''Lepidodermella squamata'' is a freshwater

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of minute worm in the phylum

Gastrotricha The gastrotrichs (phylum Gastrotricha), common name, commonly referred to as hairybellies or hairybacks, are a group of microscopic (0.06-3.0 mm), worm-like, acoelomate animals, and are widely distributed and abundant in freshwater and Marin ...

Description

''Lepidodermella squamata'' is a small worm-like organism growing to a length of 190 μm (0.007 inch). It is roughly cylindrical with a head, a slightly narrower neck, and a slightly wider and much longer body ending with a forked tail. There are two adhesive suckers on the posterior end. The surface of the trunk is covered in scales. There are tufts of bristles on the head and two rows of

cilia The cilium, plural cilia (), is a membrane-bound organelle found on most types of eukaryotic cell, and certain microorganisms known as ciliates. Cilia are absent in bacteria and archaea. The cilium has the shape of a slender threadlike projecti ...

on the ventral surface of the body.

Distribution and habitat

''Lepidodermella squamata'' is found in North and South America, Japan and much of Europe. It is a freshwater species and is found on the surface of water plants in lakes, ponds, streams and marshes. It is also found between the particles of sediment at the bottom of the water body.

Biology

''Lepidodermella squamata'' feeds on

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

and

detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...

. It glides across the substrate by means of the cilia on its ventral surface. Development is direct and growth is rapid. A few days after hatching it develops both male and female reproductive organs. About four eggs are laid over the course of a few days, however these develop without fertilisation. In adverse conditions, the eggs can survive desiccation and freezing.

Systematics

The phylogenetic relationships of the Gastrotricha are still unclear: Morphological studies place Gastrostricha near the

Gnathostomulid Gnathostomulids, or jaw worms, are a small phylum of nearly microscopic marine animals. They inhabit sand and mud beneath shallow coastal waters and can survive in relatively anoxic environments. They were first recognised and described in 1956. ...

a, the

Rotifer The rotifers (, from the Latin , "wheel", and , "bearing"), commonly called wheel animals or wheel animalcules, make up a phylum (Rotifera ) of microscopic and near-microscopic pseudocoelomate animals. They were first described by Rev. John H ...

a or the

Nematoda The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a broa ...

. Molecular data have shown that the Gastrotricha are sister taxon to the Platyhelminthes. Later studies have placed them elsewhere, including close to the

Ecdysozoa Ecdysozoa () is a group of protostome animals, including Arthropoda (insects, chelicerata, crustaceans, and myriapods), Nematoda, and several smaller phyla. They were first defined by Aguinaldo ''et al.'' in 1997, based mainly on phylogenetic tr ...

or the

Lophotrochozoa Lophotrochozoa (, "crest/wheel animals") is a clade of protostome animals within the Spiralia. The taxon was established as a monophyletic group based on molecular evidence. The clade includes animals like annelids, molluscs, bryozoans, brachi ...

References

{{Taxonbar, from=Q2045452 Gastrotricha Animals described in 1841