The Infrakingdom Ecdysozoa is a member of the Branch Protostomia. Here is the complete "parentage" of Ecdysozoa:
- Domain: Eukaryota Whittaker & Margulis,1978 - eukaryotes
The Infrakingdom Ecdysozoa is further organized into finer groupings including:
- Superphylum (3): Articulata · Aschelminthes · Panarthropoda
- Phylum (9): Arthropoda · Chaetognatha · Kinorhyncha · Loricifera · Nematoda · Nematomorpha · Onychophora · Priapulida · Tardigrada
An arthropod is an invertebrate animal having an exoskeleton (external skeleton), a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda (from Greek ?rthron, "joint", and p?d?? pod?s "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 animal species, and are one of only two animal groups that are very successful in dry environments ? the other being the amniotes. They range in size from microscopic plankton up to forms a few meters long. [more]
Chaetognatha, meaning hair-jaws, and commonly known as arrow worms, are a phylum of predatory marine worms that are a major component of plankton worldwide. About 20% of the known species are benthic, that is belonging to the lowest zone of the ocean, or benthic zone, and can attach to algae and 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, but some deep-sea species are orange. They range in size from 2 to 120 millimetres (0.079 to 4.7 in). [more]
Kinorhyncha (Gr. ?????, kineo 'move' + ??????, rhynchos 'snout') is a phylum 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]
The nematodes () or roundworms (phylum 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 28,000 have been described, of which over 16,000 are parasitic. The total number of nematode species has been estimated to be about 1,000,000. Unlike cnidarians or flatworms, roundworms have tubular digestive systems with openings at both ends. [more]
Nematomorpha (sometimes called Gordiacea, and commonly known as horsehair worms or Gordian worms) is a phylum of parasitic animals that are superficially morphologically similar to nematode worms, hence the name. They range in size in most species from 50 to 100 centimetres (20 to 39 in) long and can reach in extreme cases up to 2 metres, and 1 to 3 millimetres (0.039 to 0.12 in) 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, orthopterans, and crustaceans. About 351 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]
The velvet worms (Onychophora ? literally "claw bearers", also known as Protracheata) are a minor ecdysozoan phylum. These obscurely segmented organisms have tiny eyes, antennae, multiple pairs of legs and slime glands. They have variously been compared to worms with legs, caterpillars and slugs. Most common in tropical regions of the Southern Hemisphere, they prey on smaller animals such as insects, which they catch by squirting an adhesive slime. In modern zoology, they are particularly renowned for their curious mating behaviour and for bearing live young. They are becoming increasingly popular as pets due to their bizarre appearance and eating habits. [more]
Priapulida (priapulid worms or penis worms, from Gr. p???p??, priapos 'Priapus' + Lat. -ul-, diminutive) is a phylum of marine worms. They are named for their extensible spiny proboscis, which, in some species, may have a shape like that of a human penis. They live in the mud, which they eat, in comparatively shallow waters up to 90 metres (300 ft). [more]
Tardigrades (commonly known as waterbears or moss piglets) form the phylum Tardigrada, part of the superphylum Ecdysozoa. They are small, water-dwelling, segmented animals with eight legs. Tardigrades were first described by Johann August Ephraim Goeze in 1773 (kleiner Wasserb?r = 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 millimetres (0.059 in), the smallest below 0.1 mm. Freshly hatched larvae may be smaller than 0.05 mm. [more]
At least 1,107 species and subspecies belong to the Phylum Tardigrada.
More info about the Phylum Tardigrada may be found here.
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