Thermarces cerberus (Rosenbatt and Cohen 1986)

Background
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Family: Zoarcidae

Geography and Distribution
Thermarces cerberus is the dominant species of fish found in the hydrothermal vent environment of the East Pacific Rise and Galapagos Ridge (Fig. 1) (Geistdoerfer, 1991; Geistdoerfer and Laurent, 1995; Biscoito et al.¸2002; Sancho et al., 2005). Fish are relatively rare at all vent sites, and as such T. cerberus shows a high degree of endemism as well becoming the prevalent species at such sites (Biscoito et al., 2012). They mainly live amongst the Riftia and other worm species within the vestimentiferan zone of these sites (Micheli et al., 2002; Sancho et al., 2005), although they can also sometimes be found amongst mussels in the suspension-feeder and sessile zone. They tend to prefer waters with temperatures of 8-12oC (Sancho et al., 2005).

adapted from VRIJENHOEK (2010)
Figure 1: Adapted from Vrijenhoek (2010), this map of all hydrothermal vent sites and rift boundaries highlights the general location of Thermarces cerberus, with the red lines. It is a broad location as T. cerberus is found at multiple sites along the East Pacific Rise and Galapagos Rift ridges.

Appearance and Identification
Like many other deep sea species, T. cerberus looks relatively strange (Fig. 2). With no scales or lateral line, as well as no pelvic bone or fin rays (Rosenblatt and Cohen, 1986), this species doesn’t particularly resemble the normal fish appearance of shallow-water and/or surface fish species. Rosenblatt and Cohen (1986) also described this species as having a blunt and rounded snout, a small eye covered by skin, and dentary teeth (Fig. 2).

close up image of Thermarces cerberus which clearly shows the characteristic 'blunt' head, scaleless body, and small eyes.
Figure 2: A close-up image of Thermarces cerberus which  shows the species’ characteristic ‘blunt’ head, scaleless body, and small eyes that are covered by skin.

Feeding Strategy
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References
Biscoito, M., Segonzac, M., Almeida, A.J., Desbruyeres, D., Geistdoerfer, P., Turnipseed, M. & Van Dover, C. (2002) Fishes from the hydrothermal vents and cold seeps – an update. Cahiers De Biologie Marine, 43, 359-362.

Deep Sea Photography. (2009) Thermarces cerberus close-up (figure 2). Available: http://archive.noc.ac.uk/chess/education/edu_dive.php [09/12/2014]

Geistdoerfer, P. & Seuront, L. (1995) Redescription and biology study of Thermarces cerberus (zoarcidae) of hydrothermal vents of the east pacific ridge. Cybium, 19, 167-178.

Micheli, F., Peterson, C.H., Mullineaux, L.S., Fisher, C.R., Mills, S.W., Sancho, G., Johnson, G.A. & Lenihan, H.S. (2002) Predation structures communities at deep-sea hydrothermal vents. Ecological Monographs, 72, 365-382.

Rosenblatt, R.H. & Cohen, D.M. (1986) Fishes living in deepsea thermal vents in the tropical eastern pacific with descriptions of a new genus and two new species of eelpouts zoarcidae. Transactions of the San Diego Society of Natural History, 21, 71-79.

Sancho, G., Fisher, C.R., Mills, S., Micheli, F., Johnson, G.A., Lenihan, H.S., Peterson, C.H. & Mullineaux, L.S. (2005) Selective predation by the zoarcid fish Thermarces cerberus at hydrothermal vents. Deep Sea Research Part I: Oceanographic Research Papers, 52, 837-844.

Vrijenhoek, R.C. (2010) Bythograea thermydron distribution map, from: Genetic diversity and connectivity of deep-sea hydrothermal vent metapopulations. Molecular Ecology, 19, 4391-4411.

 

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