ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)

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The SOB and OH of tigers

The Supraoccipital breadth(SOB) relative to the Occipital height(OH) In previous studies, it was considered a significant distinguishing feature between different subspecies of tigers, and even now it has at least valuable population identification significance.

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In tigers, the relative width of SOB can be clearly defined as gradually increasing from south to north on the Asian continent, which seems to be a functional adaptation caused by their corresponding ecological environment.

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However, there does not seem to be much data on SOB in the literature, and it is generally not a major measurement value.

Its measurement method is"the smallest distance between notches of lateral margins of the occiput; the notch being situated approximately where sutura occipitoparietalis, sutura parietotemporalis and sutura occipitotemporalis meet"(Ji H. mazák 2008)

I have seen a good structural diagram(see blow, Narimane Chatar et al.2022) that can clearly distinguish these bone sutures. Please pay attention to the intersection of the occipital and parietal and the temporal in the diagram.

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In the posterior view provided by Ji H. mazak, the specific location is the highest point on the dorsal side of the mastoid process And the Dorsal view can be seen in Figure B. Búzás and B. Farkas 1996.

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In the publications of V. mazák and Ji H. mazák, it seems that I can only find specific data on island tigers and indochinese tigers (including Malayan tigers)

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However, in his publication<Recent Advance in Tiger Phylogeny, In the Evolution and Geographical Variation >(Chinese version), he listed the scatter plot data of male SOB for all subspecies.

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According to the scatter plot, we can see that the Amur tiger has a significantly widest SOB, both in terms of relative width and absolute width.Corresponding to the logarithmic axis of SOB, the SOB of some particularly wide male Amur tiger individuals may even reach around 90mm, almost 1.8 to 2 times that of some small Java and Bali tigers.

One of the male Sumatran tigers is very interesting, with a maximum recorded SOB of 83.4mm. Such a huge size makes it easy to find in scatter plots. From the graph, it can be seen that its SOB is almost as wide as the widest male Bengal tiger and comparable to many male Amur tiger individuals, which is very astonishing.

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