Thyroscyphus
Thyroscyphus is a genus of colonial hydroids, classified within the family Sertulariidae. These hydrozoans are characterized by their distinctive, branching polyp colonies, which are typically found in marine environments. The genus name, Thyroscyphus, is derived from the Greek words “thyros” (meaning “door”) and “skyphos” (meaning “cup”), a reference to the cup-shaped structure of their hydrothecae, which are the protective coverings for their polyps.
Common Names
Thyroscyphus species do not have widely recognized common names.
Characteristics
Members of the genus Thyroscyphus share several key characteristics, including:
- Colonial growth: Thyroscyphus species form branching colonies, with individual polyps connected by a shared, tubular stalk known as the coenosarc.
- Hydrothecae: These are cup-shaped structures that enclose and protect the feeding polyps (hydranths). Thyroscyphus species are distinguished by having hydrothecae that are distinctly "door-shaped" - meaning they have a hinged lid called an operculum that can open and close to allow the polyps to extend their feeding tentacles.
- Gonothecae: These are specialized structures that enclose the reproductive polyps (gonophores). They are often found on the branching stems of the colony.
Environments
Thyroscyphus species are typically found in shallow, coastal marine environments, often attached to rocks, seaweeds, or other marine substrates. They are common inhabitants of temperate and subpolar seas.