Geoplanidae

Image:Obama anthropophila.JPG is a land planarian with dull colors.]]

Image:Terrestrial Flatworm (Terricola) from a Sulawesi rainforest - Indonesia.jpg

Land planarians are distinguished from their marine and freshwater relatives by their terrestrial habits, as well as by morphological distinctions. Some species have dull colors, including shades of brown and grey, that make them inconspicuous in their environment, but most species are marked by very colorful patterns.{{cite journal | last1 = Seitenfus | first1 = Ana Lúcia Ramos | last2 = Leal-Zanchet | first2 = Ana Maria | title = Uma introdução à morfologia e taxonomia de planárias terrestres (Platyhelminthes, Tricladida, Terricola) | journal = Acta Biologica Leopoldensia | volume = 26 | issue = 2 | pages = 187–202 | year = 2004 | language = pt}} At first they may be confused with slugs or leeches,{{cite journal | last = Schirch | first = P. F. | title = Sobre as planarias terrestres do Brasil | journal = Boletim do Museu Nacional | volume = 5 | year = 1929 | pages = 27–38 | language = pt}} but they lack the anterior tentacles of slugs and the segmentation of leeches. Their size vary greatly, from a few millimeters in length to about one meter.{{cite journal | last1 = Sluys | first1 = Ronald | last2 = Mateos | first2 = Eduardo | last3 = Riutort | first3 = Marta | last4 = Álvarez-presas | first4 = Marta | title = Towards a comprehensive, integrative analysis of the diversity of European microplaninid land flatworms (Platyhelminthes, Tricladida, Microplaninae), with the description of two peculiar new species | journal = Systematics and Biodiversity | volume = 14 | issue = 1 | year = 2016 | pages = 9–31 | issn = 1477-2000 | doi = 10.1080/14772000.2015.1103323| s2cid = 87583502 }}{{cite book | first1 = Ian R. | last1 = Ball | last2 = Reynoldson | first2 = T. B. | title = British Planarians. Platyhelminthes: Tricladida. Keys and notes for the identification of the species. | year = 1981 | publisher = Cambridge University Press}}{{cite journal | last1 = Kawakatsu | first1 = Masaharu | last2 = Makino | first2 = Naoya | last3 = Shirasawa | first3 = Yasuko | title = Bipalium nobile sp.nov. (Turbellaria, Tricladida, Terricola), a New Land Planarian from Tokyo | journal = Annotationes Zoologicae Japonenses | volume = 55 | issue = 4 | pages = 236–262 | year = 1982 | url = http://ci.nii.ac.jp/naid/110003353327/en}}

The most distinguishing feature that characterizes land planarians is the presence of a creeping sole, a highly ciliated region on the ventral epidermis that helps them to creep over the substrate.{{cite journal | last = Sluys | first = Ronald | title = Phylogenetic relationships of the triclads (Platyhelminthes, Seriata, Tricladida) | journal = Bijdragen tot de Dierkunde | year = 1989 | volume = 59 | issue = 1 | pages = 3–25| doi = 10.1163/26660644-05901001 | doi-access = free }} The creeping sole may be wide and flat, occupying most of the ventral surface, or narrow and pronounced, being easily distinguished from the rest of the ventral surface.{{cite book | last = von Graff | first = Ludwig | date = 1899 |title = Monographie der Turbellarien. II. Tricladida Terricola | location = Leipzig | publisher = Engelmann | page = 540 | language = de}}

The epidermis of land planarians is composed by a simple epithelium of cubic or columnar cells. The cells are ciliated only on a ventral region, called creeping sole, which the animal uses to glide over surfaces. Numerous secretory cells open throughout the epidermis, the most characteristic ones being the rhabditogen cells, which produce a secretion in the form of small rod-like structures, the rhabdites. Rhabditogen cells are very numerous on the dorsal epidermis, but rare on the ventral side.

The nervous system of land planarians has the longitudinal nerve cords reduced to one ventral pair that is located much deeper in the body than in other triclads. These ventral cords are usually connected by many comissures, so that they fuse into a single ventral nerve plate. Additionally, land planarians have a highly developed ventral nerve plexus just below the epidermis that is probably associated to the presence of a creeping sole.

