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RE: Basal Elapids and Viperids Must Be F

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Posted by: CKing at Mon Apr 10 03:51:36 2006  [ Report Abuse ] [ Email Message ] [ Show All Posts by CKing ]  

>>One thing that suprises me about Evolutionists is that most of them even the Cladists stick to fixed "Creationist" ideas about Taxonomy. As a forinstance an Elapid must be a snake with short relatively immobile front fangs (the "protoroglyphous" condition). A viperid must be a snake with long front fangs on a swinging maxilary bone (the "solenoglyphous" condition).

You seem to object to the use of characters to define taxa. It just so happened that I have recently read a paper that criticizes the alternative approach:

While many of us are in search of meaningful morphological
characters to delineate lineages, De Queiroz and Gauthier (1990, p. 310) note that “The use of phylogenetic definitions liberates biological taxonomy from a 2,000-year-old tradition of basing the definitions of taxon names on characters.” These definitions
may be liberating to some, but their implementation is difficult, and they are devoid of information or utility, and are exceptionally misleading.--Feduccia et al. (2005 J. Morphol. 266:158)

>>However evolutionarily speaking these merely represent the current end condition of the evolutionary process and not its beginning. Therefore I dont think we should be looking for basal elapids and vipers amongst snakes that have already reached the classic viper and elapid conditions. Rather the place to find basal vipers and elapids or transitional forms if you will is amongst the vast assemblage of Rear Fanged snakes and venom glanded aglyphis "colubrids".
>>Because the earliest advanced vipers like the Fea's viper and African night adders have all of the head shields and other features of a "colubrid" it will be rather hard to find the basal vipers amongst the rear fanged snakes by any other means than streight DNA testing. However it will probably be easier to find the basal elapids because advanced elapids have other visible features bsides fangs and venom that tell them apart from "colubrids" that would probably carry "backwards" to the rear fanged or aglyphous basal forms. Probably the most prominant one of these is the lack of the loreal scale between the preocular and inner nasal scales at the sides of the head. Another common elapid tendency that has nothing to do with fangs or venom is to have both undivided and devided subcaudal (bottom of the tail) scales although this is less common than the lack of the loreal head scale. Therefore we would know to find the basal elapids amongst rear fanged or even aglyphous "colubrids" with venom glands but no loreal scale.
>>From this point we can probably check the venoms of these snakes
>>for elapid nurotoxins. (Many of the suspected basal elapids in the current "colubrid roster" using a true evolutionary standard (the rear fanged or aglyphous venomous snakes as the base) like American crowned, earth and black headed snakes and African centepede eaters tackle highly venomous albeit invertibrate game themselves like the afore mentioned centepedes as well as scorpions and may well have developed the elapid nurotoxins to in effect be able to "shoot first" against highly venomous for a small snake invertabrate prey.)
>>If elapid nurotoxins are found in rear fanged and aglyphous venomous snakes lacking loreal scales like American Crowned, Earth and Black headed snakes and African Centepede eaters a DNA test can finally be used to cinch the fact that we have found the true basal elapids and first bone fide evolutionary transitional forms in nature.
>>In otherwords to find the basal or so called "transitional" form
>>for a type of animal we should not be looking to its classic advanced condition no matter how primitive we go within it. In otherwords if the African Homoroselaps is an elapid it is not the true basal form but only the beginnings of the classic elapid evolutionary condition. Rather we have to look to the least advanced form possible and for vipers and elapids that is to be found somewhare amongst the aglyphous snakes with venom glands and the rear fanged snakes.

The search for transitional forms among living taxa is often difficult and not often fruitful. Often living transitional forms may have evolved their own autapomorphs and are therefore very different from their ancestors. Quite often the transitional forms may have become extinct. This is of course well known in most cases. Transitional forms between fishes and land vertebrates are long gone, for example. Transitional forms between reptiles and birds (or glorified reptiles) are also missing among extant taxa, as are the transitional forms between lizards and snakes. One must therefore be careful about identifying any particular living species as a transitional form.


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<< Previous Message:  Basal Elapids and Viperids Must Be Found Amongst the Rear Fanged and Aglyphous Venomous Snakes - CoralSnake, Wed Jun 8 04:56:10 2005