The Snakes of the Genus Atractus Wagler (Reptilia: Squamata: Colubridae) from the Manaus Region, Central Amazonia, Brazil
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The snakes of the genus Atractus Wagler (Reptilia: Squamata: Colubridae) from the Manaus region, central Amazonia, Brazil. M Martins & M.E. Oliveira Martins, M. & M.E. Oliveira. The snakes of the genus Atractus Wagler (Reptilia: Squamata: Colubridae) from the Manaus region, central Amazonia, Brazil. Zool. Med. Leiden 67 (2), 30.vii.1993:21-40, figs. 1-8.— ISSN 0024-0672. Key words: serpentes; Colubridae; Atractus; taxonomy; natural history; central Amazonia. Taxonomic and natural history data are presented on eight species of Atractus from the Manaus region, central Amazonia, Brazil, namely: A. alphonsehogei, A. latifrons, A. major, A. poeppigi, A. schach, A. snethlageae, A. torquatus, and A. trilineatus. Four of these species are recorded for the first time for the region, which indicates the scarcity of snake collections in central Amazonia. Apresentamos dados sobre a taxonomia e a histdria natural de oito especies de Atractus da regiao de Manaus, Amazonia central, Brasil: A. alphonsehogei, A. latifrons, A. major, A. poeppigi, A. schach, A. snethlageae, A. torquatus e A. trilineatus. Quatro destas especies sao registradas pela primeira vez para a regiao, o que indica a escassez de coletas de serpentes na Amazonia central. M. Martins, Laboratorio de Zoologia, Departamento de Biologia, Instituto de Ciencias Bioldgicas, Universidade do Amazonas, Campus Universitario, 69068 Manaus AM, and Nucleo de Animais Peconhentos, Instituto de Medicina Tropical de Manaus, Avenida Pedro Teixeira s/n°, 69040 Manaus AM, Brasil. M. E. Oliveira, Nucleo de Animais Peconhentos, Instituto de Medicina Tropical de Manaus. Introduction The Neotropical snake genus Atractus Wagler, 1828, comprises nearly 80 species distributed from southern Central America southward through Amazonia to Amazonian Bolivia and southern Brazil. Savage (1960) monographed 16 Ecuadorian species of Atractus and emphasized the need of an extensive revision of the genus. Peters & Donoso-Barros (1970) tabulated the diagnostic characters of 72 species of Atractus. Hoogmoed (1980) reviewed eight species of Atractus from Suriname and Cunha & Nascimento (1983,1984) reviewed the genus Atractus in eastern Amazonia describing three new forms. Additional taxonomic data on Atractus from several localities are found in studies of local and regional snake faunas (e.g., Chippaux, 1986; Dixon & Soini, 1986; Duellman, 1978; Gasc & Rodrigues, 1980; Lancini, 1979; Nascimento et al., 1985; Roze, 1966). When identifying snakes in central Amazonia we found that the snake fauna of this region is very poorly known (see, e. g., Dixon, 1979; Hoogmoed, 1979,1980). The main accounts on the fauna of this region are those of Hoge & Nina (1969) on some snakes deposited in the collection of the Instituto Nacional de Pesquisas da Amaz6nia, Manaus (no Atractus included), Vanzolini (1985) on Micrurus averyi, and Zimmermann & Rodrigues (1990) on the structure of a snake community around Manaus. The latter authors reported five species of Atractus, namely A. latifrons, A. major, A. snethlageae, A. torquatus, and an unidentified species. Schmidt & Inger (1951) 22 ZOOLOGISCHE MEDEDELINGEN 67 (1993) recorded A. badius for Manaus, although this may be a misidentification (see "Discussion" in the present paper). The purpose of this paper is to diagnose the eight species of Atractus of the Manaus region and provide data on their natural history. We analysed specimens deposited in the following collections: Nucleo de Animais Pegonhentos, Instituto de Medicina Tropical de Manaus (IMTM); Instituto Butantan, Sao Paulo (IB); and Nationaal Natuurhistorisch Museum, Leiden (RMNH). The region considered encompasses localities within a radius of 250 km from Manaus, Amazonas, Brazil, north of the Rio Solimoes (fig. 1). This region is covered by lowland forests, includ• ing areas seasonally flooded by black and white waters ("igapo" and "v&rzea", respectively). Detailed descriptions of forests around Manaus are provided by DNPM (1976) and Guillaumet (1987). Total annual rainfall in the region is about 2100 mm; a marked wet season (165-300 mm/month) occurs from November to May, and Fig. 1. Map of the Manaus region showing localities where snakes were collected. Manacapuru: urban area (1); Novo Airao: Archipelago of Anavilhanas (2); Manaus: urban area (3), Highway BR-174, Km 18 (4), Km 37 (5), and Km 86 (6), Highway AM-010, Km 25 (7) and Km 35 (8); Rio Preto da Eva: urban area (9); Presidente Figueiredo: Balbina hydroelectric power plant (10) and Pitinga hydroelectric power plant (11). MARTINS & OLIVEIRA: ATRACTUS FROM BRAZIL 23 a drier season (<65 mm/month) from July to September (Leopoldo et al., 1987). Temperature at Manaus ranges