Bursatella leachii | |
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From the collection of Auckland Museum | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Mollusca |
Class: | Gastropoda |
Subclass: | Heterobranchia |
Clade: | Euopisthobranchia |
Clade: | Anaspidea |
Superfamily: | Aplysioidea |
Family: | Aplysiidae |
Genus: | Bursatella |
Species: | B. leachii |
Binomial name | |
Bursatella leachii Blainville, 1817 [1] | |
Synonyms | |
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Bursatella leachii, whose common name is the ragged sea hare or shaggy sea hare, is a species of large sea slug: a marine gastropod mollusk in the sea hare family Aplysiidae. [15] It has an almost pantropical distribution, from the Mediterranean to the Caribbean, but excluding the central and eastern Pacific Ocean. Its long planktonic larval period and short life cycle make able to colonise new areas and increase dramatically in number if food supplies are favourable.
After Bursatella leachii was described in 1817 by Henri Marie Ducrotay de Blainville, [1] numerous other species were added to the genus. [16] In 1935 Eales and Engel synonymised these all with B. leachii, proposing six subspecies; [7] one more was added by Bebbington in 1969, [6] at which point Bursatella was considered a monotypic genus with a nearly pantropical distribution, containing the following subspecies:
These subspecies were supposedly distinguishable by "wooliness", their background colour, and the colour of their eyespots, though other observers found these traits varied within local populations and few consistent differences could be seen. [17]
A 2020 molecular analysis by Bazzicalupo et al. found no consistent genetic differences between B. leachii subspecies, and recommended that this classification scheme be abandoned. In their view, B. leachii is a morphologically variable species with a pantropical distribution and limited gene flow between Indo-Pacific and Atlantic populations. [16] Bazzicalupo et al. resurrected the name Bursatella ocilligera (Bergh 1902) for genetically-distinct specimens from the Philippines, and that same year Nimbs and Wilson described B. hirsuta from southern and western Australia, [18] making three species in the genus Bursatella .
This species is more widely-distributed than any almost other species of heterobranch sea slug, being found in coastal areas of the Atlantic down to South Africa and parts of the Indo-West Pacific ocean. Although it spans 20,000 km of tropical waters from the Caribbean to Japan, it is absent from the central and eastern Pacific. It has been hypothesised that the Atlantic and Indian-Pacific populations could be intermittently linked by the Agulhas Current around the tip of South Africa, explaining the small divergence in genetic sequence between the two populations. [16]
This species colonised the Mediterranean Sea in about the mid-20th century. It was first noted in the 1950s on the Levantine coast and Italy, reaching Morocco, southern Spain, and France in the 2000s. [19] Because it was first noted from the eastern Mediterranean, the population was assumed to have originated in the Red Sea via the Suez Canal, but genetic sequencing revealed Mediterranean and Atlantic populations had almost identical haplotypes, meaning the species probably arrived from the Atlantic. [20] Rather than being carried in ballast water like many other species invading the Mediterranean, B. leachii probably arrived naturally as sea surface temperatures that would normally prevent it entering the Strait of Gibraltar have shifted north with climate change. [20]
Bursatella leachii is green to greenish brown. It has a broad and short head. Its mantle is covered with papillae (finger-like outgrowths), which give it a thorny aspect. The mantle has a network-like pattern with blue eyespots (ocelli) in black spots and green areas. It moves slowly on a broad foot. There is short, sharp tail. The short parapodia (fleshy, winglike outgrowths) are fused on their rear end.
The maximum recorded length is 120 mm. [21]
The species is usually found in protected marine bays and estuaries, tidal pools, occurring in the intertidal zone and down to at least 10 m. [22] It is a benthic detritivore which grazes for food on muddy or sandy bottoms. [16] Populations in the wild have been observed feeding on a range of macroalgae including the green alga Enteromorpha, as well as the cyanobacteria Calothrix crustacea , forming large populations in response to bacterial blooms. [23]
This sea hare may be found in dense concentrations or singly; it follows a daily rhythm, assembling in groups at sunset and dispersing in the morning. [24] These patterns are also followed in captivity, with copulation predominantly in the morning and feeding in the afternoon. [24] The species lays egg ribbons in long green stringy tangles. [25] After hatching the veliger larvae grow rapidly and reach full size at 15 days, and are able to metamorphose to adult form aged just 19 days (the shortest larval period reported for sea slugs), but can live as plankton for up to three months. Larvae metamorphose on cyanobacteria, taking 1–2 days, discarding their shell when they reach 2.5–3.0 mm long. Adults grow relatively quickly, attaining maturity at the age of 2 or 3 months after hatching. [26]
Nudibranchs are a group of soft-bodied marine gastropod molluscs that shed their shells after their larval stage. They are noted for their often extraordinary colours and striking forms, and they have been given colourful nicknames to match, such as "clown", "marigold", "splendid", "dancer", "dragon", and "sea rabbit". Currently, about 3,000 valid species of nudibranchs are known.
