Secernentea

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Secernentea
Scientific classification edit
Kingdom: Animalia
Phylum: Nematoda
Class: Secernentea
Subclasses

Diplogasteria (disputed)
Rhabditia (paraphyletic?)
Spiruria
Tylenchia (disputed)
and see text

Secernentea was a class of nematodes in the Classical Phylogeny System (Chitwood, 1958) and is no longer in use.[1][2] This morphological-based classification system has been replaced by the Modern Phylogeny system, where taxonomy assignment is based on small subunit ribosomal DNA (SSU rDNA).[3][4]

Characteristics of Secernentea are:

  • Amphid apertures are pore/slit-like
  • Derids are present in some; located near nerve ring
  • Phasmids are present; posterior
  • Excretory system is tubular
  • Cuticle is striated in two to four layers; lateral field is present
  • Three esophageal glands; esophageal structure varies
  • Males generally have one testis
  • Caudal alae are common
  • Sensory papillae are cephalic only; may be caudal papillae in males
  • Mostly terrestrial
  • Rarely found in fresh or marine water

Systematics[edit]

Subclasses and orders of Secernentea are:[5]

Some families traditionally considered to be Rhabditida seem to be closer to the Tylenchida. If the Tylenchia are to be maintained as separate, they probably will be included therein.

References[edit]

  1. ^ "WoRMS - World Register of Marine Species - Secernentea". Retrieved May 24, 2018.
  2. ^ Olsen, Oliver Wilford (1986). "Animal Parasites: Their Life Cycles and Ecology". Courier Corporation.
  3. ^ De Ley, P., and M. Blaxter. 2004. "A New System for Nematoda: Combining Morphological Characters with Molecular Trees, and Translating Clades into Ranks and Taxa." Nematology Monographs and Perspectives 2. Brill, Netherlands: 633–53.
  4. ^ De Ley, P., Wilfrida Decraemer, and A. Eyualem. 2006 "Introduction: Summary of Present Knowledge and Research Addressing the Ecology and Taxonomy of Freshwater Nematodes." CABI.
  5. ^ Tree of Life Web Project (ToL) (2002): Nematoda. Version of January 1, 2002. Retrieved November 2, 2008.