Terebrasabella heterouncinata Fitzhugh and Rouse, 1999

Status
Pest, Indigenous

Description
Small, ~2 – 5 mm; all have 8 thoracic and 3 abdominal chaetigers.
Branchial crown with 2 pairs of radioles, each with 4 – 6 pairs of pinnules. Thoracic uncini on chaetigers 2 – 6 (3 – 4 per fascicle) with main fang, 1 pair large lateral teeth, and smaller subequal teeth, on chaetigers 7 – 8 lack main fang, each with ~22 rows of teeth, 5 teeth per row, up to 23 uncini per chaetiger. Companion chaetae present. Abdominal uncini similar to thoracic uncini.

Reproduction
Simultaneous hermaphrodite: sperm in chaetiger 8, eggs in chaetigers 9 & 10. Semi-continuous brooders, larvae lecithotrophic, remain in parental burrow until ready to settle.

Ecology
Live in burrows in shell of abalone, turban shells, whelks. Don’t excavate own burrows; larvae settle on inner surface of growing edge of host shell and induces host to secrete nacreous shell around it, forming tube

Distribution
South Africa: Western Cape and Eastern Cape provinces.
California, Chile

Notes
When present in very high densities cause shells to become deformed. Problems on local farms mostly under control. Probably complex of host-specific species in South Africa. Needs to be resolved.