Texas Natural History Collection (Quest)

"​Dear TMNH# 64380,

It's an honor and a privilege to be dissecting you in the lab this week. I visit your webpage all the time. I'm one of your biggest fans. I hope you're taking it easy in your big jar now, after our long day together. See you in the morning...




March 19th 2014".

I dissected this and other specimens while spring breaking as a visiting researcher at the Texas Natural History Collection in Austin. There, I was granted the priviledge of adding more specimens to my monitor lizard hyoid project sample. This venomous beaded lizard is not a monitor lizard at all. It's one of my outgroups. A terrifying-when-x-rayed outgroup.

Why dissect to see the skeleton of a specimen that's already been x-rayed? Because lizards have large hyoid apparatuses and the size of the x-ray field is limited. In case you're curious, here are the dimensions for this machine:

Max. sample size up to 500mm x 600mm in height;

3D scanning area max. 290mm x 400mm

So, for a specimen this large, the whole hyoid isn't recoverable using one scan. Also, lizard hyoids are largely cartilaginous and so, in most cases, are not represented in their entirety on digimorph.com. For the record, it's fully possible to target and recover a detailed view of a cartilaginous structure using CT scanning technology. The only problem is that if the structure isn't the objective of the researchers and techs performing the scan, then there's no guarantee that you'll see it. During my dissection, I saw a few things that the scan did not show us....

Behold.... This specimen was cut in half for easier handling during digital scanning. Pre-dissection. It's wrapped so it stays wet, and restrained so that I can turn it over quickly and easily for shots beneath the mounted camera.

One thing I noticed....

Another thing...The cartilaginous anterior processes (hypohyal + ceratohyal) are fused, as in outgroups, the Bornean earless monitor (Lanthanotus borneensis) and to an extent, the black and white tegu (Tupimambis teguixin), although fusion there is analogous. The anterior processes are separate (unfused) in monitor lizards (Varanus). So, there are no anterior head shapes in the outgroups that can be qualitatively compared with members of Varanus, where a lot of head shape variation exists. I realize that this is kind of a crummy picture. Illustrations to come.

True story! Although.... a morphometric approach could change that.


Post dissection photos below. Here, so that you don't get the wrong idea about the people who let me alter a voucher specimen.

I didn't use sutures because the skin is like rawhide memory foam. When released from it's binding (cheesecloth, saran wrap and tape) the skin pounced right back into place. Unless you poke at it, you can't tell that anything out of the ordinary has happened. Convenient!

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©DWasserman Oct 2019