85mya Laurasiatheres

DOGS, CATS, BEARS, SEALS, HORSES, TAPIRS, RHINOS, DEER, CATTLE, PIGS, HIPPOS, BATS, MOLES, SHREWS, HEDGEHOGS, WHALES, DOLPHINS.

Laurasiatheria is another very large superorder of six orders that includes moles, shrews, hedgehogs, the very successful bat radiation, carnivores, ungulates, and whales.  Because this group had a rapid evolutionary radiation, the phylogenetic relationships among the six orders of Laurasiatheria remain a subject of heated debate and several issues related to its phylogeny remain open.  This superorder originated on the northern supercontinent of Laurasia, after it split from Gondwana when Pangaea broke up. Its last common ancestor is supposed to have diversified ca. 76 to 90 million years ago.

The Laurasiatheria is defined by DNA sequence analysis. The group does not share any obvious anatomical features. It includes these living orders:

Eulipotyphla: hedgehogs, gymnures, moles, shrews, solenodons

Cetartiodactyla: combines former orders Cetacea (whales, dolphins and porpoises) and Artiodactyla (even-toed ungulates, including pigs, hippopotamus, camels, giraffe, deer, antelope, cattle, sheep, goats)

Pholidota: pangolins or scaly anteaters in Africa and South Asia

Chiroptera: bats

Carnivora: carnivores

Perissodactyla: odd-toed ungulates

There are various ideas as to how these groups are related to each other, and no tree of descent is agreed by experts so far.

It is this group that has suffered the most at our hands.  We have domesticated several species for our own use, condemning them to short, confined and brutal lives so that we can have a few rashes of bacon or sausage with breakfast accompanied with eggs from sauropsids we met earlier.  Others have been used for beef and milk, usually under factory farm conditions to keep prices low.  Many of the charismatic wild species have fallen prey to hunters for their magnificent horns which are used in traditional chinese medicine.  Although our companion animals also fall into this superorder, their indiscriminate breeding for profit has created puppy mills where they are no different from factory farms.

New fads in pet foods are now trending towards raw meat and bone diets for dogs but recent research at the University of Guelph has shown that properly formulated vegetarian and vegan diets for dogs confers similar benefits of reduced illness and enhanced longevity as they do for humans.  The jury is still out for cats which are obligate carnivores but now with cell cultured proteins becoming mainstream, they will also be able to thrive on cruelty free diets.

Our common ancestry with bats leaves us vunerable to mutations of their viruses which have been proven to be deadly in recent epidemics including the most recent SARS-CoV-2 pandemic which is thought to have originated in bats and passed through an intermediate host to become infective to and between humans.