Tag: chiroptera

Hassianycteris

Hassianycteris messelensis was an early bat that lived in what is now Germany during the mid-Eocene, about 47 million years ago.

It’s generally considered to be very closely related to the common ancestry of modern bats – but a recent study suggests that the stem-bat evolutionary tree is actually quite a bit more complicated than previously thought.

It had a 35-40cm wingspan (~14″-16″), and thanks to the exceptional preservation of the Messel Pit fossil site we actually know some details about its external life appearance. One specimen preserves a soft-tissue impression of its ear shape, and fossilized melanosomes suggest that its fur was colored reddish-brown.

Its wing proportions indicate it was adapted to fly high and fast in open spaces, and its strong jaws and preserved gut contents show it mainly preyed on tough-shelled insects like beetles.

Continue reading “Hassianycteris”

Eons Roundup 4

Some more recent commission work for PBS Eons!

  • An illustration of an extinct entelodont, an omnivorous hoofed mammal. It has a hippo-like head and a body proportioned rather like a hyena, with high shoulders and long slender legs. It has cloven-hoofed feet and a short tail, and its body is covered in a coat of short bristly fur.
    Eoentelodon
  • An illustration of an extinct entelodont, an omnivorous hoofed mammal. It has a hippo-like head and a body proportioned rather like a hyena, with high shoulders and long slender legs. It has cloven-hoofed feet and a short tail, and its body is covered in a coat of short bristly fur.
    Brachyhyops

The entelodonts Eoentelodon and Brachyhyops, from “The Hellacious Lives of the Hell Pigs”
https://www.youtube.com/watch?v=trJpxwMGoCw

  • An illustration of an extinct ichthyosaur, an ancient marine reptile. It has a short narrow snout full of rounded teeth, large eyes, a long tapering body, four flippers, and a long tail ending in a vertical fin.
    Tholodus
  • An illustration of an extinct mosasaur, an ancient marine reptile. It has long triangular jaws full of many small sharp teeth, a long lizard-like body, four paddle-like flippers, and a long tail ending in a vertical fin.
    Pluridens

The early ichthyosaur Tholodus and the mosasaurPluridens, from “When Ichthyosaurs Led a Revolution in the Seas”
https://www.youtube.com/watch?v=V342aXQs9XY

  • An illustration of an extinct early bat in flight. It has claws on all five fingers on each wing, along with small ears and a long tail.
    Onychonycteris
  • An illustration of an extinct early bat in flight. It has claws on both its thumb and the first wing finger one each wing, along with small ears and a long tail.
    Icaronycteris

The early bats Onychonycteris and Icaronycteris, from “When Bats Took Flight”
https://www.youtube.com/watch?v=zWeYCULC0UQ

Unsolved Paleo Mysteries Month #23 – Puzzling Proto-Bats

Let’s finish off this month the same way we started: with flying vertebrates without any transitional forms!

Much like the pterosaurs, bats appear suddenly in the fossil record already fully flight-adapted. Despite being the second-largest group of mammals, bats’ small fragile bones and terrestrial habitats make fossils of them incredibly rare, and transitional forms are still entirely unknown. (Even the ancestral form illustrated above is a generic hypothetical mammal!)

The most “primitive” known bats come from the Early Eocene* (~55-52 mya) and various early representatives have been found as far apart as North America, Europe, India, and Australia – indicating they were already a widespread and diverse group by that time, and making it difficult to pin down just where and when they actually might have originated.

*I’ve seen mentions of a potential bat-like tooth from the Late Cretaceous of South America, but can’t find any actual references for it. So it’s possible bats may even have evolved before the K-Pg extinction.

Although bats were once thought to be related to archontans (treeshrews, colugos, and primates) based on morphological similarities, more recent genetic studies have shown them to instead be grouped with the laurasiatheres (eulipotyphylans, carnivorans, pangolins, ungulates, and whales). Based on this phylogenetic position the earliest ancestors of bats may have been small tree-climbing shrew-like animals who evolved flight while leaping in pursuit of insects. They might even be closely related to an obscure group called nyctitheriids – but without a lucky find of an exceptional fossil, we just don’t know.