Callovian first appearances

Equisetum (; horsetail) is the only living genus in Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds.

The Opluridae, or Madagascan iguanas, are a family of moderately-sized lizards native to Madagascar and Grande Comore. There are eight species across two genera, with most of them being under Oplurus. The other genus, Chalarodon, is easily distinguishable from Oplurus as it contains species with a dorsal crest, particularly distinct in males, and has a smoother tail covered in similarly sized scales. Genus Oplurus has large segmented spiny scales, and no dorsal crest along the spine.

Choristodera (from the Greek χωριστός chōristos + δέρη dérē, 'separated neck') is an extinct order of semiaquatic diapsid reptiles that ranged from the Middle Jurassic, or possibly Triassic, to the Miocene (168 to 20 or possibly 11.6 million years ago). Choristoderes are morphologically diverse, with the best known members being the crocodile-like neochoristoderes such as Champsosaurus. Other choristoderans had lizard-like or long necked morphologies. Choristoderes appear to have been confined to the Northern Hemisphere, having been found in North America, Asia, and Europe, and possibly also N

left|thumb|Life restoration of Muraenosaurus Cryptoclididae is a family of medium-sized plesiosaurs that existed from the Middle Jurassic to the Early Cretaceous. They had long necks, broad and short skulls and densely packed teeth. They fed on small soft-bodied preys such as small fish and crustaceans. The earliest members of the family appeared during the early Bajocian, and they represented the dominant group of long-necked plesiosaurs during the latter half of the Jurassic.

thumb|Pholcus phalangioides The Haplogynae or haplogynes are one of the two main groups into which araneomorph spiders have traditionally been divided, the other being the Entelegynae. Morphological phylogenetic studies suggested that the Haplogynae formed a clade; more recent molecular phylogenetic studies refute this, although many of the ecribellate haplogynes do appear to form a clade, Synspermiata.

Akera is a marine genus of sea hare in the family Akeridae, known from the late Callovian (Jurassic) to the recent periods.

Perisphinctes is an extinct genus of ammonite cephalopod. They lived during the Middle to Late Jurassic epochs and serve as an index fossil for that time period. The species P. boweni was named after the English chemist and geologist E. J. Bowen (1898–1980).

Colymbosaurus is a genus of cryptoclidid plesiosaur from the Middle-Late Jurassic (Callovian-Tithonian) of the UK and Svalbard, Norway. There are two currently recognized species, C. megadeirus and C. svalbardensis.

Kosmoceratidae is an extinct ammonite family from the Callovian (Middle Jurassic) to Early Cretaceous.

Vermetus is a genus of sea snails, marine gastropod mollusks in the family Vermetidae, the worm snails or worm shells.