Agkistrodon bilineatus and A. taylori - Cantils
Agkistrodon taylori
Agkistrodon bilineatus and A. taylori - Cantils
Agkistrodon taylori
Parkinson et al. (2000) used mitochondrial DNA to analyse the phylogeny of the genus Agkistrodon, and in particular the affinities of the different subspecies of A. bilineatus. The northeastern subspecies, A.b. taylori, turned out to represent a highly distinct lineage. In addition to genetic differences, consistent differences in colour pattern and the presence of strong sexual dimorphism in pattern led Parkinson et al. to regard this form as a distinct species, Agkistrodon taylori.
Bothriechis thalassinus
Campbell & Smith (2000) described a new species of palm pitviper from the Atlantic versant of Guatemala and Honduras: Bothriechis thalassinus. The new species is most similar to Bothriechis bicolor. Its distribution extends along a series of mountains along the Guatemala-Honduras border, where it has been recorded at altitudes of 885-1730 m. An image can be found here.
Crotalus ruber / exsul - Red diamondback
rattlesnake, Cedros Island rattlesnake
The correct name of the red diamondback has been a confused issue since Grismer et al. (1994) and Murphy et al. (1995) first noted the conspecificity of the widespread red diamondback rattlesnake, then widely known as C. ruber Cope, 1892, and the Cedros Island rattlesnake, then widely known as C. exsul Garman, 1884. Since C. exsul is the older of the two names, the rules of the International Code of Zoological Nomenclature give this name precedence over the name C. ruber. However, since the name C. ruber is much more widely used than the name C. exsul, following a strict interpretation of the Code would result in considerable instability in the long-established name of a well known species. Smith et al. (1998) therefore petitioned the International Commission of Zoological Nomenclature to give the name C. ruber precedence over the name C. exsul. This was accepted by the Commission in a ruling published in 2000 (Anon., 2000).
The upshot of this is that the red diamondback rattlesnake of southern California and Baja California should continue to be referred to as C. ruber, as it was before the present confusion erupted. The same applies to the Cedros Island rattlesnake, unless new evidence suggests that it may deserve subspecific or specific status, in which case the name exsul remains available.
Crotalus viridis complex - Western
Rattlesnake
Crotalus
viridis viridis Crotalus viridis oreganus
Pook et al. (2000) used mtDNA to analyse the phylogeography of Crotalus viridis. Their study identified three highly distinct clades, which may well deserve the status of separate species: an eastern clade, comprising the subspecies viridis and nuntius, an Arizona clade consisting of cerberus, and a western clade consisting of the remaining subspecies. The status of several conventional subspecies is questionable. The haplotypes of C.v. nuntius are rooted among C.v. viridis haplotypes, and the C.v. caliginis haplotypes are rooted among C.v. helleri haplotypes. See also later study in Crotalinae 2001 page.
Triceratolepidophis sieversorum
Ziegler et al. (2000) describe a new genus and species of pitviper from Vietnam: Triceratolepidophis sieversorum. The only known specimen of the new species, a male, measures approximately 125.5 cm, making this a rather large pitviper. In pattern, it looks similar to Protobothrops mucrosquamatus. However, it has fragmented and raised supraoculars, and the keels of its dorsal scales consist of three consecutive humps. The only known specimen was found preserved in a bottle of rice liquor in the house of a local medicine man. It had been caught in a local chicken coop. For more details and a photo, click here (linked .pdf document in German)