Taxonomic key to the snakes (Squamata: Ophidia) species of the Itajaí Valley, Santa Catarina, Brazil

Snakes represent the richest Reptile group in Brazil, amounting to 412 species and 40% of them are endemic for the country. This great richness combined with the poor taxonomic knowledge makes the identification a difficult process. To correctly identify a specimen, guides, taxonomic revisions, identification keys, and consulting specialists are the most used methods. Identification keys are based on separation and segregation of characters, where the chosen paths lead to the appropriate taxa. These tools are normally used by students and non-taxonomists. Also, they can be very helpful with the general public, where they can identify the species with simple characters. This study aims to develop keys for the snakes from the State of Santa Catarina state, Brazil, focusing on the Itajaí Valley species. We surveyed 351 specimens deposited in Universidade Regional de Blumenau Zoological Collection (CZFURB), Universidade Federal de Santa Catarina (CHUFSC), and Natural History Museum of Capão da Imbuia (MHNCI) herpetological collections. Characters including pholidosis, dentition, and coloration patterns were examined from the 46 snake species registered from Itajaí Valley.


INTRODUCTION
Snakes have a major number of species among the Brazilian reptiles (Costa & Bérnils, 2018). With 412 species, this represents more than 50% of the total amount (Nogueira et al., 2020). This abundance ranks Brazil in third place of countries with most reptile species (Uetz et al., 2020). To study some species or deposit it in a zoological collection, first, it is necessary the correct identification of the animal (Papavero, 1994). There is a variety of options to correctly identify any species, the most used are consulting specialists, bibliography, taxonomic keys, and surveillance in biological collections (Ferrarezzi & Monteiro, 2001). Taxonomic keys are based on separation and segregation of characters, in a way that the choices lead to the correct identification (Papavero, 1994). These tools are normally used by students, also, they can be helpful for non-taxonomists or the general public (Di Nicola, 2019). There are few books (Peters & Orejas-Miranda, 1970;Dixon et al., 1993;Quintela & Loebmann, 2009;Bernarde, 2014), journal articles (Dixon, 1989;Zaher et al., 2008;Passos et al., 2009;Abegg et al., 2016), monographs (Di- Bernardo, 1992) and non-published works (Ferrarezzi & Monteiro, 2001) providing keys for Brazilian species, yet, most of them are outdated. For the state of Santa Catarina, the studies about snakes are based on records of geographic distributions (Fortes et al., 2010;Kunz et al., 2011), chromatic anomalies (Sueiro et al., 2010), field guides (Oliveira et al., 2020) and surveys in zoologic collections (Bérnils et al., 2001;Althoff, 2014). Bérnils et al. (2001) listed 46 species of snakes for the Itajaí Valley region; however, they provided no identification keys for such species. Thus, this study aims to develop identification keys for species of snakes from Itajaí Valley.

Species identifications
We followed the nomenclature of Costa & Bérnils (2018) and nomenclatural modifications posterior to this publication, like the transfer of Mastigodryas bifossatus (Raddi, 1820) to the genus Palusophis  and synonymization, such as Sibynomorphus with Dipsas (Arteaga et al., 2018), and Uromacerina ricardinii (Peracca, 1897) with Cercophis auratus (Schlegel, 1837). The bibliography used for the identification of the specimens is listed in Table 1, Appendix I.

RESULTS AND DISCUSSION
We examined 351 specimens housed in the collections. The specimens were predominantly from the State of Santa Catarina and Itajaí Valley (Appendix II). Due to the species distribution, some records might have been unavailable for the region. Also, to complement the database, some specimens from other states were included in this study, since they are known to occur in the Itajaí Valley.

Taxonomic key
The key is mainly based on the count of scale rows around the neck, mid-body, and near the cloaca. Examination of dentition, head shields, number of ventral and subcaudal scales, and the condition of dorsal scales (smooth, keeled, or with apical pits) (Fig. 2) are other characters used. Color patterns were only used in cases where one or more pholidosis values were analogous between species. "Background color" indicates the color between dorsal rings, marks, and bands (Di Nicola, 2019). "Rings" refers to a circular band, which surrounds both dorsal and ventral scales "bands" refers to transverse markings on the body (Rasmussen et al., 2011). Thus, the key is accompanied by figures to aid the identification process.

