Paleozoic life of Yukon

Hyoliths are an extinct group of invertebrates with small conical shells, known from fossils from the Palaeozoic era. They are at least considered lophotrochozoans, possibly being lophophorates, a group which includes the brachiopods (hyoliths may even be brachiopods themselves), while others consider them as being basal lophotrochozoans, or even molluscs.

Favosites is an extinct genus of tabulate coral characterized by polygonal closely packed corallites (giving it the common name "honeycomb coral"). The walls between corallites are pierced by pores known as mural pores which allowed transfer of nutrients between polyps. Favosites, like many corals, thrived in warm sunlit seas, feeding by filtering microscopic plankton with their stinging tentacles and often forming part of reef complexes. The genus had a worldwide distribution from the Late Ordovician to Late Permian. ==Distribution== Favosites had a vast distribution, and its fossils can be

Nucula is a genus of very small saltwater clams. They are part of the family Nuculidae.

Atrypa is a genus of brachiopod with round to short egg-shaped shells covered with many fine radial ridges (or costae). Growth lines form perpendicular to the costae and are spaced approximately 2 to 3 times further apart than the costae.. The pedunculate valve is slightly convex, but oftentimes levels out or becomes slightly concave toward the anterior margin (opposite the hinge and pedicle). The brachial valve is highly convex. Neither valve contains an interarea (a flat area bordering the hinge line, approximately perpendicular with the rest of the valve). Atrypa had a large geographic rang

thumb|270x270px|Agnostus sp. from the Middle Cambrian of Couloma, Hérault, France. Max Rouger Collection.

thumb|Monograptus sp. from the Wenlock of Vailhan, Hérault, France. 12 cm block. Graptolites preserved in three dimensions.

Leptaena is an extinct genus of mid-sized brachiopod that existed from the Dariwilian epoch to the Emsian epoch, though some specimens have been found in strata as late in age as the Tournasian epoch. Like some other Strophomenids, Lepteana were epifaunal, meaning they lived on top of the seafloor, not buried within it, and were suspension feeders.

Leonaspis is a widespread genus of odontopleurid trilobite that lived from the Late Ordovician to the late Middle Devonian. Fossils of various species have been found on all continents except Antarctica.

genus of arthropods (fossil)

Spirifer is a genus of marine brachiopods belonging to the order Spiriferida and family Spiriferidae. Species belonging to the genus lived in the Carboniferous (certainly in the Tournaisian and in the Visean, possibly also in the Serpukhovian and the Bashkirian).

Didymograptus is an extinct genus of graptolites with four rows of cups. They lived during the Middle Ordovician, to Late Ordovician.

Chonetes is an extinct genus of brachiopods. It ranged from the Late Ordovician to the Middle Jurassic.

Terataspis is a comparatively huge, 60 centimetre long lichid trilobite genus from the Early Devonian, about 397 million years ago. It lived in a shallow sea in what is now New York State and Ontario. No whole specimens have been found, only disarticulated fragments of its exoskeleton, but enough fragments have been found to allow researchers to form reconstructions of the whole animal. The genus only contains one species, T. grandis.

Pentremites is an extinct genus of blastoid echinoderm belonging to the family Pentremitidae.

Tentaculites is an extinct genus of conical fossils of uncertain affinity, class Tentaculita, although it is not the only member of the class. It is known from Lower Ordovician to Upper Devonian deposits both as calcitic shells with a brachiopod-like microstructure and carbonaceous 'linings'. The "tentaculites" (i.e. tentaculita) are also referred to as the styliolinids.

Acmarhachis is a genus of trilobites in the order Agnostida, which lived in what are now Australia (Queensland, Tasmania), Canada (British Columbia, Newfoundland, Northwest Territories), China (Anhui), Kazakhstan, Russia (Kharaulakh), and the US (Alaska, Alabama, Nevada, Maryland, Vermont). It was described by Resser in 1938, and the type species is Acmarhachis typicalis.

Syringopora is an extinct genus of phaceloid tabulate coral. It has been found in rocks ranging in age from the Ordovician to the Permian, although it was most widespread during the Silurian, Devonian, and Carboniferous periods. Among other places, it has been found in the Columbus Limestone in Ohio, and in the Spring Branch Member of the Lecompton Limestone in Kansas.

Ozarkodina is an extinct genus of conodonts in the family Spathognathodontidae.

Illaenus is a genus of trilobites from Russia and Morocco, from the middle Ordovician.