Symphurus thermophilus ist eine kleine Plattfischart aus der Familie der Hundszungen (Cynoglossidae). Die Art kommt disjunkt im westlichen Pazifik in Tiefen von etwa 240 bis 730 Metern ausschließlich in der unmittelbaren Umgebung von hydrothermalen Quellen vor, worauf das Art-Epitheton verweist (thermophilus = wärmeliebend). Nachgewiesen wurde Symphurus thermophilus im Bereich der Bonininsel südlich von Japan und bei den Kermadecinseln nördlich von Neuseeland.[1] Zwischen den beiden bisher bekannten Verbreitungsgebieten liegt eine Distanz von etwa 6500 km. Deshalb ist es wahrscheinlich, dass die Art auch bei dazwischen gelegenen Hydrothermalquellen vorkommt.[2]
Symphurus thermophilus wird etwa zehn Zentimeter lang und hat 47 bis 51 Wirbel. Die Augenseite von Kopf und Körper ist mittel bis dunkel schokoladenbraun gefärbt und durch fünf bis acht dunkle, in den meisten Fällen unvollständige Querbänder und mit zahlreichen, dunklen oder weißlichen unregelmäßig geformten Flecken gemustert. Direkt hinter dem Kiemendeckel, wo die Bauchhöhle der Tiere liegt, sind die Fische schwärzlich-braun.[1] Von anderen Symphurus-Arten unterscheidet sich Symphurus thermophilus unter anderem durch den deutlich breiteren Körper und die relativ großen Augen.[2]
Symphurus thermophilus lebt in großer Individuendichte ausschließlich in unmittelbarer Umgebung von heißen Quellen. Am Unterseeberg Nikko fraß Symphurus thermophilus fast ausschließlich die Garnelenart Opaepele loihi, die nur an hydrothermalen Quellen vorkommt. An anderen Tiefseebergen fraßen die Fische auch andere kleine Krebstiere und Vielborster, sowie den Bakterienrasen auf den Schwefelablagerungen.[2]
Symphurus thermophilus ist eine kleine Plattfischart aus der Familie der Hundszungen (Cynoglossidae). Die Art kommt disjunkt im westlichen Pazifik in Tiefen von etwa 240 bis 730 Metern ausschließlich in der unmittelbaren Umgebung von hydrothermalen Quellen vor, worauf das Art-Epitheton verweist (thermophilus = wärmeliebend). Nachgewiesen wurde Symphurus thermophilus im Bereich der Bonininsel südlich von Japan und bei den Kermadecinseln nördlich von Neuseeland. Zwischen den beiden bisher bekannten Verbreitungsgebieten liegt eine Distanz von etwa 6500 km. Deshalb ist es wahrscheinlich, dass die Art auch bei dazwischen gelegenen Hydrothermalquellen vorkommt.
