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tammy.horton

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

- Porifera -

Hyalonema sp.

Porifera (Phylum) > Hexactinellida (Class) > Amphidiscophora (Subclass) > Amphidiscosida

(Order) > Hyalonematidae (Family)

These small hexactinellid sponges were more frequent in the deeper water at Lavani, Zafarani

and the Mzia sites. Identification is not certain because inspection of the spicules

is required but it is most likely Hyalonema sp. The dense covering of zoanthids (small

anemone-like organisms) on the sponge above left have been recorded previously on

other Hyalonema specimens from other study areas.

Monorhaphis chuni

Porifera (Phylum) > Hexactinellida (Class) >

Amphidiscophora (Subclass) > Amphidiscosida

(Order) > Monorhaphididae (Family)

The only accepted species in the genus Monorhaphis

is anchored to the sediment by a single giant

basal siliceous spicule which can be up to three

metres in length. These are the largest biogenic siliceous

structures known on Earth. These sponges

are slow-growing and extremely long-lived, among

the longest living organisms known. A specimen from the China Sea was estimated to

be 11,000 years old. The basal spicule increases in diameter as the animal grows and

the environmental conditions at the time are reflected in the chemistry of the structure.

Analysis of these spicules shows promise as a paleoenvironmental archive. Such data can

be used to estimate water temperature at different times during the life of the animal,

which can then be used to indicate past climatic conditions.

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