The genus Puellina contains ten British species within three sub-genera. Globally, the genus contains 57 described species. Colonies are encrusting and composed of a single layer of autozooids. Autozooids are small and may appear similar across species.
Superficially the species are very similar, but size and shape of secondary orifice; number of orals spines; presence and form of suboral lacuna; number of frontal costae; avicularia morphology; and attributes of ovicells are important in species identification
The frontal shield is formed of fused, but discernible spines (= costae) in a more or less pinnate or radiating pattern. Each costa generally has one or more small pseudopores. The fusion of successive costae is separated by a few to many small intercostal pores. The orifice is bordered proximally by an apertural bar formed from the distal-most pair of costae. Oral spines are present. Avicularia are interzooidal where present. Ovicells are hyperstomial, globular, punctuate or non-punctate ovicells.
Puellina species mostly inhabit deep-water hard substrates and cryptic habitats in shallower water which may be either large (e.g. underwater caves) or small (e.g. rock cracks, crevices, the underfaces of stones and shells.