Sinornithosaurus form from those found on birds from the same geological deposits. The body (contour) feathers were generally between 3-4.5 cm long and included two types: the first type are formed of several filaments joined together into "tufts", similar to modern down feathers. The second type, including those on the arms, were composed of rows of filaments ("barbs") joined together along a main shaft ("rachis"), making them similar in structure to modern bird feathers. However, unlike the wing feathers of flying birds, they did not have the secondary branches with tiny little hooks ("barbules") that flight feathers have, which allow the
Calamus caryotoides Calamus caryotoides Calamus caryotoides (also "Palmijuncus caryotoides"), more commonly known as fishtail lawyer cane is a North-East Queensland tropical forest climbing palm with very thin () flexible trunks; no crownshaft; small spikes; dark green, glossy, fish-tail shaped leaves reaching up to high ( spread); and very thin hooked flagella. It tends to clump and grow up into the shaded understory of Queensland's wet tropical forests, and is a close relative of the more infamous "Calamus radicalis" (aka Wait-a-While). The Cairns Botanical Gardens records local Yidinydji, Yirrganyydji, Djabuganydji, and Gungganydji use "Calamus caryotoides" (also known to Yidinydji as Bugul, pronounced BOOK-KOOL)