Two new cave-dwelling genera of short-tailed whip-scorpions from Brazil ( Arachnida : Schizomida : Hubbardiidae )

Two new genera of short-tailed whip-scorpions are described based on material from Brazilian iron ore and canga caves in the Carajas region, Para, Brazil. Naderiore gen. nov. with a single species N. carajas sp. nov. and also monotypic Cangazomus gen. nov. (type species C. xikrin sp. nov.). The relationships of the two new genera with previously described genera are discussed. Naderiore most closely resembles Adisomus Cokendolpher & Reddell, 2000, Piaroa Villarreal, Tourinho & Giupponi, 2008 and Calima Moreno-Gonzalez & Villarreal, 2012, and can be distinguished from them by Dm3 modified as macrosetae in the male flagellum. Cangazomus most closely resembles Naderiore , Adisomus Cokendolpher & Reddell, 2000, and Piaroa Villarreal, Tourinho & Giupponi, 2008. It differs from all of them by the presence of two pairs of ramified spermathecal lobes, each composed of a differentiated stalk and distoterminal ramified bulbs, chitinized arch without anterior branch and notched lateral tip, pedipalps unarmed and not sexually dimorphic, and the male flagellar setae Dm3 as a microsetae.

The low diversity of Schizomida, 258 species according to Harvey (2007), especially in the Neotropical region, is not surprising in view of the small size of these arachnids (usually 2-7 mm of total length) and their cryptic habits, which are poorly known.Studies on South American schizomids have intensified in the 21st century.a review of schizomids recorded on this continent can be found in armas (2010) where 34 described species in nine genera are cited.Additionally, the author mentions that there are at least 11 undescribed species and three undescribed genera in South America.Since then, two genera and 13 species have been described, most of them from Colombia (armas & DelgaDo-santa 2012a, b, moreno-gonzález & villarreal 2012, villarreal & garcía 2012, DelgaDo-santa & armas 2013, santos et al. 2013, villarreal et al. 2014, moreno-gonzález et al. 2014), resulting in 47 described species on South America.This number is probably an underestimate of the true diversity of Schizomida, considering that the region of Manaus (Amazonas, Brazil), the only area reasonably well sampled, harbors seven species.
The following factors have contributed to the poor knowledge of this group in South America: first, there are only a few South American specialists in the group, and arachnologists from the Neotropics began to collect and describe new taxa from the region only in the 21 st century; second, Winkler and Kempson apparatus (but see aDis et al. 1999) have not been widely used to collect arachnids in the Amazonian and Andean regions.As a result, suitable habitats there such as leaf litter, forest canopy and caves have been poorly sampled.In more recent years, Rolando Teruel and Luis de Armas have described a large number of new species from Central America, particularly from the Caribbean region.It is expected that the number of described species in South America will increase exponentially when the group receives more attention from researchers and is collected more intensively.This has already happened in other parts of the world during the last 40 years (Harvey 2007: fig.2).More research in this group is needed to clarify the relationships among the many monotypic genera that have been proposed and to generate phylogenetic hypotheses (see moreno-gonzález & villarreal 2012).
In this contribution, two new genera and two new species of short-tailed whip-scorpions (schizomids) are described based on material collected from Iron ore and Canga caves of Serra dos Carajás, Pará, Brazil, elevating the number of South American genera to 11, and the number of described species to 49.The relationships of the two new genera with those previously described are discussed.

