• 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

(Wood and Okamura, 2005)

Diagnostic description
Fan-shaped, gelatinous colonies. The lemon-shaped statoblasts are unmistakable.

Lookalikes
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.

Lophopus crystallinus is commonly known as the bellflower animal or the crystal moss animal.Lophopus crystallinus has the honour of being the first bryozoan ever described ( Trembley 1744, Pallas 1768)This colonial freshwater bryozoan has a gelatinous outer wall and appears fan shaped when viewed with the naked eye.Lophopus crystallinus catches suspended algae using its beautiful, horseshoe-shaped tentacle crown (the lophophore).

Bryozoans can reproduce either sexually, in which a free-swimming stage results, or asexually either through 'budding' or by the production of a dormant 'statoblast' stage. These statoblasts are packages of cells, in which there is stored food, surrounded by a tough layer. They can survive freezing and drying-out, and can persist for many years (5). L. crystallinus produces distinctive lemon-shaped statoblasts, which may allow the species to disperse over quite long distances (2). These statoblasts are approximately 1mm long and 0.5mm wide and range in colour from dark to light brown (2).

There are 11 described species of freshwater bryozoa in the UK; this bryozoan is the only member of the family Lophopodidae to be found here (3). Bryozoans are a group of small aquatic animals that live as colonies. The colony is comprised of zooids, or individual animals, that each contain a set of internal organs and a crown of tentacles, surrounding the mouth, which is used to gather food (2). The gelatinous colonies (4) of L. crystallinus form cream-coloured globular patches that grow to about 1cm in diameter. When L. crystallinus is submerged, the horseshoe-shaped crowns of tentacles of the component zooids are visible with the use of a hand-lens (2).

Size
Colonies can reach up to 1cm in diameter and collectively cover large areas of substratum when growing conditions are favourable.

Growth
Growth occurs by budding of new zooids.Colonies can divide and slowly glide apart to form new daughter colonies.

Lifecycle
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.

Life expectancy
Genotypes are potentially very long-lived as a result of clonal reproduction.

Reproduction
Asexual production is the main reproductive mode. There are two forms:

1. Budding to increase colony size
2. The production of dormant stages (statoblasts)

Lemon-shaped statoblasts are released from colonies. Statoblast dormancy is broken by poorly understood environmental cues.Sexual reproduction is rare (Wöss 1996) and its timing poorly known.

Portuguese Exclusive Economic Zone, Spanish Exclusive Economic Zone

The freshwater bryozoan is found in various countries in Europe, but its precise status is presently unclear, although it is classified as Rare in the British Red Data Book (1). Since 1970 it has only been recorded from 5 sites in Norfolk, Oxfordshire, Humberside and Lancashire (3). Following recent work commissioned by Action for Invertebrates and further work conducted by Reading University, two sites are currently known, Barton Blow Wells in north Lincolnshire, and Chil Brook in Oxfordshire (6). Elsewhere, it also occurs in the Middle East, and America, where it is rare (4).

This species grows on the underside of various substrate types such as plants, rock, wood, plastic, glass, and shells in freshwater lakes, ponds, ditches and rivers (2).

The myxozoan parasite, Buddenbrockia allmani, is parasitic in L. crystallinus (Canning et al. 2007) and reduces colony growth, fission and statoblast production (Hill and Okamura, 2007).No other bryozoan hosts are known for B. allmani nor has it been linked with any fish disease (Hill et al. 2007). A close relative (Tetracapsuloides bryosalmonae) is known to cause a disease of salmonid fish (Anderson et al. 1999).

Distribution
Occurs in Europe but generally rare.

Habitat
Colonies are found loosely attached to a variety of substrata, often on:

• floating debris
• roots
• wood
• plastic
• aquatic plants

Population biology
Laboratory studies suggest colony fission doubles the number of colonies every 1-2 weeks at 20^oC (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.

Feeding
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).

The following is a representative barcode sequence, the centroid of all available sequences for this species.


There is 1 barcode sequence available from BOLD and GenBank.   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.


Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 1
Specimens with Barcodes: 1
Species With Barcodes: 1

Conservation status
Rare (IUCN Red Data Book 1992)

Threats
Not enough is known about the biology of L. crystallinus to classify specific threats.

Trends
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
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.

Classified as Rare in Great Britain (2).

Water abstraction and eutrophication are thought to have affected this species, along with over-zealous tidying of waterways (3). Habitat loss and increased boat traffic are also likely to have played a part in the decline (4).

This bryozoan is a priority species under the UK Biodiversity Action Plan; the Species Action Plan aims to maintain all populations of the freshwater bryozoan and assist an increase in the species' range by 2010, perhaps using artificial substrata to aid research and monitoring (3). One of the sites that supports this species is designated a Site of Special Scientific Interest (SSSI), and therefore receives a degree of protection (4).