AMNH 18678: the largest Wanhsien tiger

In previous
post, I manage to calculate the Greatest Skull Length (GSL) and Condylobasal
length (CBL) for the largest specimen of the Wanhsien tiger (*Panthera tigris acutidens*) using the
ratios obtained from modern tigers (AMNH 18678 – Pm4 with a anteroposterior
length of 42 mm).

In the
first occasion, using the ratios of GSL-CBL-Pm4 from males of Java, Indochina,
India and Russia, I obtained the average value of 408.2 mm in GSL, but I leave
open the question about the reliability of the result, as this will depend of
the evolutionary history that we choose, in other words, with which modern tiger
subspecies is more related this giant Chinese tiger.

Latter in
my second attempt, I discarded those from Indochina, but this time, I also
calculated the Correlation coefficient for all variables and by each
subspecies. The average result was of 414 mm in GSL, however I stated that the
greatest correlations between variables was that of the Javanese tiger, which
have a result of 409 mm in GSL. This is about the same than the previous
result.

Now, in
this occasion, I followed a different way. We have the picture of the only
complete skull available of the Wanhsien tiger (AMNH 18624), but we also have
its mandible length (215 mm) and its Pm4 anteroposterior length (33.3 mm). With
this data, this time, I examined the relation between these variables in the
particular skull and extrapolated the results to estimate the skull size and
the head-body length (straight line).

**First: The GSL-CBL in relation with the Pm4.**

In the
next image I measured the length of the Pm4 and latter estimated how many Pm4
we need to get the GSL (higher line) and the CBL (lower line).

The
results were that the ratio GSL-Pm4 is of 8.56, while that of CBL-Pm4 is of
8.25. These values seem very close to those of the Indochinese tigers
previously calculated. However, is important to mention these points:

* The
length of CBL seems to be somewhat enlarged while that of the GSL is shortened,
as the sagital crest is broken. The skull is deformed in several parts, something
that Hooijer pointed out, so the ratios are at some point erroneous.

* Also,
the ratios are too close and the diference between GSL and CBL seems too small
in relation with all the other tiger subspecies. This is caused by the
deformation of the fossil.

Taking
this in count, I proceeded to make the following calculations:

GSL-Pm4 ratio - 8.56 → 42*8.56
= 359.5 mm in GSL

CBL-Pm4
ratio - 8.25 → 42*8.25 = 346.5 mm in CBL

Later,
using these results, I made the next calculations to obtain the GSL and the CBL
of each value; this is the image and the results *(left side)*:

GSL-Pm4
ratio - 8.56 → 42*8.56 = 359.5 mm – CBL 318.2 mm

CBL-Pm4
ratio - 8.25 → 42*8.25 = 346.5 mm – GSL 391.5 mm

**Average value: GSL 375.5 mm, CBL 332.3 mm.**

This
result shows that this specimen was no larger than a large Indian tiger. In
fact, this size is very close to the largest Bengal tiger skull measured by
Mazák (1983; GSL 378 mm, CBL 334.7 mm).

Using the
modern Amur tigers from Dr Christiansen, I calculated a head-body length of
c.197 cm for this large specimen, which is the same than that of the Sauraha
male. The shoulder height was probably about 1 meter.

**Second: The Mandible Length in relation with the Pm4.**

The next step
was to prove the relation between the mandible and the Pm4 of this specimen,
and at the same time, put to test the reliability of the image comparison
method. Here is the image:

Here are
the original measurements of the specimen:

* Mandible
– 215 mm

* Pm4 –
33.3 mm

Now, here
I found a problem. The image gives me a ratio of 6.25, but the fossil itself
gives me a ratio of 6.46! This indicates that the ratios obtained from the
GSL-CBL-Pm4 are probably also an Underestimation.

Here are
the results of my calculations:

*From
fossils:

ML-Pm4 - 6.46
→ 42*6.46 = 271.3 mm mandible length.

*From
comparative image:

ML-Pm4 - 6.25
→ 42*6.25 = 262.5 mm mandible length.

These
results produce mandibles of great size, as large as the largest record for the
Amur-Bengal tiger (276 mm). This suggests a large skull and not the “small” one
obtained from the GSL-CBL-Pm4. Besides, the difference between the two values
is not as large as those obtained in the first steep (only 88 mm).

The next step
is the calculations of the skull size, using the known ratios of CBL-ML, which have
a Correlation coefficient of no less than 0.92 for the four tiger subspecies
used in this study *(right side)*:

The result
suggests an average GSL of 404.1 mm, between the two values and a head-body
length of c.212 cm. However if we use the original data of the skull, which gives
a mandible of 271.3 mm, the GSL for the specimen “AMNH 18678” is of 411 mm and
with a CBL of 363.5 mm, I calculated a head-body length of c.215 cm. This size
is just 3 cm longer than that of the average results, but is significantly
larger than that obtained by the GSL-CBL-Pm4 method.

As this
final result uses the real size of the fossil, I am inclined to believe that a skull
length of **411 mm** and head-body length
of **215 cm (shoulder height of 110 cm)**
seems correct for the largest specimen of the Wanhsien tiger. However, this
size is still on the range of the largest Amur-Bengal tigers. For example, the
largest tiger of Brander measured 221 cm between pegs in head-body, while the
longest skull recorded by Hewett was of 413 mm. Besides, with this estimated
weight, the maximum body mass of **267.3
kg** fits very well, although I still believe that there is the possibility of
a maximum figure of 300 kg. The only fossils that are larger than this are the
giant skull and the mandible of the private collections, which surely will
produce truly gigantic values.

Finally,
take in count that this analysis gives only a suggestive result, although based
in actual specimens and from my point of view, very reliable for comparison
issues.

In a next
post, I will present my new image with the Wanhsien tiger on it, scaled with
the presented size.

Greetings.