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Post by sebbe67 on Feb 28, 2005 22:05:19 GMT
Rangifer tarandus dawsoni
This subspecies lived in muskeg habitat on the Queen Charlotte island it once also lived on Graham island were reports from locals people who lived there antlers and tracks was also found on the island during the late 1800.
The last Dawson caribou ever was reported 1908 on Charlotte island.
The cause of this subspecies extinction is a mystery.
Over hunting is one possibility. It probably wasent the native people who hunted them to extinction but the europeans.
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Post by sebbe67 on Feb 28, 2005 22:10:29 GMT
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Post by Peter on Mar 1, 2005 8:51:27 GMT
On the Extinct Birds List, Kevin (aspenparkland) posted:
TI: Evolution of the Dawson caribou (Rangifer tarandus dawsoni).
AU: Byun, SA; Koop, BF; Reimchen, TE
SO: Canadian Journal of Zoology. 2002 May; 80(5): 956-960.
AB: The Dawson caribou (Rangifer tarandus dawsoni) was a rare subspecies of caribou that inhabited Haida Gwaii, an archipelago located 80 km off the west coast of Canada. It became extinct during the early part of the 20th century and to this day all that remains of Dawson caribou are several pelts, skulls, and antlers. With the exception of a physical description based on these remains, not much is known about the taxonomy of this subspecies of caribou. Using molecular and ancient-DNA techniques, we sequenced 215 base pairs of the mitochondrial gene cytochrome b and compared these sequences with those from conspecifics Rangifer tarandus caribou (woodland caribou) and Rangifer tarandus granti (barren-ground caribou). These analyses suggest that the Dawson caribou was not genetically distinct. The unique morphology characterizing this extinct
form of caribou may have been of recent origin, either from local
selection pressures or from environmentally induced phenotypic plasticity.
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Post by Peter on Mar 1, 2005 8:54:11 GMT
After that I asked, if they were no longer seen as a valid subspecies! ;D
Some answers:
From Eike:
Interesting questin underlining the central problem of
molecular taxonomy: they only compared (part of)
mitochondiral cytB, and from their results, there are
no differences between Dawsons and mainland
caribous... in ancient DNA studies, one can nowadays
generally assume the DNA sequence is correct.
Sequencing of modern DNA is much more prone to error,
because you don't have to work at such extremely high
standards. The results are easier to achieve, making
researchers sloppy. Estimates are that around half of
GenBank sequence data is too faulty to use in
taxonomy.
Anyways, the research seems to suggest that Dawson's
is of recent (Holocene or Late Pleistocene) origin.
That would make subspecies status a bit dubious.
However, due to the fact that it was reproductively
isolated and morphologically distinct, the best
classification would be that it was a 'nascent'
subspecies, one that would have become a true
subspecies in its own right in some 100000s of years
or so, had not extinction of the population
intervened.
From Kevin:
The article says that Dawson's Caribou is an extinct population. The limited genetic sample can't find a major difference with main land population. The genetics suggest that Caribou are split into too subspecies.
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Post by Peter on Mar 1, 2005 8:55:24 GMT
Another question there was:
does anyone know if the hides or the antlers of this critter look markedly different than the mainland variety?
Answer from Eike:
Basically, no (though it was long believed) and yes,
very much.
To sum up the article (nice piece of work I say, with
a repro of the picture of the last specimen taken):
The difference to the mainland population was believed
to be smaller size, lighter hair (rather uniform in
shade, that is, not much of a difference between back
and belly color) and smaller, irregular antlers, a
strong tendency in females to be antler-less.
Basically, the question raised in this article is:
Which suggestion is correct - that Dawson's was a
subspecies that was trapped on its island by the last
Ice Age, and could therefore be considered a good and
distinct subspecies in every respect, or that it came
to the island only at the end or after the Ice Age
(10-15000 years before present)? The cytB genetic
markers they us seem to give a good answer to the
questions, because as has been shown with other
populations from the island and region, if the first
assumption were true, one would expect that
genetically, the island individuals would be more
similar to each other than to any mainland individual.
Turns out that this is not the case; Dawson's
specimens show a genetic sequence that cannot be
uneqivocally be distinguished from mainland caribou -
you can't tell whether a caribou comes from the island
or the mainland by simply looking at the cytB region's
genetic code they determined. Thus, the founders of
the island population came there some 10000 years ago.
They don't give a firm recommendation on whether this
subspecies should be withdrawn. Two of the Dawson's
specimen are possibly genetically distinct, but this
would have to be compared with more mainland caribous.
The other specimen is more similar to mainland than to
the first two.
They note that the hair color is probably an artifact
due to storage, as photographic evidence suggests no
difference in color. The differences in size and
antlers stand, however. That the color difference is
not real is not surprising, they note, for populations
of other species on the island seem to have a tendency
to be darker, not lighter. Sub-fossil bones show that
the colonizing caribou were ordinary mainland
specimens in size, yet modern specimens show that in
some 1000s of years, notable 'island dwarfism' has
already occurred.
