Tag Archives: Jaws

Fossil Evidence Reveals Early Platypuses Had Strong Teeth and Powerful Jaws

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Recent fossil discoveries from the Namba Formation in South Australia have revealed that 25 million years ago, Obdurodon’s insignis — an ancient, larger, toothed ancestor of the modern platypus (Ornithorhynchus anatinus) — thrived alongside freshwater dolphins and other now-extinct species in verdant inland lakes.

An artist’s impression of the approximately 25-million-year-old fossil platypus and its surroundings. Image credit: Gen Conway, Flinders University Institute of Paleontology

“The platypus is extremely rare in the fossil record, mostly limited to tooth remains, making the discovery of new fossils significant for understanding this unique mammal,” stated Flinders University palaeontologist Dr. Aaron Camens.

First described in 1975, Obdurodon’s insignis inhabited the vast permanent lakes, slow-flowing rivers, and forested lowlands of central Australia during the late Oligocene, approximately 25 million years ago.

This species notably differs from today’s platypuses, possessing fully formed molars and premolars, unlike modern platypuses, which lose their vestigial teeth shortly after hatching.

Previously, Obdurodon’s insignis was known only from limited remains, including one and a half molars and fragments of the jaw and pelvis. However, this recent find includes one of the few well-preserved fossils of a related younger species, Obdurodon dicksoni, identified in 1992.

While Obdurodon dicksoni resembled modern platypuses, it had a slightly larger skull and a stronger bite.

“The new material of Obdurodon’s insignis includes the first premolars, the key teeth located in front of the molars,” said Dr. Camens. “This species had large, pointed front teeth and formidable molars capable of crushing shelled animals, such as yabbies.”

Dr. Trevor Worthy, also from Flinders University, highlighted an intriguing discovery: the scapulochoroid bone, which supports the arms and forelimbs. “This finding indicates that the limb structure closely resembles that of modern platypuses, suggesting ancient platypuses were adept swimmers like their modern relatives,” he noted.

“These fossils, dating back 25 million years, provide a glimpse of an ancient platypus that was larger and possessed teeth compared to modern variants.”

Research indicates that during this period, dense forests nurtured diverse communities of arboreal mammals, including koalas and various possum species.

On the forest floor, a sheep-sized marsupial coexisted with numerous other species, including familiar lizards, frogs, and small carnivorous marsupials.

These ancient trees also hosted a variety of birds, including the impressive Steller’s sea eagle, Archehieracus.

The ancient lakes teemed with lungfish and other small fish, while several species of waterfowl, cormorants, and flamingos thrived along the shores, feeding on fish, plants, and small invertebrates.

Interestingly, these freshwater ecosystems were also home to small dolphins, with their teeth and bones discovered at several fossil locations, revealing signs of this diverse ancient community.

“This rich environment was where the ancient toothed platypus lived 25 million years ago, before its remains settled into the lake’s depths,” explained Dr. Jen Conway, also from Flinders University.

This remarkable discovery is detailed in the latest issue of Australian Zoologist.

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Trevor H. Worthy et al. 2026. New material for the toothed platypus Obdurodon’s insignis (Monotremata: Ornithorhynchidae) from the Late Oligocene fauna of Pimpa, Billeroo Creek, South Australia. Australian Zoologist 45 (1): AZ26011; doi: 10.1071/AZ26011

Source: www.sci.news

Triassic Fossil Discovery: Ancient Crocodile Cousin with Powerful Jaws Unveiled at Museum

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CT scans of specimens from the Yale Peabody Museum of Natural History have unveiled a new species of short-nosed crocodilian with remarkably robust jaws, offering a glimpse into late Triassic ecological specialization.

Eosphorosuchus lacrimosa (left) is disturbed by Hesperosuchus agilis (right) near the carcass of Coelophysis at Ghost Ranch, New Mexico, USA. Image credit: Julio Lacerda.

Eosphorosuchus lacrimosa thrived 210 million years ago, inhabiting areas near rivers and lakes in present-day New Mexico, USA.

This ancient reptile was known for its speed, featuring large hind legs and small, slender arms.

Characterized by a short snout, a heavily fortified skull, and powerful jaw muscles, Eosphorosuchus lacrimosa was adept at swiftly catching sizable prey.

“This discovery highlights the early diversification of primitive crocodiles at the onset of the reptilian era,” stated Dr. Bart Anjan Brar, a paleontologist at Yale University and the Yale Peabody Museum of Natural History.

“During this Late Triassic period, two dominating reptilian lineages were emerging: one lineage led to modern crocodiles, while the other gave rise to birds—and, eventually, dinosaurs.”

