Rankias

Rankias is a genus of freshwater snails belonging to the family Ampullariidae, commonly known as apple snails. These snails are native to the freshwater ecosystems of Central and South America, with several species found across the Amazon Basin and other river systems. They are characterized by their relatively large, globular shells, which can range in color from yellowish-brown to dark brown, and sometimes exhibit spiral banding. The aperture of the shell is typically ovate and wide.

The morphology of Rankias is adapted for their aquatic lifestyle. They possess a single gill for respiration and a lung for aerial respiration, allowing them to survive in environments with fluctuating oxygen levels. This dual respiratory system enables them to venture out of the water for short periods, often seen climbing vegetation or surfaces above the water line. They are herbivores, feeding primarily on algae, aquatic plants, and decaying organic matter.

Reproduction in Rankias involves sexual reproduction, with females laying clutches of gelatinous egg masses above the waterline, often on emergent vegetation or rocks. The eggs are typically a bright pink or reddish color, which is a distinctive feature of the family. Rankias species play a role in their aquatic habitats as detritivores, contributing to nutrient cycling. Some species have been introduced to non-native regions, where they can sometimes become invasive, impacting local ecosystems and agriculture due to their rapid reproduction and voracious appetites.