Post by grrraaahhh on Nov 24, 2013 22:42:29 GMT -9
From the same forum section "General" thread quote:
¨
Using dental microwear textures to assess feeding ecology of extinct and extant bears
Donohue, Shelly Lynn
Abstract
Dramatic environmental changes associated with a global cooling trend beginning in the late
Miocene, and the onset of glacial-interglacial cycles in the Pleistocene served as a backdrop to
the evolutionary radiation of modern bears (family Ursidae). These environmental changes likely
prompted changes in food availability, and triggered dietary adaptations that served as motive
forces in ursid evolution. Here, I assess correspondence of dental microwear textures of first and
second lower molars with diet in extant ursids. I use the resulting baseline data to evaluate the
hypothesis that the giant short-faced bear, Arctodus simus, was a bone consumer and hyper-scavenger
at Rancho La Brea, California. Significant variation along the tooth row is consistent with functional
differentiation, with the second molar serving as a better dietary recorder than the first. Results evince
significant variation among species: carnivorous and omnivorous ursids (Ursus maritimus, U. americanus)
have significantly higher and more variable complexity (Asfc) than more herbivorous bears (Ailuropoda melanoleuca, Tremarctos ornatus, U. malayanus), and A. melanolueca is differentiated from U. maritimus and U. americanus by significantly higher and more variable anisotropy (epLsar) values. Arctodus simus exhibits wear attributes most comparable to its closest modern relative (T. ornatus) and inconsistent with hard object (e.g., bone) consumption, and the hypothesis that short-faced bears were bone consuming hyper-scavengers across their range. Rather, plant matter was likely an important component of the diet of Ar. simus at Rancho La Brea.
______________________________________________________________________________________
______________________________________________________________________________________
► etd.library.vanderbilt.edu/available/etd-03222013-102508/
► www.google.com/url?sa=D&q=http://www.google.com/search%3Fq%3Dcache:http://etd.library.vanderbilt.edu/available/etd-03222013-102508/&usg=AFQjCNHTZOpvobv0YxzL2sflctu2m1w3PA
______________________________________________________________________________________
______________________________________________________________________________________
Thanks. I hope to acquire this thesis when I return to the states. If anyone has accessed the paper and wants to share/provide relating info I think many here would be interested. For me, the interest is in the examined specimen sample. Cox (1991) and Scott (1993) showed that some large specimens were present at Rancho La Brea, but that the measurable sample is skewed towards females (the majority of adult specimens) and adolescent males, where long-bone epiphyses were not fused (S. Cox, pers. comm. to Richards, 26 July 1989; Agenbroad and Mead, 1986; Cox, 1991; Scott and Cox, 1993).
On a side note, I think a GSFB Diet thread would prove useful even though we have a handful of threads with numerous citations covering the topic[/size].[/quote]
¨
Was the Giant Short-Faced Bear a Hyper-Scavenger? A New Approach to the Dietary Study of Ursids Using Dental Microwear Textures
.
_____________________________________________________________________
_____________________________________________________________________
► www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0077531
_____________________________________________________________________
_____________________________________________________________________
Thanks again Sarus on the follow up. Good article read about GSFB diet at Rancho La Brea. After reading the article I was motivated to create the following thread (see first quoted post) examining GSFB diet through its range in the Americas. Numerous forum posts and one thread have been made addressing GSFB diet, however, I thought it was time as the authors have suggested in the cited article to examine GSFB diet throughout its range. There is variation in diet to consider. Earlier GSFB diet examination from different sites have resulted in different diet hypothesis ranging from the early meat eating hunter predator to herbivorous giant to hyper bone crushing scavenger to omnivorous bear. Without access to a lot of my literature (I'm going off memory here) it maybe the case (excluding the Bjorn Kurten meat eating hunter model) that earlier scientists were correct with respect to their GSFB specimen analysis but that their findings were limited to locality meaning maybe GSFB of Alaska & Canada were more carnivorous and GSFB in the lower 48 states consumed a lot more plant material especially at Rancho La Brea. Anyhow, I have provided earlier forum relating material/posts for anyone interested in the history of GSFB diet in the scientific literature.
LINK
LINK
Forum readership reminder, I want this thread to cover the Americas which include GSFB in South America.
Lastly, if anyone wants to create a thread about the GSFB as an omnivore or herbivore or any of the argued dietary models feel free to do so. One forum thread addressing GSFB as hyper scavenger and Kleptoparasite already exists. IMO, I see no problem on focusing in on the different models of GSFB diet.
