Here’s something a bit different from my usual Mystery Dissection images: a Mystery CT Slice with an indicated structure for you to identify. I can definitely do this quite regularly. And I’ll try to always draw the arrow on using MS Paint, quite shakily to indicate my frenetic mental state. Bonus points for identifying the organism. It’s not super hard but let’s see how you do with this one. Go for it!
EDIT: OK, you’ve had a good go at it, definitely. Almost everyone was more or less right in some way, so here, have a treat! We’re looking at a cross section of a ~6 month old emu (Dromaius novaehollandiae) from the RVC Structure and Motion Lab’s aviary. And indeed the structure is the ventriculus; the technical term for the gizzard; the muscular organ that acts like teeth for birds, grinding up food. The proventriculus is the more enzyme-producing, non-grinding compartment connected to the ventriculus. This emu had just eaten a bit of grit (the bright spots in the scan) whereas its comrade had eaten relatively huge pebbles, which surprised me when I scanned it and certainly was not accidental ingestion. Here are some labels to help orient you in this cross-sectional x-ray CT image; we’re in the cranial (anterior) region of the thorax, just a bit behind the heart and in front of the guts:
For the less anatomically-jargon-loving, the synsacrum is the hip region (fused pelvis, backbone in birds), the femur is the thigh bone, tibia and fibula are shank bones, and the tarsometatarsus is an elongate “sole bone” of the foot; actually 3 fused metatarsals and tarsal bones integrated into one unit in birds as a likely strength:weight maximizing adaptation. The air sacs of course are outpockets of the lungs, much famed among dinosaur workers of late. Of course, Dr. Oliver Wings of the Humboldt Museum in Germany is the reigning authority on dinosaur gizzards, gastric mills and the lack thereof in many dinosaurs (most notably sauropods), so look his stuff up if you’re interested in this!
Well done and thanks for playing! Another session will come soon enough, plus I have some big posts planned for later this summer once work calms down!
it’s a big bird (Ostrich?) with visible fermora, tibiae fibulae, metatarsi and a vertebra. As for the dense stuff….some gut contents (gastroliths in there?) i guess
Are those pneumatised bones? If so then a (large) bird. Then said structure could be gizzard? Looks like it’s full of particulate stuff.
Wild guess before looking up anything: the lung of a chicken.
The triangular blackish thing on the left could be its spine, the big black blob in the center could be the heart. The two pairs of round white objects look like front legs of the chicken to me: the white rings with the black center thighs, the pair in the middle lower legs and the small pair on the far right the wing(tip)s.
However i don’t have any idea what the structure with the arrow is, looks too irregular for the lungs, maybe the stomach (with the small white blobs being stones eaten by the chicken)?
Anyway, great game, keep them coming!
I sees legs, folded. I sees a very pneumatised vertebra. Emu?
Is it the ventriculus of a bird?
whith that spine, it must be as fush, as they say in NZ.
I’ll blush if I’m right
and what’s arrowed, is either the gut
but it could be the egg sack
you know, cavaiar and such
Aldo
i see a happy lady sitting at the edge of a pond listening to the frogs croak.
😐
Answer posted above with extra info; thanks for all the wise answers (I see some experienced anatomists had it too easy on this one!) and if you didn’t get it right, try again next time!
[…] do not exist, mysteriously. At the time, in the jumbled freezers of my mind, they corresponded to Mystery CT Slice(1) and Mystery CT Slice 2. But we can pretend that MD2-3 are just an eternal mystery of this blog, […]