Feb 5, 2007

Parasite or Devoted Father?

LuAnne alerted me to this tiny fishie. What you're looking at is the smallest vertebrate on the planet. Actually, you're probably looking at the female, which is the larger of this pairing. Pairing, you say? Yes - take a look at that thing stuck on the back of the fish. That is the male fish.

This is a classic example of sexual parasitism (oh, so many joke opportunities here!). With this fish (Photocorynus spiniceps, found in peat swamps in Southeast Asia), the male (measuring at only 6.2 mm) attaches itself to the female. This is a permanent union which allows the male to partake of the nutrients supplied by the female, which in turn lets him focus on his job; nearly all of his body cavity is filled with his testes. He is a one-purpose fish: breeding. She benefits by having him at hand for baby time.

Is this an example of parasitism, or is it an example of a truly dedicated father? You be the judge.

Thanks for the article, LuAnne.

UPDATE: There is a lot of junk on the web, or at least a lot of less-than-factual stuff. Unfortunately, this site can too often be found in the same pile o' doo-doo. Our preeminent ichtyologist, Rasmus, has pointed out two flaws with this post - I suggest you read his comment. But thanks for the encouragement, Swintah, and for helping me save some face.

Photo courtesy: Nutmeg's StumbleUpon


bats said...

I guess when you're that small in a big world, it's just best to find the first female that swims along and hang on for the ride!

Rasmus said...

I'm afraid you've gotten it a bit mixed up. Photocorynus is a deep-sea anglerfish, and doesn't live in fresh water, let alone Asian peat swamps. However, these habitats are home to the actual smallest vertebrate, Paedocypris progenetica, in which both male and female grow to a size of less than 1 mm.

Swintah said...

You know, half the fun of this blog is fact-checking.

Thanks, Raging Wombat, for giving all of us the opportunity to be smarty-pants.

Rasmus said...

You're right swintah. I'll take the opportunity to fact-check myself. I really meant 1 cm, not mm.

Swintah said...

I'm aglow with pride!

Anonymous said...

Didn't they just find a new species of fish in Thialand that takes the "smallest vert" prize? I'm sure I read that last week... must go check

- Arachnophile

Anonymous said...

My bad rasmus - you were right. [i]Paedocypris progenetica[/i] was who I was thinking of and it was found in Sumatra. I nevah should have doubted. ;)

- Arachnophile

Anonymous said...

Thought you might find this graphic relevant Washington Post: What is the smallest vertebrate?

Raging Wombat said...

That is a good graphic!