|Reconstruction of Kulindadromeus zabaikalicus showing integument patterns preserved on the fossils.|
Godefroit et al., 2014
The fossil shows clear signs of feather-like structures on its body. This is important because it was not known whether this group had proto-feathers. These structures probably had the function of temperature regulation: they were not flight feathers.
The original specimen was a partial skull with lower jaws. The volcanic ash layers of the formation form a Konservat-Lagerstätte with exceptional preservation. From 2010 onwards, more fossil material has been discovered, including subadult and juvenile individuals.
Features of the body surface[change | change source]
Specimens show large parts of its body surface (skin or 'integuent'). There are rows of scales on top of its tail and a covering of scales branching into feather-like structures. Until its discovery proto-feathers were thought to be only in the Theropoda. The feather remains discovered are of three types.
The first type consists of hair-like filaments covering the trunk, neck and head. These are up to three centimetres long and resemble the "dino-fuzz" already known from theropods like Sinosauropteryx. The second type shows groups of 1.5 centimetres-long filaments, each group coming from a base plate. These are on the upper arm and thigh. The base plates are ordered in a hexagonal pattern but do not touch each other. The third type is unique. It was found on the upper lower legs and consists of bundles of six or seven ribbon-like structures, up to two centimetres long. Each ribbon is made from about ten parallel filaments up to 0.1 millimetres wide.
The filaments earlier reported in Ornithischia, on Psittacosaurus and Tianyulong, could be homologous to the "protofeathers" found in non-avian theropods. This would imply that feathers are original to the Dinosauria as a whole and possibly to the Archosauria as a whole, since there are similar structures in the Pterosauria.
There are also three types of scales. Overlapping hexagonal scales, up to 3.5 millimetres in diameter, are present on the lower shins. Small round non-overlapping scales, less than one millimetre in cross-section, cover the hands, ankles and feet. The top of the tail is covered by five long rows of arched rectangular scales, measuring up to one by two centimetres. With these scales the trailing edge of each scale slightly overlaps the front edge of the scale behind it. In the middle, to the contrary, a small spur projects forward, covering the trailing edge of the preceding scale. The authors think the scales were not ossified scutes or osteoderms.
References[change | change source]
- Andrea Cau (November 24, 2015). "Cosa è Lepidocheirosaurus?". Theropoda. Retrieved November 25, 2015.
- Ghosh, Pallab 2014. 'Fluffy and feathery' dinosaurs were widespread. BBC News Science & Environment. 
- Godefroit, Pascal et al 2014, A Jurassic ornithischian dinosaur from Siberia with both feathers and scales. Science 345 (6195): 451-455. 
- Vergano, Dan 2014 Siberian discovery suggests almost all dinosaurs were feathered. National Geographic Daily News.