Contrary to aquatic planarians, land planarians do not have a distinct brain, i.e., there is no clear frontal cluster of nerve cells other than the ventral nerve plate.{{cite book | last = Hyman | first = Libbie H. | date = 1951 | title = The invertebrates. II. Platyhelminthes and Rhynchocoela | location = New York | publisher = McGraw-Hill | page = 550}}

The family Geoplanidae is composed of five subfamilies:

• Bipaliinae
• Geoplaninae
• Microplaninae
• Rhynchodeminae
• Timyminae

Although there are over 830 known species of Geoplanidae in the world,{{cite journal | last1 = Schockaert | first1 = E. R. | display-authors = etal | year = 2008 | title = Global diversity of free living flatworms (Platyhelminthes, "Turbellaria") in freshwater | url = http://each.uspnet.usp.br/planarias/Artigos/Geoplanidae/2008%20-%20Schockaert%20-%20Global%20diversity%20of%20free%20living%20flatworm.pdf | journal = Hydrobiologia | volume = 595 | pages = 41–48 | doi = 10.1007/s10750-007-9002-8 | s2cid = 21471933 }}{{Dead link|date=December 2019 |bot=InternetArchiveBot |fix-attempted=yes }} the diversity of land planarians is still poorly known. The highest diversity occurs in tropical forests in South America, Asia and Australia. Europe and North America are relatively species-poor, while the diversity of Africa may be as high as that of other tropical regions, but is highly understudied.

Image:Polycladus gayi.jpg

Most species of land planarians live at the soil of forests, especially in the leaf litter layer, but some may inhabit galleries constructed by other invertebrates or be found on vegetation, such as bromeliads.{{cite journal|last1=Beauchamp|first1=P.|title=Planaires des Broméliacées de Costa Rica Recueillies par Mr C. Picado.|journal=Archives de Zoologie Paris|volume=51|year=1913|pages=41–52|language=fr}} Despite being sensitive to dehydration, some species are well adapted to considerably dry environments, such as savannas.{{cite journal|last1=Cumming|first1=Meg S.|title=Activity patterns of termite-eating land planariansMicroplana termitophaga(Platyhelminthes: Tricladida)|journal=Journal of Zoology|volume=237|issue=4|year=1995|pages=531–542|issn=0952-8369|doi=10.1111/j.1469-7998.1995.tb05013.x}}

During unfavorable conditions, such as dry seasons, land planarians tend to seek shelter by burrowing in the soil or building a cyst composed of soil particles united by mucus.{{cite journal|last1=Ogren|first1=Robert E.|title=Ecological Observations on the Occurrence of Rhynchodemus, a Terrestrial Turbellarian|journal=Transactions of the American Microscopical Society|volume=74|issue=1|year=1955|pages=54–60|issn=0003-0023|doi=10.2307/3223842|jstor=3223842}}

Some species are well adapted to human-disturbed environments and many of those have been introduced in areas outside of their native range. In some localities, such as the United Kingdom, the number of introduced land planarian species greatly surpass the number of described native species.{{cite journal|last1=Jones|first1=H.D.|last2=Boag|first2=B.|title=The distribution of New Zealand and Australian terrestrial flatworms (Platyhelminthes: Turbellaria: Tricladida: Terricola) in the British Isles—the Scottish survey and MEGALAB WORMS|journal=Journal of Natural History|volume=30|issue=7|year=2007|pages=955–975|issn=0022-2933|doi=10.1080/00222939600770511}}

Image:Endeavouria septemlineata feeding on Bradybaena similaris.png

Land planarians are carnivorous and most species are active predators, but some are mainly scavengers.{{cite journal|last1=McDonald|first1=Jillian C.|last2=Jones|first2=Hugh D.|title=Abundance, reproduction, and feeding of three species of British terrestrial planarians: Observations over 4 years|journal=Journal of Natural History|volume=41|issue=5–8|year=2007|pages=293–312|issn=0022-2933|doi=10.1080/00222930701219149|s2cid=85830660|url=https://zenodo.org/record/5233756 }}

All planarians feed through a muscular and eversible pharynx located slightly posteriorly to the middle of the body length and opening through a ventral mouth. The pharynx is an extensible tube-like organ bearing a complex muscular coat. It specializes as a penetration organ for those planarians that feed on arthropods; or as a grasping organ for those planarians that feed on other soft bodied invertebrates such as earthworms. All geoplanidae pharynxes are equipped with glandular secretions that externally digest and dissolve their prey.

