Prostoma jenningsi

Prostoma jenningsi is a species of ribbon worm known only from one site near Croston, Lancashire. It was described in 1971, and is believed to be the county's only endemic species. It grows up to 20 mm (0.8 in) long, with 4–6 black eyespots, and has a long eversible proboscis.

Prostoma jenningsi
Scientific classification
Kingdom:
Animalia
Phylum:
Nemertea
Class:
Enopla
Order:
Hoplonemertea
Family:
Tetrastemmatidae
Genus:
Prostoma
Species:
P. jenningsi
Binomial name
Prostoma jenningsi
Gibson & Young, 1971

Distribution

The only site where P. jenningsi has ever been found is a former clay pit now used for recreational fishing between Bretherton and Croston in Chorley borough, Lancashire.[1] It was discovered there in 1967, and described by Ray Gibson and Johnstone O. Young in 1971.[2] It is thought to be the only species endemic to Lancashire.[3]

Prior to the discovery of P. jenningsi, there had only been four reports of freshwater nemerteans in the British Isles, in the River Cherwell at Oxford, the River Cam at Cambridge, a tank in Regent's Park, London, and the Grand Canal at Clondalkin, County Dublin.[2]

Description

Prostoma jenningsi is a slender worm, with an elliptical cross-section. Young animals are translucent white, but take on a yellowish hue as they age, eventually becoming "dark yellowish or pale reddish-brown".[2] They are 0.5 millimetres (0.020 in) long when they hatch, reach their adult colouration above 6 mm (0.24 in) and can reach up to 20 millimetres (0.8 in) long as adults.[2] P. jenningsi has 4–6 black eyespots on the top of the head,[3] The eversible proboscis is two-thirds to three-quarters of the body length, and is armed with one central stylet and paired pouches each containing 2–5 accessory stylets.[2]

P. jenningsi is one of eleven species in the genus Prostoma,[4] and can only be told from related species by dissection. Uniquely, it has eleven nerves innervating the proboscis, rather than nine or ten, as seen in other species.[2] The specific epithet jenningsi commemorates J. B. Jennings of the University of Leeds, a scientist who studied invertebrate digestive physiology.[2] No taxonomic synonyms are recognised.[5]

Ecology

Prostoma jenningsi lives among the vegetation at the edges of the pond, including the plant species Juncus effusus, Elodea canadensis, Myriophyllum spicatum, Phragmites communis, Potamogeton natans and Typha latifolia.[2] Its numbers vary in an annual cycle, with smallest numbers when vegetation growth is highest.[6]

References
  1. The Wildlife Trust for Lancashire, Manchester & North Merseyside. "Memorandum submitted by The Wildlife Trust for Lancashire, Manchester & North Merseyside". House of Lords. Retrieved November 29, 2011.
  2. Ray Gibson & Johnstone O. Young (1971). "Prostoma jenningsi sp. nov., a new British freshwater hoplonemertean". Freshwater Biology. 1 (1): 121–127. doi:10.1111/j.1365-2427.1971.tb01550.x.
  3. Lancashire Biodeiversity Action Plan (2001). "Prostoma jenningsi (a ribbon worm)" (PDF). Lancashire Biodiversity Partnership.
  4. Per Sundberg & Ray Gibson (2008). "Global diversity of nemerteans (Nemertea) in freshwater". In Estelle Virginia Balian; Christian Lévêque; Hendrik Segers & Koen Martens (eds.). Freshwater Animal Diversity Assessment. Developments in hydrobiology. 198. Springer. pp. 61–66. doi:10.1007/s10750-007-9004-6. ISBN 978-1-4020-8258-0.
  5. R. Gibson (1995). "Nemertean genera and species of the world: an annotated checklist of original names and description citations, synonyms, current taxonomic status, habitats and recorded zoogeographic distribution". Journal of Natural History. 29 (2): 271–561. doi:10.1080/00222939500770161.
  6. Chris Lowe (2011). "Confirming the existence of the "Croston Worm" (Prostoma jenningsi)". Undergraduate Research Internship Scheme. University of Central Lancashire. Archived from the original on September 13, 2012. Retrieved November 29, 2011.

Further reading
  • R. Gibson & J. O. Young (1976). "Ecological observations on a population of the freshwater hoplonemertean Prostoma jenningsi Gibson and Young 1971". Archiv für Hydrobiologie. 78: 42–50.
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