Migmanychion

MEANING: Claw mixture

PERIOD: Early Cretaceous

CONTINENT: Asia

Migmanychion is a small theropod with a peculiar combination of features shared with therizinosauroids and oviraptorosaurs. Migmanychion is a maniraptoran theropod, but its precise placement within the clade is unclear. It seems most closely related to Fukuivenator, which is thought to be a basal therizinosaur. Migmanychion was roughly 2 m in length.

Abstract from paper: A new small-bodied theropod dinosaur, Migmanychion laiyang gen. et sp. nov., is erected based on appendicular skeletal material from the Lower Cretaceous of the Pigeon Hill locality, Inner Mongolia, China. This theropod shows a peculiar combination of features in the hand, in part shared with therizinosauroids, oviraptorosaurs and with the enigmatic Fukuivenator paradoxus from Japan. Phylogenetic analysis supports the closest affinity of Migmanychion with Fukuivenator, yet alternative placements among Oviraptorosauria or among the non-avialan paravians result suboptimal descriptions of the character distribution. Although this new taxon is confidently referred to Maniraptora, this result is based uniquely on derived features of the hand: only additional material could substantiate its precise placement among the bird-like theropods. Fragmentary appendicular material from the same locality cannot be unambiguously referred to Migmanychion. One specimen, including associated partial pelvis and hindlimbs, is tentatively referred to a paravian maniraptoran.

Migmanychion is from the Early Cretaceous. The Cretaceous is the third and final geological period of the Mesozoic Era, with the Early Cretaceous making up roughly the first half, lasting from about 143 to 100 million years ago. The poles were ice-free, due to the relatively warm climate, and forests extended into high latitudes. The continued breakup of the continents created new coastlines and isolated landmasses, influencing the evolution of distinct dinosaur faunas.

It was a time of transition, as many groups of animals and plants began to take on more modern forms while others declined or disappeared. Pterosaurs continued to thrive, though early birds were becoming more diverse and widespread. Mammals remained small but adapted to a variety of ecological niches. In the oceans, ichthyosaurs and plesiosaurs were common, and early mosasaurs began to appear.

Dinosaurs remained the dominant land animals, with groups like iguanodontians, spinosaurids, and carcharodontosaurids rising to prominence. While sauropods declined in some regions, they remained abundant in the Southern Hemisphere. The first true ceratopsians appeared, and ankylosaurs replaced stegosaurs in their niche. Dromaeosaurs and other small theropods diversified. During this time, the first flowering plants evolved, gradually changing global ecosystems by providing new food sources for herbivores.

Migmanychion is a therizinosaur. Therizinosauria is an unusual group of theropod dinosaurs. Though descended from classic carnivorous ancestors, therizinosaurs underwent a dramatic evolutionary shift toward herbivory. Derived members are known for their bizarre and distinctive body plan: large, bulky bodies, small skulls with beaks, long necks, and some of the longest claws known in any land animal. These claws, while intimidating, were likely used for pulling down branches or defense rather than hunting. Their teeth were small and leaf-shaped, adapted for processing plant material, and some members even show evidence of a partially feathered or fully feathered coat, a trait inherited from their maniraptoran lineage.

Therizinosaurs lived during the Cretaceous Period and have been found primarily in Asia and North America. Their fossils are often discovered in floodplain or coastal environments, suggesting they may have browsed on a variety of vegetation. Despite their odd appearance, therizinosaurs are a clear example of how flexible theropods could be, evolving to fill ecological roles far beyond their predatory origins.