Snake assemblages of Marajó Island, Pará state, Brazil

Abstract

ABSTRACT. We describe the diversity, natural history and structure of snake assemblages from Marajó Island, state of Pará, Brazil, after analyzing 439 specimens deposited in herpetological collections. We tested the hypothesis that snake assem- on habit and habitat. In all, 19 species were exclusive to forest areas, 10 were exclusive to open areas and 26 species were recorded in both areas. Our results revealed greater richness for forested areas, probably due to greater habitat heterogeneity.The species composition for forested area in Marajó was similar to that found in other Amazonian assemblages, while that for open areas was more similar to the Pantanal region than other open area assemblages. The general structure of the snake assemblage of Marajó was dominated by anurophagous, terrestrial and diurnal species. Terrestrial, arboreal and semi-arboreal snakes showed a seasonal offspring production pattern, while the pattern for aquatic and semi-aquatic species was aseasonal.The structure of assemblages was influenced by both historical and ecological factors. KEY WORDS. Amazon, assemblage, functional groups, herpetofauna.GM Rodrigues et al.ZOOLOGIA 33(1): e20150020 | DOI: 10.1590/S1984-4689zool-20150020 2 / 13 produced a list of 38 snake species. Subsequently, yuki & SantOS (1996) listed 52 species of snakes for these two islands using specimens deposited in the MPEG. This set of data resulted in a list of snake species for the island but did not include details about their structure and functional groups.Given that Marajó Island includes both densely forested and open areas, we test the hypothesis that their snake assemblages are distinct with regard to structure, composition and functional groups. Additionally, we compared the snake composition of forested versus open areas of Marajó with comparable assemblages in other regions of Brazil. We provided more detailed information on natural history, including diet, reproduction and species distribution throughout the island. MATERIAL AND METHODSMarajó Island, located between the Brazilian states of Amapá and Pará (0°59'39"S, 49°44'25"W), has an area of approximately 49,000 km 2 (gOulding et al. 2003), being delimited to the south by the Pará River, to the north by the Atlantic Ocean, to the east by the Marajó Bay and to the west by the mouth of the Amazon River. Three distinct ecological regions can be found on the island: dense forests predominate in the western half; successional formations or alluvial fields cover almost its entire eastern half; and Cerrado (natural grasslands) (BritO & ilkiu-BOrgeS 2013) predominates in small areas of the central-north and south eastern regions of the island (radam 1974) (Fig. 1). Our main objective was to test if there are differences between the snakes assemblages of forested and open areas of the island. To make the comparison more robust we considered both the successional formations and the Cerrado together as comprising open habitat.There is a distinct relationship between the vegetational distribution on the island...

Reproductive and feeding biology of the common lancehead Bothrops atrox (Serpentes, Viperidae) from central and southwestern Brazilian Amazonia

“…Ontogenetic dietary shifts were also reported in most species of the genus . Other studies on Bothrops diet, including the current investigation, have corroborated both ideas (Nogueira et al 2003;Oliveira 2003;Monteiro et al 2006;Santos-Costa et al 2015;Rodrigues et al 2016;Silva et al 2017a). The most important items in Bothrops diets (considering only known generalist species) are mammals, lizards and anurans .…”

“…Snake species known to have been preyed upon by B. atrox include the colubrid Tantilla melanocephala (also recorded in the current study), and another unidentified colubrid (Martins and Gordo 1993), the dipsadids Atractus torquatus (Oliveira and Martins 1996) and Oxyrhopus melanogenys (Gavira and Loebmann 2011), and the viperid Porthidium lansbergii (Roldan and Lucero 2011). Bernarde and Abe (2006) also recorded ophiophagy in B. atrox, but did not specify the prey species, whereas Rodrigues et al (2016) observed the occurrence of cannibalism in this species. We recorded a specimen of Imantodes cenchoa (Serpentes, Dipsadidae) among the prey items of B. atrox, which represents, to our knowledge, the first record of this snake in the diet of the common lancehead.…”

Snakes of the Pernambuco Endemism Center, Brazil: diversity, natural history and conservation

“…8D ), being found in Forest and urban areas when these are close to forests ( Araújo et al 2019 ). Chironius carinatus feeds on amphibians, birds, lizards and mammals ( Dixon et al 1993 , Silva et al 2010 , Rodrigues et al 2016 ). Its litter can have 5 to 12 eggs ( Dixon et al 1993 , Goldberg 2007 ).…”

Species richness and composition of snake assemblages in poorly accessible areas in the Brazilian Amazonia

“…Although some studies of Amazonian herpetofauna have been conducted in places far from urban centers (e.g. Frota et al 2005, Prudente & Santos-Costa 2005, Bernarde et al 2006, Turci et al 2008, França & Venancio 2010, Ferrão et al 2012, Pantoja & Fraga 2012, Santos-Costa 2015, Vaz-Silva et al 2015, Rodrigues et al 2016, França et al 2017, Fonseca et al 2019, for example there is a sampling bias in favor of densely populated areas as shown for plants (Nelson et al 1990).…”