Amaltheidae
Sign in to saveAmaltheidae is a family of eoderoceratoidean ammonitids from the Lower Jurassic consisting of genera characterised by stigated discoidal oxycones—narrow involute shells with narrowly rounded to angular venters that bear a series of grooves, or ridges, along broad flanks, which according to the Treatise L, 1957, evolved into strongly ribbed planulates (discoidal evolute shells) with quadrate whorls, typically with crenulated keels; involving all together four genera.
~2 min read
Encyclopedic overview
1 sectionsContents
- References
Amaltheidae is a family of eoderoceratoidean ammonitids from the Lower Jurassic consisting of genera characterised by stigated discoidal oxycones—narrow involute shells with narrowly rounded to angular venters that bear a series of grooves, or ridges, along broad flanks, which according to the Treatise L, 1957, evolved into strongly ribbed planulates (discoidal evolute shells) with quadrate whorls, typically with crenulated keels; involving all together four genera.
Donovan in Donovan et al. (1981) retains the Amaltheidae in the sense of Arkell, et al. 1957, as shown in the Treatise but synonymizes Pseudoamaltheus with Amaltheus, (a subgenus in the Treatise), reducing the number of valid genera to three. These are Amaltheus, Amauroceras, and Pleuroceras.
Excerpted from Wikipedia’s “Amaltheidae” article, available under the CC BY-SA 4.0 licence.