Thetys vagina, or the twin sailed salp, is the largest known solitary species of salp and the only valid species of the genus Thetys. First described by W.G Tilesius in 1802, the species is transparent and gelatinous, making it difficult to be seen in water, which is helpful in avoiding predators.[1][2][3] The fossil range is very recent.[4] Other animals often mistaken for T. vagina are Salpa fusiformis, Aurelia aurita, and Pegea confoederata. There is no known status of conservation in this species. T. vagina DNA was sequenced as part of a larger project in 2014 where spiny lobster larvae were found attached to T. vagina and consuming it.[5]
T. vagina can reach up to 333 mm (13 in) long.[6] They develop into two distinct forms; the aggregate generation and the solitary generation. The aggregated sexual blastozooids (aggregate form) can get to the size of 250 mm and has five muscle bands. The solitary asexual oozooids (solitary form) can get to size of 300 mm.[7] Vaginas of this form have around 20 muscle bands, which are characterized as “striped” with two short dark-colored tentacles at their ends, attached at the upper and lower halves of the body.[8] Both the aggregate and the solitary forms have tests covered in ridges and grooves. They have a colored digestive system seen as a dark or colorful lump.[8] The embryos have been found to be between 10-15 mm.[9]
T. vagina is found in pelagic marine environments.[10] It occurs in tropical and temperate waters of the Pacific, Atlantic and Indian Ocean and is occasionally found in colder waters in the northern Atlantic, likely following warm water currents.[9][6][7] The species is widespread but at low density (although they may occasionally be found at very high density), resulting in only rare accounts of it being caught.[7]
T. vagina has been found off the central coast of British Columbia, marking its north-most occurrence to date.[3] It has been found by cataloging volunteers along the West Coast of the U.S. and reportedly congests nets of fisherman off the coast of northern Honshu and southern Hokkaido, Japan.[7] In January 2009, the largest measured biomass of T. vagina was recorded at 852 g WW m−3 in the Tasman sea.[11]
T. vagina stays in the photic zone and is often found in places of high chlorophyll concentration, likely due to its phytoplankton rich diet.[7] A large increase of T. vagina is associated with an increase in phytoplankton.[7] The ecology of this species is not fully understood.[7]
Like other salps, T. vagina feeds by consuming plankton nutrient water on one end of its body, filtering it via an internal net made of mucus, and spewing the water out the other end.[3] Their internal net is very effective, catching particles spanning four magnitudes in size.[8] This action also allows them to move through the water column, classifying them as nektonic. T. vagina feeds on marine plankton, including single-celled organisms such as dinoflagellates, silicoflagellates, diatoms, and tintinnids, as well as copepods and other small particles.[7] Continuing up the food chain, T. vagina is preyed upon by medusae, siphonophores, ctenophores, heteropods, sea turtles, late stage larvae of the spiny lobster, marine birds, along with various species of fish.[7] They have a high energy content at (11.00 kJ g−1 DW).[11]
