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Panarthropoda

(Superphylum)

Overview

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Panarthropoda is a taxon combining the phyla Arthropoda, Tardigrada and Onychophora. Originally, they were considered to be closely related to the annelids, grouped together as the Articulata, but newer studies place them among a group called the Ecdysozoa.

Common characters of the Panarthropoda include:

Photos

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Taxonomy

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The Superphylum Panarthropoda is a member of the Infrakingdom Alveolata. Here is the complete "parentage" of Panarthropoda:

The Superphylum Panarthropoda is further organized into finer groupings including:

Phyla

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Arthropoda

Arthropods are 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 the possession of a segmented body with appendages on at least one segment. They have a dorsal heart and a ventral nervous system. All arthropods are covered by a hard exoskeleton made of chitin, a polysaccharide, which provides physical protection and (among terrestrial species) resistance to desiccation. Arthropods grow by shedding this covering in what are termed molts. [more]

Chordata

Chordates ( Chordata) are a group of animals that includes the vertebrates, together with several closely related invertebrates. They are united by having, at some time in their life cycle, a notochord, a hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail. Some scientists argue that the true qualifier should be pharyngeal pouches rather than slits. [more]

Ciliophora

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Haptophyta

The haptophytes, classed either as the Prymnesiophyta or Haptophyta, are a of algae. The chloroplasts are pigmented similarly to those of the heterokonts, such as golden algae, but the structure of the rest of the cell is different, so it may be that they are a separate line whose chloroplasts are derived from similar endosymbionts. [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. The Lobopodia, possible ancestors of velvet worms from the Cambrian period, are of great interest in paleontology. [more]

Oomycota

Oomycetes 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). The name "water mold" refers to their earlier classification as fungi, which stemmed from their preference for conditions of high humidity and running surface water, although they are now known to have evolved separately and show a number of differences. For instance, their cell walls are composed of cellulose rather than chitin and generally do not have septations. Also, in the vegetative state they have diploid nuclei, whereas fungi have haploid nuclei. [more]

Tardigrada

Tardigrades (commonly known as water bears) form the 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 Wasserbär = little water bear). The name Tardigrada means "slow walker" and was given by Spallanzani in 1777. 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 1,097 species and subspecies belong to the Phylum Tardigrada.

More info about the Phylum Tardigrada may be found here.

References

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Sources

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Last Revised: October 07, 2008