Belongs within: Secernentea. The Ascaridomorpha are a group of often large roundworms parasitic in vertebrates. The small intestinal roundworm Ascaris lumbricoides inhabits the gut of humans, in which it is the most abundant parasitic worm worldwide. Ascaridomorpha [Ascaridida] | i. s.: PolydelphisJ02 | Pseudoterranova decipiensJ02 [=Phocanema decipiensL02b, Terranova decipiensL02c] | Metaterakis govindiJ02 | Nematoxys ornatusH02… Continue reading Ascaridomorpha


Belongs within: Cycloneuralia.Contains: Gordionus. The Nematomorpha, Gordian or horsehair worms, are a group of elongate worms that are parasitic as larvae on insects or crustaceans, emerging into water upon maturity. A single genus Nectonema is marine and bears dorsal and ventral rows of cuticular natatory bristles as an adult; the remaining genera (forming the taxon… Continue reading Nematomorpha


Belongs within: Dorylaimia. The Mermithida are a group of nematodes that are parasitic on insects and other invertebrates. Members of the family Mermithidae emerge from the host as adults to breed whereas Tetradonematidae remain in their host. Fossil mermithids found in Dominican and Baltic amber have been assigned to the genus Heydonius (Poinar 1992). Characters… Continue reading Mermithida


Belongs within: Ecdysozoa.Contains: Nematomorpha, Kinorhyncha, Priapozoa, Dorylaimia, Enoplia, Desmoscolecida, Monhysterida, Chromadorida, Desmodorida, Araeolaimida, Plectida, Secernentea. The Cycloneuralia are a clade of worm-like animals in which the brain neuropil forms a ring around the anterior part of the intestinal system. Members include the Nematoda, roundworms, a hyperdiverse group of mostly minute species, though some parasitic forms… Continue reading Cycloneuralia


Belongs within: Spiruromorpha. The Onchocercidae are a group of parasitic nematodes whose life cycles alternate between insect and tetrapod hosts. The early larval stages lack spines and accumulate in host tissues, and the adults have a smooth and rounded head. <==Onchocercidae |–LitomosoidesL07 | |–L. oxymycteriL07 | `–L. sigmodontisPB07 [incl. L. cariniiJ02] `–OnchocercaPB07 |–O. armillataG02 |–O.… Continue reading Onchocercidae


Belongs within: Secernentea.Contains: Dipetalonema, Onchocercidae. The Spiruromorpha are a group of parasitic nematodes with life cycles alternating between vertebrate and invertebrate hosts. Some species, notably among the superfamily Filarioidea, are regarded as significant pathogens of humans and other mammals, causing debilitating illnesses. These include the African eye worm Loa loa which inhabits the subcutaneous tissue… Continue reading Spiruromorpha


Belongs within: Cycloneuralia.Contains: Aphanolaimidae. The Plectida are a group of terrestrial and aquatic free-living nematodes with cephalic setae, a cylindrical stoma and unispiral amphids. <==Plectida [Leptolaimina] |–HaliplectoideaLB02 | |–HaliplectidaeLB02 | |–AulolaimidaeLB02 | `–Manunema Gerlach 1957L86 [PeresianidaeLB02] | `–M. proboscidisL86 |–CeramonematoideaLB02 | |–TarvaiidaeLB02 | |–TubolaimoididaeLB02 | `–Ceramonema [Ceramonematidae]LB02 | `–C. carinatumL02b |–PlectoideaLB02 | | i. s.:… Continue reading Plectida


Belongs within: Secernentea. The Oxyuridomorpha are a group of animal-parasitic nematodes characterised by the possession of a large, valvate esophageal bulb. Members of the superfamily Thelastomatoidea are parasites of insects whereas Oxyuroidea mostly infect vertebrates. Oxyuridomorpha [Oxyurida] | i. s.: Blatticola monandrosWPT01 | Protellus dixoniWPT01 | Hammerschmidtiella diesingiL02 | Aspiculuris tetrapteraJ02, P02 | AuchenacanthaJ02 |… Continue reading Oxyuridomorpha


Belongs within: Rhabditina. The Rhabditoidea is an assemblage of free-living nematodes, though it is probably paraphyletic to parasitic groups such as the Strongyloidea. Members of the Rhabditoidea are characterised by having the phasmid in males posterior to all other bursal rays (Ley & Blaxter 2002). The bacteriovorous Caenorhabditis elegans has become a model organism in… Continue reading Rhabditoidea


Belongs within: Secernentea.Contains: Rhabditoidea, Strongyloidea, Cylindrocorporidae. The Rhabditina is a group of nematodes including both free-living and animal-parasitic forms. Possible synapomorphies of the group include the presence of a bursa with rays in the male, and a short muscular part to the stegostom, consisting of less than four muscle sets in at least the juvenile… Continue reading Rhabditina