Discovery of prehistoric mammals suggests rapid evolution of mammals
after dinosaur extinction

Date:
August 18, 2021
Source:
Taylor & Francis Group
Summary:
Scientists have discovered three new species of ancient creatures
from the dawn of modern mammals that hint at rapid evolution
immediately after the mass extinction of the dinosaurs.



FULL STORY ========================================================================== Research published today in the peer-reviewed Journal of Systematic Palaeontology describes the discovery of three new species of ancient
creatures from the dawn of modern mammals, and hints at rapid evolution immediately after the mass extinction of the dinosaurs.


========================================================================== These prehistoric mammals roamed North America during the earliest
Paleocene Epoch, within just a few hundred thousand years of the Cretaceous-Paleogene boundary that wiped out the dinosaurs. Their
discovery suggests mammals diversified more rapidly after the mass
extinction than previously thought.

New-to-science, the creatures discovered areMiniconus jeanninae, Conacodon hettingeri,andBeornus honeyi. They differ in size -- ranging up to a
modern house cat, which is much larger than the mostly mouse to rat-sized mammals that lived before it alongside the dinosaurs in North America.

Each have a suite of unique dental features that differ from each other.

Beornus honeyi, in particular has been named in homage to The Hobbit
character Beorn, due to the appearance of the inflated (puffy) molars
(cheek teeth).

The new group belong to a diverse collection of placental mammals called archaic ungulates (or condylarths), primitive ancestors of today's hoofed mammals (eg, horses, elephants, cows, hippos).



========================================================================== Paleontologists from the University of Colorado in Boulder unearthed
parts of lower jaw bones and teeth -- which provide insights into the
animals' identity, lifestyle and body size.

The three new species belong to the family Periptychidae that are
distinguished from other 'condylarths' by their teeth, which have swollen premolars and unusual vertical enamel ridges. Researchers believe that
they may have been omnivores because they evolved teeth that would have
allowed them to grind up plants as well as meat, however this does not
rule out them being exclusively herbivores.

The mass extinction that wiped out the non-avian dinosaurs 66 million
years ago is generally acknowledged as the start of the 'Age of Mammals' because several types of mammal appeared for the first time immediately afterwards.

As lead author Madelaine Atteberry from the University of Colorado
Geological Sciences Department in the USA explains, "When the dinosaurs
went extinct, access to different foods and environments enabled mammals
to flourish and diversify rapidly in their tooth anatomy and evolve
larger body size. They clearly took advantage of this opportunity,
as we can see from the radiation of new mammal species that took place
in a relatively short amount of time following the mass extinction."
Atteberry and co-author Jaelyn Eberle, a curator in the Museum of
Natural History and Professor of Geological Sciences at the University of Colorado, studied the teeth and lower jaw bones of 29 fossil 'condylarth' species to determine the anatomical differences between the species, and
used phylogenetic techniques to understand how the species are related
to each other and to other early Paleocene 'condylarths' in the western
United States.

The evidence supports the discovery of these three new species to science.

About the size of a marmot or house cat, Beornus honeyi was the largest; Conacodon hettingeri is similar to other species of Conacodon, but
differs in the morphology of its last molar, while Miniconus jeanninae
is similar in size to other small, earliest Paleocene 'condylarths',
but is distinguished by a tiny cusp on its molars called a parastylid.

"Previous studies suggest that in the first few hundred thousand years
after the dinosaur extinction (what is known in North America as the
early Puercan) there was relatively low mammal species diversity across
the Western Interior of North America, but the discovery of three new
species in the Great Divide Basin suggests rapid diversification following
the extinction," says Atteberry.

"These new periptychid 'condylarths' make up just a small percentage of
the more than 420 mammalian fossils uncovered at this site. We haven't
yet fully captured the extent of mammalian diversity in the earliest
Paleocene, and predict that several more new species will be described." ========================================================================== Story Source: Materials provided by Taylor_&_Francis_Group. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Madelaine R. Atteberry, Jaelyn J. Eberle. New earliest Paleocene
(Puercan) periptychid `condylarths' from the Great Divide Basin,
Wyoming, USA. Journal of Systematic Palaeontology, 2021; 1 DOI:
10.1080/ 14772019.2021.1924301 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210818083945.htm

--- up 14 weeks, 5 days, 22 hours, 45 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)