A New Species of Riama from Ecuador Previously Referred to as Riama hyposticta (Boulenger, 1902) (Squamata: Gymnophthalmidae)

ABSTRACT We describe Riama crypta, new species, from the western slopes of the Cordillera Occidental, Ecuador. This taxon was formerly referred to as Riama hyposticta, a rare species described on the basis of an adult male from northern Ecuador and here recorded from southwestern Colombia. The new species differs principally from Riama hyposticta by an incomplete superciliary series, formed just by the anteriormost superciliary scale (superciliary series complete in R. hyposticta, formed by five or six scales), no nasoloreal suture [= loreal absent] (complete [= loreal present] in R. hyposticta), distinct dorsolateral stripes at least anteriorly (scattered brown spots dorsally without dorsolateral stripes in R. hyposticta), and ventral coloration composed of small cream or brown spots or longitudinal stripes (dark brown with conspicuous transverse white bars and spots). Additionally, we document the presence of distal filiform appendages on the hemipenial lobes of both species.


INTRODUCTION
Although the diversity of Riama in Ecuador has been reviewed (Kizirian and Coloma, 1991;Kizirian, 1995Kizirian, , 1996; also see Reyes- Puig et al., 2008), some taxonomic uncertainties remain to be resolved. One of these problems is the taxonomic status of a series of specimens collected at or near Pilalo, province of Cotopaxi, referred to as Riama hyposticta in the literature (e.g., Hillis, 1985;Kizirian and Coloma, 1991;Kizirian, 1995Kizirian, , 1996Doan, 2003;Doan and Castoe, 2005). Boulenger (1902) described Proctoporus hypostictus based on a single adult male from [Hacienda] Paramba [Imbabura], Ecuador, near the border with Colombia. Later, Kizirian (1996) redescribed the species based on the holotype and 39 additional specimens, most of which were from Pilalo. Kizirian noted several differences between the holotype and the speci¬ mens that he tentatively allocated in this taxon and cautioned that multiple species may have been confounded under the same name, but he concluded that additional key specimens were required to allow more than one species to be recognized.
Recently, we discovered a new specimen of Riama hyposticta deposited in the Museo de Historia Natural of the Universidad de Narino that was collected in extreme southwestern Colombia near the type locality. This new specimen is virtually identical to the holotype, which supports Kizirian's (1996) hypothesis and enables us to propose an emended diagnosis for Riama hyposticta and formally name and describe the specimens from Pilalo and adjacent areas as a new species.

MATERIALS AND METHODS
We made measurements with dial calipers read to the closest 0.1 mm. If sex could not be determined based on the presence of everted hemipenes, it was determined by subcaudal incision.
Hemipenis preparation follows Myers and Cadle (2003) and Zaher and Prudente (2003). The calcified structures of the hemipenis of KU 135104 were stained in alcoholic solution of alizarin red, in an adaptation of the procedures described by Uzzell (1973) and Harvey and Embert (2008). Terminology for the everted hemipenis follows Kizirian (1996). To facilitate comparisons with other species of Riama the characters and the head-scale nomenclature are those of Kizirian (1996). When scale counts are given for both sides, they are indicated thus: 00/00 (left and right, respectively). For comparative purpose, we examined specimens from all the species known from Ecuador and eight taxa from other countries where Riama are known (see appendix). Data for R. inanis, R. laudahnae, and R. rhodogaster were obtained from the literature (Doan and Schargel, 2003;Kohler and Lehr, 2004;and Rivas et al., 2005). We adopt Kluges (1990) definition of the species category as the class whose members are the smallest historical individuals within which there is a parental pattern of ancestry and descent. The following abbreviation pertains to mea¬ surement made on each specimen: SVL = snout-vent length.
Specimens examined are in the following collections (listed alphabetically by institutional The holotype was redescribed and illustrated by Kizirian (1996).  Riama simotera occurs on the Colombian-Ecuadorian border. Riama simotera has one or two (six) lateral scale rows and one or two (three) genials.
Distribution: Riama crypta is known from Pilalo, Cotopaxi, and adjacent areas on the western slope of the Cordillera Occidental between 2320-2700 m, Ecuador ( fig. 7).

DISCUSSION
One specimen from El Chiral ( fig. 7), El Oro, Ecuador (represented by only a severed head and anterior portion of the body), AMNH 18310, has been referred to Riama oculata (Burt and Burt, 1931), and R. striata (Uzzell, 1958), and tentatively assigned to R. hyposticta (Kizirian, 1996). We have examined the specimen again and believe that it may represent another unde¬ scribed species, agreeing with the conclusions of Peters (1967) and Kizirian (1996). Therefore, we prefer to refer it to Riama sp. until additional material from that region is collected and the question about its taxonomic status is settled.
The distal filiform appendages on the hemipenial lobes of Riama hyposticta and R. crypta are presumably a unique synapomorphy within the genus, suggesting that these species are closely related. Nevertheless, the unequivocal detection of such structures requires that the hemipenial lobes be fully everted, which may not have been done for other putatively related species (e.g., R. afrania). Among Gymnophthalmidae, single distal filiform appendages on the hemipenial lobes are also present, at least, in Cercosaura manicata and in some populations of Iphisa elegans (Nunes and Rodrigues, unpubl. data), attest¬ ing to the homoplastic occurrence of these elongated structures. In other gymnophthalmids (e.g., Anadia ocellata and Anadia blakei; see Myers et al., 2009), similar apical soft-tissue papillae are present atop each lobe; however, these protuberances are paired and markedly more robust.
With the description of Riama crypta, 17 of the 28 species currently assigned to the genus occur in the Ecuadorian Andes. Although the distributions of most taxa are poorly known, based on the available evidence Kizirian (1996) noted that most species have restricted geo¬ graphic distributions and occupy narrow elevational ranges. Riama hyposticta and R. crypta appear to inhabit different elevational zones (and consequently different habitats). The type locality of R. hyposticta is between 777-1050 m and the Colombian locality is between 1100-1600 m, while the type locality and adjacent areas where R. crypta occurs are between 2320-2700 m. Although the data for R. hyposticta are not precise, we presume that, among the Andean Riama, this species inhabits lower elevations.
The formal recognition of Riama crypta has consequences in Riama systematics. Doan (2003) used specimens of R. crypta to score morphological characters for R. hyposticta in her phylogenetic study of Proctoporus sensu lato, thus morphological evidence for the relationships of R. hyposticta sensu stricto is lacking. Due to lack of material most of the species allocated to Riama (including the species treated herein) were not included in the molecular-based phy¬ logenetic analysis of Castoe et al. (2004), but their placement in the genus was supported by morphological affinities (Doan and Castoe, 2005).