Sarsia tubulosa (M. Sars, 1835) Common name(s): Clapper hydroid, clapper medusa, clapper hydromedusa, thimble jellyfish
Synonyms: Syncoryne mirabilis
Phylum Cnidaria  Class Hydrozoa Order Hydroida  Suborder Athecata (Anthomedusae)  Family Corynidae
	Sarsiatubulosa. 8 mm long, captured at night at Sharpe Cove dock by Jamie Anderson Fields. Note the 4 tentacles, each connected to its own tentacular bulb which also has a black ocellus.
	(Photo by:  Dave Cowles, August 2025)

Description:  This hydromedusa has four tentacles originating at the margin of the bell, each of which arises from a separate tentacle bulb. Each bulb also contains an ocellus. The height of the bell is only slightly greater than the diameter, and it has no marginal vesicles. The apex of the bell is rounded not pointed (photo). The tentacles have swollen batteries of nematocysts all along their length (photo). It has a highly extensible manubrium which can extend out to at least the height of the bell beyond the bell margin. The gonad of this species is a thick, bumpy growth wrapped around most of the manubrium, but it does not extend clear to the top of the manubrium (photo  photo). Mostly colorless but may have blue, red, green, or orange on the manubrium, tentacles, or tentacle bulbs. Bell up to 4 cm tall. This species may be introduced. 

How to Distinguish from Similar Species:Sarsia princeps is rare, conical, and has height up to 2x the diameter. Sarsia viridis has iridescent green on its manubrium and tentacle bulbs.

Geographical Range:  Bering Sea to central CA

Depth Range:  Epipelagic (near the surface)

Habitat:  Pelagic

Biology/Natural History: Sarsia eat mainly crustaceans. 

The normal life cycle of hydrozoans is for male and female medusae to release sperm and eggs. After fertilization, the fertilized egg divides and becomes a small, ciliated planula larva. The planula settles to a surface and grows into a branched colony of attached polyps. Medusae bud from some of the polyps in the colony to complete the life cycle. Another athecate hydrozoan, Turritopsis dohrnii, however, which is widespread in warm oceans, has recently been discovered to have an unusual skill. If the sexually mature medusae are injured or encounter unfavorable conditions such as warmth, modified salinity, or pinching, the mature, differentiated cells of the medusa can de-specialize and form into a cyst, which is a ball of pluropotent stem cells. The cyst settles to the bottom and grows back into a new polyp colony. This behavior thus allows them to take a shortcut backwards to an earlier stage in their life cycle. Currently this is the only known sexually mature, multicellular animal that can do this. Not even Turritopsis rubra, a member of the same genus, appears to be able to do this. Some of the main scientists who discovered this phenomenon include Maria Pia Miglietta, Maria Pascual-Turner, and Stefano Piraino. A summary of their research and a list of several key references can be found here in the journal "The Scientist". Whether other athecate  hydroids such as Sarsia can do this is not known.

References:

General References:
  Lamb and Hanby, 2005
  Wrobel and Mills, 1998

Scientific Articles:
 

Web sites:

General Notes and Observations: Locations, abundances, unusual behaviors:

The tentacles are covered with batteries of nematocysts. Photo by Dave Cowles, August 2025

The distal end of the manubrium is covered with bumps, which apparently are the gonads. Photo by Dave Cowles, August 2025

The apex of the subumbrella, where the manubrium connects, has a small, orange projecting cone. Such a conelike stomach is found in S. tubulosa. Also, notice that the bumpy gonad completely wraps around the manubrium except for a short space just under the subumbrella. This is also characteristic of S. tubulosa. The four radial canals are also visible. The exumbrella is out of sight to the right but the conelike stomach does not project out to the exumbrella.  Photo by Dave Cowles, August 2025

This view, zoomed out a bit from the view above, shows the exumbrella out beyond the orange stomach. Note also that the exumbrella apex is rounded as in S. tubulosa, not pointed.

This whole view shows the animal attatched to a substrate by its 4 tentacles. The tentacles are extremely sticky, likely due to discharge of nematocysts. Note the orange on the tentacle bulbs. Photo by Dave Cowles, August 2025

Authors and Editors of Page:
Dave Cowles (2025):  Created original page
CSS coding for page developed by Jonathan Cowles

Salish Sea Invertebrates web site provided courtesy of Walla Walla University