As part of the soil ecosystem, land planarians feed mainly on other invertebrates, such as earthworms, snails, slugs, nemerteans, velvet worms, woodlice, millipedes, insects and arachnids.{{cite journal|last1=Boll|first1=Piter Kehoma|last2=Leal-Zanchet|first2=Ana Maria|title=Predation on invasive land gastropods by a Neotropical land planarian|journal=Journal of Natural History|volume=49|issue=17–18|year=2014|pages=983–994|issn=0022-2933|doi=10.1080/00222933.2014.981312|s2cid=85280766|url=https://zenodo.org/record/4005881}}{{cite journal|last1=Prasniski|first1=Maria E. T.|last2=Leal-Zanchet|first2=Ana M.|title=Predatory behavior of the land flatworm Notogynaphallia abundans (Platyhelminthes: Tricladida)|journal=Zoologia (Curitiba)|volume=26|issue=4|year=2009|pages=606–612|issn=1984-4670|doi=10.1590/S1984-46702009005000011|doi-access=free}} Some may even feed on other land planarians.{{cite journal|last1=Boll|first1=Piter K.|last2=Rossi|first2=Ilana|last3=Amaral|first3=Silvana V.|last4=Leal-Zanchet|first4=Ana|title=A taste for exotic food: Neotropical land planarians feeding on an invasive flatworm|journal=PeerJ|volume=3|year=2015|pages=e1307|issn=2167-8359|doi=10.7717/peerj.1307|pmid=26500817|pmc=4614845 |doi-access=free }}

Some species of land planarians have become invasive pest species. The New Zealand flatworm Arthurdendyus triangulatus and the Australian flatworm Australoplana sanguinea alba have been introduced in the British Isles and are considered to be pest species because they prey upon earthworms and thus may negatively affect soil structure and fertility.{{cite journal|last1=Santoro|first1=Giulio|last2=Jones|first2=Hugh D.|title=Comparison of the earthworm population of a garden infested with the Australian land flatworm (Australoplana sanguinea alba) with that of a non-infested garden|journal=Pedobiologia|volume=45|issue=4|year=2001|pages=313–328|issn=0031-4056|doi=10.1078/0031-4056-00089}}{{cite journal|last1=Murchie|first1=Archie K.|last2=Gordon|first2=Alan W.|title=The impact of the 'New Zealand flatworm', Arthurdendyus triangulatus, on earthworm populations in the field|journal=Biological Invasions|volume=15|issue=3|year=2012|pages=569–586|issn=1387-3547|doi=10.1007/s10530-012-0309-7|s2cid=7041377}} Another species, Platydemus manokwari, has been used as an agent of biological pest control of the introduced giant African snail Achatina fulica in Hawaii, the Maldives, Irian Jaya, and Guam, but has become an even worse pest and today threatens several native snail populations in the Pacific.{{cite journal|last1=Sugiura|first1=Shinji|last2=Yamaura|first2=Yuichi|title=Potential impacts of the invasive flatworm Platydemus manokwari on arboreal snails|journal=Biological Invasions|volume=11|issue=3|year=2008|pages=737–742|issn=1387-3547|doi=10.1007/s10530-008-9287-1|s2cid=44641680}}

