Tetilla capillosa explained

Tetilla capillosa, the furry sponge, is a species of demosponge from southern Africa.

Description

This brown to grey-green sponge has a hemispherical to ovoid form. It is firm and tough and typically grows to be 60mm wide.^[1] The surface is completely covered in outward projecting spicules which may be up to 4mm long. It has a single large oscule (NaNmm) at the top. The cortex is undifferentiated.

Spicules

The following spicules make up the skeleton of this species:^[2]

• Protriaenes (spicules with three short prongs projecting forwards from one end of a longer ray) and prodiaenes (two prongs instead of three) with straight branches pointing upwards. The part of the spicule from which the prongs protrude is initially straight, but curves towards the base.
• Anatrienes (megasceleres with one long and three short rays) which may be curved towards the end.
• Straight oxeas (needle-like spicules with pointed ends) that are noticeable asymmetrical.
• Very thin and slightly rough sigmaspires (spirally curved s-shaped spicules).

Skeleton

Tracts of protriaenes, anatrienes and oxeas form a form a radial or spiral skeleton. They pierce the ectosome. These projecting spicules are soft and fuzzy. This is where the common name of the species comes from. Scattered oxeas are also present between these tracts. Sigmaspires are abundant throughout the sponge.

Distribution and habitat

This species is found on the south and west coasts of southern Africa. It is found living at depths of NaNm (-2,147,483,648feet) off the coasts of South Africa and Namibia.

References

1. Book: Atkinson. Lara J. Field guide to the offshore marine invertebrates of South Africa. Sink. Kerry J. 2018. South African Environmental Observation Network. 978-1-86868-098-6. Pretoria. 1037159161.
2. Uriz, María Jesús (1988). Deep-water sponges from the continental shelf and slope of Namibia (south-west Africa). Classes Hexactinellida and Demospongiae. CSIC-Instituto de Ciencias del Mar (ICM)