Melanoides tuberculata (Müller, 1774)
Melanoides tuberculata is a medium-sized, predominantly freshwater snail of warm-temperate to subtropical regions, but it has colonized estuaries with marine salinities (Englund et al. 2000; Wingard et al. 2007; Barroso and Matthews-Cascon 2009). It has an elongate-conical dextrally coiled shell, of 8-12 whorls with a strongly pointed spire, though the tip is usually eroded. The shell is sculptured with fine spiral striations and vertical weakly curved ribs. The middle and upper whorls have more strongly-defined vertical ribs. The aperture has a tear-drop shape and the operculum is horn-colored. The shell reaches a length of about 30-36 mm. The color is light brown, with a dark reddish spiral band formed of transverse streaks and spots (Thompson 2004).
Melanoides tuberculata has a large native and introduced range and displays a wide degree of morphological variation, which is largely genetic in origin. This snail is capable of both sexual and parthenogenetic reproduction and is often patchily distributed. These scattered populations are prone to divergence both through local selection and genetic drift (Samadi et al. 1999). On the Caribbean island of Martinique, multiple introductions and occasional hybridization have led to dramatic genetic variation in morphology and life history among populations in different streams (Samadi et al. 1999; Facon et al. 2008). This degree of local variation is likely seen elsewhere in this species' introduced and native ranges. According to one online database (Galli 2013), there are 47 named species of Melanoides, excluding synonyms, so it is possible that multiple named and unnamed cryptic species have been introduced and identified as M. tuberculata.
Very similar, possibly conspecific