Symphurus thermophilus is a species of tonguefish notable for being the only flatfish known to be an obligate inhabitant of hydrothermal vents. It is known from several widely dispersed locations in the western Pacific Ocean and occurs in great numbers. They are tolerant of harsh conditions and are often found in close association with elemental sulfur, including molten sulfur pools that exceed 180 °C in temperature.[2] As they are not significantly different in appearance and feeding habits from other tonguefishes, they are thought to be relatively recent colonizers of vent ecosystems.[3]
These fish were first observed in nature in 1988, and were provisionally assigned to the species Symphurus orientalis before being recognized as a new species. The species name thermophilus is from the Greek thermos meaning "heat" and philos meaning "lover", referring to its association with hydrothermal vents.[1]
This species has a wide, disjunct distribution in the western Pacific, from the Kaikata Seamount near the Bonin Islands off southeastern Japan, to the Rumble 3 and Macauley Submarine Volcanos on the Kermadec Ridge off northern New Zealand, including the Nikko Seamount near Minami-Iohjima Island, the Minami-Ensei Knoll in the Mid-Okinawa Trough, the Kasuga-2 and Daikoku Seamounts in the Marianas Islands arc, and the Volcano-1 and Volcano-2 Seamounts in the Tonga arc. S. thermophilus likely also occurs at yet-unexplored vent sites between these locations.[3][1]
S. thermophilus occurs only within relatively shallow active hydrothermal vent sites at a depth of 239–733 m, with most found between 300–400 m. Both adults and juveniles are found in the same habitats. Unusually for a vent fish, S. thermophilus favors environments that are rich in sulfur; they have been observed oriented vertically on solid sulfur walls, resting on beds of newly congealed sulfur adjacent to a rivulet of molten sulfur, and even on a thin crust of consolidated sulfur pebbles overlaying a molten sulfur bed with a temperature of 187 °C (though the crust is considerably cooler).[3]
While many flatfish species prefer a fine substrate to burrow in, S. thermophilus frequents coarse substrates and is sometimes found over solid surfaces.[3] At the Kaikata Seamount, S. thermophilus was observed on coarse sand bottoms where water of 19-22 °C was percolating through the sediment. At the Minami-Ensei Knoll, this species was found on white metachromatic sediments in water 5-10 °C warmer than the ambient seawater. At the Kasuga-2 Seamount, it occurred on a variety of dark- and light-colored gravel sediments and on bacterial mats.[1]
Where it occurs, S. thermophilus is often extremely abundant; it is the most numerous obligate vent vertebrate known to date. At the Kaikata Seamount, they are found in such numbers that the fish overlap one another on the bottom. Point densities at the Daikoku Seamount have been recorded as high as 392 individuals per square meter; these densities are an order of magnitude higher than flatfish densities reported anywhere else.[3]
Like other tonguefishes, S. thermophilus has a laterally flattened body with united dorsal, caudal, and anal fins. Both eyes, which are fairly large and rounded in this species, are located on the left side of the head in adults. The pectoral fins and lateral line are absent, and there is only a single, right-side pelvic fin.[3] The head is moderately long, with a blunt snout and long, broadly arched jaws. There are 4-5 rows of teeth on the upper and lower jaws of the blind side, and 2-3 and 1 rows on upper and lower jaws respectively of the eyed side. The teeth are sharp and recurved, and better developed on the blind-side jaws.[1]
The body is notably deep compared to other Symphurus species. The origin of the dorsal fin is located above the eyes and contains 88-94 rays. The dorsal fin pterygiophores and neural spines have a 1-2-2-2-2 interdigitation pattern. The pelvic fin is moderately long, contains 4 rays, and is connected to the body by a delicate membrane. The anal fin contains 74-80 fin rays. The caudal fin is relatively long and contains 14 rays. The scales are small and strongly ctenoid in shape, numbering 47-56 rows transversely and 100-112 rows longitudinally.[1]
The eyed side of the body is medium to dark chocolate brown in color, mottled with numerous dark, irregularly shaped blotches and white speckles. There are also five to eight darker, complete or incomplete crossbands. Some individuals have a white patch over two-thirds of the abdominal cavity, sometimes with bluish-green tints and bordered posteriorly by a black blotch. The abdominal area posterior to the gill opening is blackish brown and much darker than the rest of the body. Occasionally there are one or two irregular to nearly circular white spots along the body midline. The fin rays are dark at the base and lighter towards the tips, and there is an irregular dark spot at the base of the caudal fin. The blind side of the body is white, with scattered dark melanophores.[1]
