Description of two new species of Plesiopelma ( Araneae , Theraphosidae , Theraphosinae ) from Argentina

Two new species of Plesiopelma Pocock, 1901 from northern Argentina are described and diagnosed based on males and habitat descriptions are presented. Males of Plesiopelma paganoi sp. nov. differ from most of species by the absence of spiniform setae on the retrolateral face of cymbium, aspect of the palpal bulb. Plesiopelma aspidosperma sp. nov. differs from most species of the genus by the presence of spiniform setae on the retrolateral face of cymbium and it can be distinguished from P. myodes Pocock, 1901, P. longisternale (Schiapelli & Gerschman, 1942) and P. rectimanum (Mello-Leitão, 1923) by the separated palpal bulb keels and basal nodule of metatarsus I very developed. It differs from P. minense (Mello-Leitão, 1943) by the shape of the palpal bulb and basal nodule on metatarsus I well developed. Specimens were captured in Salta province, Argentina, inhabiting high cloud forests of Yungas eco-region.

Theraphosidae is a family of spiders comprising the largest known specimens in the world, with 950 described species in 124 genera constituting the most speciose family of the Mygalomorphae (Platnick, 2013).They are distributed throughout all tropical and many subtropical areas, mainly in Neotropical, Ethiopian, Oriental and Australian regions, with a few species in Europe (Miglio et al., 2013).Most of the known species inhabit the Neotropics and are included in the Theraphosinae, endemic to this region.Very little is known about the biology of the Theraphosidae and due to the homogeneity of theraphosinae morphology and the scarcity of taxonomic characters, its taxonomy is in a chaotic state (Raven, 1990, Pérez-Miles et al., 1996;Bertani, 2000).Despite the progress in the taxonomy of Theraphosidae in the last twenty years, much is yet to be done (Bertani et al., 2012;Miglio et al., 2013).
The genus Plesiopelma Pocock, 1901 comprises nine species recorded in Argentina, Brazil, Paraguay, Uruguay and Venezuela (Platnick, 2013).The type species, Plesiopelma myodes Pocock, 1901 was described by original designation and monotypy based on a male specimen from Uruguay.Piza (1976) described Plesiopelma imperatrix based on a female from Brazil, but with unknown locality.This species exhibit some diagnostic characters, such as presence of urticating hairs type I, femur III incrassate and spermathecae with one single receptacle that belong to other theraphosid genus (Pérez-Miles et al. 1996, Nagahama, unpublished data) and will be not considered for comparisons in this study.Pérez-Miles et al. (1996) considered Plesiopelma as a senior synonym of Ceropelma Mello-Leitão, 1923, containing at that time five species: C. flavohirtum (Simon, 1889), C. semiaurantiacum (Simon, 1897), C. insularis Mello-Leitão, 1923, C. longisternalis Schiapelli & Gerschman, 1942and C. gertschi Capocariacco, 1955.Plesiopelma flavohirtum was transferred to Catanduba by Yamamoto et al. (2012).Plesiopelma semiaurantiacum was described by Simon (1897) based on a male and female from Colonia Risso, Paraguay.Then, Mello-Leitão (1923a) described Plesiopelma insulare based on a male from Ilha de Alcatrazes, state of São Paulo, Brazil.In this same work, the author described Hapalopus rectimanum, later transferred to Plesiopelma by Pérez-Miles et al. (1996).Plesiopelma longisternale was established by Schiapelli & Gerschman (1942) based on a male specimen from Campo Gallo, Santiago del Estero Province, Argentina.This is the only species recorded for Argentina (Schiapelli & Gerschman, 1942;Platnick, 2013) with a wide distribution, comprising the provinces of Buenos Aires, Catamarca, Chaco, Córdoba, Corrientes, Entre Ríos, La Pampa, La Rioja, Mendoza and Santiago del Estero.Later, Capocariacco (1955) described Plesiopelma gertschi from a female of Barcelona, Anzoátegui, Venezuela, significantly expanding the geographical distribution of the genus.Yamamoto et al. (2007) transferred Tmesiphantes physopus Mello-Leitão, 1926 andT. minensis Mello-Leitão, 1943 to Plesiopelma.Plesiopelma physopus was described by Mello-Leitão (1926) based on a male from Campina Grande, state of Paraíba, Brazil, but the type material is probably lost (Yamamoto et al., 2007).Finally, Nagahama (unpublished data presented a revision and cladistic analysis of the genus Plesiopelma for his M.Sc.thesis dissertation.Unfortunately, according to the International Code of Zoological Nomenclature (articles 8 and 9, chapter 3, 4 th edition) any proposal of nomenclatural changes and/or designation of types or type localities on a dissertation work are not valid as a publication (ICZN, 1999).However, the contribution of Nagahama (unpublished data) allowed us to make comparisons of our material with the description and illustrations of the taxa treated in its work.
In a recent survey carried out in northern Salta province, Argentina, two new species of Plesiopelma were discovered and are herein described, diagnosed and some aspects on natural history are presented.

