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Posted by Scott Eipper on May 06, 2002 at 06:15:32:
In Reply to: Re: Cannia australis posted by WW on May 02, 2002 at 03:23:20:
I can see your point of view, Taking the conservative and at the moment generally accepted view.
Pseudechis I personally believe should be used for P. porphyriacus (which in itself, has a number of separate populations). It being viviparous and the rest of the genus being oviparous is a fair start in different snakes, as the internal reproductive system in the female snakes I would think would be some what different.
Also in many ways the snakes themselves are different. P. porphyriacus is generally a riparian species while the others are more generalistic. It is definatly true however that Mulgas and Spotted Blacks are found in Wet areas (Mulgas around Fogg Dam (N.T), and Spotted in and around the Maquarie Marshes and Gundy (N.S.W)).
Collett's, Mulgas tend to be larger in size than most Red Bellys...biggest P. porphyriacus I have personally seen was just over 6 foot (I know of a specimen near 7 ft), but the biggest Mulga I have handled was over 9.5 feet and I have a Collett pushing 7'1.
Frogs for memory are more prevalant in P. porphyriacus' diet, than the other species, certainly skin worms are more common in P. porphyriacus than in the rest of the species and these are linked fairly strongly to most other Frog feeders (Eg Copperheads Austrelaps and Tigers Notechis).
Again from memory (my files are in disarray) but Mengen's 86 paper clearly show P. porhyriacus to be of a different lienage within Pseudechis.
In Greer's Biology and Evolution of Australian Snakes (1997) State that
" The values (Immunological distances)for these three species of Pseudechis, P. australis, P. butleri and P. colletti ranged from 13 to 22 whereas the other species ranged from 27 to 51.Although there are no clear features that allow Pseudecis to be recognized cladistically, it is retained here as a matter of conveince and comfort. However it should be remembered that because the group may not be a natural entity any work or dicussion predicated on its being should be tempered with caution."
I am personally of the view that P. australis, P. butleri, P. colletti and P. papuanus are of one genus (Cannia)and that P. porphyriacus retains its the previous Generic term Pseudechis.
P. guttatus is also somewhat of a problem, but I am of the belief that it is also Cannia, due to its distinctive staining section of Chromosome 5 and is very closely allied to P. colletti because of this feature.
P. guttatus and P. colletti have cross bred in captivity and I have recorded them as fighting (Male combat) with 2 males (One a Collett and one a Spotted).
I just felt that I might clarify why I have came to my conclusions.
Hope this was helpful,