New records of the rare Troschel ’ s Pampas Snake , Phimophis guianensis ( Serpentes : Dipsadidae ) in Brazil

The Troschel’s Pampas Snake, Phimophis guianensis (Troschel, 1848), is widely distributed in Amazonian Savannas at northern South America and a small portion of southern Central America, being recorded to Brazil based on three historical records, that ranged from 1997 to 2002, in Amapá and Pará states. In this study, we revise all known records of P. guianensis, providing an updated distribution map, and the first record to Roraima state.


INTRODUCTION
Amazonian Savannas are sparsely distributed and fragmented across northern South America, being characterized by a unique phytophysiognomy of arbustive and grassland plant species, that contrast with the tall-canopy tropical rainforest that encircle it (Eiten 1978, França et al. 2006, Carvalho et al. 2016).It has also been suggested that these grassland enclaves within the Amazon forest constitute relictual portions of a once wide savanna formation, that encompassed most of northern South America, southwards to central Brazil, and rose during the Pleistocene epoch, as the outcome of glacial periods (Eden 1974, Ab'Sáber 1982, Bigarella and Andrade-Lima 1982, Huber 1982, França et al. 2006).These areas usually present poorly diverse, although highly endemic reptile communities, that have been seldom studied (Ávila-Pires 1995, Vitt and Carvalho 1995, Colli 1996, França et al. 2006).

MATERIALS AND METHODS
While conducting fieldwork in the municipality of Cantá (2.2000N, -60.4833W,DATUM WGS 84), Roraima State, Brazil (Figure 1), on 28 April 2017, at 22:25 hours, the authors encountered two individuals of P. guianensis, shortly apart from each other, at the Km 16 of the BR-401.Identification follows Starace (1998) and Mumaw et al. (2015).Tissue samples were deposited in 90% ethanol, and individuals were fixated in a solution of 10% formalin, then preserved in 75% ethanol, and deposited in the herpetological collection of Universidade Federal do Rio Grande (Rio Grande, Rio Grande do Sul, Brazil) under the voucher CHFURG 5888 and CHFURG 5889.Measurements were taken with a flexible ruler or a dial caliper.SVL refers to "snout-vent length", TL to "tail length", HL to "head length", and HW to "head width".

RESULTS
The specimen CHFURG 5889 is a subadult male (Fig. 2a), that presents 350 mm snout-vent length, 120 mm tail length, 10.5 mm head length and 8.9 mm head width.In life, both individuals presented a white supralabial and gular region, with a a black stripe that extended 14 dorsal scale rows from the head, with grey scale margins on the head surface; dorsal coloration composed of a irregular black pattern, over an orange background, with a white dorsolateral surface.Ventral coloration immaculate white on both specimens.

DISCUSSION
Phimophis guianensis (Troschel 1848) was first recorded to Brazil by Frota et al. (2005), based on a specimen from Monte Alegre (CHUNB 33929), Pará state, northern Brazil.França et al. (2006), seemingly unaware of the work of Frota et al. (2005), presented three new individuals for Amapá (CHUNB 03824-5, locality given as "Amapá, 22.vii.1997";CHUNB 33929, locality given as "Tartarugalzinho, 02.v.1997"), claiming these, erroneously, as the first record to Brazil of the species.Since then, no new records arose from highly sampled areas (e.g.Thomas 1976, Cunha and Nascimento 1980, 1993, Hoogmoed 1982, Cunha et al. 1985, Vanzolini 1986, Zaher 1996, Vanzolini and Calleffo 2002), and this species has been only known based on specimens from outside Brazil (Table I), which corroborates the hypothesis that this species might be rare in Brazil (França et al. 2006).The individuals from Cantá here described represent new records to Brazil, filling a distribution gap of approximately 140 km southward from the record of Pirara, Sabana, Guyana, and 882 km northward from the record of Monte Alegre, Pará, Brazil, and the first record of the species to Roraima state.These specimens also fit the literature diagnosis of the species (Troschel 1848, Starace 1998, Gaiarsa et al. 2013, Mumaw et al. 2015).
Roraima state is located in the northern portion of the Brazilian Amazon, presenting an area of 224.299 km² (Barbosa andLima 2008, Carvalho et al. 2016), of which nearly 20% is composed of savannas (Flores 2014), being these savannas largely composed of "lavrado" (Morais and et al. 2016).The municipality of Cantá presents 10.48% of its territory over lavrado areas (Morais and Carvalho 2016).
Little is known about the biodiversity of the lavrado, since these areas have been scarcely sampled in the past (Barbosa andFerreira 2004, Flores 2014).The lavrado also lacks a specific protection within conservation units, also suffering a large anthropic pression, harboring most of the state population (Campos et al. 2008, Flores 2014).Given these circumstances, large impacts could interfere in the faunal conservation of these areas, highlighting the importance of faunal samplings and directed conservation efforts to these areas.

TABLE I Geographic distribution of Phimophis guianensis.
Carvalho 2016).The Lavrado is an ecorregion of open vegetation, covering approximately 43.281 km² (De Carvalho and De Carvalho 2012, Carvalho