In a study done in the Japan Sea in 2006, the gut contents of T. vagina where evaluated.[7] The diatom Coscinodiscus spp. (13–55 µm in diameter) was found to be the major makeup of the guts, with the diatom Coscinodiscus wailesii (219–313 µm) being the second most prevalent.[7] Another study off the coast of Maine found T. vagina gut content to be mainly made up of two dinoflagellates; Prorocentrummicans and Dinophysis norvegica. The study also found T. vagina to be an indiscriminate feeder over a broad size spectrum.[9]
Waste from T. vagina is densely packed, sinks quickly, and is full of carbon. Their carcasses also sink quickly and are carbon rich (31% dry weight, DW).[11] This makes them efficient carbon sinks, but also harder to study. This carbon exchange could be responsible for up to 67% of the mean organic daily carbon flux in the area.[11] In 2007 and 2009, the Tasman sea floor was analyzed from 200m to 2500m in depth and large quantities of T. vagina were found. The quantities found were some of the largest gelatinous zooplankton depositions ever recorded.[11] Further, benthic communities were found consuming T. vagina carcasses.[11] This sink provides nutrients to these benthic communities and are likely a large source of carbon input.[11]
The generic name of Thetys refers to Tethys or Thetis, Greek mythological figures.[12][13] The former being the mother of river gods and the Oceanids, and the latter being the goddess of water, a nereid, or a sea nymph. The species epithet is Latin vagina and means "sheath" or "scabbard."[13][12] At the time of Tilesius' naming, the term had not acquired the modern-day anatomical meaning and had referred solely to a sheath, likely referring to its appearance.[12]
{{cite journal}}: Cite journal requires |journal= (help) {{cite journal}}: Cite journal requires |journal= (help) Thetys vagina, or the twin sailed salp, is the largest known solitary species of salp and the only valid species of the genus Thetys. First described by W.G Tilesius in 1802, the species is transparent and gelatinous, making it difficult to be seen in water, which is helpful in avoiding predators. The fossil range is very recent. Other animals often mistaken for T. vagina are Salpa fusiformis, Aurelia aurita, and Pegea confoederata. There is no known status of conservation in this species. T. vagina DNA was sequenced as part of a larger project in 2014 where spiny lobster larvae were found attached to T. vagina and consuming it.
큰살파(학명: Thetys vagina)는 알려진 살파 중 가장 큰 종이자 큰살파속의 유일한 종이며 1982년에 처음 기술되었고 투명하고 젤라틴과 비슷한 몸 때문에 물에서 잘 보이지 않는다. 이는 포식자의 눈에 보이지 않아 포식자를 피하는 데에 도움이 된다.[1][2][3]
화석 범위는 최근의 것으로, 큰살파로 자주 오인되는 동물로 송곳살파, 보름달물해파리, Pegea confoederata가 있다. 보존 상태는 알려져 있지 않고, DNA는 2014년에 대형 프로젝트의 일환으로 시퀀싱되었으며 닭새우과 유충이 큰살파에 부착되어 그것을 먹는 것이 나타났다.[4]
길이는 최대 333mm에 이르는데 다른 두 가지 형태로 발전하는데 집계형과 단독형으로 나뉜다.[5] 집계형은 성별이 있고, 크기는 250mm 이르며, 근육 띠 5개가 있다. 난생인 단독형은 무성이며, 크기는 300mm에 이른다.[6]
단독형은 근육 띠 약 20개가 있고 그 띠는 몸의 상반부와 하반부에 붙은 끝 부분에 짙은 색을 지녔고, 짧은 길이를 가진 줄무늬가 특징이다.
어두운 색 및 다채로운 색의 덩어리 모양의 소화 기관을 가지며 배아의 크기는 10~15mm로 밝혀졌다.[7]
주로 원양 해양 환경에서 발견되는데 태평양, 대서양, 인도양의 열대 및 온대 해역에서 분포하고 난류를 따라가는 북대서양의 온도가 낮은 해역에서 종종 발견된다.[7][6] 널리 퍼져 있으나, 멀리 떨어져 살고 있어 잡히는 경우는 거의 없다.
|제목=이(가) 없거나 비었음 (도움말) 큰살파(학명: Thetys vagina)는 알려진 살파 중 가장 큰 종이자 큰살파속의 유일한 종이며 1982년에 처음 기술되었고 투명하고 젤라틴과 비슷한 몸 때문에 물에서 잘 보이지 않는다. 이는 포식자의 눈에 보이지 않아 포식자를 피하는 데에 도움이 된다.
화석 범위는 최근의 것으로, 큰살파로 자주 오인되는 동물로 송곳살파, 보름달물해파리, Pegea confoederata가 있다. 보존 상태는 알려져 있지 않고, DNA는 2014년에 대형 프로젝트의 일환으로 시퀀싱되었으며 닭새우과 유충이 큰살파에 부착되어 그것을 먹는 것이 나타났다.
