Researchers from the Mansoura University Vertebrate Paleontology Center (MUVP) in Egypt, in collaboration with colleagues from the University of Michigan and KU Leuven in Belgium, have unveiled the Qreiya 3 Lagerstätte, an exceptionally rich fossil locality dated to approximately 62.2 million years ago, situated within the Danian Age of the Paleocene epoch. This site remarkably preserves a diverse assemblage of offshore marine fish fossils that surpasses all previously known Danian fish communities in both diversity and stratigraphic certainty. With over twenty types of ray-finned fishes documented, Qreiya 3 provides an unprecedented window into early Paleocene marine biodiversity.

What astonishes paleontologists about Qreiya 3 is not merely the sheer number of fossils, but the ecological composition they represent. Contrary to earlier assumptions that post-extinction marine faunas might be dominated by lingering Cretaceous holdovers, this assemblage reveals a community structurally similar to the modern marine ecosystems we observe today. The dominance of percomorph fishes—a vast clade encompassing familiar families like tunas, flounders, and jacks—suggests that foundational components of today’s oceanic fish diversity were already well established during the earliest Paleocene.

The presence of key modern lineages extends beyond percomorphs. Detailed osteological comparisons reveal that several ecologically distinct groups, including early representatives of tunas, mackerels, snake mackerels, moonfishes, and pipefishes, are present in the fossil record here for the earliest time yet observed. By enabling bone-for-bone comparisons with extant species, the Qreiya 3 fossils confirm that critical diversification within the teleost fish tree had occurred by the Danian, thus recalibrating the timeline of marine evolutionary history.

Intriguingly, the fossil assemblage also offers insights into what was lost during the mass extinction. Groups of predatory fishes that were prevalent in Cretaceous marine ecosystems are conspicuously absent despite the exceptional preservation and sampling effort at Qreiya 3. This absence strongly implies that the K–Pg extinction not only eradicated numerous lineages but also facilitated a rapid ecological reorganization that saw modern fish groups exploiting niches vacated by their extinct predecessors.

Environmental context further enriches the significance of the Qreiya 3 site. Unlike many other Danian fossil fish localities, which are typically from shallower waters, Qreiya 3 was deposited in an offshore marine environment with an estimated paleodepth of 150 to 250 meters. It coincides with the Latest Danian Event, a transient global warming phase, and was likely characterized by low-oxygen bottom water conditions that promoted exceptional fossilization. Such depositional settings are rare for this interval and provide critical paleoecological data that deepen understanding of early Paleocene marine dynamics.

This discovery also opens new avenues for investigating biogeographic patterns in post-extinction marine ecosystems. Situated in what was then a tropical region during the Paleocene, the Qreiya 3 fauna hints that tropical marine environments may have been crucibles for the early development and radiation of modern fish faunas. This could imply a spatial heterogeneity in recovery rates and evolutionary processes following the mass extinction, an area ripe for further research pending additional fossil discoveries.

The implications of the Qreiya 3 find resonate beyond biostratigraphy and paleobiology; they also reshape prevailing narratives about oceanic resilience and innovation after mass extinction events. By documenting a rapid establishment of modern marine fish communities within just four million years of the K–Pg boundary, these fossils underscore the capacity of marine ecosystems for swift reorganization and adaptation in the wake of catastrophic upheaval.

Principal investigator Hesham Sallam emphasizes that the current report captures only an initial glimpse of what this site can reveal. Ongoing preparation and detailed studies of the extensive collections from Qreiya 3 promise to unravel further complexities regarding the evolutionary pathways and ecological transformations that shaped today’s oceans immediately following one of Earth’s most profound extinction events.

Collectively, this research represents a major step forward in paleontological science, providing a robust chronological anchor and detailed taxonomic framework that elucidate the tempo and mode of marine recovery after the end-Cretaceous disaster. The findings indicate that the oceanic fisheries and ecosystems recognizable in modern times have deep roots extending back to the earliest Paleocene, challenging models that posited prolonged or staggered faunal turnovers.

Moreover, the Qreiya 3 Lagerstätte sets a new standard for the quality and completeness of early Paleocene marine fossil records, enabling nuanced analyses of anatomical, ecological, and environmental parameters that have hitherto been elusive. Such comprehensive insights will augment understanding of evolutionary mechanisms, from speciation rates to ecosystem resilience, in the context of one of Earth’s pivotal biotic turnovers.

As scientists continue to probe the depth and breadth of this extraordinary fossil site, the hope is that further revelations will emerge, enriching the broader understanding of how present-day marine biodiversity was forged through the crucible of deep time. The rapid establishment of modern marine faunas evidenced by Qreiya 3 not only enhances scientific comprehension of past life but also informs predictions about how contemporary ocean ecosystems might respond to future environmental challenges.

This landmark discovery from Egypt’s Eastern Desert is set to redefine early Paleocene paleontology and inspires renewed exploration of underrepresented fossil horizons worldwide, showcasing the unparalleled potential of sedimentary Lagerstätten in reconstructing the evolutionary heritage and ecological history of marine life.

Subject of Research: Evolution and rapid establishment of modern marine fish faunas in the early Paleocene.

Article Title: Rise of Modern Marine Fishes Captured in an Early Paleocene Lagerstätte.

News Publication Date: 3-Jun-2026.

Web References: DOI: 10.1126/sciadv.aec8978.

Image Credits: Ian Baylatry.

