Caribbean Christmas tree worms (Annelida: Polychaeta: Serpulidae: Spirobranchus) are considered host generalists in their associations with anthozoan (Scleractinia) and hydrozoan (Millepora) stony corals. As planktonic larvae, they settle on coral surfaces and start secreting a calcareous tube to be used as a dwelling. This tube usually becomes overgrown by the host coral (except for its opening) and may get encapsulated deep inside the coral skeleton. In this manner, the well-protected worms grow and survive predation and other hazards, allowing them to live for over four decades. When the host corals are overgrown by other organisms, such as octocorals and sponges, these may act as secondary hosts.
A collection of shrimp from deep reefs in the Dutch Caribbean is described. Most material originates from the Bonaire deep reef expedition (2013) by Wageningen Marine Research of Wageningen University. Some additional material was available from dives on Curaçao (2014). A new species of Pseudocoutierea Holthuis was recognized in the material collected off Bonaire. The new species is described and illustrated and its position in the phylogeny of the genus Pseudocoutierea analyzed. A key to the species in the genus is presented.