Gorgonops
Name: Gorgonops
(Gorgon face).
Phonetic: Gore-gon-ops.
Named By: Richard Owen - 1876.
Synonyms: Chiwetasaurus dixeyi,
Gorgonognathus longifrons, Gorgonops longifrons, Leptotrachelus
eupachygnathus, Leptotracheliscops eupachygnathus, Pachyrhinos
kaiseri, Scymnognathus whaitsi, Scymnosuchus whaitsi.
Classification: Chordata, Synapsida,
Therapsida, Gorgonopsia, Gorgonopsidae.
Species: G. torvus (type),
G. longifrons, G. whaitsi.
Possible further species include G. dixeyi, G.
kaiseri and G. eupachygnathus (see
main text for more detail).
Diet: Carnivore.
Size: Depending upon the species, between 1.2
and 2 meters long. Skull between 20 to 35 centimetres.
Known locations: South Africa - Karoo Basin and
Malawi.
Time period: Wuchiapingian to Changhsingian of the
Permian.
Fossil representation: Multiple individuals,
usually from partial to complete skull material, but post cranial
remains are also known.
Gorgonops
is the type genus of the Gorgonopsia,
though paradoxically it is not
the best represented by fossil remains. Gorgonops
was a therapsid,
a kind of creature more derived than a therapsid, yet still much
more primitive than mammals which would eventually evolve from them.
Because of the mammal lineage there has been several suggestions that
Gorgonops and relative genera may have had warm
blooded metabolisms and
hence a possible covering of hair. Unfortunately these ideas remain
speculation as so far no proof to prove, or indeed disprove, the
warm-blooded theory exists. What is known however is that our
definitions of cold and warm-blooded animals have changed somewhat
thanks to new and more precise study techniques, so it could also be
possible that Gorgonops might have had something
between a ‘cold’
and a ‘warm’ blooded metabolism, yet again, this is only
speculation at this point.
Relative
to body size, Gorgonops had a deep skull which
had a triangular
profile when viewed from above. Perhaps the most distinctive features
were two enlarged canine teeth that were so big they almost protruded
beyond the lower jaw. To help protect these teeth, the lower jaws
grew in such a shape so that the anterior (front) portion was
thicker than the posterior (rear) portion. This form would have
protected the enlarged canine teeth from accidental damage, and was
similar in bone function to the flanges of bone of some false
sabre-toothed cats (nimravids
and barbourofelids) and sabre-toothed
cats (machairodonts)
that would live over two-hundred million years
later.
Gorgonops
would have been one of the key predators across southern Africa during
the Permian, and here we look at the teeth again. Because the
canines were so large, they would have had little trouble in
penetrating the tough hides of some of herbivores of the time,
particularly pareiasaurs such as Bradysaurus.
Aside from the teeth,
one of the key predatory advantages that Gorgonops
had over prey were
that the legs supported the body from below rather than sprawling out
to the sides like in most prey animals of the time. Aside from
allowing for more energy efficient locomotion, the legs would have
also allowed for a much faster pace. What animals were hunted however
would depend upon the size of the individual Gorgonops,
and there
were some quite broad differences between species in terms of size.
There
are three species of Gorgonops that are widely
recognised amongst the
majority of researchers, and these are the type species G.
torvus
as well as G. longifrons and G.
whaitsi. The species are usually
differentiated by skull features such as G. torvus
having a
proportionately longer snout, the skull of G. whaitsi
being wider
at the rear and G. longifrons having a longer
snout and larger
orbital fenestra (opening in the skull for the eye) than G.
whaitsi. Aside from allowing for identification of
species, the
differences might denote slight variations towards differing hunting
between species, with some specialising in different prey and/or
modes of prey capture.
There
are three other species at the time of writing that are not always
recognised for different reasons. G. kaiseri is
known from a single
incomplete skull which has a rear narrower than other species and a
slightly higher snout, but the lack of overall preservation means
that it cannot be confidently assigned to Gorgonops
to quell all
doubt. Likewise, G. dixeyi is named from a partial skull that has
been flattened during its fossilisation. Finally G.
eupachygnathus
was named from a partial and flattened skull of what may have actually
been a juvenile of another already named species, particularly G.
torvus, or G. whaitsi.
Unfortunately, since no clear
determination can be made to either species, so G.
eupachygnathus
continues to be listed even though it is probably a synonym to one of
the other two species.
Further reading
- Investigations in South
African fossil reptiles and amphibia. 7. On some new gorgonopsians. -
Annals of the South African Museum 12:82-90. - S. H. Haughton - 1915.
- Therapsids from the Permian Chiweta Beds and the age of the Karoo
Supergroup in Malawi - L. L. Jacobs, D. A. Winkler, K.
D. Newman, E. M. Gomani, & A. Deino - 2005.
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