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Protostomia

(Branch)

Overview

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A Branch in the Kingdom Animalia.

Photos

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Taxonomy

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The Branch Protostomia is a member of the Subkingdom Bilateria. Here is the complete "parentage" of Protostomia:

The Branch Protostomia is further organized into finer groupings including:

Phyla

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Acanthocephala

The Acanthocephala ( a?a????, akanthos, thorn + ?efa??, kephale, head) is a phylum of parasitic worms known as acanthocephales, thorny-headed worms, or spiny-headed worms, characterised by the presence of an evertable proboscis, armed with spines, which it uses to pierce and hold the gut wall of its host. Acanthocephalans typically have complex life cycles, involving a number of hosts, including invertebrates, fishes, amphibians, birds, and mammals. About 1150 species have been described. [more]

Acoelomorpha

[more]

Annelida

The annelids, collectively called Annelida (from annelés "ringed ones", ultimately from Latin anellus "little ring"), are a large phylum of segmented worms, with over 17,000 modern species including ragworms, earthworms and leeches. They are found in marine environments from tidal zones to hydrothermal vents, in freshwater, and in moist terrestrial environments. Although most textbooks still use the traditional division into polychaetes (almost all marine), oligochaetes (which include earthworms) and leech-like species, research since 1997 has radically changed this scheme, viewing leeches as a sub-group of oligochaetes and oligochaetes as a sub-group of polychaetes. In addition, the Pogonophora, Echiura and Sipuncula, previously regarded as separate phyla, are now regarded as sub-groups of polychaetes. Annelids are considered members of the Lophotrochozoa, a "super-phylum" of protostomes that also includes molluscs, brachiopods, flatworms and nemerteans. [more]

Arthropoda

An arthropod is an that has an exoskeleton (external skeleton), a segmented body, and jointed attachments called appendages. Arthropods are animals belonging to the Phylum Arthropoda (from Greek ?????? arthron, "joint", and p?d?? podos "foot", which together mean "jointed feet"), and include the insects, arachnids, crustaceans, and others. Arthropods are characterized by their jointed limbs and cuticles, which are mainly made of a-chitin; the cuticles of crustaceans are also biomineralized with calcium carbonate. The rigid cuticle inhibits growth, so arthropods replace it periodically by molting. The arthropod body plan consists of repeated segments, each with a pair of appendages. It is so versatile that they have been compared to Swiss Army knives, and it has enabled them to become the most species-rich members of all ecological guilds in most environments. They have over a million described species, making up more than 80% of all described living species, and are one of only two animal groups that are really successful in dry environments – the other being the amniotes. They range in size from microscopic plankton up to forms a few meters long. [more]

Brachiopoda

Brachiopods (from brachium, arm + New Latin -poda, foot) are a small phylum of benthic invertebrates. Also known as lamp shells (or lampshells), "brachs" or Brachiopoda, they are sessile, two-valved, marine animals with an external morphology superficially resembling bivalves to which they are not closely related. Paleobiologists estimate that 99 percent of all documented brachiopod species are both fossils and extinct. [more]

Bryozoa

Bryozoans, also known as ectoprocts, are tiny colonial that generally build stony skeletons of calcium carbonate, superficially similar to coral (although some species lack any calcification in the colony and instead have a mucilaginous structure). Members of the phylum Bryozoa are known as "moss animals" or "moss animacules" (which is the literal translation of the Greek term ß?????a, "bryózoa") or as "sea mats". They generally prefer warm, tropical waters, but are known to occur worldwide. There are about 8,000 living species, with several times that number of fossil forms known. [more]

Chaetognatha

Chaetognatha, meaning hair-jaws, is a of predatory marine worms that are a major component of plankton worldwide. About 20% of the known species are benthic and can attach to algae or rocks. They are found in all marine waters from surface tropical waters and shallow tide pools to the deep sea and polar regions. Most chaetognaths are transparent and are torpedo shaped. Some deep-sea species are orange. They range in size from 2 mm to 12 cm. The common term for the phylum is Arrow Worms. There are more than 120 modern species assigned to over 20 genera. Despite the limited diversity of species, the number of individuals is staggering. [more]

Ciliophora

Cycliophora

Symbion is the name of a of aquatic animals, less than ½ mm wide, found living attached to the bodies of cold-water lobsters. They have sac-like bodies, and three distinctly different forms in different parts of their two-stage life-cycle. They appear so different from other animals that they were assigned their own, new phylum Cycliophora shortly after they were discovered in 1995. This was the first new phylum of multicelled organism to be discovered since the Loricifera in 1983. [more]

