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Phylogeny System (Chitwood, 1958) and is no longer in use.[1][2] This morphological-based classification system has been replaced by the Modern Phylogeny system, where taxonomy assignment is based on small subunit ribosomal DNA (SSU rDNA).[3][4]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
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
Wikimedia Commons has media related to Secernentea.
^Olsen, Oliver Wilford (1986). "Animal Parasites: Their Life Cycles and Ecology". Courier Corporation.
doi:
10.1086/408868. {{
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^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.
^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.