A small (up to 10cm tall, but more typically 5cm) branching-erect sponge with a short stalk. The branches are compressed and 'webbed' together. The colour is bright to deep yellow. In Northern Ireland this species is has been recorded from Rathlin Island; Skerries (Portrush); Causeway coast and The Maidens (Larne). It is usually very scarce apart from one area at the White Cliffs on Rathlin Island which is often referred to as 'Damicornis Bay'. It occurs on sloping, lower circalittoral bedrock and stable boulders in areas exposed or semi-exposed to wave action and tidal streams. Several studies using molecular data have shown that this species is not an axinellid and recommended its transfer to Hymerhabdia: Agelasida (Morrow et al., 2012; Morrow & Cardenas, 2015).

In brief

• Found at Rathlin Island, Skerries (Portrush), Causeway coast and the Maidens (Larne).
• occurs on sloping, lower circalittoral bedrock and stable boulders in areas exposed or semi-exposed to wave action and tidal streams.
Listed as Northern Ireland Priority Species (NIPS) due to its scarcity and restricted range and Rathlin Island being a stronghold for this species.

Species description: A small (up to 10cm tall, but more typically 5cm) branching-erect sponge with a short stalk. The branches are compressed and 'webbed' together. The colour is bright to deep yellow, verging sometimes towards deep orange at the margins. It is distinctively 'bright'. The surface has a characteristic 'mealy' appearance, as though dusted with small yellow particles. Small oscules are borne on the apices of the branches. When alive, the open oscules are partially surrounded by a small triangular 'flap' of tissue.

Life cycle: Axinella damicornis is an oviparous sponge releasing eggs and sperm directly into the water column. In the Mediterranean it has a prolonged reproductive period, releasing eggs over 7–8 month period in Autumn to Spring (Riesgo & Maldonado, 2009). Its reproduction in UK waters has not been studied.

Similar species: The overall form is similar to Stelligera montagui but the mealy appearance of the surface and bright yellow colour are characteristic. Most readily confused with Axinella verrucosa, so far only recorded as far north as Roscoff and the Channel Islands.

How to see this species: This sponge is normally found at depths between 25–40m on circalittoral bedrock and stable boulders that are subject to moderate wave exposure and tidal streams. In Northern Ireland it may be found at scattered sites around Rathlin Island but it is particularly frequent at a site off the White Cliffs, commonly referred to 'Damicornis Bay'. There are also records of it from Skerries (Portrush), Causeway coast and the Maidens.

Current status: The species is known from only four locations in Northern Ireland, and is regarded as rare throughout Britain and Ireland. It has no legal protection.

Why is this species a priority in Northern Ireland?

• Listed as a Species of Conservation Concern on account of its rarity and restricted range.
• Northern Ireland is a Stronghold for this species.

Threats: This erect sponge is vulnerable to bottom fishing and potting activities. It is especially vulnerable due to its dependence on a very small number of sites in Northern Ireland.

Action:

• Maintain the number of viable populations
• Maintain the range
• Monitor the populations (or a sample of them) from key sites.

Objectives: Records of new sites for this species, with details of habitat and population are always valuable. Send these to CEDaR, National Museums Northern Ireland, 153 Bangor Road, Cultra, Holywood, County Down, BT18 0EU. Tel 028 9039 5257 or e-mail cedar.records@nationalmuseumsni.org, or via the online portal. You can also record observations including a photograph using iNaturalist, find the MBDP-NI iNaturalist project here.

Conservation: Rathlin Island and its waters have been designated as a Marine Conservation Zone (MCZ) with a ban on bottom fishing.

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

iNaturalist: Axinella damicornis at iNaturalist World Species Observations database.

WoRMS: Axinella damicornis at World Register of Marine Species. Accepted name: Axinella damicornis (Esper, 1794). AphiaID: 132472.

Literature:

Morrow, C.; Picton, B.; Erpenbeck, D.; Boury-Esnault, N.; Maggs, C.; Allcock, A. (2012). Congruence between nuclear and mitochondrial genes in Demospongiae: A new hypothesis for relationships within the G4 clade (Porifera: Demospongiae). Molecular Phylogenetics and Evolution. 62(1): 174-190.

Morrow, C.; Cárdenas, P. (2015). Proposal for a revised classification of the Demospongiae (Porifera). Frontiers in Zoology. 12: 7.

Riesgo, A.; Maldonado, M. (2009). Ultrastructure of oogenesis of two oviparous demosponges: Axinella damicornis and Raspaciona aculeata (Porifera). Tissue and Cell. 41(1): 51-65.

Classification: Biota; Animalia; Porifera; Demospongiae; Heteroscleromorpha; Axinellida; Axinellidae; Axinella

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(2026). Axinella damicornis. (Esper, 1794). [In] Priority species, Marine Biodiversity Portal NI. https://www2.habitas.org.uk/marbiop-ni/priorityaccounts.php?item=C3510. Accessed on 2026-07-28