| Bipalium adventitium | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Platyhelminthes |
| Order: | Tricladida |
| Family: | Geoplanidae |
| Genus: | Bipalium |
| Species: | B. adventitium |
| Binomial name | |
| Bipalium adventitium Hyman, 1943 | |
Bipalium adventitium, the wandering broadhead planarian, is a land planarian in the subfamily Bipaliinae. It has been accidentally introduced in the United States, where it is considered invasive. [1]
Most adult individuals of B. adventitium are 5–8 cm (2.0–3.1 in) in length. The head is expanded and fan-shaped, being easily distinguishable from other common species of Bipalium, such as Bipalium kewense and Bipalium pennsylvanicum , because these have a head in the shape of a half moon. [1] The body has a yellow to tan color and has one dark dorsal stripe that does not extend over the head. [2]
Bipalium adventitium is known to prey on earthworms. In order to catch its prey, it follows a chemical trail given off by the earthworm. [3] Chemoreceptors on the head are responsible for sensing the trail left by the prey. [4] After finding an earthworm, the planarian quickly crawls over it and wraps itself around the prey, preventing its escape. In addition, it is known to attack and eat any earthworm, including those that are 100 times their own mass. [5] In North America, where B. adventitium is an introduced species, most earthworms do not immediately recognize the flatworm as a predator. They try to escape only after being pierced by the planarian's everted pharynx, which is one of the reasons of B. adventitium's success in invading this continent. [3]
Recently, it has been confirmed that the potent neurotoxin tetrodotoxin is present in B. adventitium. Its function is yet unknown, but it may be used as a defense against predators or as a way to subdue prey. [6]
Differently from Bipalium kewense, which usually reproduces asexually by fission, Bipalium adventitium more commonly reproduces sexually. It is suggested that it has only one breeding season per year. [2] As in most land planarians, mating occurs by internal fertilization when two individuals meet. The eggs are deposited in egg capsules and after about 3 weeks they release 1–6 juveniles. [7]
Bipalium adventitium is believed to have been introduced in the last century to the United States from Asia. It is believed that this broadhead planarian was introduced and spread to most Northern states passively by human dispersal and has become abundant in the region it occupies. [8] It is more commonly found in suburban areas and nurseries where exotic plants are prevalent. [2] It is found in gardens and woodlands under objects like leaf litter, where the soil is moist. The ecological consequences of this invasion have not yet been fully explored.
In 2019, the species has been recorded for the first time in Montréal, Quebec, Canada. [9]
The New Zealand flatworm is a large land flatworm native to New Zealand. It can vary from 5 mm in length when hatched to approximately 17 centimetres (6.7 in) in mature adults.
Geoplanidae is a family of flatworms known commonly as land planarians or land flatworms.
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", a highly ciliated region on the ventral epidermis that helps them to creep over the substrate. Native to Asia, several species are invasive to the United States, Canada, and Europe. Some studies have begun the investigation of the evolutionary ecology of these invasive planarians.
Platydemus manokwari, also known as the New Guinea flatworm, is a species of large predatory land flatworm.
Bipalium kewense, also known as the shovel-headed garden worm, is a species of large predatory land planarian with a cosmopolitan distribution. It is sometimes referred to as a "hammerhead flatworm" due to its half-moon-shaped head, but this name is also used to refer to other species in the subfamily Bipaliinae.
Dugesiidae is a family of freshwater planarians distributed worldwide. The type genus is Dugesia Girard, 1850.
Girardia is a genus of freshwater planarians belonging to the family Dugesiidae.
Bipaliinae is a subfamily of land planarians found mainly in Madagascar, the Indian subcontinent and Southeast Asia, although some species have been introduced worldwide.
Bipalium pennsylvanicum, the three-lined land planarian, is a species of land planarian in the subfamily Bipaliinae. They are native to Asia, but found mostly in Pennsylvania and the surrounding areas. They can reach a length of 5.1 inches (130 mm) or more, with a diet consisting mostly of earthworms. They reproduce sexually by creating a cocoon in the spring, but unlike related planarians, they cannot reproduce through binary fission. It is not recommended to touch these flatworms without gloves, because their mucous contains a toxin that is used for digesting prey and can cause skin irritation for some people.
Diversibipalium multilineatum is a species of large predatory land flatworm.
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Amaga is a genus of land planarians from South America.
Obama anthropophila is a species of Brazilian land planarian in the subfamily Geoplaninae. It is a very common land planarian in human-disturbed environments in southern and southeastern Brazil.
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Obama josefi is a species of Brazilian land planarian in the subfamily Geoplaninae.
Obama nungara is a species of land planarian in the family Geoplanidae. It is native to South America, but has been introduced in Europe.
Novibipalium is a genus of land planarians of the subfamily Bipaliinae.
Humbertium is a genus of land planarians of the subfamily Bipaliinae.
Bipalium vagum, the wandering hammerhead worm, is a land planarian in the subfamily Bipaliinae. It has been accidentally introduced in the United States, Bermuda and various islands in the Caribbean and was recorded for the first time in Europe, in Italy, in 2021.
Vermiviatum covidum is a species of predatory land flatworm, found in France and Italy. The Holotype specimen is MNHN JL351B.
