Cristatella

Cristatella is a genus of freshwater bryozoans (ectoprocts) in the phylum Bryozoa. The most well-known species is Cristatella mucedo, found in temperate regions of Europe and North America. Cristatella forms soft, gelatinous colonies that are often disc- or cup-shaped and may float on the water surface or rest on submerged substrates. Colonies can reach several centimeters in diameter and appear as a single, circular organ consisting of many connected zooids.

Morphology and biology: A Cristatella colony is composed of numerous zooids (autozoids) arranged around a central cavity. Each zooid bears a lophophore, a crown of ciliated tentacles used for filter feeding. The colony functions as a single integrated unit, with nutrient sharing among zooids. The surface often has a delicate, translucent appearance, and the colony can exhibit sluggish movement by body-wall contractions.

Reproduction and life cycle: Cristatella reproduces both sexually and asexually. Budding by zooids enlarges the colony, while sexual reproduction produces larvae that disperse to form new colonies. In addition, Cristatella forms statoblasts, durable asexual propagules that enable overwintering and dispersal to new habitats when conditions improve.

Habitat and distribution: These bryozoans inhabit still or slow-moving freshwater bodies, such as ponds, lakes, and calm streams. They prefer clean, nutrient-balanced waters and are distributed across temperate zones in Europe, Asia, and North America.

Ecology and significance: As filter feeders, Cristatella colonies contribute to water quality and aquatic community dynamics. They are studied for insights into bryozoan colony organization, reproduction, and life history strategies in freshwater environments.