Hammer Head leech (Bipalium) “hammerhead worms“ or “broadhead planarians“ Bipalium fuscatum 001

Bipalium is a genus of large predatory land planarians. They are often loosely called “hammerhead worms“ or “broadhead planarians“ because of the distinctive shape of their head region. Land planarians are unique in that they possess a “creeping sole“ on their ventral side.[2] Several species are considered as invasive to the United States[3] and to Europe.[4][5] Some studies have begun the investigation of the evolutionary ecology of these invasive planarians.[6] Bipalium Model of Bipalium strubelli Graff, 1899 Scientific classification Kingdom: Animalia Phylum: Platyhelminthes Class: Rhabditophora Order: Tricladida Suborder: Continenticola Family: Geoplanidae Subfamily: Bipaliinae Genus: Bipalium Stimpson, 1857[1] Type species Bipalium fuscatum Stimpson, 1857 Synonyms Sphyrocephalus Schmarda, 1859 Dunlopea Wright, 1860 Bipaliura Stimpson, 1861 (misspelling?) Perocephalus von Graff, 1896 (in part) Placocephalus von Graff, 1896 (in part) Description Edit The genus Bipalium was initially defined by Stimpson to include land planarians with the head broadened, forming a head plate. Later, in 1899, Ludwig von Graff divided it into three genera according to the shape of the head:[7] Bipalium: with a well-developed head plate, much broader than long, and with elongated lateral auricles Perocephalus: rudimentary head plate, not much broader than the body Placocephalus: flat head plate with a circular outline Josef Müller, in 1902, considered that no sufficient anatomical basis existed for this distinction, and reunited them under Bipalium. Later, von Graff accepted Müller’s conclusions.[7] Towards the end of the 20th century, Robert E. Ogren and Masaharu Kawakatsu started a series of publications called “The Land Planarian Index series“ in which they reviewed and organized all taxonomic information regarding land planarians. At first, they retained all broad-headed planarians in the genus Bipalium, but later split them into four genera based on the anatomy of the reproductive organs: Bipalium, Novibipalium, Humbertium, and Diversibipalium.[8] Under this scenario, the genus Bipalium is defined as containing broad-headed land planarians with simple copulatory organs, without accessory ducts or copulatory bursa, and with a fold of tissue separating the male and female exit ducts.[8] Etymology Edit The name Bipalium comes from Latin bi-, two pala, shovel or spade, because species in this genus resemble a pickaxe.[9] Species Edit The genus Bipalium currently includes the following species: Bipalium adensameri Graff, 1899 Bipalium admarginatum de Beauchamp, 1933 Bipalium adventitium Hyman, 1943 Bipalium alternans de Beauchamp, 1930 Bipalium bergendali (Graff, 1899) Bipalium cantori (Wright, 1860) Bipalium choristosperma de Beauchamp, 1925 Bipalium crassatrium de Beauchamp, 1939 Bipalium distinguendum Müller, 1907 Bipalium dubium Loman, 1890 Bipalium ephippium Loman, 1890 Bipalium fuscatum Stimpson, 1857 Bipalium fuscolineatum Kaburaki, 1922 Bipalium gestroi Graff, 1894 Bipalium glandiantrum Kawakatsu, Sluys & Ogren, 2005 Bipalium glaucum (Kaburaki, 1922) Bipalium gracile Loman, 1890 Bipalium graffi Müller, 1903 Bipalium haberlandti Graff, 1899 Bipalium hilgendorfi (Graff, 1899) Bipalium interruptum Graff, 1899 Bipalium javanum Loman, 1883 Bipalium kaburakii Kawakatsu, Sluys & Ogren, 2005 Bipalium katoi Kawakatsu, Sluys & Ogren, 2005 Bipalium kewense Moseley, 1878 Bipalium kisoense Kaburaki, 1922 Bipalium koreense Frieb, 1923 Bipalium kraepelini (Ritter-Záhony, 1905) Bipalium marginatum Loman, 1887 Bipalium mjobergi de Beauchamp, 1925 Bipalium monolineatum Kaburaki, 1922 Bipalium moseleyi Loman, 1887 Bipalium muninense Kawakatsu, Sluys & Ogren, 2005 Bipalium myadenosum de Beauchamp, 1939 Bipalium nigrum (Ritter-Záhony, 1905) Bipalium nobile Kawakatsu & Makino, 1982 Bipalium ochroleucum Kaburaki, 1922 Bipalium pennsylvanicum Ogren, 1987 Bipalium penrissenicum Kawakatsu, Ogren & Froehlich, 1998 Bipalium penzigi Müller.