Fast spread followed by anagenetic evolution in Eurasian and North American Amphimachairodus

Abstract

The charismatic sabretooth cat Amphimachairodus has numerous but largely fragmentary records across late Miocene deposits of Africa, Eurasia and North America. The genus has a complex taxonomic history, and the majority of Amphimachairodus materials come from isolated localities, often studied without stratigraphic context. Here, we analyse the long, continuous records from the classic Chinese Baode strata, which produce Amphimachairodus throughout the section, and demonstrate that an A. palanderi-horribilis chronospecies succession represents a continuum of in situ anagenetic evolution of increasing size. We then synthesise chronological occurrences of Amphimachairodus from all Holarctic records and reframe their evolution as a case of chronospecies succession. Two parallel anagenetic lineages are evident: a Eurasian A. giganteuspalanderi-horribilis chronospecies succession and second, a North American A. coloradensis-alvarezi chronospecies succession following an immigration event in the early Hemphillian. In addition to greater hypercarnivory evidenced by dental specialisation, the Eurasian lineage shows a trend towards a large body size, whereas the North American lineage decreases in size. We take this opportunity to describe materials of Amphimachairodus alvarezi from Yepómera (latest Hemphillian) in the state of Chihuahua, Mexico, and previously undescribed materials from San Miguel de Allende Basin. We review taxonomic status of Chinese A. horribilis and related taxa.

Eurasian wanderer: an island sabre‐toothed cat (Felidae, Machairodontinae) in the Far East

“…The overall similarity of machairodontine morphology also poses a global challenge to any statistical or phylogenetic analysis of fragmentary material (Wang et al . 2022), as also shown in our attempts (Fig. 2); even the same species (extant and extinct) could be clustered in separate groups (see Figs S1–S6 for more details).…”

Parallelism and lineage replacement of the late Miocene scimitar-toothed cats from the old and New World

“…Wang et al. 62 recently proposed an anagenetic evolution of A. coloradensis-alvarezi in North America with a tendency of reduction of body size, which is different from the general increasing body size pattern seen in North American Nimravides and Eurasian Amphimachairodus . The influential factors of body size can be varied from temperature, vegetation coverage, and food source.…”