The biological ‘five finger rule’ is strikingly consistent throughout living tetrapod vertebrates. Humans and other primates, most carnivorous mammals, crocodiles, lizards and tortoises all typically possess the five digits (fingers and toes) characteristic of tetrapod limbs. It wasn’t always so – the ancient ancestors of the first vertebrates to walk on land, such as Ichthyostega and Acanthostega, had up to…
Tag: dissection
Metamorphosis made eas(ier)! Breathtaking 3D scans reveal secrets of a developing butterfly
Ever wondered what biological witchcraft is going on inside the chrysalis (‘cocoon’) of a developing butterfly? One team from Manchester University and the Natural History Museum has a better idea than most – Tristan Lowe and colleagues used CT scanning technology to trace the development of living animals undergoing metamorphosis. Their use of CT ingeniously…
#TomographyTuesday: Watch incredible CT scan reveal young brittle stars developing inside their parent!
Most marine invertebrates, and certainly most brittle stars, spawning gametes (eggs and sperm cells) into the oceans and the embryos are formed and grow externally. But a few species carry live young, with their offspring developing within the parent’s body. How exactly these creatures – which have pretty small central bodies to begin with – accommodate…
Sections through tough wombat femur show possible adaptation to digging.
Wombats are marsupial mammals that are only found in Australia. They are fossorial and dig out extensive networks of burrows. Wombats have a variety of adaptations to this lifestyle, which is energetically demanding and unusual in marsupials, including a unique backwards-facing pouch to prevent young being smothered with dirt while digging. This lovely section, which represents a…
Cast of the trachea, bronchi and bronchioles of a domestic dog.
This resin cast shows the branching of the windpipe or trachea (centre top) into bronchi and then bronchioles through the lungs. Air is drawn into these ever-smaller channels until they reach the alveoli, where gas exchange between the lungs and the bloodstream occurs. Image courtesy of the RVC.
Resin cast of a canine kidney
Plastinated cast of the blood vessels (pink) supplying the kidney and the renal pelvis (yellow, not the same as the pelvic bone), which collects urine and carries it to the bladder. Plastination and cast-making provide an excellent way to study complex networks of vessels such as this one, and help biologists to examine them without the…
Skull of a python: can snakes hear through their jaws?
The vertebrate ear tends to have three parts: the outer, middle and inner ear. Snakes have greatly reduced outer and middle ears, yet with just the inner ear and one remaining part of the middle ear they are able to hear. The middle ear ossicle has become connected to the jaw, suggesting that vibrations of…
Chiton radula (Chaetopleura articulata) capped with magnetite
Most molluscs (slugs, snails and many shellfish) use a radula to scrape algae and other food from the surface of rocks and shells. It’s a large, complex structure which resembles a giant alien tongue with many rows of teeth, and can be more than half the length of the whole animal! But chitons have an even more…
Branchial basket of the dogfish Squalus acanthias
The branchial basket is a cartilagenous structure which supports the gills (around the fine branches at either side). Image courtesy of RVC
Shell of the oyster Ostrea edulis, embedded in resin and sectioned to show growth lines.
As molluscs like the oyster grow, so too must their protective shell. Like tree rings, we can use the rings produced by seasonal growth to age these animals. This information is vital to monitoring and sustaining natural and harvested populations. Image courtesy of Dr Lawrence Eagling.
In focus: Chelonians (turtles and tortoises)
This week, we were lucky enough to examine two turtles which had been donated to the RVC. Turtles, tortoises and terrapins belong to a group of reptiles called Testudines or chelonians, which is thought to be one of the very oldest groups of reptiles. They have (slowly) walked the Earth for more than 220 million…
Anatomy To You 