230-million-year-old arthropods in amber

I won’t discuss this new observation in detail, since the detail is mostly of interest to specialists, but it’s still a cool observation. A new paper in Proc. Nat. Acad. Sci. USA by Alexander Schmidt et al. (reference at bottom) describes specimens of two groups of arthropods—flies and mites—from Italian amber (fossilized resin) that is 230 million years old.

That pushes the amber-preserved individuals of these groups back a full 100 million years, and makes these the earliest fossils of the mite superfamily Eriophyoidea, a highly specialized group of plant parasites. Most eriophyoid species feed on angiosperms (flowering plants), producing galls, while about 5% of the species feed on gymnosperms (conifers, cycads, etc.); the latter mites are considered to be ancestral because the most primitive group of these mites still live on gymnosperms, and gymnosperms precede angiosperms in the fossil record (the latter originated from gymnosperm-like ancestors only about 130 myr ago).

Here are some galls of Eriophyes tiliae on lime (see more galls here); weird, eh?

And here’s the beast who makes them; note how bizarre and specialized it is:

The amber came from gymnosperms in a family of extinct conifers (Cheirolepidaceae); here’s one of their fossils (all captions in photos and drawings are from the original paper):

Cheirolepidiaceous shoots associated with amber. Museo delle Regole, Cortina d’Ampezzo, Italy, MRCA 7170.

The authors examined 70,000 (!) ancient amber droplets for arthopod inclusions, and found only three. I’ll show them all.  The first is a midge, which is a fly (Diptera); it is disarticulated and small (1.5-2 mm).  The specimen, though not whole, is very detailed.

(G and H) Disarticulated nematoceran fly, showing details of antenna and apical tarsomere. Museum of Geology and Paleontology, University of Padova, Italy, MGP 31345. Scale bars: B, 2 cm; C–F, 1 mm; G and H, 200 μm.

And here are the two mite specimens, preserved whole. Note that the scale bar is 10 microns, or 0.01 mm. These things are small!

Eriophyoidmite in the Italian Triassic amber: Triasacarus fedelei gen. et sp. nov., Holotype, MGP 31343. (A and C) Habitus in ventral view [reconstruction and photomicrograph, respectively; photo is a stacked image using differential interference contrast (DIC) illumination]. (B) Dorsal structures of anterior region, as viewed ventrally. (D) Gnathosoma, arrow pointing to infracapitular ledge [bright field (BF) illumination; f.p (focal plane) 2,347]. (E) Detail of F; arrows pointing to empodial featherclaws (BF, f.p. 2,324). (F) First and second leg pairs, with tip of proboscis in focus (arrow) and empodial featherclaw of first left leg indicated with arrow (BF, f.p. 2,324). (G) First and second leg pairs, with some solenidia denoted, tibial one by phi, tarsal ones by omega (DIC, f.p. 2,160). Scale bars: 10 μm.

Eriophyoid mite in the Italian Triassic amber: Ampezzoa triassica gen. et sp. nov., Holotype, MGP 31344. (A and B) Habitus, dorsal view. (A) Digitally stacked photomicrographic composite. (B) Rendering of complete specimen, as preserved. (C) Anterior portion of body, including gnathosoma. White arrows indicate infracapitular guides; black arrow points to second left leg (f.p. 2,904). (D) Portion of prodorsal and coxisternal region; arrows point to shadowy images of right legs I and II below prodorsal shield (f.p. 2,692). (E) Posterior apex of body; arrows point to caudal setae h2 (f.p. 2,932). All photos in DIC illumination. Scale bars: 10 μm.

What’s the significance? Well, it supports the phylogenetic (“family tree”) evidence that eriophyoid mites did indeed evolve feeding on gymnosperms, for these samples date 100 million years before angiosperms even existed. So it’s a nice confirmation of what we suspected from other data.  It also supports the age of the mite group, since there was some doubt about when it originated.  Other findings are of interest mainly to arthropod systematists, but the quality of these ancient specimens is so nice that I thought I’d present them.

____________

Schmidt, A. R, S. Jancke, E. E. Lindquist, E. Ragazzi, G. Roghi, P. C. Nascimbene, K. Schmidt, T. Wappler, and D. A. Grimaldi. 2012. Arthropods in amber from the Triassic Period. Proc. Nat. Acad. Sci. USA 109: 14796-14801.

35 Comments

  1. Posted September 19, 2012 at 8:45 am | Permalink

    So…a quarter of a billion years ago, some mites got stuck in some tree sap..and I’m looking at pictures of them.

    Consider my mind well and truly blown.

    b&

    • JBlilie
      Posted September 19, 2012 at 9:37 am | Permalink

      Indeed!

