Context: Mucrospirifer is a genus of extinct brachiopods in the class Rhynchonellata (Articulata) 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 Devonian is a geologic period and system of the Paleozoic, spanning 60 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied.
The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. Various terrestrial arthropods also became well-established. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the "Age of Fish". The first ray-finned and lobe-finned bony fish appeared, while the placodermi began dominating almost every known aquatic environment., The lophophore is a characteristic feeding organ possessed by four major groups of animals: the Brachiopoda, Bryozoa, Hyolitha, and Phoronida, which collectively constitute the Lophophorata. All lophophores are found in aquatic organisms., Spiriferida is an order of extinct articulate brachiopod fossils which are known for their long hinge - line , which is often the widest part of the shell . In some genera ( e.g. Mucrospirifer ) 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 ; 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 . They were rare during the Silurian but underwent a dramatic evolutionary radiation during the Devonian period , reaching peak development in variety and numbers . Spiriferida survived the great Permian extinction , finally becoming extinct during the Early Jurassic . Fossils of this order are often preserved as pyrite ., Brachiopods, phylum Brachiopoda, are a group of Lophotrochozoan animals that have hard "valves" (shells) 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. Two major groups are recognized, articulate and inarticulate. Articulate brachiopods have toothed hinges and simple opening and closing muscles, while inarticulate brachiopods have untoothed hinges and a more complex system of muscles used to keep the two halves aligned. In a typical brachiopod a stalk-like pedicle projects from an opening in one of the valves near the hinges, known as the pedicle valve, keeping the animal anchored to the seabed but clear of silt that would obstruct the opening., The Lophotrochozoa ("crest/wheel animals") are a major grouping of protostome animals. The taxon was discovered based on molecular data. Molecular evidence such as a result of studies of the evolution of small-subunit ribosomal RNA (rRNA) supports the monophyly of the phyla listed in the infobox shown at right., Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals), are a phylum of aquatic invertebrate animals. Typically about long, they are filter feeders that sieve food particles out of the water using a retractable lophophore, a "crown" of tentacles lined with cilia. Most marine species live in tropical waters, but a few occur in oceanic trenches, and others are found in polar waters. One class lives only in a variety of freshwater environments, and a few members of a mostly marine class prefer brackish water. Over 4,000 living species are known. One genus is solitary and the rest are colonial., Subject: spiriferida, Relation: parent_taxon, Options: (A) brachiopoda (B) bryozoa (C) hyolitha (D) lophophore (E) lophotrochozoa (F) moss (G) mya (H) phyla (I) protostome (J) rhynchonellata (K) spiriferida
Output: rhynchonellata