Dino of the Week: Serikornis

Type Species: Serikornis sungei

Classification: Dinosauria – Saurischia – Theropoda - Coelurosauria - Maniraptora - Paraves - Avialae

Time Period: Middle Jurassic

Location: China 

Diet: Insectivorous 

Serikornis is one of the earliest members of Paraves, a group of bird-like dinosaurs that is nevertheless outside the Eumaniraptora clade that includes the deinonychosaurs (such as troodontids and dromaeosaurs) and birds. Serikornis’ name means ‘Ge Sun’s silk bird,’ in reference to the feather-like body covering evident in the single complete articulated skeleton preserved on a slab in China’s fossil beds. The specimen’s nickname, ‘Silky,’ is given due to the resemblance of the hind-limb filaments to those of the modern Silky breed of chicken. This little critter would’ve been only two feet long beak-to-tail and stood only half a foot at the hips. Serikornis had wispy bundles of feathers along its neck, short and symmetrical vaned feathers on its arms, and both fuzz and long pennaceous feathers (also called ‘contour feathers,’ with a central shaft called a rachis with vanes spreading to either side) on its hind legs. Its tail was covered by filaments and distally by fine tail feathers. 

That Serikornis had feathers isn’t debated; but whether this small dinosaur could fly is another matter entirely. One of the key researchers, Ulysse Lefevre, notes, “The feathering of Serikornis shows for the first time a complete absence of barbules – that is, the microstructures that allow feathers to resist air pressure during wing beats. The plumage is composed of four wings, as with many theropod dinosaurs from China, but it did not allow ‘Silky’ to take off from the ground or from a tree.” According to Lefevre, Serikornis was a ground-hugger incapable of flight. The feathers, then, would’ve provided other functions: perhaps they were for insulation, or they were brightly colored and used in mating displays, intimidation of rivals, species recognition, or warding off predators. But not all paleontologists agree. Bristol University’s Professor Mike Benton argued that the presence of hind wings on its hind legs would’ve been more hindrance than help if Serikornis was fully terrestrial; he writes, “The hind wings would be inconvenient for a ground runner. The long feathers on the thigh and calf would be like very elaborate bell-bottomed trousers, rubbing and catching as the animal walked or ran.” He and others believe that the four-wing arrangement may represent a transitional stage between gliding and powered flight; Serikornis, then, may have been largely arboreal. Serikornis may give us a workable model for the evolution of powered flight, “in which little dinosaurs such as Serikornis clambered into trees, perhaps chasing insects and other small tree-dwellers for food. To escape predators or to get around, they would glide from bough to bough.” So if you were to take a trip into late Middle Jurassic China, you might encounter Serikornis leading its chicks on the ground – or perhaps you’d see them flying bough-to-bough in the conifer branches high above your head. Because we don’t have a time machine, we’ll never know for sure.