MATERIAL AND METHODS
The type material is deposited in the Museu Paraense Emilio Goeldi (MPEG, curator A. B. Bonaldo)  The illustrations of the chelicerae and spermathecae are based on photographs taken with a Zeiss Axioskop 50 microscope, integrated with the Carl Zeiss photo software Zen Lite, using the edition software Inkscape version 0.48.4 (www.inkscape.org).Z-axis photographs were created with a Leica M125 stereoscope with trinocular tube, integrated to the Leica software.The female genitalia were cleared with lactic acid 95% for about 1-2 hours at room temperature.Measurements are given in millimeters (mm); total length excludes the flagellum.
Remarks.A significant character of the genus is the presence of Dm 3 modified as macrosetae in the male flagellum (Fig. 1), a unique condition among the Neotropical species of Hubbardiinae.
Etymology.Named after the Carajás Formation, located in northern South America.The Carajás Formation is a banded iron-formation (BIF) that contains a large number of small iron ore and canga caves where the specimens were collected.The name is treated as a noun in apposition.
Etymology.In reference to the canga, ferruginous breccias that covers the banded iron formation (BIF), where is located the cave from the type locality, and zomus, part of the name Schizomus.Gender masculine.
Remarks.The spermathecal lobes with ramified bulbs displayed by Cangazomus xikrin (Fig. 20) are a very novel condition among the Neotropical genera of Hubbardiidae; among the New World four-segmented genera, the North American genus Hubbardia Reddell & Cokendolpher, 1995, and the Caribbean genus Luisarmasius Reddell & Cokendolpher, 1995 share both an apparently similar spermathecal morphology, having spermathecae composed of more than three lobes in each side (reDDell & cokenDolpHer 1995: 75, 81); however, the presence of multiple spermathecal lobes is a very distinct condition, compared with the presence of two pairs of lobes, each with ramified bulbs, exhibited by C. xikrin (Fig. 20).For this reason, we believe this character represent a synapomorphy for the genus.
Chelicerae (Fig. 15).Fixed finger (Fig. 15: bottom) with two smaller teeth between two large outer teeth.Movable finger (Fig. 15: top): serrula composed of 9 hyaline teeth; guard tooth pre sent, lamella present, accessory tooth absent.Setae: G1 = 3 setae, G2 = 3, G3 = 3, G4 = 2, G5 = 7, G6 = 1; setae G1 with spicules on their base.Opisthosoma.Tergite I with two pairs and tergite II with three pairs of anterior microsetae.Tergites I-VII each with one pair of dorso-submedian setae; VIII-IX each with one pair of dorso-submedian setae and one pair of distolateral setae; X-XI narrow, each with one pair of lateral setae and five ventral setae; XII with one pair of dorso-submedian setae, two pairs of lateral setae and four pairs of ventral setae.Segments X-XII not elongated.Posterodorsal abdominal process of segment XII absent.Legs: Anterior dorsal margin of femur IV produced at about 90 degrees angle, 2.1 times as long as high.Flagellum (Figs. 4-6).Dorsoventrally flattened, bulb sub-rhomboidal, 1.7 times longer than wide, with short pedicel (1/5 total length).Setation: Vm 1 at same level of Dm 1 and Vm 2 ; pair Dl 1 (microsetae) proximal to Vm 1 ; pair Vm 4 at same level of Dl 2 level; pair Dm 3 (microsetae) at same level of Dl 2 ; Dl 3 positioned slightly distal to Vl 2 ; Vm 5 proximal to Dm 4 level, closer to Vl 1 than to Vl 2 ; Vl 2 proximal to Dl 3 level, and distal to Dm 4 level.With distolateral microsetae patches composed of three microsetae from the same level of Vm 5 to slightly anterior to Vl 2 .With one pair of separated oval shaped and deep dorso-submedian depressions at same level of Dl 2 (microsetae), located at approximately half of the flagellum length, without any dorsal swelling.With several glandular openings (GOP) (see Fig. 11) appearing as many grooves radiating from a central pore (see santos & pinto-Da-rocHa 2009) on lateral and dorso-median to subapical region; without pores on central ventral region.
Etymology.Named after the Xikrin, an indigenous tribe located about one hundred kilometers from Parauapebas, the city close to the caves where the specimens were collected.The name is a noun in apposition.

Natural history of N. carajas sp. nov. and C. xikrin sp. nov.
The specimens of both species were found in several iron ore and canga (ferruginous breccias) caves, from the entrance (photic zone) to the aphotic zone, on the ground, in areas with high moisture, under boulders, between roots, leaf litter, and in some cases near bat guano.The caves in the Serra dos Carajás, located in Eastern Amazonia (state of Pará), are composed of banded iron-formation -(BIF) from the Neoarchean.A large number of caves have been recorded in the area (more than 1,500 known caves, according to data from cecav 2015).Serra dos Carajás comprises a set of isolated plateaus (Fig. 21), most of which are located in the Carajás National Forest, a federally protected area that is used for different purposes, including the operation of iron ore mines.The caves where the two species described here were found are situated on scarps in different landscapes, including the edges of ponds, scarps at the top of the plateaus, and the colluvial foot slopes of ridges.The caves have developed in the inner part of the canga, within the iron ore, and at contact points between them (piló et al. 2015).Savannah vegetation has grown on these iron crusts and particularly on top of ranges, and is surrounded by Ombrophylous Forest; in low areas out of the Carajás National Forest an altered landscape can be found.The xerophytic savannah vegetation is a singular ecosystem in the Amazon, and is known for its high level of endemism (campos & castilHo 2012).Most caves are small (< 30 m long) and shallow; the trophic resources include vegetal debris, roots, and feces of vertebrates such as bats and anurans.Neither one of the two new species displays the features of typical troglobitic schizomids (e.g.elongated pedipalps, pale integument) found, for instance, in some Protoschizomus Rowland, 1975 or Agastoschizomus Rowland, 1971 (both Protoschizomidae) and Rowlandius Reddel & Cokendolpher, 1995 (Hubbardiidae).However, it should be noted that not all troglobiotic species have troglomorphic traits (sket 2008).Further studies should be conducted in epigean environments to confirm the degree of association of this species with hypogean habitats (see santos et al. 2013).One possible troglomorphic trait, absence of eyespots, is also found in many epigean species.Only a phylogenetic hypothesis may help to determine whether such trait has evolved in response to the cave environment.