Fossil canids from the Mehrten Formation, Late Cenozoic of Northern California

First bone-cracking dog coprolites provide new insight into bone consumption in Borophagus and their unique ecological niche

“…For medium to large carnivorans from the Mehrten Formation, Wagner (1976 , 1981) listed a bone-crushing dog Borophagus secundus (= Osteoborus cyonoides ), a small coyote-sized Eucyon davisi , an ancestral badger Pliotaxidea garberi , an early wolverine Plesiogulo marshalli , and an ancestral cat Pseudaelurus near P. hibbardi . Most recently, Balisi et al (2018) added a fox, Vulpes stenognathus , to the list. Of the above, Vulpes , Eucyon , Pliotaxidea , and Plesiogulo can be ruled out as being too small to produce scats of the size of the Mehrten coprolites, whereas the true nature of Mehrten felids is poorly known.…”

“…Of the large Mehrten canids, Balisi et al (2018) recognized two bone-crushing canids, B. secundus and B. parvus , which are the only wolf-sized taxa large enough to be the producers of the Mehrten coprolites. Of these two species, B. secundus is rare, represented by two fragmentary jaws and teeth plus 1–2 questionably referred teeth, whereas B. parvus is far better represented by 27 specimens.…”

“…Of these two species, B. secundus is rare, represented by two fragmentary jaws and teeth plus 1–2 questionably referred teeth, whereas B. parvus is far better represented by 27 specimens. At the main coprolite-producing locality (see Materials and methods), LACM locality 3937 (=Dennis Garber T-34 locality), an isolated P2 or P3 (UCMP 235515) is questionably referred to B. secundus ( Balisi et al, 2018 ), whereas in LACM locality 3935, no identifiable carnivoran is found (Figure 9).…”

“…Wang et al, 1999 and Tedford et al, 2009 listed selected borophagine and canine canids from the Mehrten Formation without description or illustration. A systematic revision of Mehrten canids was completed by Balisi et al (2018) that recognized four species: Borophagus parvus , B. secundus , Vulpes stenognathus , and Eucyon davisi . See Wagner (1981) for a preliminary faunal list of the rest of the unpublished mammals.…”

Peer Review #1 of "Hypercarnivorous teeth and healed injuries to Canis chihliensis from Early Pleistocene Nihewan beds, China, support social hunting for ancestral wolves (v0.1)"

“…Most of the remaining pathological dentaries also preserved dental anomalies, predominantly supernumerary teeth (particularly in the first and second premolars) or a missing lower first premolar (p1) and/or third molar (m3). Because both the p1 and m3 (Balisi et al 2018;Buchalczyk et al 1981;Wang 1994) vary in their presence among canids, we excluded anomalies in these teeth from our comparison with Nihewan C. chihliensis. Across 200 C. dirus jaws (both left and right) bearing abscesses and alveolar infections, the lower first molar or carnassial showed the highest frequency of injury (87 total specimens with m1-associated injuries), likely inflicted by bone-crushing during the consumption of prey, followed by the second premolar (79 total specimens with p2-associated injuries), likely the result of biting and killing while chasing prey or in fighting with conspecifics or competitors of other species (Fig.…”