Some land planarians show hunting behaviour, using chemical signals to detect their prey. Most land planarians have chemical sensory organs in the anterior part of the body, such as sensory pits and epidermal folds which serve as chemical radars for detecting their food. The mucus trails from the slime of slugs, snails and other planarians orient planarians towards their prey.{{Cite journal | last1 = Fiore | first1 = C. | last2 = Tull | first2 = J. L. | last3 = Zehner | first3 = S. | last4 = Ducey | first4 = P. K. | title = Tracking and predation on earthworms by the invasive terrestrial planarian Bipalium adventitium (Tricladida, Platyhelminthes) | doi = 10.1016/j.beproc.2004.06.001 | journal = Behavioural Processes | volume = 67 | issue = 3 | pages = 327–334 | year = 2004 | pmid = 15518983| s2cid = 23159802 }}{{Cite journal | doi = 10.1007/s00114-010-0717-4| pmid = 20853096| bibcode = 2010NW.....97..997I| title = Prey-tracking behavior in the invasive terrestrial planarian Platydemus manokwari (Platyhelminthes, Tricladida)| journal = Naturwissenschaften| volume = 97| issue = 11| pages = 997–1002| year = 2010| last1 = Iwai | first1 = N. | last2 = Sugiura | first2 = S. | last3 = Chiba | first3 = S. | s2cid = 23021634}} Different species use different techniques for capturing and immobilizing their prey, such as entrapment with sticky mucus and immobilization by physical force.{{cite journal | last1 = Boll | first1 = Piter Kehoma | last2 = Leal-Zanchet | first2 = Ana Maria | title = Predation on invasive land gastropods by a Neotropical land planarian | journal = Journal of Natural History | volume = 49 | issue = 17–18 | year = 2014 | pages = 983–994| issn = 0022-2933 | doi = 10.1080/00222933.2014.981312| s2cid = 85280766 | url = https://zenodo.org/record/4005881 }}

Cannibalism has been observed in land planarians.{{citation needed|date=April 2016}}

File:Land planarians.jpg

Until very recently, land planarians were classified as a suborder within Tricladida, named Terricola. However, recent phylogenetic studies revealed that they are actually the sister-group of Dugesiidae, a family of freshwater planarians (at that time part of the suborder Paludicola). The most recent classification puts both land and freshwater planarians within a single suborder called Continenticola, with land planarians forming a single family, Geoplanidae.

The following phylogenetic supertree after Sluys et al., 2009 presents the current classification of planarians:

{{clade| style=font-size:100%;line-height:80%

|label1=Tricladida

|1={{Clade

|1=Maricola

|2={{Clade

|1=Cavernicola

|label2=Continenticola

|2={{Clade

|label1=Planarioidea

|1={{Clade

|1=Planariidae

|2={{Clade

|1=Kenkiidae

|2=Dendrocoelidae

}}

}}

|label2=Geoplanoidea

|2={{Clade

|1=Dugesiidae

|2=Geoplanidae

}}

}}

}}

}}

}}

In the former suborder Terricola, land planarians were separated into three families according to morphological features:{{cite journal | last1 = Ogren | first1 = R. E. | last2 = Kawakatsu | first2 = M. | year = 1988 | title = Index to the species of the family Rhynchodemidae (Turbellaria, Tricladida, Terricola) Part I: Rhynchodeminae | journal = Bulletin of Fuji Women's College | volume = 26 | issue = 2| pages = 39–91 }}{{cite journal | last1 = Ogren | first1 = R. E. | last2 = Kawakatsu | first2 = M. | year = 1991 | title = Index to the species of the family Geoplanidae (Turbellaria, Tricladida, Terricola) Part II: Caenoplaninae and Pelmatoplaninae | journal = Bulletin of Fuji Women's College | volume = 29 | issue = 2| pages = 35–58 }}

• Bipaliidae: head expanded in a spatula-like shape and multiple eyes;
• Rhynchodemidae: non-expanded head and a single pair of eyes. It included two subfamilies: Rhynchodeminae, with subepithelial longitudinal muscular fibers grouped into large bundles, and Microplaninae, with weaker subepithelial longitudinal muscular fibers not forming bundles;
• Geoplanidae: non-expanded head and multiple eyes. It included three subfamilies: Geoplaninae, with dorsal testicles and strong subepithelial longitudinal muscles, Caenoplaninae, with ventral testicles and strong subepithelial longitudinal muscles, and Pelmatoplaninae, with ventral testicles and weak subepithelial longitudinal muscles.