Opisthobranchs is a now informal name for a large and diverse group of specialized complex gastropods which used to be united in the subclass Opisthobranchia. That taxon is no longer considered to represent a monophyletic grouping.
Aplysiidae is the only family in the superfamily Aplysioidea, within the clade Anaspidea. These animals are commonly called sea hares because, unlike most sea slugs, they are often quite large, and when they are underwater, their rounded body shape and the long rhinophores on their heads mean that their overall shape resembles that of a sitting rabbit or hare. Sea hares are however sea snails with shells reduced to a small plate hidden between the parapodia, and some species are extremely large. The Californian black sea hare, Aplysia vaccaria is arguably the largest living gastropod species, and is certainly the largest living heterobranch gastropod.
Dolabella is a genus of sea slugs or sea hares, marine opisthobranch gastropod mollusks in the family Aplysiidae, the sea hares.
Notarchus is a genus of sea slugs or sea hares, marine opisthobranch gastropod mollusks in the family Aplysiidae, the sea hares.
Aplysia is a genus of medium-sized to extremely large sea slugs, specifically sea hares, which are a kind of marine gastropod mollusk.
Stylocheilus is a genus of sea slugs, specifically sea hares, marine opisthobranch gastropod mollusks in the family Aplysiidae, the sea hares.
Syphonota geographica, or the geographic sea hare, is a species of sea slug or sea hare, a marine opisthobranch gastropod mollusk in the family Aplysiidae, the sea hares.
Scutus is a genus of large sea snails or limpets with the common name "shield shells". These are marine gastropod molluscs in the family Fissurellidae, the keyhole limpets and slit limpets.
Bursatella is a genus of sea slugs or sea hares, marine opisthobranch gastropod mollusks in the family Aplysiidae, the sea hares.
Dolabrifera dolabrifera is a species of sea hare, a marine gastropod mollusc in the family Aplysiidae, the sea hares. Dolabrifera dolabrifera, otherwise known as a Warty Seacat. The animal goes by many names, including the common sea hare. The Hawaiian name for Dolabrifera dolabrifera, is Kualakai.
Aplysia dactylomela, the spotted sea hare, is a species of large sea slug, a marine opisthobranch gastropod in the family Aplysiidae, the sea hares.
Aplysia extraordinaria, common name the "extraordinary sea hare", is a very large species of sea slug, more specifically a sea hare, a marine opisthobranch gastropod mollusk in the family Aplysiidae, the sea hares.
Aplysia juliana, the walking sea hare, is a species of sea hare, a marine gastropod in the family Aplysiidae.
The dwarf sea hare or pygmy sea hare, Aplysia parvula, is a species of sea hare, a marine gastropod mollusc in the family Aplysiidae.
Coriocella nigra is a species of sea snail, a marine gastropod mollusk in the family Velutinidae. An Indo-Pacific species, it lives on rocks at depths of up to 15 m. It is up to 10 cm long and has an internal shell; body color is black or brown. C. nigra is probably a predator of tunicates.
Stylocheilus striatus is a species of sea hare found in the Indo-pacific region living from the intertidal zone to a depth of 30 metres. Common names include lined sea hare, blue ring sea hare and furry sea hare. Mature animals can reach sizes of up to 65 mm in length and are brown in colour with blue spots. Their diet mainly consists of blue algae. They play an important role in controlling toxic blooms of the cyanobacterium Lyngbya majuscula.
Sander Rang or Paul Charles Leonard Alexander Rang was a French conchologist and interpreter of Arabic texts. He was, in 1816, one of the survivors of the sinking of the frigate Medusa, on which he was an ensign. He spent a good part of his life in La Rochelle, where he published his early zoological observations, in particular in the bulletins of the Society of Natural Sciences of Charente-Maritimes.In 1841 Rang was one of the founding members of the Société des Amis des Arts now the Musée des Beaux-Arts de La Rochelle.He specialised in marine fauna notably in sea hares, cephalopods and other molluscs and on the heterogenous group known as zoophytes. Sander Rang described many new mollusc species including the sea hares Aplysia dactylomela, Dolabrifera dolabrifera, the cuttlefish Sepia hierredda and the land snails Striosubulina striatella, Pleurodonte desidens and Opeas hannense.
Bursatella hirsuta is a species of large sea slug or sea hare, a marine gastropod mollusk in the family Aplysiidae, the sea hares.