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237 1 1 Preliminary Report on Salamanders (Lissamphibia; Caudata) from the Late Cretaceous (Late Cenomanian– Late Campanian) of Southern Utah, U.S.A. James D. Gardner, Jeffrey G. Eaton, and Richard L. Cifelli Here we report on salamander fossils (vertebrae and jaws) and taxa identified from 19 microvertebrate localities of late Cenomanian–late Campanian age (an interval of about 25 million years) from the Dakota, Straight Cliffs, Iron Springs, Wahweap, and Kaiparowits formations in southwestern Utah, U.S.A. All three salamander families known from better-sampled upper Campanian–terminal Maastrichtian units elsewhere in the North American Western Interior are present in the Utah sequence: Scapherpetontidae and Batrachosauroididae occur throughout the late Cenomanian –late Campanian interval, whereas Sirenidae are limited to the Santonian–late Campanian. The scapherpetontid record consists of Scapherpeton (?Coniacian–late Campanian ), Lisserpeton (late Campanian), and indeterminate older occurrences, including Lisserpeton-like vertebrae from the ?Coniacian and late Cenomanian, Piceoerpeton-like vertebrae from the ?Coniacian, and vertebrae of a probable new genus from the late Cenomanian. Batrachosauroidids are represented by Opisthotriton (Santonian–late Campanian), Prodesmodon (late Campanian), and a pair of indeterminate genera, one each from the late Turonian and late Cenomanian ; the last occurrence is the oldest unequivocal record for batrachosauroidids in North America. The presence in pre-Santonian localities of scapherpetontid and batrachosauroidid specimens that cannot be assigned to known later Cretaceous and Paleogene genera indicates that both families were already present and diversifying by the early Late Cretaceous. The sirenid record is founded on Santonian–late Campanian atlantes of Habrosaurus; the Santonian occurrences are the oldest North American records for both the family and the genus. A previously unrecognized salamander of uncertain familial affinities (but showing some similarities to sirenids) is documented by distinctive trunk vertebrae and an atlantal centrum from the late Turonian–early or middle Campanian. Other enigmatic vertebrae likely pertaining to additional salamander taxa are reported from the late Cenomanian , late Turonian, and ?Coniacian. Most of the sampled localities contain multiple salamander genera and families; these diversities compare favorably with better sampled latest Cretaceous salamander assemblages elsewhere in the Western Interior, even though the compositions of those assemblages differ. Introduction Modern amphibians (Lissamphibia) consist of three clades with extant and fossil members–salamanders (Caudata), frogs (Salientia), and caecilians (Gymnophiona)–and one fossil clade, the Albanerpetontidae. Salamanders are readily identified by their small to moderate body size (typically under 30 cm in total length) and generalized tetrapod body plan that primitively consists of two pairs of similarly sized limbs and a moderately elongate trunk and tail. Salamanders include fully aquatic, semiaquatic, and terrestrial forms, and all require moist, generally temperate conditions to survive. Extant salamanders number about 550 species distributed among 10 families and have a primarily Holarctic and Neotropical distribution (Duellman and Trueb, 1986; Frost et al., 2006). Salamanders have a patchy fossil record that extends back to the Middle Jurassic (Bathonian) of England (Evans, Milner, and Mussett, 1988; Evans and Milner, 1994), Kyrgyzstan (Nessov, 1988; Averianov et al., 2008; Skutschas and Martin, 2011), Siberia (Skutschas and Krasnolutskii, 2011), and potentially China (Gao and Shubin, 2003; but see Wang, 2004) and is biased toward isolated bones and rare articulated skeletons of paedomorphic taxa (Estes, 1981; Milner, 2000). North America is an important continent for salamanders . Twelve families (nine extant and three fossil) are known from North America, and about a third of those are endemic or largely restricted to the continent (Estes, 1981; Milner, 1983; Duellman and Trueb, 1986; Petranka, 1998; Holman, 2006). The Western Interior is an important source for salamander fossils and consequently has played a critical role in interpreting the evolutionary history of North American salamanders. The oldest unequivocal salamander fossils in North America are isolated bones and several articulated skeletons from the Upper Jurassic (Kimmeridgian and Tithonian ) Morrison Formation of Wyoming and Utah (Hecht Gardner, Eaton, and Cifelli 238 and Estes, 1960; Evans and Milner, 1993; Evans et al., 2005). North American Cretaceous salamanders are known only by isolated bones, mostly vertebrae and jaws recovered from microvertebrate localities, and are best documented from the Albian of Texas (Estes, 1969a; Winkler, Murry, and Jacobs , 1990) and from the Campanian and Maastrichtian of Texas north into southern Alberta and Saskatchewan (Estes, 1964, 1965, 1969b, 1981; Sahni, 1972; Carpenter, 1979; Armstrong -Ziegler, 1980; Naylor and Krause, 1981; Breithaupt, 1985; Rowe et al., 1992; Gardner, 2000a, 2005; DeMar and Breithaupt, 2006, 2008). Although salamander fossils and taxa have been reported in preliminary faunal articles, faunal lists, and conference abstracts from the Cenomanian...

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