''Planocarina'' () is a genus of arcellinid

testate amoebae Testate amoebae (formerly thecamoebians, Testacea or Thecamoeba) are a polyphyletic group of unicellular amoeboid protists, which differ from naked amoebae in the presence of a test (biology), test that partially encloses the cell, with an apert ...

belonging to the family

Hyalospheniidae Hyalospheniidae is a family of arcellinid testate amoebae and the sole family of the infraorder Hyalospheniformes. Commonly referred to as "hyalospheniids", these lobose amoebae are characterized by their ability to generate a shell composed of ...

. It was created in 2016 to agglutinate a

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

of species that were previously assigned to the

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

genus '' Nebela''. All species of ''Planocarina'' have a compressed keel surrounding the posterior part of their shell. It is the

sister group In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

of '' Alabasta''.

Morphology

Members of ''Planocarina'' have an elongated, pyriform

test Test(s), testing, or TEST may refer to: * Test (assessment), an educational assessment intended to measure the respondents' knowledge or other abilities Arts and entertainment * ''Test'' (2013 film), an American film * ''Test'' (2014 film) ...

with a distinct neck, and lateral margins tapering towards the test opening. The posterior part of the test is surrounded entirely by a flat keel. The test hyaline or slightly yellowish in color, composed of circular and elongated scales recycled from the organism's prey, such as euglyphid testate amoeba.

Classification

''Planocarina'' contains all former species of '' Nebela'' that have a flat keel, with the exception of those that have a lateral horn, which are assigned to '' Cornutheca''. There are 4 species in total: *'' Planocarina carinata'' (=''Nebela carinata'' ) *'' Planocarina marginata'' (=''Nebela marginata'' ) *'' Planocarina maxima'' (=''Nebela maxima'' ) *'' Planocarina spumosa'' (=''Nebela spumosa'' )

References

Tubulinea Amoebozoa genera {{Amoebozoa-stub