Family Elapidae Boie, 1827
Members of this family show proteroglyphous dentition and the absence of a loreal scale Ferrarezzi (1994). The American elapids carry a body coloration composed of shades of yellow, black, white, and red, outlined by black or dark-brown rings or blotches (Campbell & Lammar, 2004).

Family Dipsadidae Bonaparte, 1838
This family stands as a monophyletic group (Zaher et al., 2009), but with a high number of unsupported clades within its subfamilies (Zaher et al., 2019). It is di-

Family Anomalepididae Taylor, 1939
Only one species of this family occurs in the region (Bérnils et al., 2001). Liotyphlops beui can be recognized by the indistinct dorsal and ventral scales; they are all cycloids and have the same size (Dixon & Koffron 1983).

Family Colubridae Oppel, 1811
For the Vale do Itajaí the species of the genera Chironius and Spilotes can be recognized by the even number of scale rows (Amaral, 1929;Dixon et al., 1993, and Palusophis bifussatus by its body coloration and 15 scale rows at mid-body (Montingelli et al., 2019).
Tribe Hydropsini Dowling, 1975 Externally, this tribe can be recognized by the eyes and nostrils directed to the top of the head (Costa et al., 2016), single internasal scale, divided anal plate, and partially or entirely keeled dorsal scales (Peters & Orejas-Miranda 1970).    Zaher et al. (2009) designed a putative synapomorphy for this tribe, that the body of the hemipenis is bigger than the lobes, with the non-sulcated face covered almost entirely by two lines of enlarged chalices. In the Itajaí Valley, Philodryas is the only genus from this tribe (Bérnils et al., 2001). The species are recognized by their slender body, round pupil, posterior reduction of dorsal scales rows, and opistoglyphous dentition (Vanzolini, 1980;Quintela & Loebmann, 2009).

Tribe Echinantherini Zaher et al., 2009
This tribe is represented by the genera Echinanthera and Taeniophallus (Zaher et al., 2009), they have hemipenis unilobed and uni capitate. Sulcus spermaticus is divided relatively distally in the calyculate area, and there is a large nude area in the asulcate side of the hemipenial body (Zaher et al., 2009). Both genera are morphologically similar, with a slender body, aglyphous dentition, and circular pupils (Di-Bernardo, 1992). Taeniophallus bilineatus can be distinguished from the other species by the number of ventral scales (> 140) (Di-Bernardo & Lema, 1990), and the other species from this tribe can be identified by its cephalic and dorsal marks (Di- Bernardo, 1992;Di-Bernardo & Lema, 1986).

Tribe Elapomorphini Jan, 1862
Members of this tribe have cephalic shields fused, reduced eyes, and strengthened skulls due to fossorial habits (Ferrarezzi, 1993). In the Itajaí Valley, Phalotris reticulatus is the only representative species from this tribe (Bérnils et al., 2001). Specimens show dorsal scale rows 15-15-15; black head followed by a yellowish nuchal collar, the dorsal color background is red with three longitudinal black stripes, one in the vertebral zone, and the other two in the pleural zones. It has a black cloacal ring, the venter is yellowish, with black semilunar blotches (Quintela & Loebmann, 2009). Tribe Tachymenini Bailey, 1967 Members from this tribe usually have a small size, opisthoglyphous dentition, elliptical pupils, and a post-orbital stripe (Bailey, 1967). In the Itajaí Valley, Gomesophis, Thamnodynastes, and Tomodon are the representant genera from this tribe (Bérnils et al., 2001). Gomesophis brasiliensis has dorsal rows in 17-17-15, smooth scales with apical pits, and a brownish-green dorsal color, with stripes (Gonzalez et al., 2014). Species from the genus Thamnodynastes show dorsal pattern checkered anteriorly and dorsal rows in 19-19-15 (Franco et al., 2017). Finally, Tomodon dorsatus has 17 scale rows at mid-body (Harvey & Muñoz, 2004), grey dorsal background color with dark marks, and black oral and cloacal mucosae (Quintela & Loebmann, 2009).