Agkistrodon taylori is a species of venomous snake, a pitviper (Crotalinae) found only in northeastern Mexico. The standardized names are Taylor's cantil (English)Liner, E. A. and G. Casas-Andreu. 2008. Standard Spanish, English and scientific names of the amphibians and reptiles of Mexico. Society for the Study Amphibians and Reptiles. Herpetological Circular 38: i-iv, 1-162. (pages 95-96)Gloyd, Howard K. and Conant, Roger. 1990. Snakes of the Agkistrodon Complex, A Monographic Review. Contributions to Herpetology, Number 6. Society for the Study Amphibians and Reptiles. vi, 614 pp. and Metapil (Spanish), although it is sometimes called the ornate cantilPorras, Louis W., Larry D. Wilson, Gordon W. Schuett, and Randall S. Reiserer.2013. A taxonomic reevaluation and conservation assessment of the common cantil, Agkistrodon bilineatus (Squamata: Viperidae): a race against time. Amphibian & Reptile Conservation, 7 (1):48-73. as well as several other colloquial names. It was named in honor of American herpetologist Edward Harrison Taylor.Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins University Press. xiii + 296 pp. . (Agkistrodon bilineatus taylori, p. 261).
It is a stout, medium sized snake, averaging 64–90 cm. in length. Taylor's cantils have prominent light and dark stripes on the head, with a pattern of black and gray-brown bands on the body, accented with white, yellow, and orange. They are sexually dimorphic, with males being significantly darker than females. Some older individuals, particularly males, may grow darker, nearly black with age. It is a viviparous species, with typical litters of 3 to 10 live young. Taylor's cantils are uncommon to rare snakes in the wild and listed as a threatened species in Mexico. It occurs in a variety of habitats on the Gulf Coastal Plain and lower foothills of the Sierra Madre Oriental, including thorn scrub, tropical deciduous forest, and grasslands, sometimes said to prefer ecotones between scrubland and forest in the vicinity of rocky limestone outcroppings. Although not overtly aggressive, it is known to be very defensive with a volatile temper and may be quick to strike when approached, threatened, or restrained. No case reports of human envenomations have been published. Its venom is believed to be similar to its close relative, the cantil Agkistrodon bilineatus, and potentially fatal.Ernst, C. H. and E. M. Ernst. 2011. Venomous Reptile of the United States, Canada, and Northern Mexico, Vol 1: Heloderma, Micruroides, Micrurus, Pelamis, Agkistrodon, Sistrurus. The Johns Hopkins University Press. Baltimore, Maryland. xviii, 352 pp. Heimes, P. 2016. Herpetofauna Mexicana Vol. I: Snakes of Mexico. Edition Chimaira, Frankfurt/ECO Publishing, Rodeo, New Mexico. 572 pp.
Etymology The original description states that the specific, or trivial name, was "Named for Dr. Edward H. Taylor in recognition of his many contributions to our knowledge of the Mexican herpetofauna."Burger, W. Leslie and William B. Robertson. 1951. A New Subspecies of the Mexican Moccasin, Agkistrodon bilineatus. The University of Kansas Science Bulletin. University of Kansas Publications, Museum of Natural History. 34(5): 213-218. Indeed, Taylor's extensive publications on Mexico's amphibians and reptiles, culminating with the "Herpetology of Mexico",Smith, H. M. and E. H. Taylor. 1966. Herpetology of Mexico: Annotated Checklist and Keys to the Amphibians and Reptiles. A reprint of Bulletins 187, 194 and 199 of the U. S. National Museum with a list of subsequent taxonomic innovations. Eric Lundberg, Ashton, Maryland. published in collaboration with his student Hobart M. Smith, is the foundation of modern Mexican herpetology. Taylor's work on Mexico alone would have secured him a prominent reputation in the field of herpetology. However, Taylor made equally important contributions to the study of Philippine land mammals, the herpetofauna of the Philippines, the herpetofauna of the south-central United States, Eumeces (skinks of the world at that time), the herpetofauna of Costa Rica, the herpetofauna of Thailand, and caecilians of the world.Taylor, Edward H., A. B. Leonard, H. M. Smith, and G. R. Pisani. 1975. Edward H. Taylor: Recollections of an Herpetologist. Monograph of the Museum of Natural History, University of Kansas. 4: 1-159. Adler, K. 1989. Contributions to the History of Herpetology, Vol. I. Society for the Study of Amphibians and Reptiles. 202 pp. .
The common name cantil is believed to have its origins in the language of an indigenous people of Chiapas, Mexico, the Tzeltal. The Tzeltal word "kantiil" was given to the snake meaning yellow lips (kan = yellow, tiil = lips). The name is thought to have first entered herpetological literature in the publication of Albert Günther's Reptilia and Batrachia in Biologia Centrali-Americana,Günther, Albert C. L. G. (published serially) 1885-1902. Reptilia and Batrachia. xx, 326 pp. IN F. D. Godman and O. Salvin, (eds). Biologia Centrali-Americana. R. H. Porter and Dulau & Co., London. [facsimile reprint with introductions by H. M. Smith and A. E. Günther. 1987. Society for the Study of Amphibians and Reptiles. athens, Ohio. lxviii, 326 pp. ] and later popularized in the writings of Raymond L. Ditmars.Conant, Roger. 1982. The origin of the name "cantil" for Agkistrodon bilineatus. Herpetological Review 13(4): 118. However, later authors questioned that attribution, as the Tzeltal are highland people and unlikely to have had significant contact with the species. Alternatively, "can" or "canti" meaning "viper", and "nil" meaning snake, are used in a more widespread Mayan language that might be the origin of the name cantil.
