Trigonellites is an extinct genus of basal ammonite, known from two or three species, discovered in outcrops of the Late Jurassic-aged Kimmeridge Clay Formation in Ely and Cumnor, England and possibly also an unnamed Early Triassic-aged rock formation in Bindlach, Germany.[2] It was originally classified as a bivalve,[1] but it has since been classed as an ammonite species. Only two species once placed in the genus are still considered valid today: T. latus and T. curvirostris, with one dubious species, T. simplex, possibly being a species of Lyrodon.[1]

Trigonellites
Temporal range: Late Jurassic,
~156–151 Ma
1895 drawing of an aptychi of T. latus
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: Ammonoidea
Genus: Trigonellites
Parkinson, 1811
Type species
Trigonellites latus
Parkinson, 1811
Other species
  • T. curvirostris Schlotheim, 1836
  • T. simplex? Schlotheim, 1863 vide Goldfuss, 1863[1]
Synonyms

The genus name Trigonellites was originally proposed for some calcareous plates found in Cretaceous oolitic rocks, but these have since been declassed as indeterminate ammonites as the name was never published. The name has since been used to represent two species of Late Jurassic (c.156-151 Ma) ammonites and one Early Triassic (c.242.7 Ma) species.[1]

References

edit
  1. ^ a b c d G. A. Goldfuss. (1863). Abbildungen und Beschreibungen der Petrefacten Deutschlands und der angrenzenden Länder. Divisio Quarta: Molluscorum acephalicorum reliquiae. Muschelthiere der Vorwelt. 1. Bivalvia. Petrefacta Germaniae 4(1):1-273
  2. ^ J. Prestwich. (1879). On the discovery of a species of Iguanodon in the Kimmeridge Clay near Oxford; and a notice of a very fossiliferous band of the Shotover Sands. Geological Magazine, new series, decade 2 6(5):193-195