BURSATELLA LEACHII PDF

Advanced Search. Bursatella leachii , the ragged sea hare, is a medium- to large-sized benthic opisthobranch mollusc within the Order Anaspide, the sea hares. The body is variably colored, grayish-green to white-tan with dark brown blotches and spots, compact and rounded, with distinct head and neck regions evident. The body is also covered with numerous long, branching fleshy papillae that give the animal its ragged appearance.

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Advanced Search. Bursatella leachii , the ragged sea hare, is a medium- to large-sized benthic opisthobranch mollusc within the Order Anaspide, the sea hares. The body is variably colored, grayish-green to white-tan with dark brown blotches and spots, compact and rounded, with distinct head and neck regions evident.

The body is also covered with numerous long, branching fleshy papillae that give the animal its ragged appearance. The gill is covered by a pair of fleshy parapodia. Two long, retractile olfactory tentacles called rhinophores occur on the head, and also two fleshy enrolled oral tentacles occur at each side of the mouth. Adults completely lack a shell Voss , Kaplan , Rupert and Fox If this convention is followed, the subspecies occurring in Florida is Bursatella leachii pleii Rang, Sea hares of the genus Aplysia co-occur with B.

Bursatella and Aplysia are easily distinguished from one another, as Aplysia are larger, lack the frilled, ragged appearance of Bursatella and possess large swimming flaps that are absent in B. Bursatella leachii is a circumtropical species found nearly worldwide in warm temperate to tropical marine environments Rudman Kruczynski and Porter list North Carolina as the northern limit of the species on the US east coast. Bursatella leachii can be found throughout the IRL system, although much of the time it apparently persists at relatively low population densities see below.

Although Bursatella leachii is spatially and temporally highly sporadic in occurrence, it is periodically encountered at high densities in the environment Rudloe , Lowe and Turner Localized populations of B. Such irruptive population outbreaks are probably attributable to vagaries of the environment and the relative rarity of situations in which environmental conditions are near-optimal.

Population explosions most likely occur when larval supply is good, dietary resources are abundant, and tides, currents, and weather conditions are favorable Rudman undated.

Just as mass-settlement events are a common aspect of the life history, so too are mass mortality events. Hundreds to thousands of dead and dying animals are sometimes encountered washed ashore, and storms, tides, and extreme high temperatures often serve as exacerbating factors.

As with most sea hares, Bursatella leachii is a cross-fertilizing simultaneous hermaphrodite Kaplan Fertilization is internal, with one individual transferring sperm via an eversible penis located on the right side of the head to the dorsally located gonopore genital opening of a second individual Van Horn Thus inseminated, individuals lay large, tangled, spaghetti-like benthic egg masses that are usually orange, yellow, green, or brown in color.

Ragged sea hares attain sexual maturity at months of age Paige At least in some parts of its range, the species appears to undergo continuous recruitment with no well-defined reproductive season Clarke The larval biology of Bursatella leachii had previously been poorly studied, largely due to lack of success at rearing specimens in the laboratory Henry , Bebbington More recently, research findings by Paige have provided more detail on larval and postlarval development.

This work is summarized here. Newly hatched veligers lack eyes and possess a pair of sensory statocysts at the base of the foot. Individuals are negatively geotropic and they maintain themselves in the water column by swimming using a well-developed velum. Growth of the planktonic larvae after hatching is rapid. Veligers attain maximum size approximately 15 days after hatching, and metamorphic competency is reached at 19 days posthatch. Paige notes that this is the shortest known larval duration for aplysiids possessing planktonic larvae.

Competent B. Individuals that are competent to metamorphose are capable of delaying settlement for as much as 2. Upon settlement, an individual will attach to the substratum via mucus threads and retract into the shell to metamorphose. The process takes days. Within a day of metamorphosis, postlarvae are seen crawling across the substratum ingesting food with a radula that is already well developed.

Postlarval growth is rapid. The shell stops growing when individuals reach 2. By this time, the juvenile begins to resemble the adult in appearance, including the presence of rudiments along the body that will become the fleshy papillae.

At this time, the juvenile also has the ability to discharge a small cloud of ink if irritated Paige Bursatella leachii is considered to be a circumtropical species whose distribution extends into warm temperate waters. The northernmost limit reported for this species on the US east coast is North Carolina Kruczynski and Porter , and this limit appears to be dictated by seasonal low water temperatures.

