Paleozoic life of Nunavut

Tiktaalik (; ) is a monospecific genus of extinct sarcopterygian (lobe-finned fish) from the late Devonian Period, about 375 Mya (million years ago), having many features similar to those of tetrapods (four-legged animals). Tiktaalik is estimated to have had a total length of on the basis of various specimens.

Lepidodendron, from Ancient Greek λεπίς (lepís), meaning "scale", and δένδρον (déndron), meaning "tree", is an extinct genus of primitive lycopodian vascular plants belonging to the order Lepidodendrales. It is well preserved and common in the fossil record. Like other Lepidodendrales, species of Lepidodendron grew as large-tree-like plants in wetland coal forest environments. They sometimes reached heights of , and the trunks were often over in diameter. They are often known as "scale trees", due to their bark having been covered in diamond-shaped leaf-bases, from which leaves grew during ear

Calamites is a genus of extinct arborescent (tree-like) horsetails to which the modern horsetails (genus Equisetum) are closely related. Unlike their herbaceous modern cousins, these plants were medium-sized trees, growing to heights of . They were components of the understories of coal swamps of the Carboniferous Period (around ).

Helicoprion is an extinct genus of large shark-like cartilaginous fish that lived from the Early to the Middle Permian, about 290-270 million years ago. Helicoprion is a member of the Eugeneodontiformes, an extinct order of cartilaginous fish within the clade Holocephali, a group today represented only by chimaeras. It is also the type genus of the Helicoprionidae, a family of eugeneodonts characterised by distinctive tooth structures called tooth whorls. Helicoprion was first named in 1899 by Alexander Karpinsky on the basis of fossils discovered in Russia and Australia, the generic name mean

Cooksonia is an extinct group of primitive land plants, treated as a genus, although probably not monophyletic. The earliest Cooksonia date from the middle of the Silurian (the Wenlock epoch); the group continued to be an important component of the flora until the end of the Early Devonian, a total time span of . While Cooksonia fossils are distributed globally, most type specimens come from Britain, where they were first discovered in 1937. Cooksonia includes the oldest known plant to have a stem with vascular tissue and is thus a transitional form between the primitive non-vascular bryophyte

Archaeopteris is an extinct genus of progymnosperm tree with fern-like leaves. A useful index fossil, this tree is found in strata dating from the Upper Devonian to Lower Carboniferous (), the oldest fossils being 385 million years old, and had global distribution.

Eurypterus ( ) is an extinct genus of eurypterid, a group of organisms commonly called "sea scorpions". The genus lived during the Silurian period, from around 432 to 418 million years ago. Eurypterus is by far the most well-studied and well-known eurypterid. Eurypterus fossil specimens probably represent more than 95% of all known eurypterid specimens.

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.

Endoceras, from Ancient Greek ἔνδον (éndon), meaning "inside", and κέρας (kéras), meaning "horn", is an extinct genus of large, straight-shelled cephalopods that gives its name to the Nautiloid order Endocerida. The genus lived during the middle and upper Ordovician 470 to 443 million years ago. The cross section in the mature portion is slightly wider than high, but is narrower laterally in the young. Sutures are straight and transverse. Endoceras has a large siphuncle, located close to the ventral margin, composed of concave segments, especially in the young but which may be tubular in the a

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

is an extinct genus of large asaphid trilobites from the Middle and Late Ordovician Period, fairly common in the northeastern United States into eastern Canada. Isotelus is the state fossil of Ohio, and through multiple specimens from the 1800s into the modern day has held the title of largest trilobite fossil in the world, reaching over long. Isotelus was carnivorous and a burrower which lived in warm shallow seas, feeding on worms and other soft-bodied animals on and below the substrate. As larvae, Isotelus was planktonic, drifting in the water column with a morphology very different from th

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

Olenellus is an extinct genus of redlichiid trilobites, with species of average size (about long). It lived during the Botomian and Toyonian stages of the Lower Cambrian (Olenellus-zone), , in what is currently North America, part of the palaeocontinent Laurentia.

thumb|right|Thin-section view of Halysites corallum

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

Hemicyclaspis ( or 'semicircle plate') is an extinct genus of primitive jawless fish, closely related to Cephalaspis, that lived in the Late Silurian (Pridoli) to Devonian period in what is now Europe and North America. A typical cephalaspid, Hemicyclaspis had a heavily armored, shovel-shaped headshield. It is thought to have been a better swimmer than most of its relatives because of its powerful tail, stabilizing dorsal fin and the keel-shaped hydrodynamic edges of its head shield. Hemicyclaspis probably foraged the ocean floor for food.

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

Calymene is a genus of trilobites in the order Phacopida, suborder Calymenina, that are found throughout North America, North Africa, and Europe in primarily Silurian outcrops. Calymene is closely related to Flexicalymene, and both genera are frequently found enrolled. Calymene trilobites are small, typically 2 cm in length. The cephalon is the widest part of the animal and the thorax usually has 13 segments.

