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Paperback or Softback. Condizione: New. Comment l'id�e vint � M. Rassinier. Book.

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Nine new records of Smithian (Early Triassic) ammonoid taxa are reported from Crittenden Springs, northeastern Nevada, of which five are newly described taxa. These new taxa include two proptychitids, an acute- ventered meekoceratid, a flemingitid and a hemiprionitid, which represents the first reported occurrence of a prionitid from the Meekoceras gracilitatis Zone. The paleoequatorial nature of the eastern Panthalassic basin ammonoid faunas is further demonstrated given that five of the new taxa are very similar to or identical to forms from Guangxi (South China) and Oman. These occurrences also further corroborate the very significant low paleolatitude faunal exchange that existed between opposite sides of the Panthalassic Ocean during Smithian time. The condensed nature of the Meekoceras and Anasibirites assemblages at Crittenden Springs is confirmed, and the M. gracilitatis Zone at this locality is shown to correlate not only with the middle Smithian Owenites koeneni beds of Tethyan NW Guangxi (South China), but a tentative correlation with the older Flemingites rursiradiatus beds is demonstrated as well. Kummel and Steele's (1962) description of Anaflemingites silberlingi is clarified, and its range of intraspecific variation is illustrated. Flemingites russelli Hyatt and Smith is assigned to Anaflemingites, and its relationship with A. silberlingi is examined. One new genus (Acutomeekoceras n. gen.) and five new species (Pseudaspidites silberlingi n. sp., Acutomeekoceras rieberi n. gen., n. sp., Galfettites lucasi n. sp., Hemiprionites roberti n. sp. and Pseudaspenites balinii n. sp.) are described. ii+41 pp., 24 figs, br. 4.…

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