Bathyal Hydroid

A new species of bathyal >hydroid found in the Gulf of Cadiz suggests that many undiscovered species may still exist on the relatively unexplored continental margins.

The Gulf of Cadiz is a geologically complex region located at the junction of the African and Eurasian tectonic plates. Cold-water coral rubble fields, inactive carbonate chimney fields, and >mud volcanoes characterize the continental margin in this area of the Northeastern Atlantic Ocean. These unique geologic features support large colonies of cnidarians. One such cnidarian, a hydroid that is associated with mud volcanoes, has been found to be new to science.

This hydroid, named Tubiclavoides striatum gen. nov. et sp. nov. (Cnidaria: Hydrozoa), was discovered during an Intergovernmental Oceanographic Commission-UNESCO "Training Through Research Programme" research cruise aboard the RV Prof. Logachev. Collected by both Television-assisted grab and >box cores in deep water (1000 to 4000 m in depth), this species is found inhabiting >scleractinian coral debris fields, carbonate structures, and active mud volcanoes. Comparisons of collected samples with the characteristics of existing hydroid species has led researchers to conclude that this is not only a new species, but a new genus, and possibly a new Family. Identifying characteristics of this newly discovered species include:

  • Filiform, or thread-like, tentacles (numbering from 5 to 30+) scattered in an undefined pattern across the body of the hydranth
  • Sporosacs, or asexual reproductive structures, forming among the tentacles
  • A central stem, called a hydrocaulus, is covered by a tough covering called a perisarc that frequently takes the form of an overlapping cone shape and has ridges, or striations, along its length.

Additionally, DNA analysis of tissue from this species was compared to published DNA sequences of other hydroid species to test for potential relationships. It was found that this species does not exhibit enough similarity to conclude that this specimen belongs to other established genera of hydroids. This further reinforces the scientists' assertion that this hydroid represents a new species, a new genus, and likely a new Family.

The discovery of this new species of hydroid suggests that there exists many more such new forms of life yet to be discovered along the deep continental margins of the world. These margins have, to date, remained relatively unexplored due to technological and logistical constraints and may represent an exciting new frontier for oceanic research.

Species Location: This species was found on he Atlantic margin of Morocco in the Gulf of Cadiz in the Northeast Atlantic Ocean (shaded area on the left map and starred on the close-up on the right).
  • What: Discovery of a new bathyal hydroid species associated with mud volcanoes in the Gulf of Cadiz
  • Who: COMARGE Scientists --> C. J. Moura, M.R. Cunha, and P. Schuchert
  • When: August 2006
  • Where: On the Atlantic Moroccan Margin (35° N, 7° W) in the Gulf of Cadiz, Northeastern Atlantic Ocean
  • How: Collected by box core / TV assisted grab
  • References: Moura, C.J., M.R. Cunha, and P. Schuchert, 2007. Tubiclavoides striatum gen. nov. et sp. nov. (Cnidaria: Hydrozoa) a new bathyral hydroid from the Gulf of Cadiz, north-east Atlantic Ocean. Journal of the Marine Biological Association of the United Kingdom, 87: 421-428.