-1-

tammy.horton

Deep%20sea%20life%20of%20Tanzania_2016_reduced.pdf?bcsi_scan_2687365ababd2c82=0&bcsi_scan_filename=Deep%20sea%20life%20of%20Tanzania_2016_reduced

Stalked crinoids (Sea lilies)

- Echinodermata - Crinoidea -

Echinodermata (Phylum) > Crinoidea (Class)

The Crinoidea comprise the sea lilies (below) and feather stars (opposite page). Sea lilies

flourished in the Paleozoic era and they are one of the oldest animal groups with living

representatives. They are sometimes described as “living fossils” owing to their age in

the fossil record and conserved body plan. Modern species are restricted to the deep sea.

In the study area off Tanzania sea lilies were uncommon but examples were seen at three

of the sites across a depth range of 1300-2600 m.

Hyocrinida

Echinodermata (Phylum) > Crinoidea

(Class) > Hyocrinida (Order)

This pale yellowish stalked crinoid with

darker arms appears to be a hyocrinid. It

is unusual with such proportionally short

rays. It was seen on two occasions on rocks

at the Pweza-3 site in 1380 m water depth.

The specimen here is approximately 50 cm

in length.

Hyocrinid on a rock at Pweza-3

Bathycrinidae

Echinodermata (Phylum) > Crinoidea (Class) >

Comatulida (Order) > Bathycrinidae (Family)

Seen only at the deepest sites, this animal is unusual

because it has a very small “head”. It appears

to be a bathycrinid, perhaps Bathycrinus or Monachocrinus.

The growth on its stalk includes barnacles

and hydroids. An amphipod crustacean also

appears to be making use of this habitat.

Bathycrinid at over 2400m water depth

-46-

Similar magazines