In contrast to dinosaurs of that time, which were slender and agile, resembling herons, ancient crocodiles were robust four-legged predators, sharing physical traits with jackals and large foxes.

The holotype specimen of Eosphorosuchus lacrimosa comprises its skull, lower jaw, spine, limbs, and sections of its armor.

Discovered in 1948 at Ghost Ranch, New Mexico, this fossil remained largely unexplored for 75 years until now.

Phylogenetic analysis positions Eosphorosuchus lacrimosa near the base of Crocodylomorpha, outside a clade that also includes the small crocodilian, Hesperosuchus agilis.

This positioning suggests that its distinct traits evolved early in crocodilian history.

The fossilized remains indicate that Eosphorosuchus lacrimosa coexisted with Hesperosuchus agilis, hinting at early ecological niche differentiation among similarly sized terrestrial predators.

“Eosphorosuchus lacrimosa is one of the few well-preserved relatives of early crocodilians, representing the ‘dawn’ of functional diversification within the lineage leading to modern crocodiles,” noted Miranda Margulis Onuma, a doctoral student at Yale University.

“Beyond its unique anatomy and preservation history, this specimen underscores the potential of existing museum collections to unveil new insights into life’s history.”

Notably, the discovery provides a rare look into an ancient ecosystem where biodiversity flourished, and species exhibited specialized feeding structures to fulfill distinct ecological roles.

The research team’s study appears this month in Proceedings of the Royal Society B.

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Miranda Margulis Onuma et al. 2026. Short-snouted phenosuchids with unusual feeding anatomy indicate that ecological specialization occurred early in crocodilian evolution. Proc Biol Sci 293 (2069): 20260130; doi: 10.1098/rspb.2026.0130

Source: www.sci.news

Powerful Jaws of Early Triassic Cyclidan Crustaceans: A Deep Dive into Ancient Marine Life

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Paleontologists have unveiled a fascinating new species of enigmatic ciclidan crustacean, identified from three exceptionally preserved specimens hailing from China’s Early Triassic Guiyang biota.

Yunnanosiculus fortis. Image credit: Sun et al., doi: 10.1002/spp2.70052.

The Cyclidae represent a unique group of arthropods that first emerged during the Carboniferous period and persisted until the late Cretaceous period.

Despite their significance, their fossil record is scant, as most findings only display the carapace (hard shell) of these creatures, with many anatomical features remaining elusive.

“Cyclida is an arthropod order integral to the Guiyang biota,” explains Dr. Xiaoyuan Sun from the China University of Geosciences, alongside collaborators from China and the United States.

“This specialized group of crustaceans originated in the Mississippi Sea (359-323 million years ago) and went extinct during the Maastrichtian (73-66 million years ago) of the Late Cretaceous Period.”

“They’re classified as crustaceans due to distinctive traits such as antennae, mandibles, and maxillae.”

“Sadly, our comprehension of ciclidan crustaceans remains limited because of their rarity in the fossil record.”

Typically, only the robust carapace is preserved, with the antennae and limbs being scarcely found.

The newly identified ciclidan species, designated Yunnanosiculus fortis, thrived during the late Dinerian period of the early Triassic, around 251 million years ago.

It is described based on three specimens sourced from the Daye Formation in Guizhou Province, China.

These fossils unveil an oval carapace featuring narrow, smooth margins, well-defined antennae, and seven pairs of thoracic segments.

Significantly, one specimen retains a pair of robust lower jaws, an exceptionally rare feature in ciclidan fossils.

The holotype’s carapace measures approximately 19.8 mm long by 14.7 mm wide, with the lower jaw spanning about 1.7 mm long and 0.8 mm wide.

Microscopic X-ray fluorescence analysis revealed elevated levels of calcium and phosphorus within the mandible and other structures, indicating they were thick and heavily calcified.

“Yunnanosiculus fortis boasted a notably sturdy oval lower jaw,” the research team stated.

Holotype of Yunnanosiculus fortis. Scale bar – 2 mm. Image credit: Sun et al., doi: 10.1002/spp2.70052.

This remarkable discovery broadens the known geographic range of Early Triassic cichlidans.

Previously, fossils from this era were primarily registered from Madagascar and select regions of Europe.

The new species signifies the oldest record of cichlidans located in the eastern Tethyan area.

“The identification of this new species from China enhances our understanding of the paleogeographical distribution of Early Triassic cichlidans,” the researchers noted.

“Early Triassic cyclidans demonstrate widespread distribution across Madagascar, Europe, and China.”

“However, by the Late Triassic, their presence was predominantly limited to Europe.”

These fossils also provide insights into the evolutionary trajectory of these enigmatic creatures.

