Asa Kaplan

  • 1 month, 1 week ago
    Asa Kaplan's profile was updated
  • 1 month, 1 week ago
  • 8 months, 1 week ago
    Asa Kaplan replied to the topic Any ideas as to what these are? in the forum What Is It?

    I don’t know about the big trapezoid, but the little lineated piece certainly looks like vascular plant material. Land plant even. I find these in Middle Devonian shaley limestones, even those whose paleoenvironments had paleodepths below normal wave-base.

  • 1 year, 2 months ago
    Asa Kaplan replied to the topic Brachiopod from Madison group Misson in the forum What Is It?

    For a more extensive list of candidate brachiopods, see

    http://ftp.maps.canada.ca/pub/nrcan_rncan/publications/ess_sst/122/122462/bu_378.pdf

    Among orthotetidines, this publication lists only Schellwienella? cf . S. alternata Weller, 1914, with some good photos on plate 1.

     

  • 1 year, 2 months ago
    Asa Kaplan replied to the topic Brachiopod from Madison group Misson in the forum What Is It?

    David, nice fossil. If this is definitely from the Madison Limestone then it is Mississippian in age — far too young to host Rafinesquina or Strophomena. I do concur that it is a strophomenide brachiopod, most likely an orthotetidine.  This article is a good jumping-off point:

    https://imnh.iri.isu.edu/digitalatlas/geo/gsa/papers/gsac1p4.pdf

  • 1 year, 4 months ago
    Jennifer Bauer and Asa Kaplan are now friends
  • 1 year, 10 months ago
    Asa Kaplan replied to the topic Identify this! in the forum What Is It?

    I’m with Jack — this looks like a Phacopid trilobite, perhaps even Phacops. In WV these are found in Middle Devonian rocks like the Marcellus Shale and the Mahantango Formation. Mahantango and Marcellus trilobites lived about 385 million years ago.

    But the Eastern panhandle of WV….aren’t all those shales metamorphosed? Maybe not all, but all the ones I have seen were metamorphosed! No chance of fossils in a rock that has been through that much heat and pressure.

  • 1 year, 10 months ago
    Asa Kaplan replied to the topic FOSSIL Webinar Series in the forum Upcoming Opportunities

    Oh, I see. Thanks, Lisa. I would like to see better support on this website for event subscription, so that updates go out to those folks who intended to attend. Otherwise, let’s leave event functionality to a platform like Eventbrite or even Facebook that can handle the relevant tasks.

    Thanksgiving food………..mushroom gravy. I would like to know what we know about mushrooms from the fossil record.

     

     

  • 1 year, 10 months ago
    Asa Kaplan replied to the topic FOSSIL Webinar Series in the forum Upcoming Opportunities

    Fossil ID webinar is tonight at 4pm PST / 5pm MST / 6pm CST / 7pm EST, right? at http://idigbio.adobeconnect.com/room

  • 1 year, 11 months ago
    Asa Kaplan replied to the topic I found this in the forum What Is It?

    The rock there is either early Cenozoic or else Mesozoic. Ediacarans are out of the question, not only for this reason, but for morphological reasons: no known Ediacaran is spiral- or tube-shaped.

    This appears to be the trace of a worm or other creature that fed in a spiral outward from a central starting point. It consumed the sediment whole and released the digested sediment behind it. If it showed a rigid, curved outer shell, then we could talk about what kind of snail or cephalopod shell it is. But since the outlines are wavy and irregular, it is almost certainly a feeding trace.

    I don’t know my trace fossil taxonomy well enough to put a genus identification on this fossil, but these lecture notes contain some spiral feeding traces you might take a look at:
    http://www.yorku.ca/lbianchi/nats1800/lecture01a.html

  • 2 years ago
    Asa Kaplan replied to the topic FOSSIL Webinar Series in the forum Upcoming Opportunities

    Ah very cool thanks.

  • 2 years ago
    Asa Kaplan replied to the topic FOSSIL Webinar Series in the forum Upcoming Opportunities

    Thanks for the tag, EG! I have no idea what this webinar is or where to find it, but I’d like to learn about the lesser-known soft-bodied preservation localities like Blue Island. And maybe a review of some amazing sites that are now off-limits (rather than played out).

  • 2 years ago
    Asa Kaplan replied to the topic Help identifying fossil from Texas in the forum What Is It?

    Although often mistaken for a trilobite, this is not a fossil at all. You will note that you can crush it with your fingernail.

    It is the egg case of a praying mantis from the 2010’s.

  • 2 years, 2 months ago
    Asa Kaplan replied to the topic Ordovician, southwestern Wisconsin, in the forum What Is It?

    Julie @julie-niederkorn, you have opened my eyes! I was assuming the entire fossil to be a pygidium, but now I take your point that it comprises the whole thorax plus the pygidium. And that makes it an excellent match for the thoracopygidium of Thaleops ovata. It also helps explain the outline that appears anterior to the thorax: It’s a cross-section through the cephalon. I note especially the robust right gena. For comparison:

    Congrats on your first complete trilobite, Julie 🙂

  • 2 years, 2 months ago
    Asa Kaplan changed their profile picture
  • 2 years, 2 months ago
    Asa Kaplan's profile was updated
  • 2 years, 2 months ago
    Asa Kaplan replied to the topic Ordovician, southwestern Wisconsin, in the forum What Is It?

    Guide to trilobite morphology:

    https://www.trilobites.info/trilomorph2007.gif

     

  • 2 years, 2 months ago
    Asa Kaplan replied to the topic Ordovician, southwestern Wisconsin, in the forum What Is It?

    The cephalon appears to belong to some ceraurine trilobite. For example, here is Ceraurus. Note the glabellar lobes and how they’re connected to the other parts of the cephalon.

    http://strata.uga.edu/cincy/fauna/trilobita/Ceraurus.html

  • 2 years, 2 months ago
    Asa Kaplan replied to the topic Ordovician, southwestern Wisconsin, in the forum What Is It?

    That pygidium is definitely not Flexicalymene! Note in this photo how triangular Flexicalymene‘s pygidium is, and how it terminates with a prominent bulb on the median lobe with hardly any posterior margin. The pygidium you show has many segments and a broad posterior margin — features typical of order Proetida, not Phacopida (of which Flexicalymene is a member). I was not able to locate an Ordovician trilobite to match your image, but I’ve included below an image of a pygidium that more closely matches the features I see in yours. (This pygidium belongs to Dikelocephalus, which is certainly not the trilobite in your hand.)

    https://upload.wikimedia.org/wikipedia/commons/d/df/Flexicalymene_meeki_pygidium_view.JPG

    https://upload.wikimedia.org/wikipedia/commons/thumb/f/f8/Dikelocephalus_minnesotensis_pygidium_draw.png/440px-Dikelocephalus_minnesotensis_pygidium_draw.png

  • 2 years, 3 months ago
    Asa Kaplan replied to the topic Another Devonian fossil ID request in the forum What Is It?

    This looks for all the world like a diagenetic oxidation halo around a bar-shaped fossil (crinoid pluricolumnal?), caused by bacterial activity after the death of the animal. Especially given the halos around the other fossils in the same rock.

    If this were the Hunsrück Slate, I would give more pause. But since soft-bodied preservation is unheard of anywhere else in the Devonian, and since Appalachia’s Devonian rocks are sufficiently well studied that we would know about instances of soft-bodied preservation, there is no good reason to consider the possibility here. Just a diagenetic halo.

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