Sertularella tenella (Alder, 1856)

Sertularella tenella

Description: The main stems arise from a basal stolon, and are zig-zag shaped and small, typically only 20mm in length. The main stem is usually unbranched and annulated in the basal region and between each hydrotheca. The hydrothecae are alternate and more widely spaced than in Sertularella rugosa. They are barrel shaped with transverse annulations, the aperture is approximately square shaped, and has a single denticle at each corner. The operculum consists of four flaps. The gonothecae are oval shaped with transverse ridges. The aperture is slightly raised with 3-4 denticles.

Habitat: This species often grows attached to other hydroids or to seaweeds in habitats with strong wave action.

Distribution: Recorded from all around the British Isles.

Similar Species: The main stems are shorter and finer than those of Sertularella rugosa, and the annulations on the hydrothecae are less well-developed but more numerous than in that species.

Key Identification Features:

Distribution Map: NBN map : National Biodiversity Network mapping facility, data for UK.

WoRMS: Species record : World Register of Marine Species.

iNaturalist: Species account : iNaturalist World Species Observations database

 Picton, B.E. & Morrow, C.C. (2016). Sertularella tenella (Alder, 1856). [In] Encyclopedia of Marine Life of Britain and Ireland. Accessed on 2024-07-13

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