Hi folks, as my birthday present to you, and big thanks for racking up 70,000 blog views in 7 months (and my 50th post!), here is a new installment of Mystery CT Slice!
This time with a pilot (or scout) scan of an odd object. A pilot/scout scan is a quick, low exposure scan used to plan a series of CT slices, which shows a a larger area that is then narrowed down to focus just on the object of interest and a bit of buffer room for those slices. It generally isn’t used for much else, but sometimes can make a neat picture. As you can see here, the pilot scan area was excessively massive relative to the object. The two odd objects below the primary object of interest are scanning phantoms, used to calibrate density from Hounsfield units to actual real-world density (one is water at 1 g/cm3; the other is “cortical bone” at 1.69 g/cm3). Ignore them.
But what is this object and from what taxon? Be as specific as you can, but pinning it down to genus/species level will be bloody hard!
Stomach Churning Rating: 1/10; it doesn’t get much tamer than a pilot scan.
Difficulty Level: small image, hazy, not a lot of diagnostic traits visible, 1 main element.
Hmm, I think that top left is the femoral head. Guessing the bottle of water is about the same size as the length of the my hand, so a short stocky femur is likely to belong to something that digs. Wombat perhaps? OTOH could it be from a pinniped? they seem to have truncated femurs due to having flippers rather than feet.
I’m going to plumb for the femur of a flightless bird. It bears some similarity to the femur of _Dromornis sp._. However, I will suggest a ratite, and nail my colours firmly to the Cassowary mast. But then . . .
If I’m correct it definitely gets my approval.
Well, it’s similar to Odobenus (pinniped) femur, but also resembles to ground sloths (xenarthran) femur…
Hmmm. It does share features with a harbour seal femur . . . can I change my suggestion?
One can always change their suggestion/guess/wild speculation/dart throw. 🙂
For some reason my mind keeps coming back to the femur of Dinornis robustus or Dinornis novaezelandiae, even though I can’t find a good image for comparison. Probably turn out to be a Hippo or something totally different…
It looks very much like a seal femur with a medial condyle extending further distally than the lateral one (birds usually have it the other way around). I also can’t find the laterally placed trochlea fibularis of birds. I would guess some kind of fairly large phocid based on how the lower legs would point away from the body. Large Grey seal?
I’m going to go ahead and guess Walrus femur, although it’s probably too small to be correct.
Answer coming tonight; last chance for glory!
So. Here we are again. That moment where fortunes either soar to proud pinnacles of preening precision, or come crashing down to deafening dirges of defeat. The answer is coming. But first, brace yourselves for the exquisite drama that is about to unfold…
The specimen is a right femur. So everyone has done well so far and can begin grinning in anticipation of their veracity’s vindication.
But is it avian, xenarthran, pinniped or otherwise? The third answer has pinned the tail on the proverbial phocid. Groans of defeat and muttered oaths of vengeance…
Aha! But did anyone get it spot-on correct? Yes.
Indeed, as Olle Håstad astutely chimed in, it is a hook-nosed sea pig, or for the taxonomists Halichoerus grypus; the grey seal, which evidently turns into a gray seal when it enters U.S. waters.
Well done, Olle- his second victory, I believe? Let’s all clap our flippers together in approbation. Better luck next time, non-winners! 🙂
Give that man a fish!
[…] (What is it and what from? Answers must be in limerick form to count. Pilot scans explained in this post.) […]