Life > Eukaryotes > Opisthokonta > Metazoa
Bilateria > Deuterostomia >
Chordata > Tunicata >
Thaliacea > Pyrosomatida > Family: Pyrosomatidae
> Genus: Pyrosoma
Forms finger-shaped pink to yellowish pink
colonies of zooids (each zooid is an individual animal with an
inhalent and an exhalent siphon), measuring up to 60 cm long by 4-6
cm wide. Colonies upwards of 4 cm long can contain sexually mature
zooids. The test on the exterior of the colony, which forms the
matrix between the zooids, has numerous protuberences, up to 15 mm
long, over the surface, each ending in a spine-like tip, although,
rarely, the exterior can be smooth. The wall of the colony is opaque
and tough, and the zooids are tightly packed. Zooids are rounded and
up to 8.5 mm long.
Distribution and habitat
Regarded as the most widely spread and common
pyrosomatid occurring in all oceans
from 50ºN to 50ºS. There are numerous records from southern African
seas (see distribution map in van Soest 1981).
Pyrosoma atlanticum like most members of
the Pyrosomatidae is bioluminescent
and colonies are able to light up for sustained periods. Each zooid
in the colony has a pair of luminescent organs flanking the orals
siphon. Light production may be the result of intracellular
bioluminescent bacteria in the cells of these luminescent organs but
this needs to be confirmed. Bowlby et al. (1990) showed how
Pyrosoma atlanticum and
bioluminesce in response to light. If you shine light on zooids on
the one side of the colony, they bioluminesce and their light
stimulates adjacent individuals. In this way, the bioluminescence
spreads over the colony from the point where the zooids were
stimulated. A colony that lights up can in turn stimulate an
adjacent colony to light up as well. At the same time as lighting
up, the zooid closes its oral siphon and the cilia inside that cause
the water flow, stop beating. Colonies are negatively buoyant so
when water flow stops, the colony starts sinking slowly. It is
thought that the ability to bioluminesce in response to light
stimulation might be an adaptation to communicating about predators
and by also closing the water flow and sinking, they can move to a
depth where there are fewer predators (Bowlby et al. 1990).
- fish. A variety of fish have been recorded preying on
Pyrosoma atlanticum, but the records so far discovered
are for species that are not native to southern African seas
Puffinus griseus (Sooty shearwater)
Thalassarche bulleri (Buller's albatross) (James
& Stahl 2000). New Zealand study: 77% of samples
contained Pyrosoma atlanticum, and this species
made up 22% of the diet by weight. One individual had 69
specimens in its stomach. The largest specimen consumed
was 14.3 cm in length.
Publications (by date)
- Bowlby MR, Widder EA, Case JF. 1990. Patterns of stimulated
bioluminescence in two pyrosomes (Tunicata: Pyrosomatidae).
Biological Bulletin 179: 340-350.
- Davenport J, Balazs GH. 1991. 'Fiery bodies' - are pyrosomas an
important component of the diet of leatherback turtles? British
Herpetological Society Bulletin 37: 33-38.
James GD, Stahl J-C. 2000. Diet of southern Buller's
albatross (Diomedea bulleri bulleri) and the importance of fishery
discards during chick rearing, New Zealand Journal of Marine and Freshwater
Research, 34(3): 435-454. doi:
- Cruz JB, Lalas C, Jillett JB, Kitson JC, Lyver PO'B, Imber
M, Newman JE, Moller H. 2001. Prey spectrum of breeding sooty
shearwaters (Puffinus griseus) in New Zealand. New
Zealand Journal of Marine and Freshwater Research 35(4):
- Lindley JA, Hernández F, Scatllar J, Docoito J. 2001.
Funchalia sp. (Crustacea: Penaeidae) associated with
Pyrosoma atlanticum (Thaliacea: Pyrosomatidae) off the
Canary Islands. Journal of the Marine Biological Association UK
- Lindsay DJ, Hunt JC, Hayashi K. 2001. Associations in the
midwater zone: the penaeid shrimp Funchalia sagamiensis
Fujino 1975 and pelagic tunicates (Order: Pyrosomatida). Marine
and Freshwater Behaviour and Physiology, 34(3): 157-170.
- Blanco C, Raduán MA, Raga JA. 2006. Diet of Risso's dolphin
(Grampus griseus) in the western Mediterranean Sea.
Scientia Marina 70(3): 407-411.
- Perissinotto R, Mayzaud P, Nichols PD, Labat JP. 2007.
Grazing by Pyrosoma atlanticum (Tunicata, Thaliacea) in
the south Indian Ocean. Marine Ecology Progress Series 330:
- Frick MG, Williams KL, Bolten AB, Bjorndal KA, Martins HR.
2009. Foraging ecology of oceanic-stage loggerhead turtles
Caretta caretta. Endangered Species Research 9: 91-97.