  2. Posted September 19, 2012 at 9:16 am | Permalink

    Would it be fair to say that these mites look a mess? As in a cobble of not particularly well-adapted body parts.

    Is this seen a lot, or might there be an explanation for it happening here?

    • Michael Fisher
      Posted September 19, 2012 at 9:54 am | Permalink

      I don’t agree with your observation. I’m sure that they are fit for their ‘lifestyle’ [a non-biologist here]

      There are around 50,000 described species of mite ~ very successful critters. I imagine if I could shrink into my carpet the landscape would be populated with herds of ravenous mites on my indoor Serengeti :)

      • Posted September 19, 2012 at 11:26 am | Permalink

        But how “fit” does one need to be to survive?

        A car with 5 doors, only two of which actually open even part-way would allow transportation, but would not be particularly fit.

      • gravelinspector
        Posted September 20, 2012 at 2:56 am | Permalink

        There are around 50,000 described species of mite ~ very successful critters.

        Just to put some perspective on that, that would be slightly over 5 species of mite for every species of mammal. 5 described species of near- to fully- microscopic mite for every single species of macroscopic mammal. (I think that the smallest mammals are on the order of a cm long by a few grammes.)
        In terms of body count … the disparity is going to be even bigger.
        Mites are popular for testing “the department’s” new electron microscope. They’re everywhere, and almost all look like extras from a high-budget, low-brow horror flick, so you’re practically guaranteed to get some pretty (awful!) pictures.

        • gravelinspector
          Posted September 20, 2012 at 3:01 am | Permalink

          DAMN, but the editor here needs a preview mode. Entering HTML code by hand is one thing, but doing it without a preview to check is another.
          (Just to provide Jerry with more ammunition if he ever chooses to take up the fight with the Powers-that-Be at WordPress.)

          • Michael Fisher
            Posted September 20, 2012 at 3:32 am | Permalink

            1] You could bookmark THIS free online HTML editor ~ it has a preview mode. Then copy/paste the happy result into this site

            or…

            2] If you are a Mozilla FireFox or Seamonkey user, then the BBCodeXtra 0.3.2 extension

            “…adds to the [right-click] context menu new commands to insert BBCode/Html/XHtml codes [...] all forum types, for example:

            * phpBB
            * Invision
            * VBullettin
            …”

            Also you can customise what appears in the right-click context menu to exclude codes you don’t use & add your own custom codes

            • gravelinspector
              Posted September 20, 2012 at 4:12 am | Permalink

              Looking at those just now. Thanks.
              Considering the number of sites that do include competent HTML editors, and/ or preview modes, WordPress remains culpable in this regard.

    • Gregory Kusnick
      Posted September 19, 2012 at 9:56 am | Permalink

      I’m no mite expert, but it looks to me like they have all the necessary parts for moving around on plants and sucking sap from them. What would you expect them to look like, if not like this?

      • Posted September 19, 2012 at 11:35 am | Permalink

        Well, I probably don’t understand the illustrations, but these don’t appear to be fully bilaterally symmetrical, for one thing.

        How do modern mites differ? How are their bodies more efficiently arranged, if at all?

        These look kludgy to me. There a few pretty ungainly creatures in existence today, too. Not even close to a stream-lined pinnacle of design. The line survives, yes, but that might be due to the happenstance of their environment – not a lot of selective pressure, perhaps.

        • Gregory Kusnick
          Posted September 19, 2012 at 11:53 am | Permalink

          The lack of symmetry is, I’m sure, a consequence of the fact that they’ve been squashed in fossilized resin for a quarter billion years. The fly in the first sample is broken apart, and I think we can confidently say that does not accurately reflect its condition in life.

          A Google image search on mites will give you an idea of what modern mites look like. It’s not obvious to me that they’re any less ungainly or more streamlined than these fossil mites.

          Come to that, I’m not sure why you think streamlining would be advantageous to a creature that doesn’t swim or fly but that does need to hang on to fibrous plant tissues. Adaptation is about function, not about visual esthetics.

    • Michael Fisher
      Posted September 19, 2012 at 10:10 am | Permalink

      BTW there mite [sorry] be 1,000,000 species of mite alive today

      THIS is the Wiki on Acari [I'm guessing it should be in italics] morphology:-

      Mites are arachnids and, as such, evolved from a segmented body with the segments organised into two tagmata: a prosoma (cephalothorax) and an opisthosoma (abdomen). However, only the faintest traces of primary segmentation remain in mites; the prosoma and opisthosoma are insensibly fused, and a region of flexible cuticle (the cirumcapitular furrow) separates the chelicerae and pedipalps from the rest of the body. This anterior body region is called the capitulum or gnathosoma and, according to some workers, is also found in Ricinulei. The remainder of the body is called the idiosoma and is unique to mites.

