Hettangian

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The Hettangian is the first stage of the Early Jurassic Epoch. It spans the time between 199.6 ± 0.6 Ma and 196.5 ± 1 Ma (million years ago). The stage follows the Rhaetian Stage of the Triassic Period.

The stage takes its name from Hettange-Grande, a town in northern France, just south of the border with Luxembourg on the main road from Luxembourg City to Metz.

In Europe this period, together with the Sinemurian, is also known as the Lower (or Blue) Lias Stage.

Contents 1 Vertebrate Fauna 1.1 Ichthyosaurs 1.2 Mammaliaformes 1.3 Ornithischians 1.4 Plesiosaurs 2 References 3 See also

[edit] Vertebrate Fauna

[edit] Ichthyosaurs

Ichthyosauria of the Hettangian
Taxa	Presence	Location	Description	Images
Ichthyosaurus	From Hettangian to Sinemurian	Belgium, England, Germany	Among the best known ichthyosaur genera, was smaller than most of its relatives, measuring 2 m (6 ft 8 inches) in length.	Ichthyosaurus

[edit] Mammaliaformes

Mammaliaformes of the Hettangian
Taxa	Presence	Location	Description	Images
Haramiya

[edit] Ornithischians

Ornithischians of the Hettangian
Taxa	Presence	Location	Description	Images
Abrictosaurus	From Hettangian to Sinemurian	Upper Elliot Formation, Lesotho and Cape Province, South Africa	Considered the most basal member of the family Heterodontosauridae	Abrictosaurus Heterodontosaurus Scelidosaurus
Fabrosaurus	From Hettangian to Sinemurian	Lesotho	As the only fossil known of it is a partial jawbone with three teeth, Fabrosaurus is a nomen dubium and may in fact be the same as Lesothosaurus.
Heterodontosaurus		Upper Elliot Formation, Cape Province, South Africa	A small, fleetfooted ornithischian that reached a maximum size of about 3 feet. The hand of Heterodontosaurus had five fingers, two of which seem to be opposable. allowing Heterodontosaurus to grasp and manipulate food. Another interesting feature is the specialization of teeth which gave rise to the animal's name. At the front of the jaw beside the beak were small teeth likely used for chopping off leaves and stems.
Lanasaurus	From Hettangian to Sinemurian	Upper Elliot Formation, Orange Free State, South Africa	A heterodontosaurid ornithischian
Lycorhinus	From Hettangian to Sinemurian	Upper Elliot Formation, Cape Province, South Africa	A small herbivore dinosaur despite long canines it sported in its jaws; due to this unique characteristic it is very clearly allied to Heterodontosaurus
Scelidosaurus	From Hettangian to Sinemurian	Charmouth, West Dorset, England; Kayenta Formation, Arizona, USA	A genus of quadrupedal, lightly plated, herbivorous dinosaur about 4 meters long (13 ft)
Scutellosaurus		Arizona, USA	A bipedal armored herbivor, was around 1.3 m (4 ft 4 inches) long, 0.5 m (18 in) tall at the hips, and weighed 10 kg (22 lb).
Stormbergia	From Hettangian to Sinemurian	Stormberg Series Formations, South Africa, Lesotho	A primitive ornithischian, about 2 meters long. The proportions of the posterior limbs show differences with those of Lesothosaurus, and reveal a lower ability to run

[edit] Plesiosaurs

Plesiosauria of the Hettangian
Taxa	Presence	Location	Description	Images
Macroplata	Hettangian to Toarcian	Harbury, Warwickshire, UK		Macroplata Rhomaleosaurus
Rhomaleosaurus	Hettangian and Toarcian	Barrow-upon-Soar, Leicestershire, England	A genus of sauropterygian carnivorous reptile belonging to the pliosaur superfamily, it was about 7m long.

[edit] References

• GeoWhen Database - Hettangian

[edit] See also

• Triassic-Jurassic extinction event

Jurassic period
Lower/Early Jurassic	Middle Jurassic	Upper/Late Jurassic
Hettangian | Sinemurian Pliensbachian | Toarcian	Aalenian | Bajocian Bathonian | Callovian	Oxfordian | Kimmeridgian Tithonian