The maximum known length is 8.7 cm for a male and 11.2 cm for a female.[4] The fish from the Nikko Seamount are nearly twice as large as those from the Kasuga-2 and Daikoku Seamounts. This may be because of the higher biological productivity at Nikko, or because Kasuga-2 and Daikoku were recently colonized.[5]
S. thermophilus spend most of their time on the sea floor, moving forwards or backwards by undulating their bodies and sometimes burying themselves completely in the substrate. They seem to be attracted to loose sediments, probably related to the uncovering of food, and often congregate in pits. The fish frequently rest atop one another without reaction.[3]
The vent communities that co-occur with S. thermophilus differs greatly between seamounts. They co-occur with large numbers of the snail Oenopota ogasawaarna at the Daikoku Seamount, and with the abundant shrimp Opaepele loihi at the Nikko Seamount. They also frequently occur with the crab Austinograea yunohana, which are found at Nikko, Daikoku, and Kasuga-2. Large bythograeid crabs have been observed attempting attacks on the fish, though not successfully.[1] S. thermophilus likely experiences little to no predation pressure, which coupled with the high food biomass available allows their high densities.[3]
The affinity of this species for native sulfur has yet to be explained. The morphology of S. thermophilus does not show any differences from other deepwater Symphurus species that would suggest adaptations to its unique habitat. However, S. thermophilus likely possesses extensive physiological and biochemical adaptations for coping with the harsh conditions around hydrothermal vents, such as temperature and pH fluctuations, and exposure to heavy metals. In particular, they must have high hemoglobin oxygen affinities and efficient respiratory systems to deal with the toxic hydrogen sulfide in venting fluid.[3] S. thermophilus is also capable of tolerating pH as low as 2, akin to sulfuric acid, and can rest over pools of molten sulfur without harm.[2] Individuals of S. thermophilus often show skeletal abnormalities such as undeveloped fin rays or fused bones, likely attributable to the vent environment.[1]
The diet of S. thermophilus varies significantly from seamount to seamount, with the only constant being polychaete worms, which are most important for individuals on Daikoku and Volcano-1 Seamounts. Other populations feed predominantly on crustaceans; the main prey item of S. thermophilus on the Nikko Seamount is the alvinocaridid shrimp Opaepele loihi, and on the Kasuga-2 Seamount they eat mostly palaemonid shrimp. The fish at these sites appear to be "sit and wait" predators, taking slow-moving shrimp that wander too close. By contrast, the fish at the Daikoku Seamount seem to be more active, opportunistic foragers; they do not eat many crustaceans and have been observed scavenging on dying fish that fall to the bottom after coming into contact with the volcanic plumes. Snails and sponge spicules have also been found in the stomachs of a few individuals, and in captivity they are known to consume any food offered to them. The large numbers of S. thermophilus found on sulfur crusts where there are no obvious prey items may feed directly on filaments of chemosynthetic bacteria. If so, this would represent a hitherto unknown behavior for vent fish species.[3][5]
Reproduction is oviparous, with females releasing buoyant eggs measuring 0.9 mm in diameter. The developmental speed of the eggs increases with temperature: they hatch in one day at 26 °C, in 3 days at 20 °C, and in 14 days at 12 °C. The newly hatched fry are initially sustained by a yolk sac, and have a completely developed mouth, eyes, and digestive system by 7 days of age.[6] The migration of the eyes begins after 30 days. Compared to other flatfish, S. symphurus is slow-growing and long-lived, with a lifespan upwards of 10 years. Growth differs between populations, due to availability of food and consequent activity level. Over half their growth in length is accomplished in the first three years, with the growth rate slowing down afterwards. Both sexes likely attain sexual maturity at around 4.4 cm long and one year of age.[3]
Symphurus thermophilus is a species of tonguefish notable for being the only flatfish known to be an obligate inhabitant of hydrothermal vents. It is known from several widely dispersed locations in the western Pacific Ocean and occurs in great numbers. They are tolerant of harsh conditions and are often found in close association with elemental sulfur, including molten sulfur pools that exceed 180 °C in temperature. As they are not significantly different in appearance and feeding habits from other tonguefishes, they are thought to be relatively recent colonizers of vent ecosystems.
These fish were first observed in nature in 1988, and were provisionally assigned to the species Symphurus orientalis before being recognized as a new species. The species name thermophilus is from the Greek thermos meaning "heat" and philos meaning "lover", referring to its association with hydrothermal vents.