      Most adult mites have four pairs of legs, like other arachnids, but some have fewer. For example, gall mites like Phyllocoptes variabilis (family Eriophyidae) have a worm-like body with only two pairs of legs; some parasitic mites have only one or three pairs of legs in the adult stage. Larval and prelarval stages have a maximum of three pairs of legs; adult mites with only three pairs of legs may be called ‘larviform’.

      The mouth parts of mites may be adapted for biting, stinging, sawing or sucking. They breathe through tracheae, stigmata (small openings of the skin), intestines and the skin itself. Species hunting for other mites have very acute senses, but many mites are eyeless. The central eyes of arachnids are always missing, or they are fused into a single eye. Thus, any eye number from none to five may occur

      • Posted September 19, 2012 at 11:27 am | Permalink

        “…only the faintest traces of primary segmentation remain in mites.”

        To me it seems the segments in this preserved mite may be more distinct than those of current mites, at least the mites I see that suck my plants.

        • gravelinspector
          Posted September 20, 2012 at 3:03 am | Permalink

          (WORDPRESS vomited the first time I tried to post this!)
          Not being a “bug” person by any means, but one of the things that stood out to me while looking through Jerry’s precis was the obvious segmentation of the organisms.

  3. JBlilie
    Posted September 19, 2012 at 9:38 am | Permalink

    Very, very cool. The level of detail preserved is astonishing.

    • JBlilie
      Posted September 19, 2012 at 9:38 am | Permalink

      And thanks for the background information — very helpful for our understanding of what we are looking at and admiring.

    • Achrachno
      Posted September 19, 2012 at 6:32 pm | Permalink

      Another amazing source of invertebrate (mostly insect) fossils is spring deposits on the Mojave Desert, where they’re preserved in silica. If anything the preservation might even be better, but they’re only c. 10-15 m.y. old.

      Here’s a popular article with some images. I couldn’t immediately find anything more rigorous. These are from Calico, but the ones I’ve seen are from Boron.

      http://www.desertusa.com/animals/find-fossil-insects.html

      • gravelinspector
        Posted September 20, 2012 at 3:17 am | Permalink

        Some of the oldest insect (loosely) specimens on the planet come from the margins of alkaline siliceous springs in an intramontane desert basin. i.e. the Rhynie Chert from near Aberdeen, Scotland. i.e., a fairly similar environment.
        I’ll just make a plug for my old palaeontology and stratigraphy lecturer’s recent book, that includes a chapter on the Rhynie Chert’s environment.
        Fossils Alive!: New Walks in an Old Field [Hardcover]
        Publisher: Dunedin Academic Press (22 May 2008)
        Language: English
        ISBN-10: 1903765889
        ISBN-13: 978-1903765883
        (Not exactly great literature, but Nige Trewin is an engaging lecturer. Or he was until he retired.)
        These are some of the oldest insect fossils in the world, and their 350-odd million year date (Devonian) is one of the key limits on the evolution of life on land. Although some interpretations of the neo-Proterozoic stromatolites have them occurring in terrestrial lacustrine settings too, but at ~1100 million years.
        EDIT : I re-read ; initially I’d been thinking of the Death Valley desert when I read “Mojave” ; I’m not so sure of the environmental conditions in the Mojave. In fact, I’m not even that sure where the Mojave is, to an accuracy of a microplate.

  4. darrelle
    Posted September 19, 2012 at 9:51 am | Permalink

    WOW! Truly amazing.

  5. Scott near Berkeley
    Posted September 19, 2012 at 9:56 am | Permalink

    Thanks again, Jerry, for bringing this wonderful work to our attention. Amber is truly a wonder material for preservation of material for hundreds of millions of years! Remarkable!

    Such microscopic creatures, successfully found at an examination rate of 3 in 70,000, seems to promote the idea that much ancient amber should be re-examined for more possible microscopic creatures that have heretofore been overlooked.

  6. Hempenstein
    Posted September 19, 2012 at 10:01 am | Permalink

    If conifers start advertising, their slogan awaits.

    Pinophyta: Making Histology-Grade Amber for 230M Years”

  7. Gregory Kusnick
    Posted September 19, 2012 at 10:04 am | Permalink

    The authors examined 70,000 (!) ancient amber droplets for arthopod inclusions, and found only three.

    Did they actually look at each droplet individually under a microscope? Or are there bulk screening techniques they could use, such as spreading them out on a light table to see which are plausible candidates for closer examination?

    • Michael Fisher
      Posted September 19, 2012 at 10:15 am | Permalink

      Hi Gregory. I imagine they would use the slave-labour-PhD-student-O-tron in conjunction with a microscope

      • Marella
        Posted September 20, 2012 at 2:31 am | Permalink

        Yeah, but how do you get a PhD out of, “I looked at 15,000 amber drops and found nothing”? Or did they have to keep looking until they found something to write a PhD on?

