Secernentea

Heterodera glycines with an egg, a parasite of the soybean

  • Diplogasteria
  • Rhabditia
  • Spiruria

The Secernentea form a monophyletic group of nematodes ( Nematoda ). The nematodes are considered in the newer system as a separate tribe of the animal kingdom, in which the Secernentea pose next to the Adenophorea one of the two classes.

Features

The main distinguishing feature of Secernentea of the group of Adenophorea the presence of Schwanzsensillen ( phasmids or Phasmidialorgane ) is considered in most species. In some species these sensilla are missing, but it is believed that they have been re-formed in the course of evolution. Other distinguishing features are the lateral Exkretionskanäle and the lack of tail and Epidermaldrüsen at the Secernentea. The males have only one testicle.

The inner systematic classification of Secernentea is made mainly on the basis of the construction of the esophagus. The Rhabditia have a three-part esophagus is constricted in the middle part. The Diplogasteria this part of the digestive tract has a front, muscular and a posterior glandular part. The Spiruria have a bottle-shaped esophagus.

Way of life

The wild species of Secernentea can be found in fresh water or in the ground. They feed saprophagous, Diatomeenfresser or predatory. Many species live as parasites of plants and animals. They cause damage to crops in agriculture or are considered pathogens in animals and humans. The species of the genus Zalophora live as parasites in the gut of millipedes, but feed on prey on other nematodes.

Among the parasites of humans, the hookworm with Necator americanus and Ancylostoma duodenale, the roundworms with the roundworm of humans ( Ascaris lumbricoides ) and the pinworm ( Enterobius vermicularis ), the filarial as Wuchereria bancrofti, Onchocerca volvulus and Loa loa and the Guinea worm include ( Dracunculus medinensis ).

At the roots of crop species parasitizing the Rübenälchen ( Heterodera schachtii ) and the Goldnematode are ( Globodera rostochiensis ), which draws in potato roots. The eggs of these roundworms can survive within cysts up to 10 years in the soil.

System

Orders with selected species:

  • Class Secernentea Subclass Diplogasteria order Diplogasterida Odontopharynx longicaudata
  • Globodera rostochiensis
  • Globodera pallida
  • Heterodera glycines
  • Heterodera schachtii
  • Order Rhabditida Caenorhabditis elegans
  • Dracunculus medinensis
  • Enterobius vermicularis
  • Rhigonema licinacanthum
  • Rhigonema tribonophorum
  • Zalophora deinostoma
  • Zalophora nemophila

The consideration of the Tylenchida as a separate subclass is discussed.

Eumetazoa Microbial cyst
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