Walchia is a primitive fossil conifer found in upper Pennsylvanian (Carboniferous) and lower Permian (about 310-290 Mya) rocks of Europe and North America. A forest of in-situ Walchia tree-stumps is located on the Northumberland Strait coast at Brule, Nova Scotia.

Carcinosoma (meaning "crab body") is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Carcinosoma are likely restricted to deposits of late Silurian to early Devonian (Llandovery to Lochkovian) age,'''' although an Early Ordovician specimen has been classified as ?Carcinosoma aurorae, which would make this the earliest known eurypterid genus. Classified as part of the family Carcinosomatidae, which the genus lends its name to, Carcinosoma'' contains several species from North America and Great Britain.

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.

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.

Platystrophia is an extinct genus of brachiopods that lived from the Ordovician to the Silurian in Asia, Europe, North America, and South America. It has a prominent sulcus and fold. It usually lived in marine lime mud and sands.

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).

Zosterophyllum was a genus of Silurian-Devonian vascular land plants with naked branching axes on which usually kidney-shaped sporangia were arranged in lateral positions. It is the type genus for the group known as zosterophylls, thought to be part of the lineage from which modern lycophytes evolved. More than 20 species have been described.

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

Deiphon is a distinctive genus of Silurian phacopid trilobites of the family Cheiruridae found in Western and Central Europe, and in Central and Eastern United States. The type species, D. forbesi, from England, Bohemia, and Sweden, was discovered and described by the French paleontologist, Joachim Barrande in 1850.

thumb|240px|right|Strophomena costellata from Bromide Formation, Oklahoma, USA

extinct genus of bryozoans

extinct genus of fishes

Euomphalus is a genus of fossil marine gastropods known to have lived from the Silurian to the Middle Permian.

Sphenopteris is a genus of seed ferns containing the foliage of various extinct plants, ranging from the Devonian to Late Cretaceous. One species, S. höninghausi, was transferred to the genus Crossotheca in 1911.

Acidaspis is an extinct genus of odontopleurid trilobite from the Ordovician to Silurian of North America and Europe. Although small, it had long spines along its body.

Sphaerexochus is a genus of trilobites from the Middle Ordovician to Late Silurian (468.1 to 418.7 Ma) of Asia, Australia, Europe, and North America.

Encrinurus is a long-lived genus of phacopid trilobites that lived in what are now Africa, Asia, Australia, Europe, North America, and South America from the middle Ordovician to the early Devonian from 472 to 412.3 mya, existing for approximately .

Qikiqtania ( ) is an extinct genus of elpistostegalian tetrapodomorph from the Late Devonian (early Frasnian stage) Fram Formation of Nunavut, Canada. The genus contains a single species, Q. wakei, known from a partial skeleton. Analysis of the fin bones suggests that Qikiqtania was well-suited to swimming, and likely incapable of walking or supporting itself out of the water, as has been suggested for the closely related Tiktaalik.

Gastrioceras is a goniatitid genus in the family Gastrioceratidae that lived during the late Carboniferous (Pennsylvanian and for most of the Permian.

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

Samaropsis is a form genus named by Goeppert in 1864. Later Sewart (1917) redefined the taxon to refer only to the seeds.

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

Catenipora is an extinct genus of tabulate corals in the family Halysitidae, known from the Ordovician to the Silurian.

Erieopterus is a genus of prehistoric eurypterid found in Silurian to Devonian-aged marine and freshwater strata of North America. The genus contains three species from the Silurian to the Devonian.'''''''' Erieopterus'' is the only genus in the family Erieopteridae, part of the Dolichopteroidea superfamily.

Ceraurus is a genus of cheirurid trilobite of the middle and, much more rarely, the upper Ordovician. They are commonly found in strata of the lower Great Lakes region. These trilobites have eleven thoracic segments, a very small pygidium and long genal and pygidial spines.

Aulacopleura is a genus of proetid trilobite that lived from the Middle Ordovician to the Middle Devonian. Some authors may classify this group as subgenus Otarion (Aulacopleura). The cephalon is semicircular or semielliptical, with border and preglabellar field. The glabella is short, with or without defined eye ridges connecting it with eyes of variable size. Spines at the rear outer corners of the cephalon (or genal spines) are present, typically reaching back to the 2nd to 4th thorax segment. The 'palate' (or hypostome) is not connected to the dorsal shield of the cephalon (or natant). The

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.

thumb|upright|Bumastus barriensis, from the [[Silurian Wenlock series, found at Dudley, Worcestershire.]]

Rhinocarcinosoma is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Rhinocarcinosoma have been discovered in deposits ranging of Late Silurian age in the United States, Canada and Vietnam. The genus contains three species, the American R. cicerops and R. vaningeni and the Vietnamese R. dosonensis. The generic name is derived from the related genus Carcinosoma, and the Greek ῥινός (rhinós, "nose"), referring to the unusual shovel-shaped protrusion on the front of the carapace (head plate) of Rhinocarcinosoma, its most distinctive feature.