Teuthidodrilus (also known as the squidworm), is a genus of marine polychaete worms first described by marine biologists from the Scripps Institution of Oceanography in November 2010. This unique animal is currently believed to represent a “transitional organism”, with physical and behavioral characteristics of both benthic (seabed-dwelling) and pelagic (free-swimming) organisms. Teuthidodrilus samae is currently the only described species of this genus. Teuthidodrilus is closely related to the recently discoveredSwima genus, another pelagic cirratuliform worm of the deep ocean.
Teuthidodrilus is one of seven recently discovered deep-sea, pelagic cirratuliforms. The first specimen was observed in the Celebes Sea in October 2007. A second specimen was discovered in a nearby area by a group of marine biologists from the Scripps Institution of Oceanography in November 2010. Using a remotely operated underwater vehicle during exploration of the deep water column of the western Celebes Sea, the team found the animals at a depth of 2.8 kilometres (1.7 mi). The Celebes Sea is a deep oceanic basin with a maximum depth of 20,300 feet (6,200 metres). It is part of the Coral Triangle, an area known for its high biodiversity.
Classification and Phylogeny
Teuthidodrilus is thought to be a previously unobserved genus which may represent a transition between the benthos and the pelagic organisms. Teuthidodrilus is one of seven newly discovered species of swimming cirratuliforms. These seven species have been assigned to four new genera, forming a new phylogenetic clade within the Acrocirridae family. Following is a brief description of the cladistics andtaxonomic classification of Teuthidodrilus:
Teuthidodrilus specimens observed and collected as of 2010 have measured up to 9.4 centimetres (3.7 inches) in length. These animals are notable for the unusual tentacular appendages (referred to as “notochaetae”) that protrude from its prostomium (anterior segment, or head). Ten of these tentacles as long or longer than its body protrude from the head, along with six pairs of free-standing, oppositely branched nuchal organs that allow the animal to taste and smell underwater. It is the notochaetae and the nuchal organs which primarily distinguish Teuthidodrilus from other polychaetes.