Echiura

The Echiura, or spoon worms, are a small group of animals. They are often considered to be a group of annelids, although they lack the segmented structure found in other members of that group, and so may also be treated as a separate phylum. However, phylogenetic analyses of DNA sequences place echiurans and pogonophorans within the Annelida. The Echiura fossilise poorly and the earliest known specimen is from the Upper Carboniferous (called the Pennsylvanian in North America). However, U-shaped fossil burrows that could be Echiuran have been found dating back to the Cambrian. [more]

Entoprocta

Entoprocta (Gr. e?t??, entos inside + p???t??, proktos anus) is a of small aquatic animals, ranging in size from 0.5 mm to 5.0 mm. They have a lophophore, and as their name suggests, are distinguished from other lophophorates by the position of the anus inside the ring of cilia rather than outside. Other names include goblet worm and kamptozoan. [more]

Gastrotricha

The gastrotrichs (from ?aste?, gaster "stomach" and ????, thrix "hair") are a phylum of microscopic (0.06-3.0 mm) animals abundant in fresh water and marine environments. Most fresh water species are part of the periphyton and benthos. Marine species are found mostly interstitially in between sediment particles. The Gastrotrich has the shortest life span of all animals, living for just 3 days. [more]

Gnathostomulida

Gnathostomulids, or jaw worms, are a small phylum of nearly microscopic marine . Most measure between 0.5 and 1 mm long. Like flatworms they have a ciliated epidermis, but are unique in having but one cilium per cell. They have no body cavity, and no circulatory or respiratory system. Each gnathostomulid is simultaneously hermaphrodite, possessing an ovary and a testis. They are characterized by a specialized, muscular jaw, which they use to scrape smaller organisms off of the grains of sand that make up their anoxic seabed mud habitat. This bilaterally symmetrical pharynx with its complex cuticular mouth parts make them appear closely related to rotifers and their allies, together making up the Gnathifera. [more]

Haptophyta

The haptophytes, classed either as the Prymnesiophyta or Haptophyta, are a of algae. [more]

Kinorhyncha

Kinorhyncha (Gr. ?????, kineo 'move' + ??????, rhynchos 'snout') is a of small (1 mm or less) marine pseudocoelomate invertebrates that are widespread in mud or sand at all depths as part of the meiobenthos. They are also called mud dragons. [more]

Loricifera

Mollusca

Molluscs are animals belonging to the Mollusca. There are around 93,000 recognized extant species, making it the largest marine phylum with about 23% of all named marine organisms. Representatives of the phylum live in a huge range of habitats including marine, freshwater, and terrestrial environments. Molluscs are a highly diverse group, in size, in anatomical structure, in behaviour and in habitat. [more]

Nematoda

The "roundworms" or "nematodes" ( Nematoda) are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 80,000 have been described, of which over 15,000 are parasitic. It has been estimated that the total number of described and undescribed roundworms might be more than 500,000. Unlike cnidarians or flatworms, roundworms have a digestive system that is like a tube at both ends. [more]

Nematomorpha

Nematomorpha (sometimes called Gordiacea, and commonly known as Horsehair worms or Gordian worms) are a of parasitic animals that are morphologically and ecologically similar to nematode worms, hence the name. They range in size from 1cm to 1 meter long, and 1 to 3 millimetres in diameter. Horsehair worms can be discovered in damp areas such as watering troughs, streams, puddles, and cisterns. The adult worms are free living, but the larvae are parasitic on beetles, cockroaches, Orthoptera and crustaceans. About 326 species are known and a conservative estimate suggests that there may be about 2000 species worldwide. The name "Gordian" stems from the legendary Gordian knot. This relates to the fact that nematomorpha often tie themselves in knots. [more]

Nemertea

Nemertea is a of invertebrate animals also known as ribbon worms or proboscis worms. Most of the 1,400 or so species are marine, with a few living in fresh water and a small number of terrestrial forms; they are found in all marine habits, and throughout the world's oceans. Nemerteans are named for Nemertes, one of the Nereids of Greek mythology, and alternative spellings for the phylum have included Nemertini and Nemertinea. Libbie Hyman named them Rhynchocoela, a name used primarily in North America but gradually abandoned since the 1980s. [more]