Symphurus thermophilus Symphurus generoko animalia da. Arrainen barruko Cynoglossidae familian sailkatzen da.
Symphurus thermophilus Symphurus generoko animalia da. Arrainen barruko Cynoglossidae familian sailkatzen da.
Symphurus thermophilus is een straalvinnige vissensoort uit de familie van hondstongen (Cynoglossidae).[1] De wetenschappelijke naam van de soort is voor het eerst geldig gepubliceerd in 2008 door Munroe & Hashimoto.
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蜇棲無線鰨為輻鰭魚綱鰈形目鰨亞目舌鰨科的其中一種，為深海魚類，分布於西太平洋海域，棲息深度239-773公尺，體長可達8.7公分，棲息在底層水域，生活習性不明。
这是一篇關於魚類的小作品。你可以通过编辑或修订扩充其内容。 
分類 界 : 動物界 Animalia 門 : 脊索動物門 Chordata 亜門 : 脊椎動物亜門 Vertebrata 綱 : 条鰭綱 Actinopterygii 目 : カレイ目 Pleuronectiformes 科 : ウシノシタ科 Cynoglossidae 属 : アズマガレイ属 Symphurus 種 : イデユウシノシタ S. thermophilus 学名 Symphurus thermophilus
イデユウシノシタ(Symphurus thermophilus)はウシノシタの一種。西部太平洋に分布する。カレイ目として唯一熱水噴出孔のみに生息し、高濃度の硫黄や高温などに耐えることができる[1]。形態的には他のアズマガレイ属に類似し、熱水噴出孔への適応は比較的最近のことだと考えられる[2]。
最初に観察されたのは1988年で、新種と認められるまではアズマガレイ(Symphurus orientalis)とされていた。種小名thermophilusは古代ギリシャ語thermos（熱）、philos（好む）に由来し、熱水噴出孔に生息することに因んだものである[3]。
西部太平洋に不連続に分布し、小笠原諸島付近の海形海山・ニュージーランド北部、ケルマデック島弧のRumble 3・マコーレー島、南硫黄島付近の日光海山・中部沖縄トラフの南奄西海丘・マリアナ島弧の第2春日海山・大黒海山、トンガ島弧のVolcano-1 Seamount・Volcano-2 Seamountで確認されている。他の熱水噴出孔にも生息する可能性がある[2][3]。
深度239-733mの熱水噴出孔で見られるが、通常は300-400m。成魚・幼魚は同所に生息する。魚類には珍しく硫黄が豊富な場所を好み、垂直な硫黄の壁、凝固したばかりの硫黄の上などで観察される。187℃の溶融硫黄に浮かぶ硫黄の小塊に乗っていた例もある[2]。
普通のカレイは細かい堆積物に埋まることを好むが、本種は礫底や岩の上を好む[2]。海形海山では19-22℃の水が湧き上がる粗い砂底に生息する。南奄西海丘では白い堆積物上に見られ、水温は周囲より5-10℃高い。第2春日海山では礫底やバイオフィルム上で見られる[3]。
生息地での密度は非常に高く、熱水噴出孔性の脊椎動物としては最も多い。海形海山では多数の個体が積み重なる姿が観察されている。大黒海山では1m2あたり392個体の記録があり、これはカレイ類としては最も高い生息密度である[2]。
