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Holonema
''Holonema'' is an extinct genus of relatively large, barrel-shaped arthrodire placoderms that were found in oceans throughout the world from the Mid to Late Devonian, when the last species perished in the Frasnian-Fammian extinction event. Most species of the genus are known from fragments of their armor, but the Gogo Reef species, ''H. westolli'', is known from whole, articulated specimens. Holonema is thought to have been a Demersal fish, benthic-dwelling fish, based on its cambered body shape, which performs better Fluid dynamics, hydrodynamically when closer to the sea bed.https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/g1999n1a4.pdf According to these specimens, species of ''Holonema'' lived by grazing on stony, horn-shaped, stromatolite-like algae called oncholite, apparently by snipping off the points with a specialized snout. Species ''H. rugosum'' ''H. rugosum'' is the type species. It was originally described as a species of the antiarch genus, ''Pteri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holonematidae
Holonematidae is an extinct family of relatively large arthrodire placoderms from the Early to Late Devonian. Almost all fossil specimens are of armor fragments, though, all have distinctive ornamentation, often of unique arrangements and patterns of tubercles, that are diagnostic of the family. The trunkshield is very elongated, giving the armor an overall "barrel" like appearance. Due to pebbles found inside articulated specimens of the Frasnian species, ''Holonema westolli'', holonematids are thought to have been specialized herbivores that grazed on a form of horn-shaped, stony algae called "onycholite," snipping off the tips with their odd snouts. Genera ''Artesonema'' A poorly known genus from the Givetian-aged Blacourt Formation of Boulonnais, France.LELIEVRE, n.; GOUJET, D., BLIECK, A. & JANVIER, P. 1986. ''Poissons du DEvonien du Boutonnais (France)''. - n:BRICE, D. d.Le DEvonien de Ferques, Bas -Boulonnais (N. France) - Biostratigraphie du PalEozoique 7: 503-522, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |