Tantilla melanocephala

Abstract: . We studied the composition, richness, abundance, and influence of abiotic factors on the seasonal activity of a snake assemblage at a fragment of savanna enclave (tabuleiro forest) of the Atlantic Forest in northeastern Brazil. The sampling methods used were pitfall traps with drift fences, timed visual encounter survey, donations from local collectors, incidental encounters, and road sampling. We obtained a total of 164 individuals distributed across 29 snake species and six families over 2 years of study. The most frequently encountered species were the two blindsnakes Amerotyphlops paucisquamus and A. brongersmianus and the two false coral snakes Tantilla melanocephala and Oxyrhopus trigeminus. Monthly snake captures were significantly correlated only with the lowest temperatures. Our results show that the study area has a rich diversity of snakes of similar composition to other Brazilian open areas with a dominance of fossorial and cryptozoic species.

Abstract: on vertebrates by large or medium-sized cursorial spiders in the families Ctenidae, Lycosidae, Pisauridae, Sparassidae, Theraphosidae, and Trechaleidae (e.g., Menin et al., 2005; Maffei et al., 2010; Nyffeler and Pusey, 2014). On the other hand, predation on vertebrates by orbicular web spiders (Nephilidae and Araneidae) seems to be less common (Nyffeler and Knörnschild, 2013), whereas predation by small spiders using diffuse webs is apparently rare (Werger, 1978; Garb et al., 2004). Herein we report the first record of a brown widow spider, Latrodectus geometricus C.L. Koch, 1841 (Theridiidae), preying on a neotropical snake Tantilla melanocephala (Linnaeus, 1758). Latrodectus geometricus is widespread in Africa and the Americas (mainly Central and South America) and has been introduced to some others countries around the world (Levi, 1959; Garb et al., 2004); it is generally considered to be of little medical importance (Vetter and Isbister, 2008; Almeida et al., 2009). The species is commonly found in urban habitats around houses, buildings, gardens, and other anthropogenicallymodified areas, such as agricultural plots (e.g., Lamoral, 1968; Anderson, 1972), but it also occurs in natural environments like cerrado (open savannah) in Central Brazil (Motta, 2014). This species is the largest theridiid spider in the Brazilian cerrado biome, with females varying from 0.7–1.2 cm in length and possessing a beige to black brown globose abdomen (depending on local luminosity; Motta, 2014). This species can be identified easily by having characteristic dorsal spots and ventrally an orange or reddish hourglass mark, and also by its spiked egg sacs. These spiders live in a small, cone-shaped silk retreat from which they build an irregular, framed web (Benjamin and Zschokke, 2003). Generally at night, brown widows extrude diffuse threads impregnated with glue droplets at their terminal ends onto the substrate (Lamoral, 1968; Foelix, 2011). Prey animals become glued to the threads at a touch and, while trying to wrestle free, neighbouring trapping threads are contacted and the prey becomes progressively more entangled, capturing the prey (Levi, 1959; Garb et al., 2004; Foelix, 2011). Latrodectus geometricus is a generalist that can feed on a wide range of animals, but it mainly consumes insects and other ground-dwelling arthropods, including spiders, scorpions, and centipedes (Rossi and Godoy, 2005; Lira and Costa, 2014; Rosa et al., 2016). Tantilla melanocephala is a small (19–25 cm in total length) snake with a large range in the Neotropics, occurring from Guatemala to northern Argentina and Uruguay (Santos-Costa et al., 2006) and showing both diurnal and nocturnal habits. This snake is found in many localities in the cerrado, but at low abundance (Marques and Puorto, 1998; França and Araújo, 2006; Braz and França, 2016). Tantilla melanocephala feeds on centipedes (Myriapoda: Chilopoda), which are immobilized and killed, and ingested always beginning with the head (Marques and Puorto, 1998; Oliveira, 2016). These snakes commonly use soil debris, termite mounds, or fallen logs as shelters in cerrado habitats Herpetology Notes, volume 10: 647-650 (2017) (published online on 10 November 2017)

Abstract: The colubrid snake genus Tantilla currently comprises 62 valid species distributed from the southern United States of America to southern Bolivia in the west, and Uruguay and northern Argentina in the east (Wilson & Mata-Silva 2014, 2015). Of these 62 species, 13 are found in South America (Wilson & Mata-Silva 2014, 2015). The most recently described of these Southamerican species is Tantilla marcovani Lema, 2004. While we were working on a checklist and key to the members of the Tantilla clade (sensu Holm 2008, including the genera Geagras Cope 1876, Scolecophis Fitzinger 1843, Tantilla Baird & Girard 1853, and Tantillita Smith 1941; Wilson & Mata-Silva 2015), it became apparent that the diagnosis of T. marcovani entirely falls to distinguish this nominal taxon from the widespread and extensively variable T. melanocephala Linnaeus 1758. Tantilla melanocephala, as presently envisioned, is the most broadly distributed member of its genus (Wilson & Mena 1980; Savage 2002; Greenbaum et al. 2004), occurring from Panama southward into the major portion of the South American continent, apart from Chile and southern Argentina.