It always seems to be the case that there are gaps in the fossil record just where things get interesting — probably with good reason, that forms in transition will be relatively rare. One such gap is the period where insects first emerge and begin to conquer the terrestrial world, a period called the arthropod gap, between 385 and 325 million years ago. Here’s a new specimen from that relatively barren stretch of time, Strudiella devonica.
a, Photograph of the part. b, Reconstruction of general habitus. Scale bar, 1 mm. White arrows indicate legs visible on part. abd, abdomen; ant, antenna; h, head; md, mandible.
It’s a classic insect: a body divided into three regions (head, thorax, abdomen), six legs, a fairly general set of omnivorous mouthparts. It lacks wings, but the small size suggests it may be in a nymphal stage (also, the genitals at the tip of the abdomen didn’t make it), so that may not mean much.
Garrouste R, Clément G, Nel P, Engel MS, Grandcolas P, D’Haese C, Lagebro L, Denayer J, Gueriau P, Lafaite P, Olive S, Prestianni C, Nel A (2012) A complete insect from the Late Devonian period. Nature 488, 82–85.
(Whew, that’s a lot of authors for a short paper.)
Very cool.
I’ve never of insects as hexapods; the usual image in my mind are things like dragons, centaurs and the crocolisks from World of Warcraft.
Hexapoda is a larger group that contains springtails and a few other odd organisms as well as insects sensu stricto.
And there are also true insects around that are ancestrally wing- and flightless (silverfish e.g.).
So, the mother of all flies and fleas, eh?
Quick! Swat it!
What, it’s from 350 mya? We’re too late.
But did it fit onto the ark?
Glen Davidson
Well, fine. But where are the fossils that show how a trilobite became this hexapod thingie, and how the hexapod thingie climbed onto land to bite the dinosaurs? Huh? Where are they? Evolutionismists are bunk. CGD!
[Swats away a skeeter.]
Tell us more about this ‘Arthropod Gap’. It sounds—slap!—wonderful!
So the arthropod gap is being filled. Now maybe the good DDMFM will be so kind as to fill up the lissamphibia gap of the Triassic/Jurrasic? Please?
The arthropod gap? Haven’t you got patriotism enough to talk about the missile gap? You traitorus librul!
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It may be a hexapod, but it does not have the sharp-toothed “smile” of ichtyostega gunnari!
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If the Devonian stem-amphibian had had six fins to carry the weight, we would indeed have been centaurs. However I cannot promise any dragons or crocolisks.
It looks a little like a larval mayfly.
There’s an article in Cosmos magazine about this find that starts out saying “One day 370 million years ago, a tiny larva plunged into a shrimp-infested swamp and drowned”. I’m not an entomologist but I would think it’s more likely that this little guy was living IN the swamp and may or may not have emerged to live its life on land if it had survived to adulthood.
So cool!
Now there are two gaps instead of one.
I hope the preservation is good enough to rule out alternative interpretations!
I’m not actually working on new fossils. But a few other people are. Rainer Schoch is redescribing Triassurus (look it up) right now; I have no idea what he’s finding… There are also a few unpublished fragments from an end-Triassic site in Poland (not the Triassic site I’ve dug at, that’s older), and there are otherwise unpublished intriguing animals from China (Early Triassic) and Russia (Late Permian) mentioned in abstracts from the 2004 and 2008 meetings of the Society of Vertebrate Paleontology. I do think we’re living in interesting times.
gunnari is Acanthostega, not Ichthyostega. However, good that you mention it. The very same site, Strud in Belgium, has yielded a jaw fragment reminiscent of Ichthyostega.
…The smile, BTW, is exaggerated. The teeth were shorter and pointed much more backwards than Jarvik reconstructed them.
I’ll have to look it up, but I don’t think Strud was a freshwater environment.
Aw, man. Where there used to be one gap, there are now TWO gaps!
It was clearly the victim of a great flood…
Pretty cool stuff. It should be noted that plenty of primitive modern day Hexapoda lack wings (e.g. Springtails).
Goddamnit. Aaaaaaaaaaaaaaaaaargh!!!!
NEVER EVER FORGET THE CAPITAL LETTER! (Sorry, my zoology professor took this very seriously and as a result I go insane whenever I see a genus name lacking the capital letter.)
Well, shit.
Ichtyostega
Ichthyostega. With –chth– (it sort of makes sense in Greek), and in italics as per Recommendation 6.
But he forgot to remind you of the italics?
I just love this sort of thing. Thanks so much!
Nope, but I forgot to put the tags in. Shame on me.
If this thing had visible external mouthparts (as appears to be the case), it was not just a hexapod but a true insect. But as I pointed out above, there are ancestrally wingless insects still around too.
A little off topic, but I had to post this after seeing this on a craft blog:
http://blog.craftzine.com/archive/2012/08/spocktopus.html
Who doesn’t love Star Trek AND Octopi?
primitive thysanura or collembola? although those mandibles look too large
All the Devonian outcroppings around here are of shallow seas. Looking for terrestrial insects wouldn’t be fruitful. Also my eyesite is not good and those fossils look small.
Dang, gotta have respect for the invert paleontologists. I agree with Christopher Taylor at Catalogue of Organisms; that thing looks like roadkill. Really really tiny roadkill.
I haven’t read the paper, yet, but one of the authors is a leading expert on Collembolans…
Oh. Everyone please follow the link in comment 25. PZ has only given us half the story!!!
and therefore s/he would know better than to use the word ‘insect’ in the title if s/he thought it was a springtail instead.
seconding DDM’s suggestion to read Taylor.
Certainly an insect, all else ambiguous.
See how well designed it is ? so complex, so irreducible.
/KenHam
The skeptical part of my brain looks at the photo then the line art and says “look canals on Mars!” or “proto-Arthropod Jesus, Mary and Joseph on toast!”
Guess I have go find Nature to get the rest of the story.
Just think, 350 million years ago all the other proto-mayflies laughed at this little guy because he didn’t reproduce. Now he’s a star whose picture is now immortalized in digital format that will live forever.
Or until we fail to get to another solar system before the sun burns out.
The external mouthparts are the insect ‘tip-off’. Sure, it is neat, it is cool, but it is not the bombshell that Rhyniognatha hirsti was.
…wait. Aren’t external mouthparts plesiomorphic?
All more basal hexapods lack them; that’s all that matters for the definition and/or diagnosis.
But yeah, of course their crustacean forebears had nice sniny mandibles, including (I think) the putative sister group to hexapods, the Xenocarida.
test
Just musing…
The entognath(sheated)mouthparts could be advantageous for the very first hexapods to emerge from water, while their bodywater retention were like those of a shrimp and waterloss was a major issue.With better waterproofing, the hexapods could redevelop external mouthparts.
Didn’t insects more or less have a common ancestor with Crustacea?
nope.
Insects are crustaceans.
Thanks! Derived from, descended from– part of the clade. Gotcha.