A remarkable discovery in the world of paleontology has unveiled a new chapter in the ancient history of Earth—a 160-million-year-old arboreal pterosaur species named ‘Monkeydactyl,’ sporting the oldest true opposed thumb ever identified in pterosaurs. This groundbreaking finding, led by an international team of researchers from China, Brazil, the UK, Denmark, and Japan, sheds light on the evolutionary adaptations of these prehistoric flying reptiles.
The newly described pterosaur species, Kunpengopterus antipollicatus, was unearthed from the Tiaojishan Formation in Liaoning, China—a region renowned for its rich deposits of Jurassic fossils. This small-bodied darwinopteran pterosaur boasted an estimated wingspan of 85 cm, making it a fascinating specimen for paleontologists worldwide.
What sets Kunpengopterus antipollicatus apart is its unique anatomical feature—an opposed pollex or “thumb” on both hands. The species name ‘antipollicatus,’ derived from ancient Greek, translates to ‘opposite thumbed,’ highlighting the significance of this newfound trait. This discovery marks the first instance of a pterosaur possessing an opposed thumb, making it the earliest record of such a structure in Earth’s history.
Opposed thumbs are a distinctive characteristic primarily observed in mammals, such as primates, and certain tree frogs, with chameleons being a notable exception among reptiles. The presence of an opposed thumb in Kunpengopterus antipollicatus challenges previous assumptions about pterosaur anatomy and highlights the diversity of adaptations these ancient creatures developed during their evolutionary history.
To unravel the mysteries of this ancient arboreal flyer, the research team utilized micro-computed tomography (micro-CT) scanning—a cutting-edge technique that employs X-rays to create detailed images of objects. Through meticulous analysis of the fossil’s forelimb morphology and musculature, they inferred that Kunpengopterus antipollicatus likely used its hand for grasping, a feature indicative of an arboreal lifestyle.
Dr. Fion Waisum Ma, a co-author of the study and Ph.D. researcher at the University of Birmingham, remarked on the significance of this discovery. “The fingers of ‘Monkeydactyl’ are tiny and partly embedded in the slab,” Dr. Ma explained. “Thanks to micro-CT scanning, we could see through the rocks, create digital models, and discern how the opposed thumb articulates with the other finger bones.”
The revelation of an arboreal lifestyle in Kunpengopterus antipollicatus is further supported by an analysis of anatomical characters related to arboreal adaptation. While this pterosaur species displayed clear adaptations for tree-dwelling, other pterosaurs from the same ecosystem did not exhibit similar features. This observation suggests niche-partitioning among these ancient flyers and provides quantitative evidence of arboreal behavior in at least some darwinopteran pterosaurs.
Xuanyu Zhou from China University of Geosciences, who led the study, commented on the ecological implications of the discovery. “Tiaojishan palaeoforest is home to many organisms, including three genera of darwinopteran pterosaurs,” Zhou stated. “Our results indicate that K. antipollicatus occupied a different niche from Darwinopterus and Wukongopterus, likely minimizing competition among these pterosaurs.”
Rodrigo V. Pêgas from the Federal University of ABC, Brazil, emphasized the significance of darwinopteran pterosaurs in understanding evolutionary transitions. “Darwinopterans are a group of pterosaurs named after Darwin due to their transitional anatomy,” Pêgas explained. “They provide valuable insights into how evolution shaped pterosaur anatomy over time.”
The discovery of Kunpengopterus antipollicatus, the ‘Monkeydactyl,’ is a testament to the ongoing exploration of Earth’s ancient past and the remarkable adaptations that fueled the diversity of life throughout history. As paleontologists continue to unearth new fossils and unlock the secrets of prehistoric ecosystems, each discovery offers a glimpse into the intricate tapestry of evolution that has shaped our planet for millions of years.
The research was published in the journal Current Biology.
Source: University of Birmingham