In focus: The mysterious extra ‘digits’ of pandas, moles and elephants

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…

Sloths’ mysterious teeth decoded

Like most mammals, we humans have a variety of tooth types for different purposes: incisors, for gripping, canines for ripping and tearing, and molars (also pre-molars) for grinding and chewing. But one group, known as the Xenarthra (a particularly excellent name meaning “strange joints”), have very simple dentition, with similar, unrooted teeth which lack enamel and…

#ThrowbackThursday individual bone cells from ‘Lucy’ tell the story of her growth

This rather abstract-looking image shows a tiny patch (around 110 micrometres across) of an ancient hominid femur. ‘Lucy’ is one of the the oldest and probably the most famous early human-like primate, belonging to the species Australopithecus afarensis. She lived around 3.2 million years ago in sub-Saharan Africa, and her remains were discovered in 1974 in Ethiopia….

Platypus x-rays show shadows of its “reptilian” ancestry

Platypuses belong to an ancient group of mammals, the monotremes. Today, these are the only living mammalian species to lay eggs, and the group also includes echidnas. But, as the x-rays of Dr Larry Vogelnest show, the platypus retains several skeletal features which link it to its distant ancestors (often called reptiles, but more technically referred…

In Focus: Can golden moles hear the earth move with a Thor-like ‘hammer’?

The golden moles (Chrysochloridae) are a group of silky and rather endearing group of mammals resembling, but distinct from, the true moles (talpids). Indeed, they are more closely related to elephants and manatees than to moles, shrews, rodents or other seemingly similar animals. They share many features with moles, such as adaptations to burrowing, and inhabit…

#ThrowbackThursday: Reconstructions show that human brains may have evolved more recently than we thought

The human brain may have evolved much faster and more recently than previously thought, researchers suggest from reconstruction of hominid skulls. By scanning the skull of Australopithecus sediba, one of the earliest complete hominid skeletons, scientists could reconstruct the shape and size of the brain from an endocast of the cranium. Essentially, this means they could use the…

Water molecule tracking reveals intricate muscle patterns in a tiny heart

The fibres of a mouse heart resemble a neat bird’s nest structure, but their specific orientations and interactions come together to drive blood around the body. The individual muscle strands were visualised using diffusion tensor imaging, which essentially tracks the movement of water molecules through single cells, revealing their position, size and shape. The pattern of…

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…

X-ray shows the bone structure of a bat’s wings

Bats are the only group of mammals to have achieved powered flight (as opposed to gliding), and represent one of only four known instances of the evolution of true flight, along with insects, birds and pterosaurs. Here, the bone structure of the wings is highlighted in the brown long-eared bat, Plecotus auritus. The majority of support for the…