.2008 (M. Ramírez).
Description. Male (MACN Ar 20036)
MEASUREMENTS. Total body length 4.1, carapace width 1.6. Distance PME-PME 160 µm, diameter PME 130 µm, distance PME-ALE 120 µm, distance AME-AME 30 µm, diameter AME 55 µm. Sternum width/length: 1.0/ 0.6. Leg 1: 35.0 (9.5 + 0.7 + 9.2 + 13.6 + 2.0), tibia 2: 6.1, tibia 3: 4.9, tibia 4: 6.1; tibia 1 L/d: 54. Femora 1–4 width (at half length): 0.30, 0.29, 0.25, 0.25.
COLOR. Specimen bleached, mostly pale ochre-yellow, carapace with distinct brown median mark, without lateral marks, clypeus not darkened, sternum and legs light brown; leg femora and tibiae with subdistal darker rings; abdomen pale gray, dorsally and laterally densely covered with purple marks, ventrally with small light brown area in front of gonopore.
BODY. Habitus as in M. iguazu (cf. Fig. 382); ocular area raised; carapace with distinct median furrow; clypeus unmodified; sternum unmodified.
CHELICERAE. With two pairs of frontal apophyses (Figs 415–416), proximal pair weakly sclerotized, rounded and distinctively diverging in frontal view; distal pair similar to putative close relatives, strongly sclerotized and close to median line, barely visible in lateral view.
PALPS. In general similar to M. iguazu and M. chapeco (cf. Huber 2000: figs 830, 833; Figs 390–391 herein); coxa apophysis as in M. iguazu (not with distinct distal process as in M. chapeco), tarsus with low but distinct retrolateral hump; procursus weakly curved, with distinctive distal elements (spine-like process, prolatero-dorsal sclerite, membranous elements; Figs 411–414).
LEGS. Without spines, without curved hairs, few vertical hairs; retrolateral trichobothrium on tibia 1 at 3%; prolateral trichobothrium present on tibia 1; tarsus 1 with>25 pseudosegments, distally fairly distinct.
Male (variation). Tibia 1 in three other males: 8.0, 9.1, 9.2.
Female (amendments; see Huber 2000)
Tibia 1 in nine females: 6.1–7.8 (mean 7.1). Epigynal plate evenly protruding towards posterior, with median pocket near posterior margin, without humps (Figs 417–418; 441–442); posterior epigynal plate large but barely visible. Some females with slightly more prominent ‘scape’ (process carrying epigynal pocket) than others.
Distribution. Apparently widely distributed in northern Argentina (Fig. 736). Mello-Leitão’s (1941) records suggest that this species ranges even further north into Jujuy Province.
description: Published as part of Huber, Bernhard A., 2018, The South American spider genera Mesabolivar and Carapoia (Araneae, Pholcidae): new species and a framework for redrawing generic limits, pp. 1-178 in Zootaxa 4395 (1) on pages 98-100, DOI: 10.11646/zootaxa.4395.1.1, http://zenodo.org/record/1202519