Adorable Mammals from the Eocene

Different fossil plants and animals from the lacustrine deposits of the McAbee Flora of the Eocene (British Columbia, Canada)

Today we return to the long-vanished summer world of the Eocene (the third epoch of the Cenezoic era). During most of the Eocene, there was no polar ice on Earth: a balmy temperate summer held sway from Antarctica to Svalbard. British Colombia was covered by a tropical rainforest where palm trees and cycads contended with warm weather conifers (and with the ancestors of elms, cherries, maples, and alders). Within this warm diverse forest, which thrived between 55 and 50 million years ago, lived numerous strange magnificent birds and insects. Shoals of tropical fish thronged in the acidic foaming waters (which were practically carbonated—since the atmospheric carbon dioxide levels of the Eocene were probably double that of the present).   The mammals of this lovely bygone forest were equally splendid–strange proto-carnivores not closely related to today’s mammalian predators,  weird lemur analogs, and strange ur-rodents. This week the discovery of two new mammal species was announced.  These remarkable fossil finds provide us with an even better picture of the time and place.

a reconstruction of the early Eocene in northern British Columbia: a tapir-like creature (genus Heptodon) with a tiny proto-hedgehog in the foreground. (Julius T. Csotonyi)

One of the two creatures discovered was a tapir-like perissodactyl from the genus Heptodon. The newly discover tapir was probably about the size of a large terrier. I really like tapirs (and their close relatives) but these remains are not a huge surprise–since many perissodactyls thrived in North America during the Eocene. The other fossil which paleontologists found is a surprise—an adorable surprise! Within a stone within a coal seam was a tiny jaw the size of a fingernail. Such a fossil would have been all but impossible to study in the past, but the paleontological team led by David Greenwood, sent the little fossil to be scanned by a CT scanner and then imaged with a 3D scanner. The tiny jaw was from a diminutive hedgehog relative since named Silvacola acares.  The little hedgehog grew to a maximum adult size of about 6 cm (2.3 inches) long or approximately thumb-sized. Since it probably lacked spines, this miniature hedgehog was a bit different than the modern hedgehog, but it was definitely a relative.

As discussed in previous posts, I like to imagine the balmy Eocene, when so many mammals which are now the mainstay of our familiar Holocene/Anthropocene world got their first start. It makes it even better to imagine that the thickets were filled with endearing hedgehogs the size of bumble bees.

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Gamboge

Here is a gorgeous warm earth color for Thanksgiving week.  Gamboge is a deep yellow/pale orange color of tremendous antiquity.  By ancient tradition, Theravada monks dye their robes this distinctive color to show their devotion to the middle path.  The color is named after the Latin word for Cambodia, “Gambogia”, which was (and is) a center of Theravada spirituality as well as a major source of milky sap from Gamboge trees (genus Garcinia). Such sap is dried into a brown gum resin which is the main constituent of gamboge dye.

Because the color plays such a large role in the religious life of South Asia, it is well known throughout the world. Gamboge is a lovely and vibrant color in its own right—a perfect medium between orange and yellow.  All sorts of animals, fruit, and flowers can be described as gamboge.  Although Thanksgiving has no color scheme per say, the fallen autumn leaves usually inspire decorations in some combination of gamboge, sienna, and russet.