First FossilAlligatorfrom the Late Eocene of Nebraska and the Late Paleogene Record of Alligators in the Great Plains

Abstract

Background: Discovery of Eocene non-marine vertebrates, including crocodylians, turtles, bony fishes, and mammals in Canada's High Arctic was a critical paleontological contribution of the last century because it indicated that this region of the Arctic had been mild, temperate, and ice-free during the early -middle Eocene (,53-50 Ma), despite being well above the Arctic Circle. To date, these discoveries have been restricted to Canada's easternmost Arctic -Ellesmere and Axel Heiberg Islands (Nunavut). Although temporally correlative strata crop out over 1,000 km west, on Canada's westernmost Arctic Island -Banks Island, Northwest Territories -they have been interpreted as predominantly marine. We document the first Eocene bony fish and crocodyliform fossils from Banks Island.

Cranial Polymorphism and Systematics of Miocene and LivingAlligatorin North America

“…5). Character 25 of Hastings et al (2013) also was recoded as multistate (0/1) for A. prenasalis based on new evidence from late Eocene fossil alligators from Nebraska that likely are referable to A. prenasalis, which also exhibit polymorphic positions of the lingual foramina (Whiting and Hastings, 2015). Character 38 of Hastings et al (2013) was recoded as 0 for A. olseni after scrutiny of several UF specimens that all exhibit gently curved dentaries between d4 and d10.…”

“…Even the earliest true alligators (Alligator prenasalis from the Chadronian and Orellan NALMAs of South Dakota, Higgins, 1971, and likely Chadronian of Nebraska, Whiting and Hastings, 2015) closely resemble the two extant species (the Chinese Alligator, Alligator sinensis, Fauvel, 1879, and American Alligator, Alligator mississippiensis, Daudin, 1801), attesting to their highly conservative morphology (Mook, 1932;Malone, 1979;Brochu, 1999Brochu, , 2004.…”

Paleoecology of Miocene crocodylians in Florida: Insights from stable isotope analysis

“…these alligators feed on many types of marine prey, but must return to freshwater to avoid excessive absorption of salt, given their lack of lingual salt-excreting glands (Taplin et al, 1982;Rosenblatt and Heithaus, 2011;Nifong et al, 2012Nifong et al, , 2015Nifong and Silliman, 2013;Rosenblatt et al, 2013). Modern coastal populations of alligators may represent an expanded ecological niche for what once was a more restricted freshwater genus, which originated during the late Eocene in the Great Plains (Brochu, 1999;Whiting and Hastings, 2015). This idea could be tested by stable isotope analysis of fossil tooth enamel from Plio-Pleistocene and modern A. mississippiensis in Florida, and comparing resulting values to the Miocene values we present in this study.…”

Some Thoughts on Interspecific Mandibular Morphology in Fossil and Modern Alligator

“…• The lingual foramen for the articular artery and alveolar nerve lies on the surangular/articular suture of the lower jaw: corrected in Whiting and Hastings (2015); the original stated location (in Brochu, 1999) "on the surangular/angular suture" appears to be an enduring lapsus calami in some works.…”