Schmitzia neapolitana is a small rare gelatinous red alga, irregularly branched and with whorls of very short branches. The whole plant is no more than 10cm long.

In brief

• Found in only four sites in Northern Ireland: Torr Head, Loughan Bay and Cushendun Bay in County Antrim and Greenore Point in Carlingford Lough, County Down
• Known only from below water to a depth of 15m
• Found in areas of strong currents
• It is scarce with Northern Ireland being an Irish stronghold for this species
• Very similar to another alga such as Calosiphonia vermicularis
• The only threat is to its habitat.

Species description: Schmitzia neapolitana is a small, gelatinous red alga growing to more than 10cm long. It forms a flattened leaf-like blade with opposite proliferations along the edges. The other similar species, Calosiphonia vermicularis, can only be distinguished microscopically.

Life cycle: The reproductive structures are microscopic. However reproduction and fertilization has been described in the scientific literature. The full life cycle is not known; one stage (the tetrasporophyte), if it occurs at all, has never been recorded in Northern Ireland.

Similar species: Schmitzia neapolitana is very similar to Calosiphonia vermicularis; microscopic examination is required to distinguish them.

How to see this species: In Northern Ireland this species has only been recorded from Torr Head, Loughan Bay and Cushendum Bay in County Antrim. The only record from County Down is from Greenore Point in Carlingford Lough. It grows below low-water mark to15m depth on small stones and boulders in places of strong currents. It is best searched for by scuba-diving.

Current status: The species is very rare, has been recorded from four sites in Northern Ireland: Torr Head, Loughan Bay and Cushendum Bay in County Antrim, and Greenore Point in Carlingford Lough, County Down.

Why is this species a priority in Northern Ireland?

• Scarce, all Irish records are from Northern Ireland.

Threats: The only threat is to its habitat.

Action:

• The status of Schmitzia neapolitana will be surveyed and monitored and appropriate conservation action undertaken if required.

Objectives:

• No relevant action.

Conservation:

• Implementation of the Northern Ireland Habitat Action Plan for Maërl Beds.

Distribution Map from NBN: Schmitzia neapolitana at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Schmitzia neapolitana at iNaturalist World Species Observations database.

WoRMS: Schmitzia neapolitana at World Register of Marine Species. Accepted name: Schmitzia neapolitana (Berthold) P.C.Silva, 1959. AphiaID: 145604.

Literature:

Hiscock, S. and Maggs, C.A. (1984). Notes on the Distribution and Ecology of Some New and Interesting Seaweeds from South-west Britain. Br. Phycol. J. 19: 73–87.

Karlson, J. (1990). On the Occurrence of the Genus Schmitzia (Rhodophyta, Gigartinales) on the Swedish West Coast. Br. Phycol. J. 25: 367–374.

Morton, O. (1994). Marine Algae of Northern Ireland. Ulster Museum, Belfast.

Classification: Biota; Plantae; Biliphyta; Rhodophyta; Eurhodophytina; Florideophyceae; Rhodymeniophycidae; Gigartinales; Calosiphoniaceae; Schmitzia