''Convolutriloba'' 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 ...

of marine

acoel Acoela, or the acoels, is an order of small and simple invertebrates in the subphylum Acoelomorpha of phylum Xenacoelomorpha, a deep branching bilaterian group of animals, which resemble flatworms. Historically they were treated as an order of ...

s. They possess shield shaped bodies with a rounded anterior and three

caudal Caudal may refer to: Anatomy * Caudal (anatomical term) (from Latin ''cauda''; tail), used to describe how close something is to the trailing end of an organism * Caudal artery, the portion of the dorsal aorta of a vertebrate that passes into th ...

lobes, though the number may vary in mature individuals. They may have an indentation on each side of the body near the anterior end. They usually are a few millimeters to a centimeter in length and under a millimeter thick. Though they have muscles throughout their body, they move using

cilia The cilium (: cilia; ; in Medieval Latin and in anatomy, ''cilium'') is a short hair-like membrane protrusion from many types of eukaryotic cell. (Cilia are absent in bacteria and archaea.) The cilium has the shape of a slender threadlike proj ...

to glide. They have symbiotic algae that give them a green or brown colour. They also prey on small crustacean larvae like artemia and copepods. However they cannot survive for long periods in the dark even if they are fed. The mouth is located on the ventral surface. When feeding, they raise their front ends and fold the lateral edges of their body downward forming a funnel. Prey are trapped by lowering the body onto them. Individuals are

hermaphrodite A hermaphrodite () is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are either male or female are gonochoric, which is the opposite of hermaphroditic. The individuals of many ...

s. They reproduce both sexually and asexually. They have captured scientific interest because of the various ways of agametic

asexual reproduction Asexual reproduction is a type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring that arise by asexual reproduction from either unicellular or multicellular organisms inherit the f ...

. During

budding Budding or blastogenesis is a type of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site. For example, the small bulb-like projection coming out from the yeast cell is kno ...

architomy Fragmentation in multicellular or colonial organisms is a form of asexual reproduction or cloning, where an organism is split into fragments upon maturation and the split part becomes the new individual. The organism may develop specific organs o ...

the offspring separate from the body by attaching to the substrate and tearing away. The offspring produced by sexual reproduction lack the symbiotic algae and will die unless they can pick them up within a few weeks. Like all members of the family sagittiferidae they possess sagittocysts on their skin. Sagittocysts are needle like bodies 18-50 μm long that contain some secretory product. They can be extruded from the body by an associated muscle. They are believed to play a role in defence and prey capture. Ultrastructurally, they have a vesicular core surrounded by a mesh of actin filaments. Due to their rapid growth in well-lit aquariums, they are considered pests.

Systematics

* ''

Convolutriloba hastifera ''Convolutriloba'' is a genus of marine acoels. They possess shield shaped bodies with a rounded anterior and three caudal lobes, though the number may vary in mature individuals. They may have an indentation on each side of the body near the an ...

'' (Winsor, 1990): The only species discovered naturally - the other three were discovered in aquaria. This species undergoes transverse fission (

) near the caudal end, with a relatively undifferentiated fragment of the animal tearing away by holding onto the substrate. The smaller fragment produced by the fission grows a new head and begins moving around in a few days. * ''

Convolutriloba longifissura ''Convolutriloba'' is a genus of marine acoels. They possess shield shaped bodies with a rounded anterior and three caudal lobes, though the number may vary in mature individuals. They may have an indentation on each side of the body near the an ...

'' (Bartolomaeus & Balzer, 1997) Asexual reproduction in this species occurs by architomy of the caudal end to give a small butterfly shaped piece. This piece splits longitudinally to give two daughter organisms. Thus at the end of each cycle, three new individuals are formed. * ''

Convolutriloba macropyga ''Convolutriloba'' is a genus of marine acoels. They possess shield shaped bodies with a rounded anterior and three caudal lobes, though the number may vary in mature individuals. They may have an indentation on each side of the body near the an ...

'' (Shannon & Achatz, 2007): This species is green in colour and has a pair of indentations on either side of the head. Asexual reproduction occurs by the formation of

buds In botany, a bud is an undeveloped or Plant embryogenesis, embryonic Shoot (botany), shoot and normally occurs in the axil of a leaf or at the tip of a Plant stem, stem. Once formed, a bud may remain for some time in a dormancy, dormant conditi ...

facing away from the head from the caudal ends. * ''

Convolutriloba retrogemma ''Convolutriloba retrogemma'' is a reddish-brown acoel 2 mm in length also commonly known as redbug, red planaria, rust flatworm, or simply red flatworm. It is a marine animal that gets energy from its endosymbiotic algae or from the consum ...

'' (Hendelberg & Akesson, 1988): Asexual reproduction occurs by the formation of buds from the caudal lobes. The body axis of these buds faces away from that of the mother. This results in an individual with one or more extra heads at the tips of the tails.

References

{{Taxonbar, from=Q3386756 Convolutidae Bilaterian genera