''Geoplana'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

land planarian Geoplanidae is a family of flatworms known commonly as land planarians or land flatworms. These flatworms are mainly predators of other invertebrates, which they hunt, attack and capture using physical force and the adhesive and digestive proper ...

s from

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

Taxonomic history

The genus ''Geoplana'' was erected in 1857 by

William Stimpson William Stimpson (February 14, 1832 – May 26, 1872) was an American scientist. He was interested particularly in marine biology. Stimpson became an important early contributor to the work of the Smithsonian Institution and later, director o ...

and included most land planarians with several eyes distributed along the body.Stimpson, W. (1857). ''Prodromus descriptionis animalium evertebratorum quæ in Expeditione ad Oceanum, Pacificum Septentrionalem a Republica Federata missa, Johanne Rodgers Duce, observavit er descripsit. Pars I. Turbellaria Dendrocœla.'' Proceedings of the Academy of Natural Sciences of Philadelphia. 9:19-31. Species with only two eyes were placed in the genus '' Rhynchodemus'', while species with a crescent-shaped head were placed in '' Bipalium''. In the same year, apparently unaware of Stimpson's paper, the naturalist

Max Schultze Max Johann Sigismund Schultze (25 March 1825 – 16 January 1874) was a German microscopic anatomist noted for his work on cell theory. Biography Schultze was born in Freiburg im Breisgau (Baden), son of the anatomist Karl August Sigismund Schu ...

, based on published information and new species collected in Brazil by the naturalist

Fritz Müller Johann Friedrich Theodor Müller (; 31 March 182221 May 1897), better known as Fritz Müller (), and also as Müller-Desterro, was a German biologist who emigrated to southern Brazil, where he lived in and near the city of Blumenau, Santa Cata ...

, also erected a genus named ''Geoplana'', but included all land planarians in it.Schultze, M. and Müller, F. (1857). ''Beiträge zur Kenntnis der Landplanarien.'' Abhandlungen der Naturforschenden Gesellschaft zu Halle. 4:61-74. However, Stimpson's system prevailed. During most of the 20th century, many new land planarian species, mostly from Australia and South America, were placed in ''Geoplana''. In 1955,

Eudóxia Maria Froehlich Eudóxia Maria Froehlich (21 October 1928 – 26 September 2015) was a Brazilian zoologist. Life Born in 1928, Eudóxia Maria de Oliveira Pinto was the daughter of Alice Alves de Camargo and the ornithologist Olivério Mário de Oliveira Pinto. ...

defined that ''Geoplana vaginuloides'' would be the type-species of ''Geoplana'', as it was the first species listed by Stimpson.Froehlich, E. M. (1955). ''Sobre Espécies Brasileiras do Gênero Geoplana.'' Boletim da Faculdade de Filosofia, Ciências e Letras da Universidade de São Paulo, Série Zoologia. 19:289-339. In 1990, Robert E. Ogren and

Masaharu Kawakatsu is a Japanese zoologist known for his studies on the taxonomy and ecology of planarians. Life Masaharu Kawakatsu was born in 1929 in the Asahi, Hokkaido, Asahi village, Kameoka town, Kyoto Prefecture, Japan, son of Masakazu Kawakatsu, a squir ...

published a review of the classification of land planarians and divided ''Geoplana'' in four genera: ''Geoplana'', '' Gigantea'', '' Notogynaphallia'' and '' Pasipha''. ''Geoplana'' retained all species with dorsal testes, a protrusible penis and a female canal entering the genital antrum dorsally. Species with ventral testes, without a protrusible penis or with a female canal entering the genital antrum ventrally were placed in other genera.Ogren, R. E. and Kawakatsu, M. (1990). ''Index to the species of the family Geoplanidae (Turbellaria, Tricladida, Terricola) Part I: Geoplaninae.'' Bulletin of Fujis Women's College. 29: 79-166. During the 21st century, molecular studies revealed that ''Geoplana'' sensu Ogren & Kawakatsu was still heterogeneous. A study published in 2013 by Carbayo et al., based on molecular data, divided ''Geoplana'' in 6 genera: ''Geoplana'', ''

Barreirana ''Barreirana'' is a genus of land planarians from Brazil, formerly considered a subgenus of ''Geoplana''. Description The genus ''Barreirana'' includes land planarians with a small and slender body, usually around 2 cm long or less. The e ...

'', '' Cratera'', '' Matuxia'', ''

Obama Barack Hussein Obama II (born August 4, 1961) is an American politician who was the 44th president of the United States from 2009 to 2017. A member of the Democratic Party, he was the first African American president in American history. Ob ...

'', and ''

Paraba ''Paraparaba'' is a genus of land planarians from South America. Description Species of the genus ''Paraparaba'' have a slender body with nearly parallel margins while creeping. The largest specimens may reach about 8 cm in length. Both s ...

''. Only three species remained as ''Geoplana'', along with several ''

incertae sedis or is a term used for a taxonomy (biology), taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...

''. By a revision of the three valid species, the number increased to thirteen, mostly by the discovery that the type-species, ''Geoplana vaginuloides'' was a complex of species.

Current description

Currently, the genus ''Geoplana'' is characterized by having the features described by Ogren & Kawatasu (dorsal testes, a protrusible penis and a female canal entering the genital antrum dorsally) plus several others, such as a slender body with nearly parallel margins, a strongly convex dorsum, monolobulated eyes (i.e., simple and circular, with only one lobe), a strong muscle tube around the intestine, a very long and muscular penis papilla, and the lack of a prostatic vesicle.

Species

There are currently only thirteen species certainly belonging to ''Geoplana'': *''

Geoplana apua ''Geoplana apua'' is a species of land planarian belonging to the subfamily Geoplaninae. It is found in areas within the Atlantic Forest in the municipalities of Nova Iguaçu and Teresópolis, Brazil. Description ''Geoplana apua'' is a flatworm ...