Using dental microwear textures to assess feeding ecology of extinct and extant bears
Donohue, Shelly Lynn
Abstract
Dramatic environmental changes associated with a global cooling trend beginning in the late
Miocene, and the onset of glacial-interglacial cycles in the Pleistocene served as a backdrop to
the evolutionary radiation of modern bears (family Ursidae). These environmental changes likely
prompted changes in food availability, and triggered dietary adaptations that served as motive
forces in ursid evolution. Here, I assess correspondence of dental microwear textures of first and
second lower molars with diet in extant ursids. I use the resulting baseline data to evaluate the
hypothesis that the giant short-faced bear, Arctodus simus, was a bone consumer and hyper-scavenger
at Rancho La Brea, California. Significant variation along the tooth row is consistent with functional
differentiation, with the second molar serving as a better dietary recorder than the first. Results evince
significant variation among species: carnivorous and omnivorous ursids (Ursus maritimus, U. americanus)
have significantly higher and more variable complexity (Asfc) than more herbivorous bears (Ailuropoda melanoleuca, Tremarctos ornatus, U. malayanus), and A. melanolueca is differentiated from U. maritimus and U. americanus by significantly higher and more variable anisotropy (epLsar) values. Arctodus simus exhibits wear attributes most comparable to its closest modern relative (T. ornatus) and inconsistent with hard object (e.g., bone) consumption, and the hypothesis that short-faced bears were bone consuming hyper-scavengers across their range. Rather, plant matter was likely an important component of the diet of Ar. simus at Rancho La Brea.
______________________________________________________________________________________
______________________________________________________________________________________
► etd.library.vanderbilt.edu/available/etd-03222013-102508/
► www.google.com/url?sa=D&q=http://www.google.com/search%3Fq%3Dcache:http://etd.library.vanderbilt.edu/available/etd-03222013-102508/&usg=AFQjCNHTZOpvobv0YxzL2sflctu2m1w3PA
______________________________________________________________________________________
______________________________________________________________________________________
Thanks. I hope to acquire this thesis when I return to the states. If anyone has accessed the paper and wants to share/provide relating info I think many here would be interested. For me, the interest is in the examined specimen sample. Cox (1991) and Scott (1993) showed that some large specimens were present at Rancho La Brea, but that the measurable sample is skewed towards females (the majority of adult specimens) and adolescent males, where long-bone epiphyses were not fused (S. Cox, pers. comm. to Richards, 26 July 1989; Agenbroad and Mead, 1986; Cox, 1991; Scott and Cox, 1993).
On a side note, I think a GSFB Diet thread would prove useful even though we have a handful of threads with numerous citations covering the topic
Was the Giant Short-Faced Bear a Hyper-Scavenger? A New Approach to the Dietary Study of Ursids Using Dental Microwear Textures
.
_____________________________________________________________________
_____________________________________________________________________
► www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0077531
_____________________________________________________________________
_____________________________________________________________________
Thanks again Sarus on the follow up. Good article read about GSFB diet at Rancho La Brea. After reading the article I was motivated to create the following thread (see first quoted post) examining GSFB diet through its range in the Americas. Numerous forum posts and one thread have been made addressing GSFB diet, however, I thought it was time as the authors have suggested in the cited article to examine GSFB diet throughout its range. There is variation in diet to consider. Earlier GSFB diet examination from different sites have resulted in different diet hypothesis ranging from the early meat eating hunter predator to herbivorous giant to hyper bone crushing scavenger to omnivorous bear. Without access to a lot of my literature (I'm going off memory here) it maybe the case (excluding the Bjorn Kurten meat eating hunter model) that earlier scientists were correct with respect to their GSFB specimen analysis but that their findings were limited to locality meaning maybe GSFB of Alaska & Canada were more carnivorous and GSFB in the lower 48 states consumed a lot more plant material especially at Rancho La Brea. Anyhow, I have provided earlier forum relating material/posts for anyone interested in the history of GSFB diet in the scientific literature.
LINK
LINK
Forum readership reminder, I want this thread to cover the Americas which include GSFB in South America.
Lastly, if anyone wants to create a thread about the GSFB as an omnivore or herbivore or any of the argued dietary models feel free to do so. One forum thread addressing GSFB as hyper scavenger and Kleptoparasite already exists. IMO, I see no problem on focusing in on the different models of GSFB diet.