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ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)
ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)
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ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)
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I think some areas of the Asian mainland does contain significant geographical barriers, like the Himalayas and Gobi. What is the historical distribution of tigers in Mongolia? I wouldn't think there was too many tigers there though I know for sure that they existed at some point.
Yeah, I am also thinking the possible geographical barrier in East Asia that caused the partial isolation of the Pleistocene tiger population in China.
 (07-05-2015, 09:30 AM)'tigerluver' Wrote: @GuateGojira, which document is that figure from?The document is "PLEISTOCENE MAMMALS FROM THE LIMESTONE FISSURES OF SZECHWAN, CHINA" from Colbert and Hooijer (1953). I tried to upload it here, but it is too heavy (c.48 MB). [img]images/smilies/sad.gif[/img] 
Thanks Guate, fortunately I've that document at hand, just lost track of it.
It's hard to determine the relative proportional size of the dentition between P. youngi, P. t. soloensis, P. t. amoyensis, and P. t. acutidens as P. youngi only has a fragmentary mandible. Looking at ratio between the M1-P1 length/M1-symphysis, the ratios are the same. The only issue with this is that some species have longer coronoid processes, increasing mandible length after the M1, increasing the skull length. For this reason, I can't say for certain if there is any difference in the proportional size of the inferior dentitions between the species at hand. (07-05-2015, 09:43 AM)'Richardrli' Wrote: I think some areas of the Asian mainland does contain significant geographical barriers, like the Himalayas and Gobi. What is the historical distribution of tigers in Mongolia? I wouldn't think there was too many tigers there though I know for sure that they existed at some point.This map from Kitchener & Dugmore (1999) show the records of tigers from Mazák (1996). There were tigers in Mongolia, but in the northern region.  *This image is copyright of its original author It clearly show a gap between Caspian an Amur tigers and an unclear border between the South China and the Amur tigers. However, we most remember that at those days (1999) no genetic study was available and the new documents from Driscoll et al. (2009) evidence that the separation between the Caspian and the Amur tiger (the gap in the map) was just about 200 years, and I think, based in that same map, that the supposed tigers in the frontier of the subspecies Amur-Amoyensis were probably transient ones, as very few records existed in that area (on 5 and very separated). Check the image from Driscoll et al. (2009):  *This image is copyright of its original author Figure 1. Range of the tiger Panthera tigris: Historical range of tiger distribution is shown in light tan and current range is shown in dark tan, while green dots indicate individual historical recordings of tigers outside of normal distribution [1]. Green ‘dot’ indicate records from the Middle Ages [4]. Black lines demarcate presumed subspecies boundaries [3]. Abbreviations correspond to traditionally named tiger subspecies, arranged chronologically by date of naming. 1) tigris Linnaeus, 1758[37]; 2) virgata Illiger, 1815[38]; 3) altaica Temminck, 1844[39]; 4) sondaica Temminck, 1844[39]; 5) amoyensis Hilzheimer, 1905[40]; 6) balica Schwarz, 1912[41]; 7) sumatrae Pocock, 1929[42]; 8) corbetti Mazak, 1968[43]; 9) jacksoni Luo et al., 2004[11]. Lettered arrows indicate postulated dispersal avenues: (A) Indian, southern route; (B) Siberian, northern route; and (C ) Silk road/ Gansu route with (D) secondary eastward dispersal. See text for details. Redrawn from Figures 19 and 20 in Mazak [1] and Figure 1 in Kitchener and Dugmore [3].Taking this in count, we can state that about 10,000 - 12,000 years ago, two great invasions succeeded in enlarge the tiger habitat, thanks to the climatic change and the end of the ice age. This change changed the old savanna type habitats in to forests, which are necessary for tigers. The first wave was to India, which succeeded in create the Bengal tiger population, the other was to the north creating the Caspian tiger and latter the Amur one. However, the habitat in India was way richer than that of the north and the population of tigers established it best population. Meanwhile, the Caspian tigers lived tied to the water sources and the constant human influence in those hard climates areas finally affect them, separating the main population from the southern Asia tigers and creating this "new" clade of the north. At the end, it seems that all make sense, one mainland subspecies separated in two clades by the deserts, high mountains and most importantly, the human intervention. That is why Caspian tiger skulls overlap greatly with the Amur and the Indian-Indochina-China tigers, but the Amur and the Indian tigers are very different.
