- Colony forming brownish-white sheets, irregular incrustations or spherical balls of zooids.
- Colony shape is largely influenced by the substrate on which it settles. Zooids can range in size from 0.38-0.7mm long and 0.17-0.4 mm wide.
- Each zooid usually has a pair of short spines distally and sometimes 3-5 pairs of slender spines laterally.
- 15-16 tentacles are present and this species does not have avicularia or ovicells.
- It has a planktonic larva and a single ancestrula.
Conopeum seurati is an encrusting bryozoan. The colony form varies from brownish-white lace-like sheets, irregular encrustations to spherical balls of zooids. The colony shape is largely influenced by the substrate type, which includes estuarine plants, such as Ruppia, as well as hard substrates.
The full distribution of this species is unknown, but it has mainly been recorded from Northern Europe and the Mediterranean. It has also been found in Florida and New Zealand, where it is regarded as an introduced species. Conopeum seurati is an estuarine, fouling bryozoan that is found in the lower intertidal and shallow waters of brackish environments.
The full distribution of this species is unknown but it has mainly been recorded from Northern Europe and the Mediterranean. It has also been found in Florida and New Zealand, where it is regarded as an introduced species. Conopeum seurati is an estuarine, fouling bryozoan that is found in brackish water.
Distribution and ecology
The full distribution of this species is unknown but it has mainly been recorded from Northern Europe and the Mediterranean.It has also been found in Florida and New Zealand, where it is regarded as an introduced species.
Conopeum seurati is known from a range of estuarine habitats (such as lagoons) and can withstand very low salinities, fluctuating concentrations, and extreme ranges in temperatures.This bryozoan is a successful marine-fouling species and has been found in Florida (Winston, 1982) and New Zealand (Gordon & Mawatari, 1992).
Colonies form brownish-white sheets, irregular incrustations or spherical balls of zooids. The shape of the colony is largely influenced by the substrate on which it settles. On flat substrates, regular lace-like colonies are typical, whereas on uneven surfaces, such as plant stems, irregular encrustations, often rising into bilaminar lobes, will tend to form.
Zooids are elongated rectangles and can range in size from 0.5 - 0.7mm long and 0.28-0.4 mm wide, again according to the substrate. Each zooid usually has a pair of short spines at the distal end (furthest from the colony origin) and sometimes 3-5 pairs of slender spines laterally. 15-16 tentacles are present on the polypide and this species does not have avicularia or ovicells.
The frontal surface of each zooid is largely membranous. The calcified section (the gymnocyst) is reduced compared to the related C. reticulum, and appears as small triangular laminae at the proximal corners (closest to the colony origin) of each zooid. A narrow granular ridge with raised lateral walls (the cryposcyst) is present, but lacking the arched distal region of C. reticulum.
In areas of the colony where the regular arrangement of zooids is disrupted, specialised elongated triangular zooids (kenozooids) may be present. The kenozooids are never present in a constant paired relationship at the distal end of the zooids, as in C. reticulum.
The operculum, a hinged flap which closes the orifice, is very characteristic in Conopeum species. It has a folded membranous edge and appears as a thick crescent-shaped structure when closed. It is lightly chitnizied and lacks the thin marginal sclerite typical of Membranipora species. In C. seurati the operculum appears as a broad semicircle, with a denser and more granular surface than that of C. reticulum.
The founding zooid (the ancestrula) is singular, distinguishing the colony from species of Membranipora. It measures 0.2-0.22 by 0.14-0.15. A pair of spines is present at the distal end, and the ancestrula polypide has six to eight tentacles.
The size of zooids varies greatly, but is frequently between 0.5- 0.7mm long and 0.28-0.4 mm wide
Species of Conopeum are easily confused with those of the related genus Membranipora. Membranipora species may be distinguished by the presence of a twinned ancestrula (the founding zooid), compared to the single ancestrula of Conopeum species. However, the ancestrula region is frequently missing from colonies, making this character insufficient to distinguish species.
Conopeum and Membranipora species also differ in their ecology. M. membranacea is the only species of its genus to occur in British waters, where it forms extensive colonies, normally on Laminaria. Membranipora tuberculata, which colonises Sargassum, and Membranipora tenuis, a tropical species, are, on rare occasions, washed up on south-western shores of the UK. Both of the British species of Conopeum colonise hard substrata or estuarine plants, but would not be expected to occur on marine algae.
