Gogia stephenensis (GSC 25954) – Paratype. Small specimen showing strongly ridged plates and three brachioles near the top. Specimen height = 16 mm. Specimen dry – direct light (left), dry – polarized light (right). Walcott Quarry.
© Geological Survey of Canada. Photos: Jean-Bernard Caron
Gogia is a common eocrinoid, related to the blastozoans, an early group of echinoderms (Sprinkle, 1973).
Gogia – from Gog Lake, 60 km southeast of Field in Mount Assiniboine Provincial Park.
stephenensis – from Mount Stephen (3,199 m), the mountain peak in Yoho National Park from which the specimens were collected. Named in 1886 for George Stephen, the first president of the Canadian Pacific Railway.
Burgess Shale and vicinity: none.
Other deposits: G. prolifica Walcott 1917 (type species) from the Middle Cambrian Mount Whyte formation of Alberta; G. gondi Ubaghs, 1987 from the upper Middle Cambrian of France; G. granulosa Robinson 1965 from the early Middle Cambrian Spence Shale of Utah and the Early-Middle Cambrian of Mexico; G. gondi Ubaghs, 1987 from the the Middle Cambrian of Montagne Noire, G. hobbsi Sprinkle 1973; G. kitchenerensis Sprinkle 1973 from the Spence Shale of Utah; G. longidactylus (Walcott 1886) Robinson 1965 from the Middle Cambrian of Nevada; G. multibrachiatus (Kirk 1945) Robinson 1965 from the Middle Cambrian Bright Angel Shale, Grand Canyon, Arizona; G. ojenai Durham 1978 from the late Early Cambrian of California; G. palmeri Sprinkle 1973 from the Middle Cambrian of Idaho; G. parsleyi Zamora 2009 from the Middle Cambrian Murero Formation of Spain; and G. spiralis Robinson 1965 from the Middle Cambrian Wheeler Shale of Utah. (See complete list of references in Sprinkle, 1973 and Zamora et al. 2010.)
The Walcott Quarry on Fossil Ridge and the Trilobite Beds on Mount Stephen.
Though the genus Gogia was described by Walcott in 1917 from material collected in the Lower Middle Cambrian Mount Whyte Formation, it was not recognized in the Burgess Shale until 1966 when a single specimen was discovered by the Geological Survey of Canada in the Walcott Quarry. Together with additional specimens identified in the Walcott collection, Sprinkle named this form G.(?) radiata (Sprinkle, 1973). Additional material collected by the Royal Ontario Museum led to designate the current species replacing G.(?) radiata (Sprinkle and Collins, 2006).
G. stephenensis consists of a rounded conical body (theca) on a short stalk with around a dozen straight arms near the top (brachioles), which in this species may branch at least once along their length. The theca is composed of a patchwork of interlocking plates. The larger plates are strongly ridged.
Though the genus is abundant in other deposits, Gogia is markedly rare in all the Burgess Shale localities.
Gogia was attached to the sea floor by a short calcified stalk and fed by capturing small water-borne particles with its thin, tendril-like arms. Food particles were transported from the arms to food grooves (ambulacrum) into a central mouth at the top of the theca.
SPRINKLE, J. 1973. Morphology and evolution of blastozoan echinoderms. Harvard University, Museum of Comparative Zoology Special Publication: 1-284.
SPRINKLE, J. AND D. COLLINS. 2006. New eocrinoids from the Burgess Shale, southern British Columbia, Canada, and the Spence Shale, northern Utah, USA. Canadian Journal of Earth Sciences, 43: 303-322.
WALCOTT, C. D. 1917. Cambrian geology and paleontology. IV. Fauna of the Mount Whyte Formation: Smithsonian Miscellaneous Collections, 63: 61-114.
ZAMORA, S. R. GOZALO AND E. LINÑÁN. 2009. Middle Cambrian Gogiid Echinoderms from Northeast Spain: Taxonomy, Palaeoecology, and Palaeogeographic Implications. Acta Palaeontologica Polonica, 54: 253-265.
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