Onychophora

The velvet worms (Onychophora — literally "claw bearers") form a within the Ecdysozoa and can be simply described as "worms with legs". Most common in the Southern Hemisphere, they prey on smaller animals such as insects, which they catch by squirting a sticky slime. In modern zoology they are particularly renowned for their curious mating behaviour and for bearing live young. They are becoming increasingly popular in the 'exotic pets' trade, due to their bizarre appearance and eating habits. The Lobopodia, possible ancestors of velvet worms from the Cambrian period, are of great interest in paleontology. [more]

Oomycota

Oomycota also known as Water molds (or water moulds: see ) are a group of filamentous, unicellular heterokonts, physically resembling fungi. They are microscopic, absorptive organisms that reproduce both sexually and asexually and are composed of mycelia, or a tube-like vegetative body (all of an organism's mycelia are called its thallus). [more]

Platyhelminthes

The flatworms, known in scientific literature as Platyhelminthes (from the p?at?, platy, meaning "flat" and ??µ??? (root: ??µ???-), helminth-, meaning worm) are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrate animals. Unlike other bilaterians they have no body cavity, and no specialized circulatory and respiratory organs, which restricts them to flattened shapes that allow oxygen and nutrients to pass through their bodies by diffusion. [more]

Porifera

Sponges are of the phylum Porifera . Their bodies consist of jelly-like mesohyl sandwiched between two thin layers of cells. While all animals have unspecialized cells that can transform into specialized cells, sponges are unique in having some specialized cells that can transform into other types, often migrating between the main cell layers and the mesohyl in the process. Sponges do not have nervous, digestive or circulatory systems. Instead most rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes, and the shapes of their bodies are adapted to maximize the efficiency of the water flow. All are sessile aquatic animals and, although there are freshwater species, the great majority are marine (salt water) species, ranging from tidal zones to depths exceeding 8,800 metres (5.5 mi). While most of the approximately 9,000 known species feed on bacteria and other food particles in the water, some host photosynthesizing micro-organisms as endosymbionts and these alliances often produce more food and oxygen than they consume. A few species of sponge that live in food-poor environments have become carnivores that prey mainly on small crustaceans. [more]

Priapulida

Priapulida (priapulid worms or penis worms, from Gr. p???p??, priapos '' + Lat. -ul-, diminutive) are a phylum of marine worms with an extensible spiny proboscis. Priapulid fossils are known at least as far back as the Middle Cambrian. Their nearest relatives are probably Kinorhyncha and Loricifera with which they constitute the taxon Scalidophora. Besides arthropods and velvet worms, it is only among Priapulida that we can find members of the Ecdysozoa which are relatively large in size. They were likely major predators of the Cambrian period. There are 16 known species of Priapulid worms. [more]

Rotifera

The rotifers make up a of microscopic and near-microscopic pseudocoelomate animals. They were first described by Rev. John Harris in 1696, and other forms were described by Anton van Leeuwenhoek in 1703. Most rotifers are around 0.1–0.5 mm long (although their size can range from 50µm to over 2 millimeters), and are common in freshwater environments throughout the world with a few saltwater species. Some rotifers are free swimming and truly planktonic, others move by inchworming along the substrate, and some are sessile, living inside tubes or gelatinous holdfasts that are attached to a substrate. About 25 species are colonial (e.g., Sinantherina semibullata), either sessile or planktonic. Rotifers play an important part of the freshwater zooplankton, being a major foodsource and with many species also contributing to the decomposition of soil. [more]

Sipuncula

The Sipuncula or Sipunculida, sipunculid worms or peanut worms, are a containing 144-320 species (estimates vary) of bilaterally symmetrical, unsegmented marine worms. Sipunculid worm jelly (???) is a delicacy in the town of Xiamen in Fujian province of China. [more]

Tardigrada

Tardigrades (commonly known as water bears) form the Tardigrada, part of the superphylum Ecdysozoa. They are microscopic, water-dwelling, segmented animals with eight legs. Tardigrades were first described by Johann August Ephraim Goeze in 1773 (kleiner Wasserbär = little water bear). The name Tardigrada means "slow walker" and was given by Lazzaro Spallanzani in 1777. The name water bear comes from the way they walk, reminiscent of a bear's gait. The biggest adults may reach a body length of 1.5 mm, the smallest below 0.1 mm. Freshly hatched larvae may be smaller than 0.05 mm. [more]

At least 1,104 species and subspecies belong to the Phylum Tardigrada.

More info about the Phylum Tardigrada may be found here.

Sources

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Last Revised: September 22, 2009
2009/09/22 05:49:48