The point whether Dawson's was a distinct subspecies
cannot be answered, really. All that can be said is
that it was on its best way of becoming one, as can be
seen by the size decrease which had already become a
fixed trait*. We know that in some birds,
subspeciation and even speciation at the end of the
last ice age did occur (the extinct emerald
hummingbird Chlorostilbon bracei is a good species),
in most it didn't. However, this is an island
population we're talking about here, so the trend
would be towards a stronger speciation. The wisest way
for the time being seems to me to uphold it as a
subspecies, BUT to note that it was not really
distinct and that this classification is based more on
the fact that the Dawson geen pool was isolated from
the mainland gene pool and some differences in
appearance, not in all respects that would make it a
proper subspecies (most notably, genetic divergence).
That being said, one can conclude that Dawson's
caribou was a population that was 'frozen' half-way in
becoming a full-fledged subspecies by its extinction.
Whether or not one considers it such is as much a
matter of personal taste as of scientific evidence.
Regards,
Eike
* IF we knew the genetics responsible for size (most
probably a sequence controlling growth hormone
production in this case, but we know not really what
that would be) it can reasonably be expected to find a
clear difference between the island and the mainland
population, so there was some degree of genetic
uniqueness already in Dawson's, but not where they
looked for it, but rather as pertains to the traits
that set Dawson's apart from the mainland population.
The cytB marker was used because the aim of the
article (which it admirably achieved, IMHO) was not
really the taxonomy, but to get a date for the
colonization of the island by caribous, and this
particular region of the cytB gene they used is a good
molecular clock for Holocene (the last 2,4 millions of
years or so) timescales.
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Post by Peter on Mar 1, 2005 8:56:42 GMT
If anyone is interested in this article, you can mail me! I have the PDF-file of it. And I think Kevin has it too.
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Post by another specialist on May 28, 2005 19:11:51 GMT
 Taxonomy There is some uncertainty about how different groups of caribou are related to each other. Technological advances in genetic analysis have clarified some issues, but studies are ongoing. In the meantime, caribou are classified by ecotype (where they occur and how they behave) for their management and conservation. There are three major types of caribou in Canada: Peary, Barren-ground, and Woodland. The Caribou dawsoni subspecies, traditionally grouped with the Woodland Caribou, is extinct. Results of recent research indicate that the caribou in the Dolphin and Union herd are unique. They resemble large Peary Caribou, but appear to be more closely related genetically to Barren-ground Caribou. Peary Caribou, the smallest, lightest-coloured, and least understood of the three races, are found only on the islands of the Canadian Arctic Archipelago. They have access to a vast area of land, but only a limited portion contains suitable habitat. Barren-ground Caribou, slightly larger and darker, are found for much or all of the year on the tundra from Alaska to Baffin Island. They are by far the most abundant caribou; some herds in northern Canada number in the hundreds of thousands. They migrate seasonally, often along predictable routes, to the sparsely treed northern coniferous forests. Woodland Caribou, the largest and darkest-coloured, are irregularly distributed throughout our boreal forest and mountains from the island of Newfoundland to British Columbia. They are not migratory, but some herds, especially those in mountainous regions, move to different elevations with the seasons. Recent genetic analyses indicate that the Caribou dawsoni subspecies may not have been as different from caribou on the mainland as previously believed; therefore, it may not merit its status as a distinct subspecies. However, it was undoubtedly at least a distinct population that is no longer represented in the fauna of British Columbia, and thus deserves its status as extinct (as applied by the Committee on the Status of Endangered Wildlife in Canada, COSEWIC). Description The limited information that is available on the Caribou dawsoni subspecies describes the animal as a small, pale caribou that stood about one metre at the shoulder. The antlers were small, poorly developed and may have been rarely borne by females. Distribution and Population The Caribou dawsoni subspecies is known only from the northwestern part of Graham Island, the northernmost of the two largest of the Queen Charlotte Islands (Haida Gwaii). It is known only from five specimens, and has not been seen since the 1930s. It was declared extinct by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in 1984. There is no information available on former population sizes for this caribou but it is suspected that it was never very numerous. Habitat The Caribou dawsoni subspecies was known to inhabit treeless bogs in the humid boreal forest, a habitat typical of Woodland Caribou. Biology Nothing is known of the biology of the Caribou dawsoni subspecies. Reasons for extinction The reasons for the decline and disappearance of the Caribou dawsoni subspecies are unclear. It has been speculated that hunting, and the deterioration of habitat due to climate change, were both important factors. www.speciesatrisk.gc.ca/search/speciesDetails_e.cfm?SpeciesID=7 |
