Choia
Encyclopedia
Choia is a fossil demosponge
dating to the Cambrian
and Lower Ordovician periods. It was unusual because it was not attached to the sea bed, and radiated spines from the edge of its flattish, conical body, producing an appearance not unlike that of the peak of a big top
, with guy lines. Water entered the sponge parallel to the spines, being expelled, presumbaly, from a central opening. It reached 28 mm in diameter.
Fossils of Choia have been found in the Burgess Shale
in British Columbia
; the Maotianshan shales
of China
; the Wheeler Shale in Utah
; and the Lower Ordovician Fezouata formation
.
Demosponge
The Demospongiae are the largest class in the phylum Porifera. Their "skeletons" are made of spicules consisting of fibers of the protein spongin, the mineral silica, or both. Where spicules of silica are present, they have a different shape from those in the otherwise similar glass sponges...
dating to the Cambrian
Cambrian
The Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...
and Lower Ordovician periods. It was unusual because it was not attached to the sea bed, and radiated spines from the edge of its flattish, conical body, producing an appearance not unlike that of the peak of a big top
Big Top
Big Top may refer to:* Big top , the biggest tent in early-20th century circuses, where the circus itself took place* Big Top , a Transformers character* Big Top , a children's television series in the 1950s...
, with guy lines. Water entered the sponge parallel to the spines, being expelled, presumbaly, from a central opening. It reached 28 mm in diameter.
Fossils of Choia have been found in the Burgess Shale
Burgess Shale
The Burgess Shale Formation, located in the Canadian Rockies of British Columbia, is one of the world's most celebrated fossil fields, and the best of its kind. It is famous for the exceptional preservation of the soft parts of its fossils...
in British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
; the Maotianshan shales
Maotianshan shales
The Maotianshan Shales are a series of lower Cambrian deposits in the Chiungchussu formation, famous for their Konservat Lagerstätten, or high number of fossils preserved in place...
of China
People's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
; the Wheeler Shale in Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
; and the Lower Ordovician Fezouata formation
Fezouata formation
The Upper and Lower Fezouata formations of Morocco are Burgess shale-type deposits dating to the Lower Ordovician, filling an important preservational window between the common Cambrian lagerstätten and the Late Ordovician Soom shale...
.