Pygmy Gobies Outdo James Dean
All right, so they are vertebrates. (Please don't kick me off the blog, Kevin.) I just wanted to write something cool during Coral Week, and I just realized that it's already Friday. So, with a bottle of "Hazed and Infused" beer at my side, I am going to wander into the world of a coral denizen that has no time to spare.
In a sad display of rampant unoriginality, most of the popular articles I found on the pygmy goby were cleverly titled "Live Fast, Die Young..." So, when I was thinking of a title for this post I struggled to resist the urge to use the phrase. It isn't clever any more, so I just had to stop myself before I finished the title.
The little buggers don't last all that long, it's true. The maximum lifespan is 59 days. So, what have you accomplished in the last fifty nine days? Probably not nearly as much as a pygymy gobi who just died today of old age; satisfied and leaving many grandchildren. It was born and lived three weeks as a larvae in the open ocean. Then it found a coral reef and settled in and hid from predators.
Females lay three clutches of eggs during their lives, and the fathers guard the eggs furiously until they hatch to become larvae who float through the ocean until they, in turn find their coral home and repeat the cycle again and again and again.
The cool part of the saga of the pygmy goby is that their short life spans their status as favored foods for predators places heavy selective pressure on them. Yep, back to evolution. (We just can't get away from it, can we?.) The pygmy gobi caught the attention of Astrobiology Magazine in 2005, following the release of a study authored by Martial Depczynski and David Bellwood of James Cook University. Depcsynski and Bellwood determined the lifespan of Eviota sigillata in part by scanning rings in the tiny fishes' otoliths (ear stones.) They lay down a ring a day, every day; and the rings are discrete, much like tree rings.
Okay, so I asked myself why Astrobiology would be interested in E. sigillata. Well, here is why:
In a series of supplemental field studies, the researchers showed that many small reef fish may be under intense pressure from predators. Daily mortality rates of 2%-8% were common, indicating the severe biological time constraints and intense selective pressure that this community experiences.
It has been a grand Coral Week in the blogosphere, and we learned that coral are not important just for themselves but also for the diversity of vertebrates dependent on them.
Until a recent marine discovery, the dwarf goby was also the record holder as the world's smallest vertebrate (animal with a backbone).
These findings on the shortest-living vertebrate, along with recent discoveries on coral reefs of the smallest and earliest-maturing vertebrate species, are helping to broaden our understanding of the range of vertebrate life histories and the potential for reef fish to contribute to this area of research.
Coral-reef ecosystems represent exceptional biodiversity and environmental stability, and this recent research is beginning to unravel the possible reasons for the ability of these ecosystems to support extremes in vertebrate evolution.
Living fast, dying young. It's over-rated, but instructive.