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Post by another specialist on Aug 6, 2005 7:07:53 GMT
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Post by sebbe67 on Mar 14, 2006 17:34:21 GMT
 Source: The Doomsday book |
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Post by another specialist on Mar 14, 2006 22:10:31 GMT
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Post by another specialist on Sept 8, 2007 19:40:01 GMT
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Post by another specialist on May 28, 2008 15:17:36 GMT
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Post by another specialist on Jun 15, 2008 9:05:35 GMT
 Annotated Bibliography of Quaternary Vertebrates of Northern North America By C.R. Harington |
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Post by another specialist on Jul 14, 2008 5:46:46 GMT
SPECIES Rangifer tarandus Author: Linnaeus, 1758. Citation: Syst. Nat., 10th ed., 1: 67. Common Name: Reindeer Type Locality: "Habitat in Alpibus Europae et Asiae maxime septentrionalibus"; identified as Sweden, Alpine Lapland by Thomas (1911a:151); based on domesticated stock. Distribution: Circumboreal in tundra and taiga from Svalbard, Norway, Finland, Russia, Alaska (USA) and Canada including most arctic islands, and Greenland, south to N Mongolia, China (Inner Mongolia; now only domesticated or feral?), Sakhalin Isl, and USA (N Idaho and Great Lakes region). Introduced to, and feral in, Iceland, Kerguelen Isls, South Georgia Isl, Pribilof Isls, St. Matthew Isl. Extinct in Sweden. Status: U.S. ESA – Endangered as R. t. caribou in Canada (SE British Columbia at the Canadian-USA border, Columbia River, Kootenay River, Kootenay Lake, and Kootenai River) and USA (Idaho, Washington); IUCN – Endangered as R. t. pearyi, otherwise Lower Risk (lc). The woodland caribou is highly endangered throughout its distribution right into Ontario (V. Geist, in litt.). Comments: Subspecies have been placed in two divisions, compressicornis or Woodland Reindeer, and cylindricornis or Tundra Reindeer (Jacobi, 1931). These names of divisions are non-Linnean; cilindricornis Camerano, 1902 is a lapsus for cylindricornis and is not a Linnean name. An additional category has since been recognised for the Peary Caribou, due to marginal or seasonal sympatry between caribou in Arctic America, following Banfield (1963). Subspecies here considered valid are based on Banfield (1961), considerably modified by Geist (1998): caribou division or Woodland Caribou (includes also buskensis, valentinae, dawsoni, fennicus, and phylarchus); populations transitional between caribou and tarandus divisions (includes osborni); tarandus division, Barren-ground Caribou or Reindeer (includes also caboti, groenlandicus, pearsoni, sibiricus, and terraenovae); and platyrhynchus division (including pearyi or Peary Caribou and platyrhynchus or Svalbard Reindeer). The extinct insular dawsoni has been treated as a distinct species (Cowan and Guiguet, 1965) but does not differ from caribou or granti (= groenlandicus) in mtDNA sequences (Byun et al., 2002). Grouping the Svalbard Reindeer with the Peary Caribou is provisional (Groves and Grubb, 1987).www.bucknell.edu/msw3/browse.asp?s=y&id=14200328 |
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Post by Bhagatí on Jan 5, 2014 15:04:26 GMT
What do you see a valid subspecies?
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Post by Melanie on Jan 5, 2014 18:34:42 GMT
What do you see a valid subspecies? Evolution of the Dawson caribou (Rangifer tarandus dawsoni) S.A. Byun, B.F. Koop, and T.E. Reimchen The Dawson caribou (Rangifer tarandus dawsoni) was a rare subspecies of caribou that inhabited Haida Gwaii, an archipelago located 80 km off the west coast of Canada. It became extinct during the early part of the 20th century and to this day all that remains of Dawson caribou are several pelts, skulls, and antlers. With the exception of a physical description based on these remains, not much is known about the taxonomy of this subspecies of caribou. Using molecular and ancient-DNA techniques, we sequenced 215 base pairs of the mitochondrial gene cytochrome b and compared these sequences with those from conspecifics Rangifer tarandus caribou (woodland caribou) and Rangifer tarandus granti (barren-ground caribou). These analyses suggest that the Dawson caribou was not genetically distinct. The unique morphology characterizing this extinct form of caribou may have been of recent origin, either from local selection pressures or from environmentally induced phenotypic plasticity. web.uvic.ca/~reimlab/Dawson.pdf |
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Post by koeiyabe on Nov 28, 2015 19:00:24 GMT
 "Living Things Vanished from the Earth (in Japanese)" by Toshio Inomata (1993) with Sea Mink, Xerces Blue, and general wolf. |
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Post by surroundx on Mar 17, 2019 4:42:51 GMT
I haven't read this paper, but they seem a little late in considering the possibility that the Dawson caribou is invalid.... Mathewes, Rolf W., Richards, Michael and Reimchen, Thomas E. (2019). Late Pleistocene age, size, and paleoenvironment of a caribou antler from Haida Gwaii, British Columbia. Canadian Journal of Earth Sciences. doi: doi.org/10.1139/cjes-2018-0246 [ Abstract] |
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Post by koeiyabe on May 20, 2019 14:16:32 GMT
 "Lost Animals (in Japanese)" by WWF Japan (1996) |
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