C. seurati has thinner calcification and a less apparent gymnocyst and cryptocyst than Conopeum reticulum. Specialised triangular zooids (kenozooids) are less frequent in C. seurati than C. reticulum, and never occur in a constant paired relationship at the distal end of the zooids, as they do in C. reticulum.
Conopeum seurati is known from a range of estuarine habitats, such as lagoons (Bamber et al., 1992), and can withstand very low salinities, fluctuating concentrations, and extreme ranges in temperatures. Hard substrates and estuarine plants such as the stems of Ruppia are common substrates for Conopeum seruati.
This bryozoan is a successful marine-fouling species and has been found in Florida (Winston, 1982) and New Zealand (Gordon & Mawatari, 1992).
Like all bryozoans, C. seurati is a suspension feeder. It feeds on small phytoplankton using ciliated tentacles of the lophophore.
Conoepeum seurati may colonise the inner surface of Ostrea valves, in association with Electra monostachys, Conopeum reticulum, or Aspidelectra melolontha.
Life History and Behavior
The founding zooid (ancestrula) develops into a young colony, and later into an adult colony through asexual budding. Sexually produced embryos develop into larvae which are released into the plankton. Larvae settle after liberation and metamorphose into a single ancestrula.
Conopeum seurati breeds from June to October in Britain. The larvae of C. seurati are planktonic cyphonautes larvae which feed and grow up to 0.125 mm in height and 0.165 mm across the base. Larvae are sub-triangular in shape and, when viewed in profile, appear “turned-up” at the posterior margin.
Colonies grow through asexual budding of new zooids at the periphery.
Relevance to Humans and Ecosystems
Conopeum seurati is a species of colonial bryozoan in the order Cheilostomata. It is native to the northeastern Atlantic Ocean, the North Sea and the Mediterranean Sea. This species has been introduced to New Zealand and Florida.
Conopeum seurati is an encrusting bryozoan that forms small colonies on seagrasses, shells and other hard surfaces. When a larva of Conopeum seurati settles on a suitable surface, it undergoes metamorphosis into a zooid known as an ancestrula. This is oval in shape and measures about 0.55 by 0.33 mm (0.022 by 0.013 in).
The ancestrula buds to produce another zooid which has a pair of long spines at the distal end and sometimes a further three to five pairs of thin spines at the sides. Further asexual reproduction takes place, with each zooid producing several buds until there is a small, roughly circular encrusting cluster of zooids, white or brownish-white in colour, with the ancestrula at the centre. On flat surfaces the colony is regular and lacy in appearance but on uneven surfaces, it is more irregular and may form lobes. Some colonies are also spherical. Each individual zooid bears a lophophore, the characteristic feeding apparatus of bryozoans, with fifteen or sixteen ciliated tentacles, used to filter phytoplankton. The operculum, a flap that hinges to form a lid over the aperture of the lophophore, has a membranous edge and is chitinised. It is thick and crescent-shaped when closed. The walls between the zooids are calcified on the proximal edge and membranous elsewhere.
Distribution and habitat
Conopeum seurati full distribution is unknown. It is found on the coasts of northern Europe and the Mediterranean Sea. It is considered to have been introduced to the Atlantic coast of Florida and to New Zealand. It is a fouling species and is found in brackish water, estuaries and lagoons where it can tolerate a wide range of salinities; these range from eighteen to forty parts per thousand in the Indian River Lagoon, and as little as one ppt. in Europe. It usually forms colonies on seagrasses, ditch grasses, floating seaweed, mussels, oysters and man-made structures.
Like other bryozoans, Conopeum seurati is a suspension feeder, filtering phytoplankton from the water with its tentacles. Breeding takes place between June and October in Britain. The cyphonautes larvae are triangular in shape with brownish bivalve shells in their later developmental stages. These larvae are planktonic and drift with the currents for some time before settling and undergoing metamorphosis into ancestrulae to found new colonies.
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- Rouse, Sally (2011-06-02). "Conopeum seurati". Bryozoa of the British Isles. Retrieved 2014-04-06.
- Cook, Patricia L.; Hayward, P. J. (1966). "The development of Conopeum seurati (Canu) and some other species of membraniporine Polyzoa". Cah. Biol. Mar. 7: 437–443.
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