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
USS Calamus (AOG-25) as did the combatant ships. While at Okinawa "Calamus" was beached as a result of Typhoon Louise, 9 October 1945, refloated 24 October 1945, repaired and returned to service. Following occupation service, "Calamus" returned to San Francisco, California, 20 March 1946 and was struck from the Navy list (date unknown). She was decommissioned 15 May 1946, and transferred to the Maritime Commission 4 September 1946. Final disposition: she was scrapped in 1964. "Calamus" received one battle star for service in World War II. Her crew was eligible for the following medals: USS Calamus (AOG-25) USS "Calamus" (AOG-25) was a "Mettawee"-class