A new species of Melloina ( Araneae : Paratropididae ) from Venezuela Rogério Bertani

A new species of Melloina Brignoli, 1985, Melloina santuario sp. nov., is described from a cave in Venezuela. This is the third species described in this rarely sampled genus, and the first species known from both male and female. The male of M. santuario sp. nov. is distinguished by a longer embolus and fewer number of spines on the anterior tarsi. Females and immatures are distinguished by having fewer numbers of labial cuspules. The description of a new species from male and female samples increases our knowledge about Melloina. This added knowledge is important to the understanding of mygalomorph relationships, mainly in the Theraphosoidina, as Melloina is a basal genus within the Paratropididae.

includes two rare species.The type species, Melloina gracilis (Schenkel, 1953), was described as Melloa gracilis Schenkel, 1953, based on a single male from Venezuela.It was only after 46 years that additional specimens were discovered, and a second species, Melloina rickwesti Raven, 1999, was described from a female and an immature from Panama.Meanwhile, the generic name had been changed from Melloa, preoccupied by a harvestman species, to Melloina Brignoli, 1985.The other name proposed to replace Melloa, Grablopelma Raven, 1985, was published concomitantly, but appeared shortly after BRIGNOLI's (1985) paper.
Besides being rare in collections, Melloina is of critical importance for the knowledge of mygalomorph relationships, mainly of the Theraphosoidina clade, which contains the families Theraphosidae, Barychelidae and Paratropididae (RAVEN 1985).RAVEN (1985RAVEN ( , 1999) ) extensively discussed the taxonomic position of Melloina, included originally in Theraphosidae (SCHENKEL 1953), and transferred by RAVEN (1985) to the Paratropididae.RAVEN (1985) showed that Melloina is a basal taxon in Paratropididae, presenting the plesiomorphic states of highly modified characters of Paratropis Simon, 1899 and related genera.Moreover, as Paratropididae is the proposed sister group of Theraphosidae (RAVEN 1985, GOLOBOFF 1993, 1995), its most basal taxon, i.e.Melloina, retains some of the most plesiomorphic character states of Theraphosidae, the most speciose mygalomorph family.However, results of recent analyses using molecular information (HEDIN & BOND 2006, BOND et al. 2012) conflict with the studies using morphological information, suggesting that Paratropididae is not closely related with Theraphosidae or Barychelidae.Therefore, any information on Melloina is important for the understanding of the evolution of Mygalomorphae, the Theraphosoidina, and, particularly, of Theraphosidae.
A new species of Melloina is described herein.It is the first species from this genus based on male and female specimens.

MATERIAL AND METHODS
The general description format follows RAVEN (1999RAVEN ( , 2005)), with modifications.A Nikon SMZ1500 dissecting microscope was used for illustrations (with a camera lucida attachment).Figures were digitized and covered using a Wacom Bamboo tablet.All measurements are in millimeters.Leg and palp measurements were taken from the dorsal aspect of the left side (unless appendages were lost or obviously regenerated).Measurements were taken from the drawings made with the dissecting microscope and converted.Abbreviations: (ALE) anterior lateral eyes, (AME) anterior median eyes, (ITC) inferior tarsal claw, (PLE) posterior lateral eyes, (PLS) posterior lateral spinnerets, (PME) posterior median eyes, (PMS) posterior median spinnerets, (STC) superior tarsal claws.
Palp (Figs 9-11): bulb pyriform; embolus very long, tapering, filiform at apex; cymbium of two dissimilar lobes.Tibia with shallow distoventral groove.Spur (Figs 12-13) with two branches originating from common base, retrolateral longest, and with slight distal curvature; prolateral straight.Prolateral with ovoid spine longer than its length; retrolateral with two spines, both digitiform, more than half of branch length.Metatarsus I straight, when folded passes by retrolateral spur branch laterally.Body covering: strongly pilose hairs and guard hairs (COOKE et al. 1972) completely lacking over entire body.
Color in alcohol: carapace and legs red brown.Abdomen dorsally gray with 3 faint pallid lenticular areas anteriorly, followed by three pairs of small spots; pallid ventrally.

DISCUSSION
According to RAVEN (1999), M. rickwesti is distinguished from M. gracilis by having "only two rows each of four spines on ventral tarsi (cf.9-12), only tarsi IV (cf.III and IV) cracked, and a relatively shorter sternum and larger labium".The difference was considered "greater than that found between male and female conspecific paratropidines in a pending revision of the sister subfamily" (RAVEN 1999).In the present work, I was able to confirm that the number of tarsal spines, mainly on tarsi I and II (Table IV), is similar in mature males, females, and immature males.Therefore, the greater number of tarsal spines in M. gracilis is an autapomorphy of the species.The other two characters are, unexpectedly, sexually dimorphic.Mature males of M. santuario sp.nov.have tarsi III and IV cracked, whereas females and immature males have only tarsus IV cracked.Females and immature males of M. santuario sp.nov.have a larger labium than mature males, and the shape of their labium is similar with females of M. rickwesti.
Paratropidids are normally found with the entire body encrusted with soil (RAVEN 1985(RAVEN , 1999) ) due to their habit of hiding in the surface layers of the soil (WEST in RAVEN 1999).However, in all analyzed specimens of M. santuario sp.nov., the integument is not encrusted with soil, except for very restricted areas on the carapace of the female paratype.

Table I .
Melloina santuario sp.nov., male holotype.Length and midwidths of right legs and palpal segments.

Table II .
Melloina santuario sp.nov.Female paratype.Length and midwidths of right legs and palpal segments.