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The
Elaphe obsoleta - complex:
In
2001 Frank T. Burbrink published a revision, based on morphological
characters, as a follow up on earlier DNA examinations made by the
same author in coorporation with others, of the Elaphe obsoleta
- complex (Burbrink et al, 2000).
Examination
of morphological characters of 1006 specimens of Elaphe bairdi,
E. obsoleta obsoleta, E. o. lindheimeri, E. o. spiloides, E. o.
williamsi, E. o. quadrivittata, E. o. rossalleni and E. o.
deckerti are made. Based on the earlier DNA study and
the new morphological results he concludes that the conservation
of these taxonomic units has no value, as it is not possible to
determin which subspecies an individual belongs to with certainty
without knowing the place of origin, because of the variationdegree
of the subspecies.
He
suggest splitting the complex into four separet species, which based
on DNA and morphology should be more alike than the previous subspecies.
The four species we therefore pressumably has to get used to are
as follows:
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Elaphe
alleghaniensis (Holbrook, 1836)
Distributed
in Connecticut, Florida, Georgia, Maryland, New York, North
Carolina, Pennsylvania, South Carolina and Virginia, USA.
The
species contains the previous subspecies Elaphe obsoleta
quadrivittata, E. o. deckerti, E. o. williamsi and
E. o. rossalleni.
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Elaphe
alleghaniensis (quadrivittatus), Florida
(© Chris Raden) |
Elaphe
alleghaniensis (williamsi) (© Steve Garrett) |
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Elaphe
bairdi (Yarrow,
1880)
Distributed
in Texas, USA and Coahuila, Nuevo Léon and Tamaulipas,
Mexico.
This
species has previous been known as Elaphe obsoleta bairdi,
but has for quite some years been treated as its own species.
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Elaphe
obsoleta (Say, 1823)
Distributed
in Arkansas, Kansas, Louisiana, Missouri, Nebraska, Oklahoma
and Texas, USA, with a single doubtfull report from Nuevo
Léon, Mexico.
This
species has previously been known as Elaphe obsoleta obsoleta
and E. o. lindheimeri.
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Juvenile
Elaphe obsoleta, Tennessee
(© Jimmy Johnson) |
Elaphe
obsoleta (lindheimeri) (© Harald Holler) |
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Elaphe
spiloides (Duméril, Bibron & Duméril,
1854)
Distributed
in Alabama, Florida, Illinois, Kentucky, Louisiana,
Michigan, Mississippi, Ohio, Pennsylvania, Tennessee
and Wisconsin, USA.
This
species was known as Elaphe obsoleta spiloides.
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Subadult
Elaphe spiloides
(© squamata.info/Markus Thums) |
Adult
Elaphe spiloides, Kentucky (© Phil Peak)
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Because
of the influence this might couse to the hobbiest keeping these
snakes, we posted a few questions about the validity of the results
on a few international fora. The threats for these postings are
to be seen on the following links:
Kingsnake.com-Taxonomy
Forum (here the question was discussed, with input from the
author of the publication and the herpetologist Wolfgang Wüster
(known from his extensive studies of mainly Asiatic cobras (Naja
sp.)
Kingsnake.com-Rat
Snake Forum (here mainly hobbiest are discussing the question)
Literature:
- Burbrink,
F.T. 2001. Systematics of the Eastern Ratsnake Complex (Elaphe
obsoleta). Herpetol. Monogr., 15: 1-53.
- Burbrink,
F.T., R. Lawson & J.B. Slowinski. 2000. Mitochondrial DNA
phylogeography of the North American rat snake (Elaphe obsoleta):
a critique of the subspecies concept. Evolution, 54: 2107-2114.
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