New X-ray scanner for the study of zoological specimens
Through the financial support from the National Lottery the Vertebrates Section has acquired a digital X-ray device. It was carefully selected on the basis of criteria such as precision, security and maintenance. This apparatus gives researchers a whole set of new opportunities.
Use in systematics
Certain zoological specimens in our collections were gathered more than seventy years ago. Collecting images by means of the X-ray machine enables researchers to study the internal anatomy of these organisms without having to dissect and thus damage these precious specimens. In fact, anatomical characters are often used in systematics. A few examples:
- for chameleons, there is a system of classification based on the complexity of the lungs;
- for snakes, a system of classification based on the position of the heart is studied;
- for frogs, the morphology of the hyoid and the number of presacral vertebrates are used;
- for fish, the presence of the Weber’s organ is used (ossifications around the swim bladder which have an auditory function).
Some organisms have internal genital organs. The male snake’s hemipenis remains inside the body and is only everted at the time of mating. This means that in general it is impossible to determine the gender of the snake without first verifying the presence or absence of the hemipenis, or the presence of eggs. The X-ray scanner is a means of determining the gender of these individuals whilst keeping the specimen intact.
Counting and measurements
The X-ray scanner produces digital files which can be exported and manipulated with other software. So counting the vertebrates (but also the morphological description of the fins – in fish) will be considerably facilitated and more precise. Certain measures, notably on curved specimens (such as the numerous coiled snakes), can be carried out more precisely. The apparatus also makes it possible to count the number of ribs an animal has or the number of eggs a female is carrying, for example. We even hope to be able to visualise and count the teeth, without causing any damage to the jaw.
The apparatus is a device elaborated by MEDEX Loncin from an RX high frequency generator and two units of digital capturing (one type CMOS 48 µm high resolution). By means of the interpolation of consecutive images, the specialised software enables you to obtain a resolution of up to 16 µm.
|Verifying the contents of the stomach is no longer a problem. |
This image shows a frog in the stomach of a Crotaphopeltis snake (click to enlarge).