Inner Beauty was on display in the Florida Museum from July 2021 through May 2023. It was so popular, we reimagined it as an online exhibit.

Museum technology is shifting how fish skeletons are processed providing more accessibility for research, education, outreach and global collaboration.

CT scan of a fish showing its last meal. Fish specimen is tan and the bones of the meal are blue
A Bonefish and its last meal prepared with CT scanning. Florida Museum image by Zach Randall

Museum Skeleton Prep

The majority of non-fossilized skeletons at the Florida Museum are processed in-house from preserved museum specimens by using flesh-eating Dermestid Beetle colonies that eat the flesh right off the bones. Specimens are skinned, dissected, dried and then placed in a container with beetles that eat away the dried soft tissue, similar to eating tasty beef jerky. The bones are then disarticulated (separated) and in this process the natural body position is lost. When skeletons of all sizes are being compared, this makes it difficult to study evolutionary relationships and development.

Flesh-eating Dermestid Beetle colony at the Florida Museum bone prep lab at the Florida Museum. Florida Museum photo by Zachary Randall
Cichlid skeleton prepared using a Dermestid Beetle colony. Florida Museum photo by Zachary Randall
Processed with a Dermestid Beetle colony, the specimen becomes a box of bones. Florida Museum image by Zach Randall

Skeletal Transformation: A Long-term Effect

The skeletonizing method chosen has a direct long-term effect on the specimen. Using either the Dermestid Beetle colony or the clearing and staining method completely transforms the specimen into a skeleton. Important anatomical and biological information such as muscles and diet content are destroyed forever. This poses a challenge for future researchers. These methods cannot be used on rare and irreplaceable specimens. The strength of using CT scanning is that it provides a digital skeleton without altering or damaging the specimen.

two fish specimens, one in a jar with specimen label and one is a CT scan of the bones of the fish
Digital skeleton of a Cichlid produced with a CT scanner; the specimen was not damaged or altered during the process. Florida Museum image by Zach Randall

Keeping the Bones Together

Ichthyologists (fish biologists) use two main techniques to prepare skeletons from preserved specimens of all shapes and sizes without losing their natural skeletal positions: clearing and staining and computed tomography (CT) scanning.

Clearing and Staining

stained fish specimen showing cartilage in blue and bony elements in red
The tail of a cleared and stained Bowfin showing cartilage (Alcian blue) and bony elements (Alizarin red). Florida Museum image by Zach Randall

This exhibit showcases specimens from the Florida Museum’s fish collection revealing the beauty in the process of clearing and staining (also known as diaphonization). This process uses a digestive enzyme called trypsin to clear away soft tissue but not the collagen, which supports the skeleton in place. Chemicals are used to stain cartilage blue and bone red. This method has been used for over 100 years and is still used today in natural history collections, remaining an affordable and easily accessible option.

The specimen is stored in glycerin which makes the specimen look clear because glycerin has the same refraction index (how light spreads from one medium to another) as the collagen, the material supporting the skeleton.

Chemicals and digestive enzyme used for clearing and staining specimens. Florida Museum photo by Zachary Randall
Using the clearing and staining technique, a specimen is permanently treated with chemicals and dyed. Florida Museum image by Zach Randall

Watch the process

Explore cleared and stained specimens

Looking to the Future: CT Scanning for Accessibility & Preservation

scan of fish specimen in a rainbow of colors to show the density of the tissue (blue, green, yellow, red)
Density in CT scans can be colorized as shown in the exhibit images. On the histogram left, is low density (usually cooler colors) and right is high density (usually warmer colors). Florida Museum image by Zach Randall

The Florida Museum and other natural history museums are using industrial micro CT scanners to capture a specimen’s anatomy in a non-destructive way. Through the use of x-rays, they digitally capture soft tissue and skeletal anatomy in 3D without causing damage or alteration to the specimen. Similar to getting a CT scan at the hospital, they capture hundreds to thousands of x-ray images of a whole specimen in a 360- degree rotation. These 2D x-ray images are then converted into slices (tomograms) and combined together to make a 3D model (volume). Preserved fish can be kept in these machines for hours without drying out or becoming damaged since they are packaged in plastic bags that help retain moisture.

This process makes the skeleton digitally and globally available for researchers, teachers, students and artists to use. CT data can be rendered different ways. The CT images shown in this exhibit are just one visual interpretation of the scan data.

Watch the process

Pros: Non-destructive and does not require dissection of the specimens. The data can be easily shared and accessed by anyone around the world.

Cons: Scanning can be expensive and not always accessible. CT rendering software can be expensive and powerful computers are needed.

Explore scanned specimens

 

Research and science communication are changing as global access to digital specimens explode in natural history collections using CT scanner technology.

scan of a fish in blues and greys
At UF, around 3,400 fish scans have been produced for more than 1,400 species. Florida Museum image by Zach Randall

Museum Specimens at your Fingertips

oVert is a collaborative initiative funded by the National Science Foundation (NSF) that provides free CT data of vertebrates preserved in natural history collections throughout the U.S. All of the data is accessible on MorphoSource, an open-access online image repository. This data provides global digital access to valuable museum collections making them accessible to researchers, educators, students, artists and the public.

oVert-generated media on MorphoSource

Art & Science

Digital access to natural history specimens is an opportunity for global collaboration and for better understanding and communication of Earth’s biodiversity. Integrating STEAM disciplines (science, technology, engineering, art and math) can make science communication more accessible. Combining visual arts and science may help people relate to an organism’s biology whereas they might get lost in complicated scientific terminology. As new technologies for visualizing data develop, communicating about science will become even more approachable.

  • scan of frog scull showing the parts of the skull in different colors
    Enlarged printed frog skull identifying every bone of the skull. Photo courtesy of Ramón González Cabrera
  • photo of fron statue, the frog is on its back with limbs spread
    This frog statue in a Carnegie Museum of Art exhibit was created in part from data generated by the oVert project. Photo courtesy of Margaret Honda
  • model of alligator skull showing are passing through the snout and through the mouth
    Digital model created from CT data shows the air passageways of an alligator. Photo courtesy of Dominique Adriaens

About Zach

Zachary Randall is an ichthyologist and imaging lab manager at the Florida Museum. He studied photography and freshwater fish systematics during his undergraduate and graduate degrees at UF. He uses visual arts as a form of science communication and utilizes imaging technology to digitize biodiversity collections for research, education and outreach. One of his most memorable moments working at the Florida Museum was the first time he saw a cleared and stained specimen, what seemed like hidden treasure, that he knew he wanted to share.

Zach in the Florida Museum’s fish collection using a photo tank for imaging fluid-preserved specimens. Museum photo by Kristen Grace
Zach showing his niece the fish collection for the first time. Photo courtesy of Luke Sauer