An remarkable fossil find in Germany is providing unprecedented insights into the appearance, movement, and evolution of marine reptiles. The specimen, a Plesiopterys wildi discovered in Holzmaden, includes preserved soft tissues offering paleontologists a new perspective on these ancient predators. The fossil, known as MH 7, features patches of skin, scale, and keratin, as detailed in a new study published in Current Biology.

MH 7: A Glimpse into a 183-Million-Year-Old Past

The MH 7 specimen, found in 1940 but prepared only in 2020, held its secrets until recently. After technicians carefully removed the surrounding limestone, they uncovered preserved skin on the tail and flipper, a rare occurrence for Jurassic reptiles. Microscopic analysis identified two types of keratin: beta-keratin on the flipper scales and alpha-keratin on the tail skin, suggesting different functions across the body. The tiny and triangular flipper scales indicate a reinforced structure for aquatic propulsion.

“The Holzmaden specimen gives us an unprecedented look at Plesiopterys wildi… allowing us to refine our understanding of this species.”

Miguel Marx, lead author from Lund University, emphasized the fossil’s importance, stating, “The Holzmaden specimen gives us an unprecedented look at Plesiopterys wildi in a more mature stage of advancement, allowing us to refine our understanding of this species and its place in plesiosaur evolution.”

The exceptional preservation is attributed to the fossil’s burial in the Posidonia Shale, a low-oxygen seabed environment that slowed decomposition and facilitated soft tissue fossilization. This find is especially significant as plesiosaurs are typically known only from skeletal remains.

Unlocking Secrets: Camouflage, Hydrodynamics, and Evolutionary Adaptations

The tail skin’s smooth, layered surface, rich in melanosomes (pigment granules), suggests potential mottled coloring.This challenges the conventional view of plesiosaurs as uniformly pale, indicating they may have possessed visual camouflage or social signaling traits, similar to modern marine animals.

The flippers,covered in scales and keratin,were likely used for both thrust and precise steering,akin to sea turtle forelimbs. The variation in skin type across the body points to biomechanical specialization, combining agility with endurance.

According to Marx and his colleagues, “It also suggests that distinct plesiosaur communities may have evolved in different regions of the European seas during the Early Jurassic.”

This discovery highlights parallel evolution, were geographically isolated groups adapted to different marine environments, influencing thier physical characteristics and behaviors.

The Tail’s Role: Steering and Acceleration

The fossilized evidence of a fleshy tail fin, a rarity among plesiosaurs, adds another layer of understanding. This broad, flexible structure likely served as a rudder or an Auxiliary Propellor, enabling sharp turns and bursts of speed. combined with their four flippers and long necks, plesiosaurs may have been more maneuverable than previously thought.

These findings suggest a unique survival strategy: outmaneuvering predators like ichthyosaurs and ancient crocodilians through agile turning, subtle control, and silent gliding, giving Plesiopterys wildi a competitive advantage in hunting and evading danger.