Eiffelospongia hirsuta (ROM 43828) – Holotype. Specimen with well preserved bearded root tuft. Specimen height = 8 mm. Specimen dry – direct light (left), wet – polarized light (right). Trilobite Beds on Mount Stephen.
© Royal Ontario Museum. Photos: Jean-Bernard Caron
This species resembles Diagoniella but belongs to sponges with calcium carbonate (calcite or aragonite) spicules (Rigby and Collins, 2004).
Eiffelospongia – from the nearby Eiffel Peak, named on account of its resemblance to Paris’ Eiffel Tower, and spongia, the Latin word meaning “sponge.”
hirsuta – from the Latin hirtus, “hairy,” referring to the hairy or beard-like appearance of the basal tuft and dermal layer of this species.
Burgess Shale and vicinity: none.
Other deposits: none.
The Trilobite Beds on Mount Stephen.
This genus was named by Rigby and Collins in 2004 based on new material collected from the Trilobite Beds on Mount Stephen by the Royal Ontario Museum.
Eiffelospongia is a small (less than 1 cm) oval or keg-shaped sponge with a large central cavity and a small osculum (opening at the top) with a flat margin. The skeleton of Eiffelospongia is composed of two orders of spicules: long thin-rayed spicules with six-pointed ends (hexaradiate), that thatch together to give shape to the sponge, and a second type of spicules which are much smaller and occur in the spaces between the long spicules. The basal part of the sponge is defined by long coarse spicules, arranged lengthways, that form a triangular tuft shape.
The species is known from only a few specimens from the Trilobite Beds on Mount Stephen.
Eiffelospongia would have lived with its bearded root tuft attached to the sea floor. Particles of organic matter were extracted from the water as they passed through canals in the sponge’s wall.
RIGBY, J. K. AND D. COLLINS. 2004. Sponges of the Middle Cambrian Burgess Shale and Stephen Formations, British Columbia. Royal Ontario Museum Contributions in Science (1): 155 p.
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