Mammals with a intimately sole predilection for meat are relatively common today , but new research uncovers one of the very first : a bobcat - sized carnivore that lived near what is now San Diego .
Newresearchin PeerJ report one of the early get laid mammalian obligate carnivores , a newly key species and genus intend Diegoaelurus vanvalkenburghae . This animal lived during the Eocene , and despite its very cat - corresponding appearing , it was n’t closely related to feline . Diegoaelurus was a machaeroidine — an out group of meat - eating mammalian and the “ oldest group of sabre - toothed animal , ” accord to the theme , co - author by palaeontologist Ashley Poust from the San Diego Natural History Museum .
“ It probably front a circle like a small mountain lion , but stockier and with a bigger read/write head , ” explained Poust in an email . “ Strangely , it was n’t closely related to CAT at all , so the similarities would have been convergent , arrived at separately as it evolved to be an efficient hunting watch . ”
Artist’s interpretation of Diegoalerus.Illustration: San Diego Natural History Museum
I care the terminal figure “ obligate carnivores , ” because it nicely describes these animals ’ culinary modus vivendi — they’re obligated to eat on flesh , featuring diets that consist of at least 70 % meat . Among hold out mammalian , instance of hypercarnivores , as they ’re also telephone , include polar bears , dolphins , lions , Liberation Tigers of Tamil Eelam , and even small cats . These animals be given to have strong facial brawniness for holding fair game and comminute osseous tissue and specialised teeth for piercing and shearing kernel .
In a press loss , Poust say that , 42 million years ago , “ mammals were only just figuring out how to hold out on meat alone , ” and that the “ one big rise was to evolve specialised tooth for slicing shape — which is something we see in this newly draw specimen . ”
palaeontologist recover a low jaw and a jumble of well - preserved teeth from the 42 - million - year - sure-enough Santiago Formation in San Diego County of southerly California in 1988 . The fossil , discover during construction near Oceanside , was shortly canvas and then housed at San Diego Natural History Museum .
The jawbone belonging to Diegoaelurus.
The name Diegoaelurus vanvalkenburghae denotes the region in which the fossil was find and the scientist Blaire Van Valkenburgh , “ in recognition of her substantial contribution to our reason of iterative development in carnivorous mammals and saber - tooth paleoecology , ” concord to the paper .
The specimen is the first machaeroidine ( label mack - ay - roid - een ) to be find along the U.S. West Coast or from any North American region outside of Utah and Wyoming . Machaeroidine fossils are comparatively rare , hence the grandness of this discovery . The specimen is offering unused insights into the behaviour , dieting , and development of one of the earth ’s first mammalian hypercarnivores — a creature that emerged some 24 million years after all non - avian dinosaur went out .
With the Diegoaelurus dodo , Poust and his colleagues were capable to canvas the relationships of these early mammalian carnivores for the first meter . Prior to this cogitation , scientist were n’t certain if multiple members of machaeroidines subsist at the same time . A orotund member of this grouping , Apataelurus , go in what is now easterly Utah at roughly the same time , so it ’s totally potential that they did .
“ One of the most exciting thing to come from our study is find out that these early saber - toothed animate being were more diverse than we thought , with more than one metal money live at a time , ” Poust severalize me . “ It also evidence us more about a really interesting time in North American story , when big semitropical rain forest extended into the southwestern United States . ”
Shawn Zack , a paleontologist from the University of Arizona and a co - writer of the paper , enounce in apress releasethat the new specimen “ raises the possibility that there may be more out there to find . ”
psychoanalysis of the Diegoaelurus fossil suggests the creature had a marked downturned chin gadget characteristic of saber - toothed mammals . It was also physically different enough from Apataelurus to justify the creation of a new genus . Diegoaelurus was an early example of a cat - like carnivore , with its saber tooth up front and slicing scissor - like carnassials at the back . Fascinatingly , several animal groups independently take on this adjustment in the millions of years after this species disappear .
Its introduction represent a pernicious new addition to the Eocene landscape painting , as nothing quite like it had appear before . Back then , San Diego was forested and wet , featuring tiny rhinos , other tapirs , sheep - like oreodonts , rodents , primates , and marsupial . For Diegoaelurus , there was muckle of food to opt from .
“ cock-a-hoop changes in the chronicle of life are exciting because they give us insight into how development works , perceptivity into how we gravel here , ” Poust said . “ Evolving to eat an all - heart and soul dieting is a big variety and expect some very specialized equipment , needlelike claw , and blade - similar dentition . Our novel fossil is a saber - toothed piranha , which is even more specialised than other carnivores . ”
Saber tooth evolved several times independently , yet no living mammal features this dental toolkit today , Poust noted . Diegoaelurus is therefore an exciting discovery , he enjoin , because “ it is one of very few fossils of the first mammal mathematical group to acquire saber - teeth , tens of millions of year before the more intimate saber - tooth khat . ”
Intriguingly , Diegoaelurus may have know at the same clock time as another saber - toothed mammal , the North American nimravids , also known as saber - toothed delusive cats . The two groups may have crossed way of life , possibly competing for dominion and prey . “ There is at least a potency for competition with other nimravids to have contributed to the quenching of machaeroidines , ” the study generator hypothecate . “ As with many other subject involving machaeroidine palaeobiology and phylogeny , the limited fossil record of the group rule out positive finish . ”
Indeed , more fossil evidence will be demand to suss this out and to in full understand the evolutionary story of machaeroidines — including why they eventually died out . The search for more fossils continues .
AnimalsApex predatorsBehaviorBiologyFossilMammal
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