Rattlesnake classification has just had a major shake up.
In fact it’s been the first such shake up in nearly a century!
Recent studies of the DNA of the group showed various lineages to be far more ancient than earlier thought.
However there was confusion as to which groups of snakes had actually been named at the genus level in the past.
It turned out that just 5 of 16 obvious subgroups had been named.
In a paper published this week, Australian zoologist Raymond Hoser reclassified the group assigning names to the other 9 groups and working out which species were closest to which.
Taking a conservative stand, all groups had diverged at least 10 million years from a common ancestor to warrant being named at the genus or subgenus level.
By contrast for great apes (including humans) anything with a divergence of more than 4 million years is placed in a separate genus.
Recent papers have placed the rattlesnakes origins back to nearly 30 million years.
Formerly all fifty-odd species were lumped into a single genus “Crotalus”, with some people placing three small species in a second genus Sistrurus.
Hoser’s paper, while seemingly radical in terms of the number of new genera named, has been described by himself as “merely stating the obvious”.
In 2004, Hoser controversially placed the world’s longest snake, the Reticulated Python, in it’s own genus, Broghammerus, taking it away from the better known genus “Python”. Later DNA studies, the results of which were published in 2008, upheld the Hoser position, showing that they had diverged from their nearest python relatives about 30 million years ago.
“Broghammerus reticulatus” is now generally accepted.
Hoser said this week, “No doubt there will be short term resistance from some quarters to use the new generic names, but, the concept of fifty odd rattlesnakes, many of radically different forms and ancient lineages, being in the same genus, is simply not tenable”.
The paper is:
“A reclassification of the Rattlesnakes; species formerly exclusively referred to the Genera Crotalus and Sistrurus.”
Originally published in hard copy in Australasian Journal of Herpetology, Issue 6 (9 March 2009):1-21.
The web link is at: http://www.smuggled.com/AJHIP1.htm
For further information:
Raymond Hoser – Australia +61 3 9812 3322
+61 412 777 211
SUMMARY OF KNOWN LIVING RATTLESNAKE (SPECIES) TAXA
AND THEIR NEW GENERIC AND SUBGENERIC PLACEMENTS
(SEE HOSER 2009)
GENUS SISTRURUS GARMAN 1883
Type species: Crotalinus catenatus Rafinesque 1918.
S. miliarius (Linne 1766)
GENUS PIERSONUS HOSER 2009
Type Species: Crotalus ravus Cope 1865
P. ravus (Cope 1865)
GENUS CROTALUS LINNE 1758
Type Species: Crotalus horridus Linne 1758
SUBGENUS SAYERSUS HOSER 2009
Type species: Crotalinus viridis Rafinesque 1818
C. scutulatus (Kennicott 1861)
C. oreganus Holbrook 1840
C. abyssus Klauber 1930
C. cerberus Klauber 1949
C. concolor Klauber 1936
C. helleri Meek 1905
C. lutosus Klauber 1930
GENUS AECHMOPHRYS COUES 1875
Type species: Crotalus cerastes Hallowell 1854
A. polystictus (Cope 1865)
SUBGENUS COTTONUS HOSER 2009
Type species: Crotalus intermedius Troschel 1865
A. pricei (Van Denburgh 1895)
A. tancitarensis (Alvarado-Diaz and Campbell 2004
A. transversus (Taylor 1940)
A. willardi (Meek 1905)
GENUS CAUDISONA LAURENTI 1768
Type species: Crotalus durissus Linne 1758
C. culminatus (Klauber 1952)
C. simus (Latreille 1801)
C. tzabcan (Klauber 1952)
C. vegrandis (Klauber 1941)
C. unicolour (van Lidth de Jeude 1887)
SUBGENUS PILLOTUS HOSER 2009
Type species: Caudisona enyo Cope 1861
SUBGENUS SMYTHUS HOSER 2009
Type species: Crotalus molossus (Baird and Girard 1853)
C. basiliscus Cope 1864
C. estebanensis (Klauber 1949)
C. totonacus (Gloyd and Kauffeld 1940)
GENUS UROPSOPHUS WAGLER 1830
Type species: Uropsophus triseriatus Wagler 1830
U. aquilus (Klauber 1952)
U. lepidus (Kennicott 1861)
U. pusillus (Klauber 1908)
CUMMINGEA HOSER 2009
Type species: Crotalus stejnegeri Dunn 1919
C. ericsmithi (Campbell and Flores-Villella 2008)
C. lannomi (Tanner 1966)
HOSEREA HOSER 2009
Type species: Crotalus atrox Baird and Girard 1853
H. tortugensis (Van Denburgh and Slevin 1921)
EDWARDSUS HOSER 2009
Type species: Crotalus adamanteus Beauvois 1799
MULLINSUS HOSER 2009
Type species: Crotalus ruber Cope 1892
H. exsul (Garman 1883)
H. lorenzoensis (Radcliffe and Maslin 1975)
CRUTCHFIELDUS HOSER 2009
Type species: Crotalus catalinensis Cliff 1954
MATTEOEA HOSER 2009
Type species: Caudisona mitchellii Cope 1861
M. angelensis (Klauber 1963)
M. tigris (Kennicott 1859)