A significant paleontological discovery in Pakistan has yielded fossilized remnants of three distinct hyaenodont species, one of which represents a previously undocumented scientific entity, all unearthed from Miocene-era geological strata.
Metapterodon anari. Image credit: Steven Jasinski / SergeyAtrox1.
“Hyaenodonts occupied a pivotal role as mammalian carnivores that predated the ascendance and subsequent dominance of modern predators like felids, canids, and their kin in those ecological niches; moreover, certain members of this group attained colossal dimensions,” stated Professor Steven Jasinski of Harrisburg University of Science and Technology.
In a recently published investigation, Professor Jasinski and his research associates meticulously analyzed fossilized specimens attributed to three separate hyaenodont lineages, which were extant between 14 and 9.5 million years ago.
These unearthed materials originated from the Chinji and Nagri geological formations, situated within the Lower and Middle Siwaliks of Pakistan.
One of the identified hyaenodonts, provisionally categorized as belonging to the genus Megistotherium or Hyainailouros, was an exceptionally massive creature, potentially achieving a body mass of up to 500 kg, comparable in scale to a polar bear.
The recovered fossils comprised deciduous dentition from immature individuals, whose permanent teeth had not yet fully developed, thereby complicating precise taxonomic identification.
Additional fossilized teeth were attributed to a representative of the genus Hyaenodon.
While this widely dispersed genus has been documented across numerous northern continental masses, including North America, Europe, and Asia, these represent the inaugural discoveries from this particular geographic locale.
Furthermore, these specimens constitute the latest known temporal occurrence of the genus and might represent a distinct species, although further paleontological evidence is requisite for definitive confirmation.
These ancient predators likely had an estimated body weight of approximately 30 kg, aligning them in size with a small gray wolf or a leopard.
The paleontological team also identified a tooth pertaining to a genus of comparatively diminutive hyaenodonts designated as Metapterodon.
Previously exclusively documented through fossil finds in Africa, the genus is now confirmed to have dispersed beyond the African continent during the Miocene epoch.
The newly identified species, christened Metapterodon anari, may also rank among the most recent hyaenodont fossils to have been formally described.
“The discovery of Metapterodon anari holds considerable scientific importance, not only due to its phylogenetic relationship with similar taxa but also its specific temporal placement,” Professor Jasinski elaborated.
“It signifies one of the terminal lineages of hyaenodonts, affording us potential insights into an era characterized by probable interspecific competition between these mammalian predators and the encroaching carnivorans, which were increasingly assuming the dominant roles as terrestrial carnivorous mammals.”
Metapterodon anari is estimated to have attained a body mass of roughly 15 kg, a size comparable to that of a large red fox or a coyote.
“The scientific value of these paleontological findings extends beyond their specific taxonomic classifications to encompass their significant geographic implications,” the researchers stated.
“They provide concrete evidence of crucial faunal connections between Africa and Europe during the Miocene and suggest the potential dispersal of hyaenodonts from adjacent regions, such as China.”
“The hyaenodonts recovered from the Miocene deposits of Pakistan are of particular interest due to their coexistence with carnivorans, offering valuable data concerning the competitive dynamics between these two faunal assemblages.”
“All exhibited characteristics indicative of hypercarnivores, with a diet predominantly composed of meat—a dietary specialization that may have ultimately rendered them susceptible to competitive exclusion by the evolving carnivoran groups.”
These fossil discoveries also contribute to a more comprehensive understanding of South Asia during the Miocene epoch, a period marked by global climatic cooling and substantial shifts in faunal communities, which consequently laid the groundwork for the contemporary ecosystems observed in the region.
“Fossils serve as more than mere historical curiosities about past flora and fauna; they are instrumental in elucidating the transformations that have occurred and the adaptive strategies employed by life forms in response to those changes,” remarked Professor Jasinski.
“Their study also offers potential foresight into future environmental shifts and can provide conceptual frameworks for addressing such forthcoming challenges.”
The research findings generated by the scientific team have been published in the esteemed journal PalZ.
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K. Mahmood et al. Hyaenodonta from the Middle to Late Miocene deposits of the Siwaliks of Pakistan with a brief account of Indian subcontinent hyaenodonts. PalZ, published online April 16, 2026; doi: 10.1007/s12542-025-00766-5
