Stratigraphic Changes in the Pliocene Carnivoran Assemblage from Hagerman Fossil Beds National Monument, Idaho

Abstract

Abstract:At least 17 carnivoran taxa occur in the Pliocene Glenns Ferry Formation at Hagerman Fossil Beds National Monument (HAFO), Idaho. This assemblage was examined for stratigraphic changes in species distribution, specimen abundance, and species diversity. Three relatively common mustelids, Trigonictis cookii, Trigonictis macrodon, and Mustela rexroadensis, occur at most stratigraphic levels, but are absent during an interval coinciding with the coolest time segment at HAFO. It is within this gap that two less-common mustelids, Ferinestrix vorax and Buisnictis breviramus, first appear at HAFO; they persist up-section with the more common mustelids listed above. Specimens of Borophagus hilli are restricted to the warm intervals at HAFO, irrespective of the relative abundance of surface water. The other canid at HAFO, Canis lepophagus, is more abundant during the dry intervals at HAFO, regardless of the estimated paleotemperature. Most remarkable is the recovery of many taxa impacted by abrupt climate change, although a notable change is the much higher relative abundance of carnivoran species following a return to warm temperatures.

Shared extremes by ectotherms and endotherms: Body elongation in mustelids is associated with small size and reduced limbs

“…Qualitative examination of the musteloid fossil record supports hypotheses relating elongate body shapes to ecological opportunity. Small extinct neomustelids such as † Cernictis , † Trigonictis , and † Sminthosinis , which are morphologically similar to extant mustelines and ictonychines (Baskin ), became abundant during the late Miocene and Pliocene of North America and Eurasia (Ruez ), and replaced stem mustelids (“paleomustelids”) lineages (Law et al. ).…”