Cladus: Eukaryota Name Haplocerataceae Zittel, 1884 References * The Paleobiology Database Accessed on 12/14/08 Haplocerataceae is a superfamily of ammonoid cephalopods belonging to the Ammonitida that unites three families, the Strigoceratidae, Oppeliidae, and Haploceratidae, listed below. The Haplocerataceae begins with all three families in the lower Middle Jurassic, Bajocian. The Strigoceratidae is limited to the Bajocian but the Oppeliidae, and Haploceratidae extend through the remaining Jurassic, well into the Cretaceous; the Oppeliidae into the middle Albian, the Haplocertidae only into the Valanginian. Diagnosis Haplocerataceae are typically compressed, discoidal Ammontida that may be keeled or unkeeled, tending to be oxyconic, with usually falcoid or falcate ribbing. The aptychi are double and differ between families and have been found in situ in e.g. Oppelia subrudiata and in Pseudolissoceras. Taxonomy The Origin of the Haplocerataceae is undetermined but it is likely all three component families have their beginnings in the Hammatoceratidae in the middle Bajocian. None of the Haplocerataceae is though to have given rise to any subsequent group. Superfamily Haplocerataceae Zittel, 1884 * Family Haploceratidae Zittel, 1884 References * Treatise on Invertebrate Paleontology, Part L Ammonoidea, (L171), Geological Society of America and University of Kansas press, 1964. Source: Wikipedia, Wikispecies: All text is available under the terms of the GNU Free Documentation License |
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