Treasure of the month - worm wishes for the holidays

The "Christmas tree" worms of the genus Spirobranchus are the best-known representatives of the marine annelids of the family Serpulidae. Their colourful and spiral-shaped head appendages are reminiscent of Christmas trees.

Those who dive into the oceans may have seen these eye-catching worms peeking out of the corals of tropical reefs and using their blue, yellow, orange or red "Christmas tree" head appendages to catch tiny food particles from the water current above them. When disturbed, the worms quickly retreat into their calcareous tubes, which they can close with a special lid made from a modified tentacle.

Christmas tree worms are not just a pretty decoration in coral reefs. They also purify the water and make food available for other organisms by drawing nutrients from the water column to the bottom.

The Annelida collection of the LIB comprises 652 specimens of the family Serpulidae, including the original type material for 22 species. Type material is of crucial importance for systematics and taxonomy as these specimens represent the physical definitions of a species. The Annelida collections of the LIB contain a total of around 3,500 type specimens.

As part of an expedition to Oman in late 2022, the LIB curator of annelids, Dr Jenna Moore, collected many Spirobranchus specimens, including the one pictured above, alongside several hundred other annelids. The expedition was an international collaboration led by researchers from the Florida Museum of Natural History and the Smithsonian Institution to describe, characterise and study the marine biodiversity of Oman and the western Indian Ocean.

Oman is a remarkable place with very different habitats and unusual current patterns. An incredibly diverse and unusual marine fauna thrives here. The annelids from Oman are currently being identified and studied by Dr Moore and other taxonomic experts from around the world. The aim is to better understand the diversity of marine annelids and their biogeographical patterns.

The Spirobranchus specimens from Oman are not the only ones getting in the mood for the festivities. Others are ready for the fireworks of the New Year, like this "feather worm" from the Sabellidae family. Sabellids are close relatives of Christmas tree worms. Their spectacular tufts of tentacles are similarly colourful, but look more like fans (or fireworks!).

Other worms seem to be real sweet tooths. This Eunice sp. with its candy cane shaped antennae has a huge jaw hidden in its throat. The development of these jaw structures is another focus of research in the LIB's Annelida department.

These specimens represent only a small part of the remarkable diversity of marine Annelida discovered in Oman, including several species new to science. They will be described shortly. Characterising species diversity through taxonomy is a prerequisite for understanding changes in biodiversity. This is an important research goal at the LIB.

However the upcoming festive season is celebrated, the Annelida Section of the LIB also sends you worm wishes for the holidays and the New Year.