''Terranova'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

parasitic nematodes The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-Parasitism, parasitic nematodes also known as eelworms. They are a diverse animal phylum inhab ...

. Species from this genus are known to parasitise

sharks Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorp ...

rays Ray may refer to: Fish * Ray (fish), any cartilaginous fish of the superorder Batoidea * Ray (fish fin anatomy), a bony or horny spine on a fin Science and mathematics * Ray (geometry), half of a line proceeding from an initial point * Ray (gra ...

sawfishes Sawfish, also known as carpenter sharks, are a family of rays characterized by a long, narrow, flattened rostrum, or nose extension, lined with sharp transverse teeth, arranged in a way that resembles a saw. They are among the largest fish wit ...

teleosts Teleostei (; Greek ''teleios'' "complete" + ''osteon'' "bone"), members of which are known as teleosts ), is, by far, the largest infraclass in the class Actinopterygii, the ray-finned fishes, containing 96% of all extant species of fish. Teleo ...

and

crocodilians Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period (Cenomanian stage) and are the closest living re ...

.Sprent, J.F.A. (1992
"Parasites lost?"
''

International Journal for Parasitology The ''International Journal for Parasitology'' is an international medical journal published for the Australian Society for Parasitology by Elsevier. The journal includes original research articles, reviews, and commentary relating to parasites ...

'' 22(2): 139-151. doi: 10.1016/0020-7519(92)90095-3 However, in 2020,

František Moravec František Moravec CBE (23 July 1895 – 26 July 1966) was the chief Czechoslovak military intelligence officer before and during World War II. He moved to the United States after the war. Biography In 1915, Moravec was drafted into Austro-Hun ...

and

Jean-Lou Justine Jean-Lou Justine (born 1955), French parasitologist and zoologist, is a professor at the National Museum of Natural History in Paris, France, and a specialist of fish parasites and invasive land planarians. Higher education and career Justine w ...

considered this

taxon In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

to be invalid on the ground that "its type species . e., ''T. antarctica''has been designated a ''

species inquirenda In biological classification, a ''species inquirenda'' is a species of doubtful identity requiring further investigation. The use of the term in English-language biological literature dates back to at least the early nineteenth century. The term t ...

''", and split many of its species into two new-described genera, ''

Euterranova ''Euterranova'' is a genus of parasitic nematodes that have life cycles involving elasmobranchs. The genus was created in 2020 to accommodate species which were previously included in'' Terranova'' Leiper & Atkinson, 1914 Leiper RT, Atkinson EL ...

'' and ''

Neoterranova ''Neoterranova'' is a genus of parasitic nematodes that have life cycles involving sharks and reptiles. The genus was created in 2020 to accommodate species which were previously included in'' Terranova'' Leiper & Atkinson, 1914 Leiper RT, Atkin ...

''. The type specimen and so far only found adult individual available for feature classification of ''T. antarctica'' is a female, and many features for such parasites are better discernible among males. Thus, in an article from 1990, the place of ''T. antarctica'' was considered as doubtful. Moravec and Justine argued that if the type species is doubtful, then by definition so is the entire genus, in this case, the genus ''Terranova''. However, their reclassification was based entirely on analysis of morphological features, and they recognised that molecular analysis again may lead to a changed taxonomy.

References

{{Taxonbar, from=Q5270626 Parasitic nematodes of fish Ascaridida Secernentea genera