"So, naturalists observe, a flea has smaller fleas that on him prey; and these have smaller still to bite ’em; and so proceed ad infinitum."
- Jonathan Swift

August 4, 2010

August 4 - Pandarus rhincodonicus

The host for today's parasite is the mighty whale shark (Rhincodon typus). Pandarus rhincodonicus is parasitic copepod which lives on the skin of the whale shark and are frequently found on the leading edge of the shark's lips and fins. As you can imagine, this is not an easy place to make a living, as the whale shark swim at a speed of about half a metre (almost 2 feet) per second, the drag forces on P. rhincodonicus is substantial. However, the copepod's streamlined shape minimises drag forces, while a series of adhesion pads and hooks allow it to cling tightly to the whale shark's skin. The edge of the carapace is also fringed, which may also help generate a vacuum which press the copepod firmly down upon the skin, acting like a living suction pad.

The photo is a dorsal and ventral view of a female copepod and it came from this paper:

Norman, B.M., Newbound, D.R., Knott, B. (2000) A new species of Pandaridae (Copepoda), from the whale shark Rhincodon typus (Smith)' Journal of Natural History 34:355-366.

Contributed by Tommy Leung.

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