Keywords: Paleocene, K–Pg extinction, marine fishes, Qreiya 3 Lagerstätte, Paleontology, marine biodiversity, percomorphs, fossil fishes, evolutionary recovery, mass extinction, marine ecosystems, Danian Age.

Bony fishes (Osteichthyes) are a diverse group marked by two main extant lineages: ray-finned fishes (Actinopterygii) and lobe-finned fishes (Sarcopterygii), the latter lineage including the ancestors of all tetrapods, which eventually led to terrestrial vertebrates including humans. Despite their evolutionary importance, the origin of bony fishes has been enigmatic due to a paucity of well-preserved fossil evidence predating the Devonian period, a time when many early fish fossils already appear as highly specialized forms.

The team’s discoveries stem from meticulous fieldwork spanning over a decade, involving fossil specimens from the Early and Late Silurian deposits of southern China. This region, encompassing Chongqing and Yunnan provinces, has proven to be a vital repository of early vertebrate fossils that unravel the complex evolutionary history preceding the Devonian radiation of jawed fishes.

The first key specimen, Eosteus chongqingensis, hails from the Early Silurian strata approximately 436 million years old. Measuring a mere 3 centimeters in length, the fossil is remarkably complete, preserving the entire organism from head to tail. This diminutive fish exhibits an intriguing mosaic of features, combining traits recognized in early ray-finned fishes with ancestral characteristics, such as the absence of lepidotrichia (the bony fin rays typical of more derived bony fishes), and the presence of an anal fin spine, a feature previously observed only in cartilaginous fishes and placoderms, which are more primitive jawed vertebrates.

Such a combination of characteristics in Eosteus chongqingensis challenges pre-existing assumptions about the timing of core bony fish traits’ emergence. Notably, morphological features thought to be exclusive to later ray-finned fishes were already present in this early bony fish, suggesting a considerably earlier advent of defining osteichthyan features than was hitherto recognized.

Complementing this discovery is the unearthing and detailed study of Megamastax amblyodus from the Late Silurian Kuanti Formation in Qujing, Yunnan, dating to approximately 423 million years ago. Megamastax stands out as the largest known vertebrate from the Silurian, surpassing one meter in length, which is extraordinary given the generally small size of contemporaneous vertebrates.

Prior to this study, efforts to reconstruct Megamastax’s anatomy were hampered by the fragmentary nature of fossil material and the complexity of internal structures. However, the application of advanced high-resolution computed tomography (HRCT) and three-dimensional digital reconstruction enabled the researchers to visualize the entirety of its cranial anatomy and internal morphology non-destructively. This breakthrough revealed intricate details of the cranial bones, braincase, and musculature, shedding light on its feeding adaptations and internal structures.

The dentition of Megamastax amblyodus is particularly revealing. Unlike modern bony fishes that generally have a single row of teeth, Megamastax’s jaws display a primitive condition with both inner and outer dental arcades. The inner row features tooth cushions resting on broad bases, a configuration that resolves long-standing debates about the taxonomic placement of similarly isolated Silurian tooth remains from the Baltic region. This anatomical evidence confirms that such dental structures are basal osteichthyan features rather than belonging to other groups.

Comprehensive phylogenetic analyses place both Eosteus and Megamastax firmly within the bony fish stem group, representing taxa that predate the divergence of ray-finned and lobe-finned fishes. This placement provides a crucial window into the ancestral condition of osteichthyans and informs reconstructions of their last common ancestor’s morphology. Their existence before the evolutionary split challenges earlier hypotheses suggesting that ancestral bony fishes resembled lobe-finned fishes more than ray-finned types.

These findings carry profound implications for understanding the early evolution of jawed vertebrates. By illuminating the morphological trajectory of key skeletal features, including jaw structure, scales, and fin architecture, the research advances our knowledge of how complex anatomical innovations arose and diversified within early bony fishes. This also refines models of how vertebrates transitioned from aquatic to terrestrial environments, through the lobe-finned lineage.

The study reinforces the significance of southern China as a pivotal paleontological region rich in vertebrate fossils that document critical episodes of early vertebrate evolution. The geological context and exceptional preservation conditions in this area have allowed scientists to capture an evolutionary snapshot that was previously inaccessible, filling a major gap in the fossil record.

Funding for this research was provided by the Key Program of the National Natural Science Foundation of China, the International Research Center of Big Data for Sustainable Development Goals, among other sources, underscoring the collaborative and interdisciplinary nature of this endeavor. The use of cutting-edge imaging technologies and fossil analysis techniques exemplifies the integration of modern scientific tools in unraveling deep-time biological mysteries.

Altogether, the discoveries of Eosteus chongqingensis and Megamastax amblyodus mark a paradigmatic shift in vertebrate paleontology by presenting the earliest clear anatomical evidence for the origin of bony fishes and elucidating critical evolutionary developments that laid the foundation for the diversity of vertebrates seen today. This work not only enhances the intricate tapestry of life’s history but also inspires continued exploration of early fossils to further decode the origins of vertebrate complexity.

Subject of Research: Origin and early evolution of bony fishes (Osteichthyes) based on new Silurian fossil discoveries.

Article Title: (Not provided in the content.)

News Publication Date: March 4 (year inferred as 2026 from DOI).

Web References:
DOI link to the article

Image Credits: Video by NICE PaleoVislab, IVPP

Keywords: Paleontology, Fossils, Bony fishes, Osteichthyes, Jawed vertebrates, Silurian period, Evolutionary biology, Vertebrate paleontology, Ray-finned fishes, Lobe-finned fishes, Early vertebrate evolution, Computed tomography (CT).