Discovery of the fossil otter Enhydritherium terraenovae (Carnivora, Mammalia) in Mexico reconciles a palaeozoogeographic mystery

Abstract

The North American fossil otter is thought to be partially convergent in ecological niche with the living sea otter, both having low-crowned crushing teeth and a close association with marine environments. Fossil records of are found in mostly marginal marine deposits in California and Florida; despite presence of very rich records of fossil terrestrial mammals in contemporaneous localities inland, no fossils are hitherto known in interior North America. Here we report the first occurrence of outside of Florida and California, in a land-locked terrestrial mammal fauna of the upper Miocene deposits of Juchipila Basin, Zacatecas State, Mexico. This new occurrence of is at least 200 km from the modern Pacific coastline, and nearly 600 km from the Gulf of Mexico. Besides providing further evidence that was not dependent on coastal marine environments as originally interpreted, this discovery leads us to propose a new east-to-west dispersal route between the Florida and California populations through central Mexico. The proximity of the fossil locality to nearby populations of modern neotropical otters suggests that trans-Mexican freshwater corridors for vertebrate species in riparian habitats may have persisted for a prolonged period of time, pre-dating the Great American Biotic Interchange.

Notes on the origin of extensive endorheic regions in central and northern Mexico, and some implications for paleozoogeography

“…The third record of a fossil otter was recently reported by us (Tseng et al, 2017) and it refers to the discovery of a jaw of Enhydritherium terraenovae (Fig. 2) in late Miocene fluvial deposits in Juchipila (Fig.…”

NEW INSIGHTS ON THE ENIGMATIC OTTERS FROM THE LATE MIOCENE OF TUSCANY: <em>TYRRHENOLUTRA MAREMMANA</em> NOV. COMB. (LUTRINAE, MUSTELIDAE, CARNIVORA), WITH A PHYLOGENY OF BUNODONT OTTERS

“…Bunodont otters of various sizes were in fact widely distributed during the Late Miocene and Early Pliocene (Fig. 2), with records in North America (Repenning 1976;Berta & Morgan 1985;Tseng et al 2017), Europe (Meneghini 1862;Pilgrim 1931Pilgrim , 1932De Villalta Comella & Crusafont-Pairó 1945;Crusafont-Pairó 1950;Crusafont-Pairó & Golpe 1962, 1962Willemsen 1983Willemsen , 1992Willemsen , 1999Hürzeler 1987;Alcalá 1994), Asia (Falconer 1868;Lydekker 1884;Pilgrim 1931Pilgrim , 1932Pickford 2007;Ji et al 2013;Jablonski et al 2014;Wang et al 2018) as well as Africa (Stromer von Reichenbach 1931;Hendey 1974;Petter et al 1991;Werdelin 2003aWerdelin , 2003b.…”

Role of feeding specialization in taste receptor loss: insights from sweet and umami receptor evolution in Carnivora

“…Molecular dating has estimated that Lutrinae arose ~8–9 million years ago in the late Miocene ( Yonezawa et al 2007 ; Koepfli et al 2008 ; Sato et al 2009 , 2012 ; Eizirik et al 2010 ). The late Miocene fossil record of otters and otter-like mustelids, which exhibit adaptations indicative of feeding on fish, molluscs, or crustaceans ( Morales and Pickford 2005 ; Pickford 2007 ; Haile-Selassie 2008 ; Peigné et al 2008 ; Villier et al 2011 ; Tseng et al 2017 ; Wang et al 2018 ), suggests that the switch to diets low in sweet and umami taste-eliciting compounds occurred in otters no later than at the origin of Lutrinae. This fossil-based conclusion concurs with the fact that all extant otters are piscivores, cancri–piscivores, or molluscivores ( Wilson and Mittermeier 2009 ).…”