        • gravelinspector
          Posted September 20, 2012 at 3:47 am | Permalink

          A PhD candidate climbing partner when I was an undergraduate was trying to study the effects of drought stress on commercial tree species in N.E.Scotland. For five years. There was no “drought” (by Scottish standards). But he still managed to write up and get his stuff “Piled higher and Deeper”.
          In this case … the leg work of learning the taxonomy of mites, their anatomy, etc is all relevant. Performing dissections on what material you found can always be written up. That “my results confirm the work of X, Y and Z in the 14th century BC” is an adequate contribution to “the literature”.
          But one of the duties of the person preparing the proposition to try to attract funding for a studentship (and a duty of those scrutinising the funding applications) is to be reasonably sure that sufficient material will be available. (tree drought) Dougie was unlucky with the weather, but there was enough he could do in the greenhouse to get him his PhD anyway. “Dr Toxic” (hi, Tim, I know you hated that name) got his specimens of granite … by walking lots of the mountains himself, carrying sample bags and a sledge hammer (and re-mapping the area in the process). I’m sure Jerry has a fund of similar “war stories”.

        • Michael Fisher
          Posted September 20, 2012 at 4:01 am | Permalink

          The first duty of a PhD student is to be lucky in her choice of Prof. :)

    • gravelinspector
      Posted September 20, 2012 at 3:33 am | Permalink

      There was a recent Geology Society podcast on amber fossils …
      Ohhh, sorry! It’s a “Palaeocast” from the Palaeontology Society. I shall commit seppuku with the blunt end of my collecting chisel in atonement later.
      Top link on this page.
      According to that podcast, the researchers had no real indication that a particular droplet might contain included fossils apart from an increased degree of rounding in the inclusion-containing droplets. Applying that criterion improved their success rate by a factor of “several”, to around one inclusion per 50-odd examined.
      OTOH, with a practised eye, you might be able to get that up to a specimen for every couple of hours at the microscope. Your “search image” improves with time, and beginners can get very depressed at the speed that an experienced eyeball can attain. I routinely tell trainees at work that, in doing their degree they may have had to describe around a thousand rock specimens. In their first month at work, they’ll “do” another thousand. In their second month, they’ll do another thousand … and I’ve been at the business end of a microscope for over 20 years. Compared to dedicated “bug watchers” (palynologists, micropalaeontologists, nannopalaeontologists (who seemingly like their mis-spelling!) and suck like), I’m pretty slack and shabby.

  8. Posted September 19, 2012 at 10:29 am | Permalink

    Creepy little guys.

  9. Tulse
    Posted September 19, 2012 at 10:45 am | Permalink

    Jerry, is there a significant difference between what is left in fossils from amber, versus those that are fossilized via mineralization? I’m just wondering if being sealed up in resin preserves more actual biological material, rather than just a cast of the structure in replacement minerals. (I know, I know, Jurassic Park was science fiction, but still…)

    • lkr
      Posted September 19, 2012 at 3:25 pm | Permalink

      ..and this is [mid-]Triassic Park. Crichton could have populated an island with funny-looking cynodonts and other 4-legs better critters.

      Given how advanced acari were, probably finds a tick rather than mosquito, though.

  10. Curt Cameron
    Posted September 19, 2012 at 2:45 pm | Permalink

    I feel embarrassed, but I just learned what galls are earlier this year. I’ve always been amazed at the complexity of parasites’ life cycles, and gall-producing critters are another example. They convince the tree to grow a protective shell around the egg/larva.

    And parasites that feed on humans frequently have the most bizarre life cycles, often requiring a specific species of snail or fly or something for part of their life.

    Since creationists are always going on about how complexity to them implies a designer, it’d be interesting to hear how they would deal with the fact that the most amazing complexity, the seemingly unlikeliest creatures, are not something that makes life beautiful, but are parasites like loa loa, where a worm crawls around under the person’s skin, or the Guinea worm. So God is responsible for those?

    Reminds me of a story a heard on Radio Lab, where this crazy professor had a bot fly larva in his scalp and left it there because he was a curious fellow. ;-)

  11. Steve
    Posted January 4, 2014 at 11:37 am | Permalink

    Newly discovered 100 million year old piece of amber shows oldest evidence of sexual reproduction angiosperms. The quality of preservation is amazing: “In Cretaceous flowers we’ve never before seen a fossil that shows the pollen tube actually entering the stigma,” said George Poinar, Jr.
    http://www.sciencedaily.com/releases/2014/01/140103204510.htm


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