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Phylogeny System (Chitwood, 1958) and is no longer in use.[1][2] This morphological-based classification system has been replaced by the Modern Phylogeny system, where taxonomy assignment is based on small subunit ribosomal DNA (SSU rDNA).[3][4]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