Here is the border between the China proper and Manchuria, so also probably the border between the Chinese tiger and the Amur tiger.
https://en.wikipedia.org/wiki/Shanhai_Pass
I think the most northern boundary for the South China tiger is probably Beijing (whch is the non-Manchurian part of North China), and further to the north, they would probably encounter the most southern population of the Amur tiger.
 *This image is copyright of its original author
Here are two other genetic and biogeographic studies about tigers:
1. Tigers of Sundarbans in India: Is the Population a Separate Conservation Unit? Source: http://journals.plos.org/plosone/article...ne.0118846 This document states that the Sundarbans tigers are part of the Bengal tiger "subspecies", but as they are the most separated population, genetically speaking, they should managed like a diferent conservation unit. 2. Prioritizing Tiger Conservation through Landscape Genetics and Habitat Linkages Source: http://journals.plos.org/plosone/article...ne.0111207 The results of this study highlight that many corridors may still be functional as there is evidence of contemporary migration between Bengal tiger populations. Enjoy the reading.  *This image is copyright of its original author It looks like studies pretty agree on tiger phylogeny. Genetically, the South China tiger is the most different from the Amur-Caspian-Indochinese forms. I'm assuming P. t. amoyensis could breed with the other subspecies regardless. What do you think has happened here?
As a regional variation, I think the South China tiger probably had the largest historical territory and overlapped with most of other tiger variations.
In North China border with South Manchuria, they overlapped with the Amur tiger. In South China border with North Vietnam, they overlapped with the Indochina tiger. In Southwest China border with Myanmar, they overlapped with the Bengal tiger. In West China, they overlapped with the Caspian tiger. (07-05-2015, 10:47 AM)'GrizzlyClaws' Wrote: I think the most northern boundary for the South China tiger is probably Beijing (whch is the non-Manchurian part of North China), and further to the north, they would probably encounter the most southern population of the Amur tiger.The great wall, another evidence of human intervention on tiger subspeciation. (07-05-2015, 10:56 AM)'tigerluver' Wrote: Perhaps this could indicate that the South China tiger is not as "mixed" as other tigers. And other mainland tigers might have heavily mixed with the Sunda tiger, thus gradually losing the archaic features from their Wanhsien ancestor. (07-05-2015, 11:01 AM)'GuateGojira' Wrote:(07-05-2015, 10:47 AM)'GrizzlyClaws' Wrote: I think the most northern boundary for the South China tiger is probably Beijing (whch is the non-Manchurian part of North China), and further to the north, they would probably encounter the most southern population of the Amur tiger.The great wall, another evidence of human intervention on tiger subspeciation. Yes, there was no natural boundary between the China proper and Manchuaria, except the artificial Great Wall.
Genetic and morphological studies suggest that the South China tigers is basal to modern tigers, and thus, is the less related with the Amur and the Bengal tigers, which are the most modern ones.
From my point of view, this tiger population is the most related with the Wanhsien tiger. The genetic studies put it even been basal to the Sunda tigers, which separated from the mainland population until about 12,000 years ago, with the end of the last ice age. Kitchener & Dugmore (1999) sugest that at about 20,000 years, mainland and Sunda tigers were still interconnected, so the genetic and morphology of the South China tiger is the base of modern tigers, and something in its skull suggest that as its looks like a mix of mainland and Sunda tigers, although not at the level of the Sumatran tigers, which are more related with the island tigers. Sadly, modern captive population is not very representative of this old lineage, but in order to save it, the best candidate for intermix would be the Indochinese tiger, from which the captive population share already DNA marks.
Finally, something to think, check the famous draws from Mazák (1981):
 *This image is copyright of its original author Check and compare the South China tiger skulls with the other ones and see the diferences and similarities. Sadly, Mazák did not present draws of mandibles, but usign the skull shape is enoght to see this variations. |
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