Mairin Balisi

• Doctor of Philosophy
• Augustyn Family Curator of Paleontology at Raymond M. Alf Museum of Paleontology

How traits influence species persistence is a fundamental question in ecology, evolution and palaeontology. We test the relationship between dietary traits and both species duration and locality coverage over 40 million years in North American canids, a clade with considerable ecomorphological disparity and a dense fossil record. Because ecomorphol...

Ecological specialization has costs and benefits at various scales: traits benefitting an individual may disadvantage its population, species or clade. In particular, large body size and hypercarnivory (diet over 70% meat) have evolved repeatedly in mammals; yet large hypercarnivores are thought to be trapped in a macroevolutionary “ratchet”, march...

Reconstructing the behavior of extinct species is challenging, particularly for those with no living analogues. However, damage preserved as paleopathologies on bone can record how an animal moved in life, potentially reflecting behavioral patterns. Here, we assess hypothesized etiologies of pathology in a pelvis and associated right femur of a Smi...

Skeletal disease may hamper the behavior of large predators both living and extinct. We investigated the prevalence of osteochondrosis dissecans (OCD), a developmental bone disease affecting the joints, in two Ice Age predators: the saber-toothed cat Smilodon fatalis and dire wolf Aenocyon dirus. As published cases in modern Felidae and wild Canida...

The trend of global cooling across the Cenozoic transformed the North American landscape from closed forest to more open grasslands, resulting in dietary adaptations in herbivores in response to shifting resources. In contrast, the material properties of the predator food source (muscle, skin, and bone) have remained constant over this transition,...

Motivation Terrestrial predators play key roles in cycling nutrients, as well as limiting prey populations, and shaping the behaviour of their prey. Prehistoric, historic and ongoing declines of the world's predators have reshaped terrestrial ecosystems and are a topic of conservation concern. However, the availability of ecologically relevant pred...

Introduced large herbivores have partly filled ecological gaps formed in the late Pleistocene, when many of the Earth's megafauna were driven extinct. However, extant predators are generally considered incapable of exerting top‐down influences on introduced megafauna, leading to unusually strong disturbance and herbivory relative to native herbivor...

An organism’s body mass is closely related to its physiology, life history, and evolutionary dynamics. Previous studies indicate that both large herbivore and carnivore body masses show persistent, and at times coincident, increases through the Cenozoic. These parallel increases in body mass suggest an ecological link between the two guilds. Here,...

Introduced large herbivores have partly filled ecological gaps formed in the late Pleistocene, when many of the Earth's megafauna were driven extinct. However, surviving predators are widely considered unable to influence introduced megafauna, leading them to exert unusually strong herbivory and disturbance-related effects. We report on a behaviora...

The general trend of global cooling across the Cenozoic transformed the North American landscape, resulting in various dietary and locomotory adaptations in herbivores in response to the expansion of open grasslands. In contrast, the material properties of muscle, skin and bone have not changed over the transition, suggesting a potential lack of bo...

The North American landscape of mammalian carnivores has shifted over the last 40 million years as prey resources have changed and genera have come and gone. In order to maximize energetic usage and reduce competition, we would expect co-occurring taxa to divide up the total functional niche space available into different functional categories, whi...

Collaborative hunting by complex social groups is a hallmark of large dogs (Mammalia: Carnivora: Canidae), whose teeth also tend to be hypercarnivorous, specialized toward increased cutting edges for meat consumption and robust p4-m1 complex for cracking bone. The deep history of canid pack hunting is, however, obscure because behavioral evidence i...

Reconstructing the behavior of extinct species is challenging, particularly for those with no living analogues. However, damage preserved as paleopathologies on bone can record how an animal moved in life, potentially reflecting behavioral patterns. Here, we assess hypothesized etiologies of pathology in a pelvis and associated right femur of a Smi...

Borophagine canids have long been hypothesized to be North American ecological ‘avatars’ of living hyenas in Africa and Asia, but direct fossil evidence of hyena-like bone consumption is hitherto unknown. We report rare coprolites (fossilized feces) of Borophagus parvus from the late Miocene of California and, for the first time, describe unambiguo...

158708 bin=4 Avizo file (plus data folder): Segmentation file for LACM 158708 in Avizo software (ThermoFisher Scientific). Voxel size has been downgraded to 108 micrometers on a side to reduce file size. Segmentation in Avizo Lite 9.2 by Stuart C. White.

The Hemphillian-age Mehrten Formation has yielded several fossil dogs (family Canidae). Initial study had identified all larger canids as Borophagus secundus ( = Osteoborus cyonoides), a bone-crushing borophagine (a diverse subfamily of extinct canids), and all smaller canids as Canis cf. C. davisi, a canine (a subfamily including all living canids...

Skeletal-injury frequency and distribution are likely to reflect hunting behaviour in predatory vertebrates and might therefore differ between species with distinct hunting modes. Two Pleistocene predators from the Rancho La Brea asphalt seeps, the sabre-tooth cat, Smilodon fatalis, and dire wolf, Canis dirus, represent ambush and pursuit predators...