他のウシノシタのように背鰭・尾鰭・臀鰭は連続する。眼は丸くて大きく、体の左側が有眼側である。胸鰭・側線・左腹鰭はない[2]。頭部は比較的長く、吻は丸い。顎は大きくて弧を描く。両顎とも無眼側歯列は4-5、有眼側歯列は上顎で2-3・下顎で1。歯は鋭く内側を向き、無眼側の方が発達する[3]。
他のアズマガレイ属魚類に比べ幅広い。背鰭は眼の上から始まり88-94軟条。背鰭の担鰭骨と神経棘は1-2-2-2-2という嵌合パターンを示す。腹鰭は長く4軟条、付け根は繊細な膜になっている。臀鰭は74-80軟条、尾鰭は比較的長く14軟条。鱗は小さく、明確な櫛鱗であり、横に47-56列、縦に100-112列[3]。
有眼側は褐色から暗褐色、不規則な黒い模様と白い斑点があり、5-8本の黒い横縞がある。稀に、体中心線に沿って1-2個の白い点がある。腹腔の2/3程度が白い個体もおり、青緑の濃淡や黒の縁取りがある場合もある。鰓孔は他の部分より色が暗い。鰭条の根元は暗く、先端は明るくなり、尾鰭基部には不規則な黒い斑点がある。無眼側は白く、メラノフォアが散らばる[3]。
最大で雄は8.7cm、雌は11.2cm[4]。日光海山の個体は第2春日・大黒海山の個体の2倍である。これは日光海山の生物生産力が高い、あるいは第2春日・大黒海山に分布を広げたのが最近であることを意味する可能性がある[5]。
海底に横たわっており、体縁をうねらせることで前後に移動できる。餌を探すため、緩い堆積物や穴に集まっていることもある[2]。
共存種は場所によって大きく異なる。大黒海山ではオガサワラマンジ、日光海山ではトウロウオハラエビと共に生息する。ユノハナガニと共にいることもよくあり、大型のユノハナガニに攻撃されることもあるが、捉えられることはないようである[3]。捕食圧はほとんどないと考えられ、バイオマスの多さと相俟って高い個体密度に達していると推測される[2]。
熱水噴出孔への生理学・生化学的適応が見られ、硫酸などによる2以下のpH・溶融硫黄の高温・重金属曝露などに耐えることができる。特に、高い硫化水素濃度に耐えるため、ヘモグロビンと酸素との親和性が高くなっている[2][1]。骨格では、未発達の鰭条や融合した骨が見られ、これも熱水噴出孔の環境に起因すると考えられる[3]。
餌は生息地毎にかなり異なる。大黒海山・Volcano-1 Seamountでは多毛類が主な餌である。他の個体群は甲殻類を食べ、日光海山ではオハラエビ科のトウロウオハラエビ(Opaepele loihi)、第2春日海山ではテナガエビ科が主な獲物である。ここでは待ち伏せ型捕食者であり、近づいてきたエビを襲う。大黒海山ではそれより活発であり、噴煙に接触して死んだ魚類を漁っている姿も観察される。胃から貝殻や海綿の骨片が見つかることもあり、捕獲下の観察では、餌として与えられたものはほぼ何でも食べる。他の餌生物のいない硫黄塊の上では化学合成細菌の糸状体を食べている可能性があり、事実だとすれば魚類の食性として初めてのものである[2][5]。
卵生で、雌は直径0.9mmの浮遊性卵を産む。発生は温度で促進され、12℃で14日・20℃で3日・26℃で1日で孵化する。仔魚には卵黄嚢があり、眼・口・消化器が完成するまで7日かかる[6]。30日後から眼の移動が始まる。他のカレイに比べ成長が遅く、寿命は10年を超える。成長速度は餌の量に影響されるが、3年間で最大長の半分程度まで成長し、その後は遅くなる。1歳、4.4cm程度で性成熟する[2]。
イデユウシノシタ(Symphurus thermophilus)はウシノシタの一種。西部太平洋に分布する。カレイ目として唯一熱水噴出孔のみに生息し、高濃度の硫黄や高温などに耐えることができる。形態的には他のアズマガレイ属に類似し、熱水噴出孔への適応は比較的最近のことだと考えられる。
最初に観察されたのは1988年で、新種と認められるまではアズマガレイ(Symphurus orientalis)とされていた。種小名thermophilusは古代ギリシャ語thermos（熱）、philos（好む）に由来し、熱水噴出孔に生息することに因んだものである。
