General extinction

[grrraaahhh]

Ancient DNA evidence for the loss of a highly divergent brown bear clade during historical times

Abstract

The genetic diversity of present-day brown bears (Ursus arctos) has been extensively studied over the years and appears to be geographically structured into five main clades. The question of the past diversity of the species has been recently addressed by ancient DNA studies that concluded to a relative genetic stability over the last 35 000 years. However, the post-last glacial maximum genetic diversity of the species still remains poorly documented, notably in the Old World. Here, we analyse Atlas brown bears, which became extinct during the Holocene period. A divergent brown bear mitochondrial DNA lineage not present in any of the previously studied modern or ancient bear samples was uncovered, suggesting that the diversity of U. arctos was larger in the past than it is now. Specifically, a significant portion (with respect to sequence divergence) of the intraspecific diversity of the brown bear was lost with the extinction of the Atlas brown bear after the Pleistocene/Holocene transition

www.sebastiencalvignac.fr/downloads/calvignac2008atlasbrownbear.pdf

[apollyon]

I suspect their has been a significant loss of genetic diversity in a wide variety of animals from order down to family. I.e. the rich diversity of Cats, Bears, Elephants, etc

[Spelaearctos]

Hello. I am Agriotherium, but I have forgot my password.
I have a question. There is a subspecies of Brown Bear - Ursus arctos nelsoni, Mexican Grizzly. But there is no this subspecies in Baryshnikov's monography. So, Mexican Grizzly Bear is synonym of U. a. horribilis?

[grrraaahhh]

Aug 2, 2012 1:33:30 GMT -9 Spelaearctos said:

Hello. I am Agriotherium, but I have forgot my password.
I have a question. There is a subspecies of Brown Bear - Ursus arctos nelsoni, Mexican Grizzly. But there is no this subspecies in Baryshnikov's monography. So, Mexican Grizzly Bear is synonym of U. a. horribilis?

As I understand it....

Mexican Grizzly Bear

Species: Ursus arctos
Valid name: Ursus arctos horribilis Ord, 1815
Trinomial name: Ursus arctos nelsoni Merriam, 1914
Synonyms: Ursus horribilis nelsoni, Ursus nelsoni

All grizzly bears are brown bears but not all brown bears are grizzly bears. Grizzly bears U.a. horribilis are associated with the interior brown bear populations of Canada, Alaska, and the lower 48 states USA. By contrast, brown bears are associated with the coastal areas of the continental North American northwest. Extirpation of the Mexican grizzly bear is believe to have occurred in the 1960s although there were reports of its possible existence as late as the 1980s.


RE: Agriotherium password, there should be member option to reset or change password.

[Spelaearctos]

"ll grizzly bears are brown bears but not all brown bears are grizzly bears."
That I know.

Mexican brown bear is a different subspecies or it is U. a. horribilis?

And one thing I cannot understand. How can live in Alaska few subspecies of Brown Bear?

[grrraaahhh]

Mexican grizzly bear = U. a. horribilis.
Trinomial name: Ursus arctos nelsoni Merriam, 1914.
Synonyms: Ursus horribilis nelsoni, Ursus nelsoni.


RE: Alaska......

Ursus arctos.
Ursus arctos middendorffi.
Ursus arctos horribilis.


General Description

Brown and grizzly bears are classified as the same species even though there are notable differences between them. Kodiak bears (brown bears from the Kodiak Archipelago) are classified as a distinct subspecies (U. a. middendorffi) from those on the mainland (U. a. horribilis) because they have been isolated from other bears since the last ice age about 12,000 years ago. “Brown bears” typically live along the southern coast of the state where they have access to seasonally abundant spawning salmon. The coastal areas also provide a rich array of vegetation they can use as food as well as a milder climate. This allows them to grow larger and live in higher densities than their “grizzly” cousins in the northern and interior parts of the state.


www.adfg.alaska.gov/index.cfm?adfg=brownbear.main


U.a.gyas, U.a.dali, U.a.richardson = Synonyms.