Taxonomy and phylogenetics
Recent molecular studiesParkinson, C. L., K. R. Zamudio, and H. W. Greene. 2000. Phylogeography of the pitviper clade Agkistrodon: historical ecology, species status and conservation of cantils. Molecular Ecology 9: 411-420.Parkinson, C. L., J. A. Campbell, and P. T. Chippindale. 2002. Multigene phylogenetic analysis of pitvipers, with comments on the biogeography. pp. 93-110. IN Schuett, G. W., M. Höggren, M. E. Douglas, and H. W. Greene ED. Biology of the Vipers. Eagle Mountain Publishing, L.C. Eagle Mountain, Utah. xii, 580 pp. Castro, T. A. and C. L. Parkinson, 2006. Bayesian mixed models and the phylogeny of pitvipers (Viperidae: Serpentes). Molecular Phylogenetics and Evolution 39: 91-110. have produced strong evidence indicating that pitvipers made a single invasion into the New World, presumably via the Bering Land Bridge in the early Tertiary or late Cretaceous, with a subsequent divergence resulting in a northern temperate group (including Agkistrodon, Crotalus, and Sistrurus) and a Neotropical group. Of the Old World pitvipers, Gloydius appears to be phylogenetically close to the New World pitvipers, but the exact relationship between Old World and New World pit vipers is not fully resolved at this time. The molecular evidence indicates the genus Agkistrodon is a monophyletic group, meaning they all share a common ancestor, and suggest that copperheads, (Agkistrodon contortrix) are the most basal (ancestral) living lineage of the genus, with the cottonmouths (Agkistrodon piscivorus) basal to Taylor's cantil (A. taylori), and A. taylori basal to the remaining cantils of Latin America.
The taxonomic history of Taylor's cantil (Agkistrodon taylori) is relatively simple and straight forward compared to many species.
Agkistrodon bilineatus, In part: Edward H. Taylor collected what was to become the holotype of A. taylori, on June 9, 1938, "crawling on the highway pavement about dark" very near the Tamaulipas, Nuevo Leon state line. Using the name Agkistrodon bilineatus, he published a detailed description of the specimen including color, pattern and scale data, noting some differences compared with the head of a specimen from Michoacán.Taylor, Edward H. 1940 (1939). Some Mexican Serpents. The University of Kansas Science Bulletin. University of Kansas Publications, Museum of Natural History.26(14): 445-487. Agkistrodon bilineatus taylori, Nomen nudum: Taylor and Hobart Smith published the name in a checklist of type localities of Mexican herpetofauna.Smith, Hobart M. and Edward H. Taylor, 1950. Type Localities of Mexican Reptiles and Amphibians. University of Kansas Science Bulletin, 33: 313-380. However, the list was published before the subspecies formal description, thus making the name a nomen nudum, a technical term for a scientific name that is invalid because it is not associated with any published description, definition, or holotype of a taxon.Lillywhite, Harvey B. 2008. Dictionary of Herpetology. Krieger Publishing Co. Malabar, Florida. viii, 376 pp. ISBN 1-57524-023-8 Taylor and Smith knew of the impending description, published about 19 months after their checklist. The authors acknowledged "Our attention was first called to this interesting situation by Dr. Edward H. Taylor.....to whom we are indebted for permission to study it", and Hobart Smith for his "advice and assistance".Agkistrodon bilineatus taylori: Formally described as subspecies in 1951, the holotype is in the collection of the University of Illinois Museum of Natural History (UIMNH 10002). It has been transferred between collections a number of times and identified as: EHT-HMS 5514 (Edward H. Taylor and Hobart M. Smith collection); EHT 5514 (Edward H. Taylor collection); and INHS 5514 (Illinois Natural History Survey).Uetz, P., Freed, P, Aguilar, R. & Hošek, J. (eds.) (2021) The Reptile Database, http://www.reptile-database.org, Agkistrodon taylori Burger & Robertson, 1951 (accessed 20 July 2021) It is a young male, 383 mm. snout-vent length, and 82 mm. tail length (465 mm. total length). A paratype was also designated, Chicago Natural History Museum 28794, an adult male from "no more than a few mile from the type locality". For the remainder of the 20th century the taxonomic status remained unchanged. Agkistrodon taylori'': Taylor's cantil was elevated to species status in research published in 2000, based on a combination of mitochondrial DNA sequences, its geographic isolation (allopatry), unique aspects of head and body colour pattern, and sexual dichromatism (sexual dimorphism) in adults. Subsequent taxonomic reviews and species accounts supported the recognition of A. taylori as a specie.
Description