Recent phylogenetic analyses, however, revealed that Rhynchodeminae and Microplaninae are not closely related and that Caenoplaninae is closer to Rhynchodeminae than to Geoplaninae. The current classification of land planarian subfamilies is shown in the following phylogenetic tree after Álvarez-Presas et al., 2008.{{Cite journal | last1 = Álvarez-Presas | first1 = M. | last2 = Baguñà | first2 = J. | last3 = Riutort | first3 = M. | doi = 10.1016/j.ympev.2008.01.032 | title = Molecular phylogeny of land and freshwater planarians (Tricladida, Platyhelminthes): From freshwater to land and back | journal = Molecular Phylogenetics and Evolution | volume = 47 | issue = 2 | pages = 555–568 | year = 2008 | pmid = 18359250}} The old subfamilies Caenoplaninae and Pelmatoplaninae have been included as tribes Caenoplanini and Pelmatoplanini inside Rhynchodeminae. Note that Spathula and Romankenkius belong to the family Dugesiidae. Their relocation inside Geoplanidae needs further investigation.

{{clade| style=font-size:100%;line-height:80%

|label1=Geoplanoidea

|1={{Clade

|1=Dugesiidae

|label2=Geoplanidae

|2={{Clade

|1=Bipaliinae

|2={{Clade

|1={{Clade

|1=Geoplaninae

|2={{Clade

|1=Caenoplaninae

|2=Rhynchodeminae

}}

}}

|2={{Clade

|1=Microplaninae

|2=(Spathula + Romankenkius)

}}

}}

}}

}}

}}

File:Bipalium adventitium close up.jpg|Bipalium adventitium close up under a rock, North California, USA.

File:Geoplana ladislavi.jpg|Obama ladislavii from a garden in Porto Alegre, southern Brazil.

File:Cephaloflexa araucariana.JPG|Cephaloflexa araucariana from the São Francisco de Paula National Forest, southern Brazil.

File:Luteostriata ernesti.JPG|Luteostriata ernesti in the São Francisco de Paula National Forest.

File:Notogynaphallia plumbea.jpg|Notogynaphallia plumbea from an Araucaria moist forest in Paraná, Brazil.

File:Platyhelminthes, Tricladida, Terricola, Atlantic forest, northern littoral of Bahia, Brazil (14617707721).jpg|Unidentified land planarian from Bahia, Brazil.

File:Geoplaninae.jpg|Unidentified land planarian from the Valdivian Rainforest in southern Chile.

File:Pseudogeoplana reticulata.jpg|Pseudogeoplana reticulata from the Valdivian Rainforest.

File:Caenoplana coerulea.jpg|Caenoplana coerulea, the blue planarian.

File:New Zealand flatworm 2.JPG|Arthurdendyus triangulatus, the New Zealand flatworm.

File:Peerj-297-fig-1 Platydemus manokwari.png|Platydemus manokwari in France.

File:Rhynchodemus sylvaticus.jpg|Rhynchodemus sylvaticus in the Iberian Peninsula.

File:Microplana sp2.JPG|Microplana robusta in Portugal.

File:Diversibipalium multilineatum from Italy - Fig 1 a - Body.png|Diversibipalium multilineatum in Italy.

File:Bipaliinae 2.jpg|Species of subfamily Bipaliinae in Sarawak, Malaysia.

File:Diversibipalium rauchi.png|Diversibipalium rauchi in Thomson Nature Park, Singapore.

File:Bipaliumjavanum15062024.jpg|Bipalium Javanum in Java, Indonesia.

{{Reflist|2}}

{{Commons category|Geoplanidae}}

• [https://www.youtube.com/watch?v=iOWtKWTlTLM Video of juvenile Land Planarian in Borneo]

{{Taxonbar|from=Q3112410}}

Category:Taxa named by William Stimpson

Category:Platyhelminthes families