- Colonies are roughly fan-shaped and often connected by mucous strings
- The outer wall is transparent, gelatinous
- The lophophore is horseshoe-shaped
- The lemon-shaped statoblasts float after exposure to air
Fan-shaped, gelatinous colonies. The lemon-shaped statoblasts are unmistakable.
L. crystallinus colonies lacking statoblasts can be confused with young colonies of Cristatella mucedo or Lophopodella carteri.Due to its gelatinous nature, large colonies could be confused with mollusc egg masses, but lophophores are evident upon submersion in water.
Colonies can reach up to 1cm in diameter and collectively cover large areas of substratum when growing conditions are favourable.
Growth occurs by budding of new zooids.Colonies can divide and slowly glide apart to form new daughter colonies.
Unusually for freshwater bryozoans, L. crystallinus is commonly found during the cold winter months.Colonies are typically present in the UK between September and March, although in sites where temperatures stay relatively low (for example, spring fed pools) colonies are found year-round (Hill 2006).Adverse conditions are survived by dormant stages (statoblasts) which develop into adult colonies when suitable conditions return.
Genotypes are potentially very long-lived as a result of clonal reproduction.
Asexual production is the main reproductive mode. There are two forms:
- Budding to increase colony size
- The production of dormant stages (statoblasts)
Diseases and Parasites
Occurs in Europe but generally rare.
Colonies are found loosely attached to a variety of substrata, often on:
- floating debris
- aquatic plants
Laboratory studies suggest colony fission doubles the number of colonies every 1-2 weeks at 20oC (Hill and Okamura, 2007).Many freshwater bryozoans appear to undergo metapopulation dynamics, involving local extinction and recolonization events (Okamura and Hatton-Ellis, 1995). These dynamics may make it difficult to assess distribution patterns and regional extinction risks for L. crystallinus.
Freshwater bryozoans feed mainly on small suspended phytoplankton and bacteria (Kaminski 1984).Colonies may contribute to nutrient cycling in the local habitat during periods of vigorous growth (Raddum and Johnsen 1983).
Molecular Biology and Genetics
Barcode data: Lophopus crystallinus
Below is the sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen.
Other sequences that do not yet meet barcode criteria may also be available.
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Download FASTA File
Statistics of barcoding coverage: Lophopus crystallinus
Public Records: 1
Specimens with Barcodes: 1
Species With Barcodes: 1
Rare (IUCN Red Data Book 1992)
Not enough is known about the biology of L. crystallinus to classify specific threats.
L. crystallinus was once abundant in the Norfolk Broads but has not been found there since the 1970s. In 2007 it was believed to occur in only 4 sites in the UK.The population decline may, however, be less severe than perceived. New sampling methods have revealed its presence in 16 new sites in southern England (Hill et al. 2007).Hartikainen et al. (2007) have increased the number of rivers known to harbour L. crystallinus to >20. These studies indicate that the species is more widely distributed than previously appreciated.
Management consists of retaining habitat complexity and protecting existing sites known to contain permanent populations.Clearing of wood and plant matter is discouraged as this provides important habitat for attached colonies.
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Life and Reproduction
The species life cycle is few months. They start dormanting in September, and reproduce by winter. They die by March. However, in spring fed pools they could live and reproduce forever. Their sexual reproduction is quite rare, and is poorly known. They grow by budding with different kinds of zooids.
- Hill S & Okamura BA Review of the ecology of Lophopus crystallinus (Plumatellida, Lophopodidae), a rare species within the UK. na ; Biologiezentrum Linz/Austria ; Denisia 16, zugleich Kataloge der OÖ.Landesmuseen Neue Serie 28 (2005), 193-201(pdf from Google Drive).
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