from 18 to 37°C throughout the year (DNPM, 1976). All measurements were made with a flexible ruler and are presented as the total length (TTL); the proportion of tail length in relation to TTL (in percents) is also pre• sented. Numbers in parentheses following taxonomic data indicate number of exam• ined individuals. Since we do not intend to extensively review the taxonomy of the species treated herein (see above), simplified synonymy citations were used. These include only the original descriptions and, when pertinent, the first citation using the names as used here. Extensive synonymy lists for most species treated herein are found in Savage (1960) and Hoogmoed (1980). Key to the species of Atractus from the Manaus region, central Amazonia 1. Dorsal scales in 15 rows 2 - Dorsal scales in 17 rows 3 2. Temporal scales 0+1 or 0+2; 1/1 postoculars; 6/6 supralabials; dorsum dark brown with light triangular spots on the flanks, reaching the ventrals; 5-6 maxil• lary teeth Atractus poeppigi - Temporal scales 1+2; 2/2 postoculars; 8/8 supralabials; dorsum light brown with three longitudinal dark stripes; 11 maxillary teeth Atractus trilineatus 3. Dorsum brown with three longitudinal slightly distinct darker stripes and a par• avertebral cream stripe on the flanks; dorsal scales with apical pits; scales of the latero-posterior part of the body with tubercles, mainly in the anal region Atractus alphonsehogei - Dorsum lacking longitudinal stripes; dorsal scales without apical pits 4 4. Dorsum with red, black, and white rings; loreal as wide as high Atractus latifrons - Dorsum lacking red, black, and white rings; loreal wider than high 5 5. Dorsum dark brown with light transversal stripes Atractus snethlageae - Dorsum greyish, greenish, reddish or dark brown, either bearing or lacking dark• er spots 6 6. Ventral scales cream, with brown spots in their center giving rise to a longitudi• nal midventral stripe, more distinct at the anterior third of the body; dorsum brown to reddish brown with a longitudinal middorsal stripe, sometimes inter• rupted, and/or short transversal bars Atractus schach - Venter lacking a middorsal dark brown stripe; dorsum either bearing or lacking dark spots 7 7. Six maxillary teeth; dorsum brown to reddish brown with transverse dark brown spots, wider on the middorsal region and bearing internal margins blackish and external margins light brown, or dark brown spots irregularly distributed throughout the dorsum Atractus major - Eight maxillary teeth; dorsum dark, greyish, greenish, or reddish brown, often bearing small dark spots (one scale wide) scattered throughout, sometimes dis• posed as short transverse or oblique bands Atractus torquatus 24 ZOOLOGISCHE MEDEDELINGEN 67 (1993) Species Accounts Atractus alphonsehogei Cunha & Nascimento, 1983 Atractus alphonsehogei Cunha & Nascimento, 1983:25. Type locality: Brasil, Par£, Bela Vista, Km 75 PA- 242, rodovia Braganca-Viseu. Material.— Presidente Figueiredo: 1 cT, IMIM 450. Diagnosis.— A small Atractus (cT TTL 251 mm) with a slightly pointed head (figs. 2a, 3a) and short tail (cT 12.2% of TTL). Head width about the same as that of body; eyes small; pupil round; internasals wider than long, shorter than parietals, and longer than supraoculars; loreal wider than high; postoculars 2/2; temporals 1+2; supralabials 7/7, third and fourth entering the orbit; infralabials 7/7, three in contact with the chin shields (fig. 2a). Dorsal scales smooth, except those of the latero-poste- rior part of the body, especially in the anal region, where they present tubercles (only in males, see "Remarks"), with two apical pits, in 17 rows throughout the body; ven- trals 157; anal plate entire; subcaudals 33/33. Six maxillary teeth. In preservative, dorsum brown with all scales cream bordered with dark brown, some of them with one half cream, the other brown; the juxtaposition of these latter scales gives rise to one middorsal and two dorsolateral slightly distinct longitudinal stripes; paraventrals with lateral borders dark brown and center cream, giving rise to a distinct cream longitudinal stripe (fig. 3a). Tail similar to the body, except for the cream lateral stripe that is less distinct. Head dark brown with indistinct cream blotches and a brown, transverse occipital stripe on the parietals and temporals, becoming cream on the temporals; three first supralabials cream at their base; triangu• lar cream spot at the contact of fifth and sixth supralabials. Underside of head cream with dark brown blotches on symphysal, infralabials, and chin shields. Venter cream with lateral borders of ventrals dark brown, giving rise to a cream midventral stripe. Habits.— No data available for the specimen examined. According to Cunha & Nascimento (1983) Atractus alphonsehogei inhabits the soil of primary and secondary forests and clearings; these authors found an