登入選單

返回Google圖書搜尋

Echinoids from the Triassic (St. Cassian) of Italy, Their Lantern Supports, and a Revised Phylogeny of Triassic Echinoids

Porter M. Kier

出版	Smithsonian Institution Press, 1984
主題	Nature / Animals / Marine LifeScience / Paleontology
ISBN	06081507629780608150765
URL	http://books.google.com.hk/books?id=3D-JWbBAo7YC&hl=&source=gbs_api

註釋

Three new species of Triassic echinoids are described from the St. Cassian (Karnian) beds of Cortina d'Ampezzo, Italy: Levicidaris furlani, L. pfaifferi, and Zardinechinus giulinii. Hundreds of echinoid fragments from the same beds show that 16 species lack apophyses (interambulacral lantern supports) and 7 possess them. Previously, paleontologists assumed that most Triassic echinoids had apophyses. Their absence from so many species and the presence of slightly developed auricles (ambulacral lantern supports) suggest that two echinoid lineages crossed from the Paleozoic to the Triassic: one, possessing apophyses, is ancestral to all modern cidaroids; a second, lacking apophyses, gave rise to all noncidaroid echinoids.