Other sources to veiw

http://en.wikipedia.org/wiki/Nemertea


http://www.earthlife.net/inverts/nemertea.html


http://www.ucmp.berkeley.edu/nemertini/nemertini.html


Rupert, Fox, Barnes. 2004, Invertebrate Zoology, Thomson

Another video link

http://video.aol.com/video-detail/nemerteans/3368359166


Kinda funny- Starts out seeming to be informative, to end up as mostly just a guy complaining about there existence.

Terrestrial species

http://www.oceanfootage.com/stockfootage/Worm_Invertebrate

4th and 6th video down

Link to a possible Large Nemertean. Referred to as a Sea Monster

http://www.livevideo.com/video/A1E97D4CDC3D4FF899F90B9FE41AB5E6/jay-s-nemertean-worm-.aspx

Annotated BIBLIOGRAPHY

Ph. Nemertea, Cl. Enopla, Or. Hoplonemertea, subOr. Monostilifera, Fam. Prosorhochmidae

•Gerlach, J., 1998, The Behaviour and captive maintenance of the Terrestrial Nemertine, Journal of Zoology, 246, 233-237

• The goal of the study was to learn more about the Geonemertes pelaensis. A generalized search will be done in there known habitat in tropical island area, Seychilles, where observations will be kept on locations found. Scientists will then try provide a sustainable habitat, and observe unknown features of there behaviour and diet.

• Until this study no Geonemertes pelaensis samples where successfully preserved alive for any period of time. They require a moist humid environment, and won’t survive otherwise. It is extremely hard to view activity (behaviour) since they are nocturnal creatures and will hide at the presence of the slightest light.

• Samples of Geonemertes were collected, and the percentage of different areas where a sample was observed was also kept (banana leaves, rotten logs). The samples were then put in a box with an abundance of prey. Four types of prey were tested, small gastropods, collembolan, mites, and isopods. G. pelaensis was found in 100% of the banana leaf sites, 33% of the palm leaf sites, and 50% of the dead tree sites. They consumed prey on an average of 0.6 a night, with 2 per night as a maximum.

• The species G. pelaensis was most commonly found 60 cm above ground, perhaps due to predation from the terrestrial crab. It was most commonly found in dead trees, banana leafs and palm leafs, and not near dry or coastal areas. They prey on small gastropods, specifically liordetiasculpta, Allopeasgracile, and subulinaoctona

Annotated BIBLIOGRAPHY

•Ph. Nemertea, Cl. Enopla, Or. Hoplonemertea, SubOr. Monostilifera, Fam. Carcinonemertidae

•Roe, P., 2004, Ecological Implications of the Reproductive Biology of Symbiotic Nemerteans, Hydrobiologia, 156, 13-22

• A closer look at several Nemertean species, and some reproductive modifications they have undertaken that suspiciously resemble that of a parasite. Is a species which lives around another species (host) and also exhibits reproductive advantages (comparable within groupings) a parasite? Are there more parasitic Nemerteans then once thought?

• The species mentioned are sometimes considered egg-predators and not parasites. The example species exhibited reproduction modifications in the form of, increased egg production, parthenogenesis, hermaphroditism, and reaching sexual maturity earlier.

• Study described several species which are potential parasites of different crustaceans and mollusks. Found reproduction to be correlated with hosts egg availability. Found that the number of gonads in most studied species were much higher then that of free-living species. The proboscis was reduced (no need for it), and they all exhibited reproductive advantages. C.carcinophila imminuta lay approx. 1200 eggs, C. epialti lays approx. 1900-3500 eggs, and the free-living comparison Protoma lays 210 eggs.

•

Findings suggest Nemerteans associated with hosts and have reproductive modifications typical of parasites should be considered parasites themselves. This way predictions of the species lifestyles can made based on reproductive and habitat observations. Following this methodology will produce more potential parasitic species for further study

Fossils...or not

The fossil record is sparse, which is no surprise for soft-bodied animals, but surprisingly the hard stylets are not even found. A fossil (Archisymplectes) which may represent a Nemertean was found in Mazon Creek (Illinois), and is dated to the Pennsylvanian (325-299 MYA). The Nemerteans are believed to have been present over 500 MYA in the Cambrian or Pre-Cambrian even though fossil evidence doesn’t imply this.

(not actual picture of Nemertea fossil)

Superficial resemblances? all look like worms to me

Nemerteans have a superficial resemblance to Annelids, they share a multiciliated glandular epidermis, protonephridia, spiral cleavage, and the ladder-like nervous system. But have clear differences which include a circular cross-section, a complete gut, a unique blood-vascular system with and endothelium, the proboscis, and the presence of a coelom (rhynchocoel).

The Nemertea also have superficial resemblance to the Nematodes. Only they have complex circular and longitudinal muscles and don’t molt.

Reproduction

The Nemertea have two separate sexes, although all the freshwater species are hermaphroditic. The fertilization is often external. Eggs get shed and dispersed in burrows, tubes, or gelatinous strings.

Systems and structures

The body of the Nemertean is made of a layer of glandular epidermis (full of cilia), a layer of connective tissue, and a thick muscular layer. Lack exoskeleton and cuticle, but can secrete a toxic substance for protection. They are quite often colourful (showing there toxicity?) or in contrast dull and plain. The musculature is made up of a thin layer of circular muscle, surrounding a think inner layer of longitudinal muscles. Helical muscles connect the longitudinal and circular muscles and allow for twisting and coiling. Dorsoventral muscles are responsible for flattening the body.

Respiration is achieved through diffusion and circulation is made possible by a coelmic system with peripheral vessels carrying fluid throughout body. The Nemertean nervous system consists of a brain and several nerve cords. The brain is 4 anterior ganglia arranged in a circular ring. The nerve cords are filled with non-circulating neuroglobin, which extends time restraints on oxygen intake. The excretory system is made of two anterior fore-gut protonephridia which filter the fluid and send the wastes to collection ducts which lead to the anus for removal from body.

Descriptive characteristic

A key defining feature of the Nemertea is there proboscis which is housed in a true coelom called the rhynchocoel. The proboscis is everted in the coelom, where it shoots out and wraps around its prey and kills it, the proboscis is then retracted back into the rhynchocoel bringing the prey with it. Nemerteans are predators of crustaceans, annelids, Mollusca and other Nemerteans, and are capable of consuming prey many times wider then themselves.

The distinction between the predatory attacks (based on proboscis being armed/unarmed) splits the phylum into two different classes. The Anopla class is unarmed and secretes a sticky fluid and an added toxin which immobilizes the prey and class Enopla has a sharp stylet on its proboscis which stabs the prey and injects toxins

Starters

The phylum Nemertea is in the kingdom Animalia, and the super phylum Lophotrochozoa. It is home to approximately 1150 different species. These species differ in trophic association along with the environments they are found in. Species of Nemertea have been found to be scavengers, parasites, and herbivores. But the common Nemertean worm is 10-15 cm long, circular, found in a marine habitat and is a carnivorous predator. Fresh water (12 sp.), pelagic, deep water, and terrestrial (approx 15 species; found in tropical areas where it is damp and humid) also exist.