The occurrence of ragged sea hares in a variety of oceanic and estuarine habitats suggests a moderate tolerance for salinity fluctuations. It can also facultatively consume some macrophyte material such as Ectocarpus and Enteromorpha Paige , Rudman undated.

Wu and Clarke report a possible dietary preference for Enteromorpha over cyanobacteria in the Pacific populations, but such preference appears not to be universal. Sea hares are likely to derive a dietary benefit from sequestering toxic metabolites e. Dietary resource competition is unlikely to be severe in most habitats inhabited by Bursatella leachii , owing to the abundance of benthic cyanobacteria mats and films.

Interspecific competition with co-occurring sea hares of genus Aplysia is unlikely since these animals typically consume various macroalgal species rather than cyanobacteria and filamentous algae eaten by B. Like other sea slugs, Bursatella leachii is chemically protected from most would-be predators by the presence of skin glands which secrete noxious or unpalatable compounds Rudman undated.

Kamiya et al. Appleton et al. The purple ink-like secretion produced from the purple gland of B. Unlike cephalopods, however, sea hares are not capable of a rapid escape response so this substance may not be primarily defensive in nature.

An alternate possibility is that the ink is a metabolic byproduct produced in response to eating algae, particularly red algae Chapman and Fox The fact that Aplysia spp. Bursatella leachii are common in intertidal and subtidal sheltered bay and estuarine habitats with sand or muddy bottoms, and are a frequently encountered component of tropical and subtropical seagrass and mangrove communities Lowe and Turner Clarke suggests that the species may at times exert a strong influence on seagrass habitats because of their sporadic high densities and their feeding specialization on cyanobacteria.

There has been speculation that adults of some populations e. Although nocturnalism has been documented for several sea hares, including Aplysia brasiliana, a nocturnal habit appears not to be typical for Bursatella leachii.

In general, Bursatella leachii are currently of little economic importance in Florida. Rudloe indicated that ragged sea hare densities can at times become so great as to negatively impact commercial shrimping operations. An anti-HIV protein, bursatellanin-P, has been isolated from the purple ink secretion of the species, although it remains to be seen whether there will be any tangible biomedical of economic benefits derived from the discovery Rajaganapathi et al.

A new biologically-active malyngamide from a New Zealand collection of the sea hare Bursatella leachii. Journal of Natural Products Avila C. Molluscan natural products as biological models: Chemical ecology, histology, and laboratory culture. Progress in Molecular and Subcellular Biology Bebbington, A. Bursatella leachi guineensis subsp.

Gastropoda, Opisthobranchia from Ghana. Proceedings of the Malacological Society of London The fate of Lyngbya majuscula toxins in three potential consumers. Journal of Chemical Ecology Bile pigment metabolism in the sea-hare Aplysia. Experimental Marine Biolgy and Ecology Clarke CL.

Eales NB and Engel, H. Proceedings of the Malacological Society, Henry LM. Observations on the sea hare Bursatella leachii plei Rang. Florida State University Studies Bioactive molecules from sea hares.

Kaplan EH. Peterson Field Guide Series. Houghton Mifflin Company, NY. A new northern record for Bursatella leachii pleii Rang Opisthobranchia , with notes on its biology. The Nautilus Aggregation and trail-following in juvenile Bursatella leachii plei gastropoda: Opisthobranchia.

Veliger On the Anaspidea Gastropoda: Opisthobranchia of the warm waters of the western Atlantic. Bulletin of Marine Science Paige JA. Biology, metamorphosis and postlarval development of Bursatella leachii plei Rang Gastropoda: Opisthobranchia. Marine Biotechnology Rudman WB. Bursatella leachii de Blainville, In: Sea Slug Forum. Australian Museum, Sydney.

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Changi, May Two pairs of tubular tentacles. Short triangular 'tail' edged with white bars. Egg mass laid by the sea hare. Pasir Ris, JUl Releases purple ink when disturbed. Pulau Sekudu, May

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Bursatella leachii , common name the ragged sea hare or shaggy sea hare , is a species of large sea slug or sea hare , a marine gastropod mollusk in the family Aplysiidae , the sea hares. This is a circumtropical sea hare , the only species in its genus. It occurs in the intertidal zone and down to at least 10 m [2] on coastal areas of the Indo-West Pacific oceans , the Caribbean Sea and the Mediterranean Sea. Bursatella leachii is green to greenish brown. It has a broad and short head.

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