MATERIAL AND METHODS
The following abbreviations are utilized: ALE = anterior lateral eyes; AME = anterior median eyes; BN = basal nodule; D = dorsal; P = prolateral; PB = prolateral branch of tibial apophysis; PI = prolateral inferior keel; PLE = posterior lateral eyes; PLS = posterior lateral spinnerets; PME = posterior median eyes; PMS = posterior median spinnerets; PS = prolateral superior keel; R = retrolateral; RB = retrolateral branch of tibial apophysis.Female genitalia was dissected and cleared in concentrated lactic acid for 60-120 minutes to study the shape of spermathecae.All measurements are given in millimeters and were made with digital dial calipers with an error of 0.01mm, rounded up to one significant decimal where appropriate and an Olympus stereoscopic microscope equipped with a calibrated ocular micrometer scale.Photographs of preserved material were taken with a SONY Hx200v.The material studied are deposited in the arachnological collection of the Museo de La Plata (MLP, Luis Pereira), Buenos Aires, Argentina and Laboratorio de Zoología de Invertebrados II, Universidad Nacional del Sur (LZI, Nelson Ferretti), Bahía Blanca, Argentina.Spine notation follows Petrunkevitch (1925).Male palpal bulb keel terminology follows Bertani (2000).Urticating setae terminology follows Cooke et al. (1972).
Diagnosis.Differs from other theraphosids, except from some species of Homoeomma, by the presence of long convergent setae at central dorsal abdomen.Males differ from the other genera of Theraphosinae in the presence of a small subapical tooth on the bulb, absent in P. paganoi sp.nov.and P. aspidosperma sp.nov., in combination with a retrolateral basal nodule on metatarsus I (less or well developed).Palpal bulb with rounded body, prolateral superior and inferior keels well developed, parallel, close or separated to each other.Females differ by the spiral-shaped spermathecae with presence of granules.
Other material examined.Plesiopelma longisternale (Schiapelli & Gerschman 1942)  Etymology.The specific name is a patronym in honor of Luis G. Pagano, Argentinean ornithologist who participated in the collection of this new species.
Diagnosis.Plesiopelma paganoi sp.nov.differs from most of Plesiopelma species, except from P. insulare, by the high number of labial and maxillary cuspules (more than 130) and absence of spiniform setae on the retrolateral face of cymbium.It differs from P. insulare by the aspect of the palpal bulb, which presents a slender shape, shorter and strongly curved embolus with tooth absent.
Distribution.Northern Salta province, Argentina, next to the southern limit of Bolivia (Fig. 17).
Habitat description.Plesiopelma paganoi sp.nov.was found only in high cloud forest in the Yungas eco-region.This region comprises one of the most diverse ecosystems in Argentina (Cabrera, 1976;Cabrera & Willink, 1980).This high cloud forest represents less than 2% of the Argentinean territory but contains even 50% of the known biodiversity.The vegetation is distinguished by floors or stripes of well differentiate physiognomic characteristics.A juvenile specimen was found at the piedmont jungle inhabiting in small crevices under decomposing logs (Fig. 7), a Figs 2-6.Plesiopelma paganoi sp.nov., male holotype (MLP 19190): 2, carapace, dorsal; 3, palp, retrolateral (arrows show the absence of spiniform setae on tibia and cymbium); 4, tibial apophyses, ventral; 5, 6, copulatory bulb prolateral and retrolateral respectively.Scale: 1 mm.microhabitat shared with specimens of an undetermined species of Acanthoscurria (Jorge Barneche, pers.obs.).The other juvenile was captured walking at about 11-12 p.m. between shrubs next to a path and a dry river (Fig. 8).In this habitat, also specimens of Grammostola sp., Melloleitaoina crassifemur Gerschman & Schiapelli, 1960 (Theraphosidae) and Diplura sp.(Dipluridae) can be found (Jorge Barneche, pers.obs.).The piedmont jungle occupies the altitudinal level of about 400 and 700 m.a.s.l.represented by valleys, plains and hills.It has been proposed that this jungle constitutes a "biogeographic relict" due to ancient connections with other South American seasonal forests, such as Caatinga in Brazil (Prado, 2000;Morrone, 2006).Moreover, this area harbors a high percentage of exclusive species (about 30% of the total species) and some of the characteristics trees species are Calycophyllum multiflorum (Palo blanco) and Phyllostilon rhamnoides (Palo amarillo).
Etymology.The species is named to the genera of an emblematic tree from the eastern Salta province, Argentina, Aspidosperma, known as "quebracho blanco" in Spanish.The characteristic species in the area is Aspidosperma quebracho-blanco (Schltr.)Lyons.It is medically important due to an extract obtained from the bark known as "yohimbe", used around the world to treat asthma, lung disorders, coughs, fevers and other conditions.The specimen of P. aspidosperma was located near to a group of trees of this species.
Diagnosis.Plesiopelma aspidosperma sp.nov.differs from P. insulare by spiniform setae on the retrolateral face of cymbium.It can be distinguished from P. myodes, P. longisternale and P. rectimanum by the separated palpal bulb keels and basal nodule of metatarsus I very developed.It differs from P. minense by embolus tooth absent, embolus slender and curved and basal nodule on metatarsus I more developed.
Description of two new species of Plesiopelma...