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New record size for north african Testudo.
A C Highfield
INTRODUCTION
The previously largest recorded dimensions for a tortoise originating
in north Africa are those given by Flower (1945) and the further notes
concerning the same tortoise by Lambert (1982). The maximum weight
attained by this tortoise was 4.366 kg. Boulenger (1902) earlier
recorded a specimen of Testudo (graeca) ibera PALLAS 1814 from Romania
weighing 3.629 kg. The largest recorded size for T. hermanni boettgeri
MOJSISOVICS 1889 is by comparison 264mm and 3.420 kg (Highfield,
1988). All of these measurements are exceeded by the tortoise reported
here.
Description
The dimensions of the specimen, which is a female, are as follows;
Straight line carapace length = 292mm
Length of carapace over curve = 355mm
Maximum carapace height = 126mm
Maximum width at posterior marginals = 215mm
Median transverse carapace width = 209mm
Weight = 4.550 kg
The carapace is broad, flattish and elongate with markedly flared and
serrated posterior marginals. The frontal vertebral scute is round, not
square. There are two large white inturned conical spurs on each thigh
measuring some 10mm long. The carapace has a golden-yellow ground
colour with radiating brown-black markings. There is a complete absence
of anterior borders or central dots on the vertebral scutes and an
absence of anterior borders to the costal scutes. The plastron has an
irregular series of radiating black markings.
This description is inconsistent with the holotype of Testudo graeca
LINNAEUS 1758 but entirely consistent with the type of Testudo whitei
BENNETT 1836 (Highfield & Martin, 1989). This latter species
invariably reaches a much greater adult size than that ever attained by
specimens conforming to the holotype of Testudo graeca L. 1758. A side
by side comparative view of the two species is provided by plate 1
where the differences of morphology and carapace marking between the
two species are immediately obvious.
We are fortunate that for both animals depicted we have a considerable
amount of historical data. Full details of growth over the period
covered by annual weight and length records will be published later.
The large T. whitei was obtained by its previous owner 18 years ago
when it measured approximately 160mm (no weight recorded). The T.
graeca was purchased by another owner in 1972 when it weighed 300g.
Over the subsequent 17 years the T. graeca increased in weight to its
present maximum of 535g. The straight-line carapace length of this
specimen is now 133mm, transverse median width 96mm, maximum width of
posterior marginals 96mm and carapace height is 73mm.
Another Algerian T. whitei was purchased by the same owner in 1968 when
it measured only 120mm and had an estimated weight of 275g. Its
dimensions as at September 1989 were; straight line carapace length
238mm, transverse median width 162mm, maximum width of posterior
marginals 162mm and carapace height 116mm. Weight was recorded at 2.580
kg.
A graph showing the relative growth of the two above mentioned
specimens compared to a similar 18 year period of growth for Flowers
specimen 'Panhard' is given in fig.1 The growth of the T. graeca is
relatively slow suggesting that this was an young adult specimen at the
time it was obtained, yet the growth patterns for 'Panhard' and our
specimen are almost identical. A typical adult male specimen of T.
graeca L. 1758 measures 145mm and weighs approximately 675g (Highfield
& Martin, 1989). These figures closely match those recorded in Morocco
by Lambert (1982) who also notes that the largest specimens of T.
graeca L. encountered in the wild measured 151mm for males and 198mm
for females. The largest male T. graeca L. ever seen by the present
author measured 188mm. This animal had been in continuous captivity
for 68 years and probably represents the maximum attainable by the
species. These figures should be compared to a typical 215mm and 1.750
kg for male T. whitei and a typical 270mm and 2. 875 kg for a female
of the species. This difference in size is even perceptible in
hatchlings of the two species, T. graeca hatchlings rarely measuring
more than 27mm long and typically weighing 8g compared to T. whitei
which typically measure 33mm long and weigh 12-14g.
The age of our very large specimen is estimated at less than 35 years.
There are clear signs that growth is still continuing quite rapidly.
Fortunately, this specimen has not been subjected to an unnatural or
damaging diet (Highfield, 1989) and has no dietary induced skeletal
abnormalities. There is some damage to the left-hand side of the
carapace consistent with the animal having survived exposure to a fire
in the wild as a juvenile. Development would appear to be perfectly
normal which raises the question of what the true maximum potential
adult dimensions of this species may actually be. Certainly T. whitei
are generally the largest known members of the genus Testudo, often
exceeding even T. marginata in body mass (with which they were often
confused in many 19th century accounts). They are certainly the
largest of north African land tortoises invariably surpassing the
Linnaean T. graeca in length, width and weight by a factor of several
fold.
The conclusions of Flower (1945) who maintained that north African
tortoises can continue growing for 40 years and that "the largest known
individuals...may not be more than 35 years old" are entirely supported
by our present findings.
REFERENCES
- Boulenger, G. A. (1902) Record Tortoise. The Field. 99:141.
- Flower, S. S. (1945) Persistent growth in the Tortoise, Testudo graeca,
for Thirty-nine years with other Notes concerning that Species. Proc.
Zool. Soc. Lond. 114:451-455.
- Highfield, A. C. (1988) New size record for T. hermanni?. The
Rephiberary 132;5-6.
- Highfield, A. C. (1989) Notes on dietary constituents for herbivorous
terrestrial chelonia and their effects on growth and development.
ASRA
Journal (3):3 7-20.
- Highfield, A. C. & Martin, J. (1989) Testudo whitei BENNETT 1836; New
light on an old carapace - Gilbert White's Selborne tortoise
re-discovered.
Journal of Chelonian Herpetology (1):1 13-22.
- Lambert, M. R. K. (1982) Studies on the growth, structure and
abundance of the Mediterranean spur-thighed tortoise, Testudo graeca in
field populations. J. Zool. Soc. London, 196:165-189.
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