The most ambitious arthropod phylogeny yet

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The top-tier journal Nature doesn’t often deal in purely phylogenetic research. So when such a study graces their pages we know it’s big stuff.

Yesterday, Nature published a 62 gene, 75 species analysis of the evolutionary history of the arthropods. Arthropods, as readers of this blog likely know, are animals with a chitinous exoskeleton and jointed legs. They include the insects, arachnids, crustaceans, centipedes, and others. This is a staggeringly diverse group, and one found just about everywhere on the planet. Most animals are arthropods.

This study has been in the works for many years. Jerry Regier’s lab at the University of Maryland has been diligently developing protocols for extracting single-copy nuclear DNA from across the arthropods, and the work has paid off handsomely. They have created the largest and most relevant data set yet assembled for addressing the hard questions in arthropod evolution. This is exciting! Today is like Christmas for arthropod systematists.

There’s a lot to digest here, but below are my first impressions:

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Monday Night Mystery

What’s this charming creature?

Ten points for the first person to get the family name right, too.

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The most feared animal in Arizona ran away from me

Centruroides sculpturatus – Arizona Bark Scorpion

I have a hard time getting worked up over stuff that happened 25 years ago. But here’s something that still angers me every time I think of it.

One of those educational safety movies we were shown back in grade school- you know, the “Stop-Drop-and-Roll” variety- presented the dangers of the Bark Scorpion. The film featured dark tones and a dramatic reenactment of a deadly encounter, complete with screams and fainting.

This was shown in Rochester, New York, mind you. We don’t have scorpions anywhere near Rochester. The climate is is far too cold. And the one potentially dangerous American species, our friend the bark scorpion, is found in Arizona. As far as anyone knows, the Bark Scorpion has only killed two people since 1968. Did I mention that Rochester consistently sports one of the highest homicide rates in the country? No? Well. At least the kids in Rochester know to check their shoes for the dreaded bark scorpion.

There was absolutely no reason to show that horrible movie, other than to instill in children the idea that arthropods are scary, icky, dangerous animals that should be killed. No reason. It still ticks me off that someone’s bug phobia got turned into a state-endorsed lesson plan.

While out photographing harvester ants this weekend, I happened upon one of these dreaded animals when I disturbed a rock. The scorpion, which as you can see is a very pretty orange animal, cowered. It tried to make itself look as small as possible. This made for a boring picture so I poked at its legs with a twig, hoping that it might brandish a claw or wave its tail about photogenically. Instead it ran for cover. I let it go.

photo details: Canon MP-E 65mm 1-5x macro lens on a Canon 20D
f/13, 1/250 sec, ISO 100, twin flash diffused through tracing paper

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