Spiriferida is an order of extinct articulate brachiopod

Brachiopod

Brachiopods are a phylum of marine animals that have hard "valves" on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, while the front can be opened for feeding or closed for protection...

 fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

s which are known for their long hinge-line, which is often the widest part of the shell. In some genera (e.g. Mucrospirifer

Mucrospirifer

Mucrospirifer is a genus of extinct brachiopod in the class Rhynchonellata and the order Spiriferida. They are sometimes known as "butterfly shells". Like other brachiopods, they were filter feeders. These fossils occur mainly in Middle Devonian strata.The biconvex shell was typically 2.5 cm,...

) it is greatly elongated, giving them a wing-like appearance. They often have a deep fold down the center of the shell. The feature that gives the spiriferids their name ("spiral-bearers") is the internal support for the lophophore

Lophophore

The lophophore is a characteristic feeding organ possessed by four major groups of animals: the Brachiopoda, Bryozoa, Entoprocta, and Phoronida. All lophophores are found in aquatic organisms.-Characteristics:...

; this brachidium, which is often preserved in fossils, is a thin ribbon of calcite that is typically coiled tightly within the shell.

Spiriferids first appear in the Early Ordovician

Ordovician

The Ordovician is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago . It follows the Cambrian Period and is followed by the Silurian Period...

. They were rare during the Silurian

Silurian

The Silurian is a geologic period and system that extends from the end of the Ordovician Period, about 443.7 ± 1.5 Mya , to the beginning of the Devonian Period, about 416.0 ± 2.8 Mya . As with other geologic periods, the rock beds that define the period's start and end are well identified, but the...

 but underwent a dramatic evolution

Evolution

Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...

ary radiation during the Devonian

Devonian

The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...

 period, reaching peak development in variety and numbers. Spiriferida survived the great Permian extinction, finally becoming extinct during the Early Jurassic

Jurassic

The Jurassic is a geologic period and system that extends from about Mya to  Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...

.

Fossils of this order are often preserved as pyrite

Pyrite

The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold because of its resemblance to gold...

.

Taxonomy

Order Spiriferida

• Suborder Delthyridina
  • Superfamily Delthyridoidea
    • Family Acrospiriferidae
    • Family Cyrtinopsidae
    • Family Delthyrididae
    • Family Hysterolitidae
    • Family Mucrospiriferidae
  • Superfamily Reticularioidea
    • Family Elythidae
    • Family Reticulariidae
    • Family Thomasariidae
    • Family Xenomartiniidae
• Suborder Spiriferidina
  • Superfamily Adolfioidea
    • Family Adolfiidae
    • Family Echinospiriferidae
  • Superfamily Ambocoelioidea
    • Family Ambocoeliidae
    • Family Eudoxinidae
    • Family Lazutkiniidae
    • Family Verneuiliidae

• • Superfamily Brachythyridoidea
    • Family Brachythyrididae
    • Family Skelidorygmidae
  • Superfamily Cyrtioidea (syn. Cyrtiacea)
    • Family Costispiriferidae
    • Family Cyrtiidae
    • Family Hedeinopsidae
  • Superfamily Cyrtospiriferoidea
    • Family Conispiriferidae
    • Family Cyrtospiriferidae
    • Family Spinocyrtiidae
  • Superfamily Martinioidea
    • Family Crassumbidae
    • Family Elythynidae
    • Family Gerkispiridae
    • Family Ingelarellidae
    • Family Martiniidae
    • Family Perissothyrididae
    • Family Tenellodermidae
  • Superfamily Paeckelmanelloidea
    • Family Paeckelmanellidae
    • Family Strophopleuridae
  • Superfamily Spiriferoidea
    • Family Choristitidae
    • Family Imbrexiidae
    • Family Reticulariacea
    • Family Spiriferellidae
    • Family Spiriferidae
    • Family Trigonotretidae
  • Superfamily Theodossioidea
    • Family Palaeochoristitidae
    • Family Theodossiidae
    • Family Ulbospiriferidae