A novel genus and species of mid-Oligocene nimuravid has been identified from fossil remains unearthed in northern China. This finding enhances our understanding of Nimurabiidae in eastern Eurasia.
Reimagining the life of Taotienimravus songi in a Chinese painting style. Image credit: Yuefeng Song.
Taotienimravus songi inhabited what is now China during the mid-Oligocene period, around 28 million years ago.
This ancient species is part of the Nimuravidae family, an extinct group of saber-toothed hypercarnivores, often referred to as pseudosaber-toothed cats.
“Carnivora demonstrates the broadest range in body sizes among mammals, with the smallest weasel weighing roughly 50 g. Pinnipeds average over 3 tons,” stated Dr. Qigao Jiangzuo of the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences.
“With few exceptions, such as the bear family, large terrestrial carnivores, particularly those exceeding 20 kg, generally maintain a macrocarnivorous diet, targeting large prey of similar size or larger.”
“Often called pseudosabertooths, the Nimurabiidae represents one of the earliest diverging lineages within the Carnivora order, noted for their large size, hypercarnivorous craniodental features, and potentially macrocarnivorous behaviors,” the researchers added.
“The earliest fossils from this family, dating back to the mid-Eocene, belonged to highly specialized species exhibiting cat-like craniodental characteristics.”
“Nimuravidae underwent radiation during the Eocene to Oligocene, with the best-preserved specimens found primarily in North America, where numerous skulls and complete skeletons have been discovered.”
“Eurasia also contains numerous fossil remains, though they tend to be poorly preserved.”
“As the first lineage within Carnivora to develop large body sizes, this family is an excellent model for studying the evolution of early large carnivorous niches in an environmental context vastly different from that of today.”
The skeletal remains of Taotienimravus songi were discovered in the Qingshuiying Formation in northern China.
Specimen analysis indicates that this new species uniquely displays non-saber-toothed morphology with bone-cracking adaptations within the Nimuravidae family.
This animal likely engaged in a killing behavior distinct from other feline carnivores, possibly employing a tearing bite akin to that of hyenas.
“The defining characteristics of the new Nimuravid include exceptionally short and robust upper canine teeth along with a notably wide palatal area,” the paleontologists noted.
“The rostrum is exceedingly wide, probably the widest of any known Nimravid.”
“In contrast to many feline carnivores, the premolars do not diminish in size; rather, they increase, eliminating the gap between the canines and cheek teeth.”
“This contrasts with most feline carnivores, which almost invariably exhibit diastema.”
“We interpret this absence of a gap as an indicator of a strong canine bite, allowing for deep penetration into prey.”
Phylogenetic analysis positions Taotienimravus songi within the Nimravinae, creating a sister lineage to those in Europe and North America, such as Nimravus and Dinahelurus.
This clade shares a close relation to the European lineage encompassing Iofelis, Denailictis, and Quercyllus.
“The increase in size within Nimuravidae seems to align with the extinction of another carnivorous group, Oxyaenidae, during the Paleogene,” the researchers stated.
“The initial emergence of large carnivorous traits within the Carnivora order likely reflects competitive interactions driven by ecomorphic dynamics.”
“Nimuravidae effectively occupied ecological niches unavailable to Felidae, probably due to the lack of competition within Carnivora for much of their evolutionary history.”
“This study emphasizes the impact of both abiotic and biotic factors in shaping niche availability for these animals and underscores the need to discuss niche evolution and change within this framework.”
A study detailing this discovery was published on November 26, 2025, in Proceedings of the Royal Society B.
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Qigao Jiangzuo et al. 2025. A new ecomorph of the Nimravidae and the exploration of early large carnivores within the order Carnivora. Proc Biol Sci 292 (2059): 20251686; doi: 10.1098/rspb.2025.1686
Source: www.sci.news
