|
Secernentea
Secernentea was a class (biology), class of nematodes in the Classical Phylogeny System (Chitwood, 1958) and is no longer in use. This morphological-based classification system has been replaced by the Modern Phylogeny system, where taxonomy assignment is based on small subunit ribosomal DNA (SSU rDNA). Description Amphid apertures of Secernenteas are pore or slit-like. Some Secernenteas have deirids which are located near nerve ring. Secernenteas have posterior Phasmid (nematode anatomy), phasmids. The Excretory systems of nematodes, excretory system of a Secernentea is tubular. Cuticle, Cuticles of Secernenteas are striated in two to four layers. Lateral field is present. Secernenteas have three Esophageal gland, esophageal glands. Their esophageal structure varies. Male Secernenteas generally have one testis. Caudal Alae (nematode anatomy), alae are common in Secernenteas. Sensory papillae of Secernenteas are cephalic only. It might be caudal papillae in male Secern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Excretory Systems Of Nematodes
The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but many are parasitism, parasitic. Parasitic worms (helminths) are the cause of Soil-transmitted helminthiasis, soil-transmitted helminthiases. They are classified along with arthropods, tardigrades and other moulting animalia, animals in the clade Ecdysozoa. Unlike the flatworms, nematodes have a tubular digestion, digestive system, with openings at both ends. Like tardigrades, they have a reduced number of Hox genes, but their sister phylum Nematomorpha has kept the ancestral protostome Hox genotype, which shows that the reduction has occurred within the nematode phylum. Nematode species can be difficult to distinguish from one another. Consequently, estimates of the number of nematode species are uncertain. A 2013 survey of animal biodiversity suggested there are over 25,000. Es ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
