Included , excluded and re-included : Chironius brazili ( Serpentes , Colubridae ) in Rio Grande do Sul , southern Brazil

Although Chironius brazili Hamdan and Fernandes, 2015 was recently described, its occurrence in Rio Grande do Sul, southern Brazil, has been discussed for at least three decades. In this work, we evaluate the occurrence of C. brazili in Rio Grande do Sul, presenting three new records, a distribution extension and comments in its available literature records. In the Pampa biome, all records are near areas of Atlantic Forest, in grassywoody steppes with gallery forest, in western Rio Grande do Sul. Our records suggest that C. brazili might occur in the Central Depression of Rio Grande do Sul, Uruguay and adjacent areas to the Western portion of Rio Grande do Sul.

Although Chironius brazili was recently described, its occurrence in Rio Grande do Sul has been discussed for at least three decades.Hamdan and Fer-nandes (2015) revised the taxonomic status of C. flavolineatus, and described C. brazili based on populations previously recognized as the former species.Lema (1994) published a list of reptile species for Rio Grande do Sul, based both on vouchers and anedoctal records.However, Di-Bernardo et al. (2004) proposed the deletion of eight species from the list, based mainly on the lack of evidence argument, since several of the portrayed taxa did not present accordingly evidence for their support as new records for the region.
One of the excluded records was of C. flavolineatus, which was recorded by Lema (1994) based on seven eggs discovered in a native forest of Poço do Carvão, municipality of São Leopoldo.His identification was made based on the analysis of two embryos, which were described as in advanced stages of development.Lema (1994) also added a comment attributed to Wiest (1978), that "the southern population (SP (São Paulo), MT (Mato Grosso), MS (Mato Grosso do Sul), PR (Paraná), SC (Santa Catarina), RS (Rio Grande do Sul) differs clearly from the others and could be a subspecies".Photographs from the individuals or the voucher material itself were not found in any collections by the authors of this work and it is believed to be discarded by the Museu de Ciências Naturais employee staff (Thales de Lema, pers. comm. 2016).Hamdan and Fernandes (2015), in the revision of C. flavolineatus, provide a geographical distribution for C. brazili in the Central and Southeastern Cerrado of Brazil, and comment that "an apparently disjunct population of C. brazili occurs in the state of Rio Grande do Sul" with two isolated records in this state, providing no further comments on its biogeographical implications.Di-Bernardo et al. (2004), in its exclusion proposal, argued that C. flavolineatus lacked voucher specimens and had not been recorded in the other Southern Brazilian states or neighboring countries.The recorded habitat for C. flavolineatus in Dixon et al. (1993), which was grass steppes of the Marajó island (Pará), in caatinga-agreste-savanna formations of northeastern Brazil, and in Campos Cerrados of Mato Grosso, Bahia, Goiás, Minas Gerais and São Paulo, also contrasted sharply with the one proposed by Lema (1994).Therefore, Di-Bernardo et al. (2004) argued that the presented embryos corresponded to another species.
Hamdan et al. (2014) designated the lectotype of C. flavolineatus (MSNM Re2729), which contains a collection locality tag of "Rio Grande do Sul".However, the authors argued that the handwriting was added by a third party, as Jan (1863) presented the type locality of the species only as "Brasile", therefore, considering "Rio Grande do Sul" as an error.In this work, we evaluate the occurrence of C. brazili in Rio Grande do Sul, presenting three new records, a distribution extension and comments in its available literature records.Collection acronyms are: MCP (Museu de Ciências e Tecnologia, Pontifícia Universidade Católica do Rio Grande do Sul) and IBSP (Instituto Butantan).Included, excluded and re-included: Chironius brazili (Serpentes, Colubridae) in Rio Grande do Sul, southern Brazil Lema (1994) -Unvouchered and unknown collection date.Seven eggs encountered in a hollow native tree, in the upper portion of the Rio dos Sinos, Poço do Carvão locality, São Leopoldo municipality (S29° 45' 19.62" W51° 9' 1.58"; 7m asl), Rio Grande do Sul.The eggs were collected and transported to the Museu de Ciências Naturais (MCN), Fundação Zoobotânica, where they were incubated.Two eggs were opened, and the examined embryos were identified as C. flavolineatus.Based on the reference to Wiest (1978), morphological distinction within southern populations of C. flavolineatus and its portrayed states, we can argue that Lema (1994) was referring to the morphotype of C. brazili.The eggs were probably discarded by the MCN employee staff (Thales de Lema, pers. comm. 2016).
Encountered by Olmiro Bochi Brum, in Avenida Batista Bonoto Sobrinho at 02 August 2015.The area presents grasslands with lotic water and gallery forest (Figure 2A).
This study -Uncollected (Figure 1E).Roadkill specimen, without meristic or morphometric data, photographed by Otávio Ribeiro, in 18 November 2013, in the highway , between the municipalities of Santiago and São Francisco de Assis.The vicinities of the highway were a rural property with a fragment of native forest.
The meristic and morphometric variables found in specimens of Rio Grande do Sul (Table 1), as well as their respective dorsal and ventral coloration, are in accordance with the described for the species (Hamdan and Fernandes, 2015).
Accordingly to Hamdan and Fernandes (2015), C. brazili is distributed in Brazilian Cerrado throughout the states of Goiás, Federal District, Minas Gerais, and São Paulo, from 70 up to 1360m asl (generally 700-900m asl), occurring in sympatry with C. flavolineatus in its northern distribution portion, the latter being usually found between 100-400m asl.Bérnils ( 2009) commented the occurrence of C. flavolineatus in the southern portion of Paraná, in areas above 800m asl.This data was apparently not analyzed by Hamdan and Fernandes (2015), considering their lack of specimens for this state.However, considering that C. flavolineatus occurs mainly in lowlands and has a centro-setentrional distribution in Brazil, we speculate that the records in Paraná actually consist with C. brazili, being the higher altitudes and the Central Southern distribution consistent with records of the species.Curiously, our new records are from localities from 7 -426m above sea level, with the most records south at lower altitudes than the north.
As related for C. flavolineatus (lato sensu) and C. brazili in its setentrional distribution portion, this species seems to occur mainly in open areas or in forests next to them, with five records for the Pampa biome.In the Pampa biome, all records are near areas of Atlantic Forest (Seasonal Deciduos Forest), in grassy-woody steppes with gallery forest, in western Rio Grande do Sul.There is a single record for the Atlantic Forest in Santa Cruz do Sul, near a woody steppe with gallery forest.Lema's record (1994) remains distinct, considering its location in a Seasonal Semideciduous Forest, which differs from our analyzed records in the state.However, the presence of steppes and gallery forests in the area reported by Lema (1994) renders highly likely the occurrence of C. brazili in the region, but may represent a geographical distribution limit to the east, considering the gradual scarcity of grasslands beyond this locality.
Except for the record in Santa Cruz do Sul (76 km), all others are relatively distant (approximately 300 km) from the municipality of São Leopoldo (Lema's record), displaying that C. brazili might occur in the Central Depression of Rio Grande do Sul (Figure 3).It is also likely that the species occurs in Uruguay and adjacent areas to the Western portion of Rio Grande do Sul.Further assessment of the phylogenetic relationships between C. flavolineatus and C. brazili, under a biogeographical framework, are needed in order to elucidate dispersal and diversification patterns between these species.

Figure 3 .
Figure 3. Distribution map for Chironius brazili in Rio Grande do Sul, southern Brazil.New records (red circle).Other colors represent literature records.