| 词条 | Astroides |
| 释义 |
| name = Astroides calycularis | image = Astroides calycularis 2008a.jpg | image_caption = Astroides calycularis colony with tentacles expanded | parent_authority = Quoy & Gaimard, 1827 [1] | taxon = Astroides calycularis | authority = (Pallas, 1766)[1] }} Astroides is a genus of stony cup corals in the family Dendrophylliidae. It is monotypic and the only species is Astroides calycularis, which is endemic to the western Mediterranean Sea. The species was first described in 1766 by the German naturalist Peter Simon Pallas. DescriptionAstroides calycularis is a colonial coral, consisting of a group of polyps, each of which sits in a stony cup known as a calyx. The colonies are {{convert|25|to|30|cm|0|abbr=on}} in diameter and {{convert|10|cm|0|abbr=on}} high and each polyp is about {{convert|1|to|2|cm|1|abbr=on}} in diameter. The polyps are yellow or orange, each with a fringe of about thirty very short tentacles surrounding a slit-shaped mouth. The colony grows by asexual reproduction, new polyps budding off existing polyps and secreting their own calices. Deep-water colonies are bush-shaped, the calices are circular and budding occurs at various heights on the calyx walls. Shallow-water colonies tend to be ellipsoid in shape, the calyces are polygonal and budding occurs in the centre of the colony as well as round the edges.[2]Distribution and habitatDuring the Pleistocene, Astroides calycularis had a wider distribution than it does now, and was present in the whole of the western Mediterranean. Since then it has disappeared from the northern part of that range as a result of the lower sea temperatures that resulted from glaciation.[2] Nowadays it is native to the part of the western Mediterranean Sea that is south of Sardinia and is also present in the Atlantic Ocean near the Strait of Gibraltar. Before 1989 it was restricted to the area west of Sicily, but in that year it appeared in the Adriatic Sea for the first time.[5] This coincided with a sudden change of circulation in the eastern Mediterranean which may have allowed the short-lived pelagic larvae to survive long enough to settle on the seabed of the Croatian coast.[3] A. calycularis is found on rocks and walls, under overhangs and in submarine caves at depths down to about {{convert|70|m|0|abbr=on}}. In suitable locations, colonies can cover 90% of the available substrate.[2] In a cave in Italy, it was more common in better lit parts than was the solitary sunset cup coral (Leptopsammia pruvoti), and was more abundant near where sulphurous spring water flowed into the cave.[4] BiologyAstroides calycularis is nocturnal, the polyps remaining retracted back into their calices during the day. When expanded at night, they feed on zooplankton, small fish and perhaps bacteria. This coral is azooxanthellate, meaning it does not contain symbiotic dinoflagellates in its tissues as do many species of coral.[1]A. calycularis colonies are gonochoristic with all the polyps in a colony being of the same sex. Males liberate sperm into the sea and fertilisation takes place in the coelenteron (gastric cavity) of the female. The eggs have yolks, and the embryos are brooded in the coelenteron until they are liberated into the water column as planula larvae.[2]References1. ^1 2 {{cite WoRMS |author=Cairns, S. |author2=Hoeksema, B. |year=2014 |title=Astroides Quoy & Gaimard, 1827 |id=135107 |accessdate=2014-12-23 }} {{Taxonbar|from1=Q626731|from2=Q2868573}}2. ^1 2 3 {{cite journal |author1=Goffredo, Stefano |author2=Gasparini, Gabriella |author3=Marconi, Giulia |author4=Putignano, Maria Teresa |author5=Pazzini, Claudia |author6=Zaccanti, Francesco |year=2010 |title=Gonochorism and planula brooding in the Mediterranean endemic orange coral Astroides calycularis (Scleractinia: Dendrophylliidae). Morphological aspects of gametogenesis and ontogenesis |journal=Marine Biology Research |volume=6 |issue=5 |pages=421–436 |doi=10.1080/17451000903428488 }} 3. ^1 {{cite book|author=Giulio Relini|title=Biodiversity in Enclosed Seas and Artificial Marine Habitats: Proceedings of the 39th European Marine Biology Symposium, held in Genoa, Italy, 21-24 July 2004|url=https://books.google.com/books?id=odX4XI-2ANYC&pg=PA12|date=10 June 2007|publisher=Springer Science & Business Media |isbn=978-1-4020-6156-1 |page=12 }} 4. ^{{cite book |author=Aldemaro Romero Díaz|title=Cave Biology: Life in Darkness |url=https://books.google.com/books?id=i3002NxjFUwC&pg=PA81|year=2009 |publisher=Cambridge University Press|isbn=978-0-521-82846-8|page=81}} 4 : Scleractinia genera|Monotypic cnidarian genera|Dendrophylliidae|Biota of the Mediterranean Sea |
| 随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。