Thelazioidea is a superfamily

Taxonomic rank

In biological classification, rank is the level in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, and class. Each rank subsumes under it a number of less general categories...

 of spiruria

Spiruria

Subclass Spiruria comprises mostly parasitic secernentean nematodes. In an alternate classification, they are treated as suborder Spirurina, with the orders listed here being ranked as infraorders....

n nematode

Nematode

The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...

s in the large order

Order (biology)

In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Spirurida

Spirurida

Spirurida is an order of spirurian nematodes. Like all nematodes, they have neither a circulatory nor a respiratory system.Some Spirurida, like the genus Gongylonema, can cause disease in humans...

. Like all nematodes, they have neither a circulatory

Circulatory system

The circulatory system is an organ system that passes nutrients , gases, hormones, blood cells, etc...

 nor a respiratory system

Respiratory system

The respiratory system is the anatomical system of an organism that introduces respiratory gases to the interior and performs gas exchange. In humans and other mammals, the anatomical features of the respiratory system include airways, lungs, and the respiratory muscles...

.

Among the families

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 placed here, only the Rhabdochonidae are notably diverse. though none is considered to be monotypic

Monotypic

In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...

 Consequently, the Thelazioidea are among the mid-sized superfamilies of Spirurida.

The families of the Thelazioidea are:

• Pneumospiruridae
• Rhabdochonidae
• Thelaziidae
  Thelaziidae
  Thelaziidae is a family of spirurian nematodes, which form the mid-sized lineage of the superfamily Thelazioidea. Like all nematodes, they have neither a circulatory nor a respiratory system.They number 7 genera or so, with a few dozen species altogether...