a b c d e f g Greene, Harry W. (2004) Snakes – The Evolution of Mystery in Nature. University of California Press, pp. 22–23 ISBN 0520224876. Christensen, Christian Bech; Christensen-Dalsgaard, Jakob; Brandt, Christian; Madsen, Peter Teglberg (2012-01-15). "Hearing with an atympanic ear: Good vibration and poor sound-pressure detection in the royal python, Python regius". Journal of Experimental Biology. 215 (2): 331–342. doi: 10.1242/jeb.062539. ISSN 1477-9145. PMID 22189777. S2CID 11909208. The origin of the reptiles lies about 310–320 million years ago, in the steaming swamps of the late Carboniferous period, when the first reptiles evolved from advanced reptiliomorphs. [33] [ failed verification]

Identification of cephalic scales is most conveniently begun with reference to the nostril, which is easily identified on a snake. There are two scales enclosing the nostril which are called the nasals. In colubrids, the nostril lies between the nasals, while in vipers it lies in the centre of a single nasal scale. [22] The outer nasal (near the snout) is called the prenasal while the inner nasal (near the eye) is called the postnasal. Along the top of the snout connecting the nasals on both sides of the head are scales called internasals. Between the two prenasals is a scale at the tip of the snout called the rostral scale. [22]Mallow D., Ludwig D., Nilson G. (2003). True Vipers: Natural History and Toxinology of Old World Vipers. Krieger Publishing Company, Malabar, Florida. 359 pp. ISBN 0-89464-877-2. Species in Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) – accessed on 14 August 2006 The dinosaurs featured in books, films, television programs, artwork, and other media have been used for both education and entertainment. The depictions range from the realistic, as in the television documentaries of the 1990s and first decade of the 21st century, to the fantastic, as in the monster movies of the 1950s and 1960s. [148] [150] [151] While scales are an integral part of reptile taxonomy, the terminology is not entirely consistent. For instance, the scales between the nostrils are sometimes called supranasals [3] and sometimes internasals. Diapsida – two fenestrae – most reptiles, including lizards, snakes, crocodilians, dinosaurs and pterosaurs

Snakeskin, with its highly periodic cross-hatch or grid patterns, appeals to people's aesthetics and have been used to manufacture many leather articles including fashionable accessories. [34] The use of snakeskin has however endangered snake populations [35] and resulted in international restrictions in trade of certain snake species and populations in the form of CITES provisions. [36] Animal lovers in many countries now promote the use of artificial snakeskin instead, which are easily produced from embossed leather, patterned fabric, plastics and other materials. [34]Divers, Stephen J.; Mader, Douglas R. (2005). Reptile Medicine and Surgery. Amsterdam: Elsevier Health Sciences. pp.481, 597. ISBN 9781416064770. Snake scales are of different shapes and sizes. Snake scales may be granular, have a smooth surface or have a longitudinal ridge or keel on it. Often, snake scales have pits, tubercles and other fine structures which may be visible to the naked eye or under a microscope. Snake scales may be modified to form fringes, as in the case of the eyelash bush viper, Atheris ceratophora, or rattles as in the case of the rattlesnakes of North America. [8]

Lyson, Tyler R.; Schachner, Emma R.; Botha-Brink, Jennifer; Scheyer, Torsten M.; Lambertz, Markus; Bever, G.S.; Rubidge, Bruce S.; de Queiroz, Kevin (2014). "Origin of the unique ventilatory apparatus of turtles" (PDF). Nature Communications. 5 (5211): 5211. Bibcode: 2014NatCo...5.5211L. doi: 10.1038/ncomms6211. PMID 25376734. Spotila, J.R.; O'Connor, M.P.; Dodson, P.; Paladino, F.V. (1991). "Hot and cold running dinosaurs: body size, metabolism and migration". Modern Geology. 16: 203–227.At birth, a rattlesnake hatchling has only a small button or 'primordial rattle' which is firmly attached to the tip of the tail. [13] The first segment is added when the hatchling sheds its skin for the first time. [14] A new section is added each time the skin is shed until a rattle is formed. The rattle grows as the snake ages but segments are also prone to breaking off and hence the length of a rattle is not a reliable indicator of the age of a snake. [15] Colour [ edit ] YOUNG, BRUCE A. (1997). "A Review of Sound Production and Hearing in Snakes, with a Discussion of Intraspecific Acoustic Communication in Snakes". Journal of the Pennsylvania Academy of Science. 71 (1): 39–46. ISSN 1044-6753. JSTOR 44149431.

The synapsid/sauropsid division supplemented another approach, one that split the reptiles into four subclasses based on the number and position of temporal fenestrae, openings in the sides of the skull behind the eyes. This classification was initiated by Henry Fairfield Osborn and elaborated and made popular by Romer's classic Vertebrate Paleontology. [16] [17] Those four subclasses were: Huey, R.B. & Bennett, A.F. (1987):Phylogenetic studies of coadaptation: Preferred temperatures versus optimal performance temperatures of lizards. Evolution No. 4, vol 5: pp. 1098–1115 PDF Cheng Chang; Ping Wu; Ruth E. Baker; Philip K. Maini; Lorenzo Alibardi; Cheng-Ming Chuong (21 May 2010). "Reptile scale paradigm: Evo-Devo, pattern formation and regeneration". International Journal of Developmental Biology. 53 (5–6): 813–826. doi: 10.1387/ijdb.072556cc. PMC 2874329. PMID 19557687. Tsuji, Linda A. & Müller, Johannes (2009). "Assembling the history of the Parareptilia: phylogeny, diversification, and a new definition of the clade". Fossil Record. 12 (1): 71–81. Bibcode: 2009FossR..12...71T. doi: 10.1002/mmng.200800011.Karasov, W.H. (1986). "Nutrient requirement and the design and function of guts Earliest Evidence For Reptiles". Sflorg.com. 2007-10-17. Archived from the original on July 16, 2011 . Retrieved March 16, 2010. While modern reptiles are predominantly carnivorous, during the early history of reptiles several groups produced some herbivorous megafauna: in the Paleozoic, the pareiasaurs; and in the Mesozoic several lines of dinosaurs. [43] Today, turtles are the only predominantly herbivorous reptile group, but several lines of agamas and iguanas have evolved to live wholly or partly on plants. [106]