Sicyases sanguineus
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| Müller & Troschel , 1843 |
Sicyases sanguineus , a tortoiseshell (family Gobiesocidae, subfamily Gobiesocinae; see Gobiesox marmoratus ), is about as common in its homeland, the Pacific coast of South America, as the sea hare ( Cyclopterus lumpus ) ison Europe's coasts. In Chile it is called pejesapo (" toad fish "). Even in the pre- Inca culture,fish playeda certain role as an easy-to-harvest subsistence commodity (source of protein) from the coast to the Andean highlands . The generic name Sicyases is a Latinized made-up word from ancient Greek. Aorist participle σικυάσας, from σικυάζειν "cupping" - that is, "one who tends to cup", cupper - both in terms of body shape and apparently also the teeth (as Schnepper ) - which is also referred to, pleonastic , sanguineus ("blood") .
The rather tadpole-like fish combines a lot of unusual anatomical, physiological and ecological features - it has an " amphibious " way of life that is unusual for fish . The coloration can be different: from yellowish to olive green to brown (i.e. not red), often with darker, but sometimes indistinct banding.
Construction and function
The pejesapo is less flattened than other shield bellies: the ventral side is of course flat because of the large suction disk, but the head and back are quite high. The mouth is accentuated by strong masticatory muscles and the forward-facing horse or ruminant incisor teeth, so that it looks like this fish has a chin. The front teeth (four times three in total) are planted in the alveoli (otherwise rare in fish) and must therefore be able to withstand greater stress. One could think of the tearing away of limpets , which occur in the same biotope and can very well suck up (e.g. because of the surf). Indeed, Sicyases eats snails - but not preferentially; If one carries out nutrition analyzes, one finds opportunistic eating behavior, as with many other "nutrition specialists according to the anatomy" ; d. That is, everything is taken that is available and can be managed, especially smaller higher crabs, mussels and the like. Ä.
As with the Australian lungfish ( Neoceratodus forsteri ; with pinched teeth), we often find the intestines filled with parts of plants (here thalli of brown, red and algae), which were only ingested for the sake of the snails sitting on them. There are studies that show that these algae ( seaweed ) are hardly digested, so Sicyases , even if he so "lazy" when Phorent these macroalgae can be seen (propagator); only their spores usually do not survive digestion. The fish has no pinch teeth, but it is enough to slowly dissolve the snail shells in the stomach, as X-rays show.
On the skull there is a strange z. B. the dismantling of the jockstrap , the front end (palatine) of which is only ligamentously connected to the quadratum, which itself looks quite different - for example because it is widened to the rear. The three pterygoids are tiny. All of this shows u. a. point out that sucking snaps and water breathing are not as important in these fish as they usually are- fin formula : D 7-10, A 5-7, P 23-28, C 14 (the pectoral fin is therefore very wide, similar to that of the porcupine fish ; the anus is much smaller than the dorsal fin). This shield belly reaches 20, allegedly even 30 cm in length.
Ecology and physiology
Although Sicyases is one of the Gobiesocinae with wide gill openings (see on the other hand Lepadogaster lepadogaster ), it lives more eu- than sublittoral , i.e. in the intertidal zone, where it often dries out. However, it is rarely found in tide pools, and when it does, it can even suffocate in the sun-warmed, stagnant water without doing anything about it. But mostly it stays under seaweed, stones in the damp or it hangs upside down on vertical rock walls, even when these are sunny. Because in this position he can apparently keep the gills moist the longest and (allegedly) also a skin area on the underside of the head, which is supposed to serve in a special way for skin breathing. So it can withstand up to 40 hours without being submerged. He provides z. B. the nitrogen excretion from ammonia (via the gills - the normal in fish) to urea (via the kidneys, as in many land animals). In connection with this, incretory glands also have some peculiarities, e.g. B. the thymus appendages on the gill arch are very large; the Stannius' corpuscles (embedded in the kidney tissue) even show a sexual dimorphism (males have two, females three or four). The spleen and gallbladder are also very large. In general, the Gobiesocidae have a very short, but extremely wide intestine (perhaps the widest of all Teleostei - a “reason” for this cannot be given); only the stomach can be locked by the circular muscles. Digestion seems to be so slow that pyloric tubes are superfluous. The reproduction takes place as usual with shield bellies, with guarding of the spawn under the waterline. To spread, the larvae go into the open water near the coast for a few weeks (with their swim bladder) (Perez 1981). The reason for the amphibious way of life is assumed to be lower predator pressure outside of the water, although of course sea birds (such as seagulls) or sea otters rummage for food here again.
Occurrence
It lives on rocky coasts of Peru and Chile, mostly also overgrown with seaweed, and - with two (?) Related species - around offshore islands, at water temperatures of 12 to 18 ° C.
swell
- ^ J. Marcus, JD Sommer, and CP Glew (1999): Fish and mammals in the economy of an ancient Peruvian kingdom.- Proc. Natl. Acad. Sci. USA 96: 6564-6570.
- ↑ (gr.) Sikya is a small pumpkin; see. (lat.) cucurbitula "cupping head" from cucurbita "pumpkin"; Wb .: Pape 1880 and Georges 1913.
- ^ RT Paine and AR Palmer (1978): Sicyases sanguineus : a unique trophic generalist from the Chilean intertidal zone.- Copeia 1978: 75-81.
- ↑ I. Paya and B. Santelices (1989): Macroalgae survive digestion by fishes. Journal of Phycology 25: 186-188.
- ↑ cf. the images at WK Gregory 1933 http://www.archive.org/stream/fishskullsstudyo00gregrich , where " Gobiesox " in reality probably represents Sicyases , and R. Perez (1981) http://www.freewebs.com/pejesapos/desarrollooseoytrfic .htm
- ^ H. Burgos y E. De la Hoz (1982): Morfología funcional cefálica de Sicyases sanguíneus (Pisces) .- Memoria para optar al título de Profesor de Biología. Universidad Católica de Valparaíso.
- ↑ http://www.euv.cl/archivos_pdf/rev_inv_marinas/marinas_articulo_29(2).pdf
- ↑ J. Cancino and J. Castilla (1988): Emersion behavior and foraging ecology of the common Chilean clingfish Sicyases sanguineus (Pisces: Gobiesocidae) .- Journal of Natural History 22: 249-261.
Web link
Sicyases sanguineus on Fishbase.org (English)