By examining the morphological data from Yunnanosiculus fortis, scientists reconstructed morphospace—an approach to analyze the diversity of body morphology within cichlidans and other related species.

The findings indicate that cichlidans underwent significant diversification early in their history during the Carboniferous period, with a gradual reduction in disparity in later geologic periods.

This pattern corroborates the “initial burst” model of evolution, where groups diversify rapidly soon after emerging, followed by a phase of slow evolutionary change.

This discovery further enriches our understanding of ecosystems following the Permian-Triassic mass extinction, which eradicated over 80% of marine life.

The fossil evidence from the Guiyang biota and other Early Triassic sites suggests that complex marine communities might have been reinstated earlier than initially believed.

By revealing new anatomical details and extending the geographic record of cichlidans, Yunnanosiculus fortis offers valuable insights into the recovery and evolution of marine life during one of Earth’s most chaotic periods.

“The addition of new species and the re-evaluation of the chronological paleogeography of Triassic cichlids illustrate that early Triassic cichlids were the most broadly distributed, with a gradual decline in distribution thereafter,” the authors concluded.

“This trend mirrors the global distribution of ammonoid and other marine invertebrate species during the Early Triassic and may relate to the reduction of environmental gradients in varying latitudinal zones post-Permian-Triassic mass extinction.”

The groundbreaking discovery of Yunnanosiculus fortis is discussed in the research paper published in the journal Paleontology Papers.

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Sun Xiaoyuan et al.. 2025. A new Induan (Early Triassic, Dinerian) cichlidan crustacean discovered from the Guiyang biota. Paleontology Papers 11 (6): e70052; doi: 10.1002/spp2.70052

Source: www.sci.news

Why Humans Are the Only Primates with Jaws: New Insights Revealed

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The Human Jaw: An Evolutionary Enigma

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Humans possess a distinctive jaw structure, setting them apart from other primates. Recent analyses reveal that this anatomical feature likely emerged not for a specific purpose but as an incidental outcome of various evolutionary adaptations driven by natural selection.

According to Noreen von Cramon-Taubadel from the University at Buffalo, New York, “It’s a misconception that every significant trait between species has been shaped by natural selection with a specific intent. Evolution is frequently more complex and directionless than anticipated.”

The chin, a prominent bony projection of the lower jaw, significantly differentiates humans from other species. Among primates, particularly Homo sapiens, its evolutionary purpose remains a subject of intrigue.

Some researchers posit that the chin might alleviate stress during chewing or play a role in speech formation, while others suggest it may have evolved through sexual selection, with individuals preferring partners showcasing this unique facial attribute.

Conversely, some scientists challenge the idea of any practical function for the chin, contemplating whether its emergence was simply a byproduct of cranial and jaw evolution.

Von Cramon-Taubadel and her team hypothesize that the development of the human chin might actually be attributable to genetic drift, a random evolutionary process.

In their investigation, they studied 532 museum skulls belonging to humans and 14 other modern ape species, including chimpanzees, bonobos, gorillas, orangutans, and gibbons.

Measurements were taken at 46 anatomical landmarks on the skull and jaw, including nine points defining the human jaw, forming a comprehensive evolutionary map.

Utilizing these data, they estimated the head and jaw characteristics of the last common ancestor of all great apes, and applied a standard quantitative genetic model to evaluate genetic drift across family branches.

The findings indicated that three traits associated with the human jaw likely underwent direct selection, while six others appeared to be either neutral or byproducts of other evolutionary changes unrelated to jaw development.

As early human ancestors became more bipedal, the base of their skulls shifted, allowing for a more supportive facial structure. This transformation led to an evolution from pronounced front teeth and strong jaw muscles to diminished traits, ultimately producing a pronounced lower jaw that extends beyond the teeth, marking the emergence of the jaw as we know it.

This unique jaw structure is likely a byproduct of adapting to upright walking, having larger brains, and smaller teeth. According to von Cramon-Taubadel, this illustrates how changes in one area can inadvertently impact others in the evolutionary process.

As noted by Alessio Veneziano from the French National Museum of Natural History in Paris, this jaw structure is a “textbook example” of maladaptation—a characteristic that arises without the direct influence of natural selection. “It’s intriguing to confirm significant evolutionary trends that occur without adaptability,” he remarks.

This evolutionary byproduct is often termed a spandrel, a concept derived from architecture describing a space created by the shape of another structure. Other examples include the human navel or features of the small tyrannosaurus rex.

The study reveals the intricate connections between skull and jaw as a cohesive unit. As highlighted by James DiFrisco at the Francis Crick Institute in London, “Observable features like the jaw may appear as separate entities, but that doesn’t imply they evolved independently.”

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