词条 | Atlanta echinogyra |
释义 |
| name = Atlanta echinogyra | fossil_range = Pliocene-Recent[1] | image = Atlanta cf echinogyra.png | image_caption = Apical view of the shell of Atlanta cf. echinogyra from the Pliocene of Philippines. Notice the flange-like keel. | regnum = Animalia | phylum = Mollusca | classis = Gastropoda | unranked_superfamilia= clade Caenogastropoda clade Hypsogastropoda clade Littorinimorpha | superfamilia = Pterotracheoidea | familia = Atlantidae | subfamilia = | genus = Atlanta | subgenus = | species = A. echinogyra | binomial = Atlanta echinogyra | binomial_authority = Richter, 1972[1] | synonyms_ref = | synonyms = }}Atlanta echinogyra is a species of sea snail, a holoplanktonic marine gastropod mollusk in the family Atlantidae.[2] DescriptionAtlanta echinogyra was described in 1972 by Dr. Gotthard Richter (from Senckenberg Museum, Frankfurt am Main, Germany) based on specimens collected during the Meteor Expedition to the northern Indian Ocean.[4] Richter named the species after the unique structure of the opercular gyre, with its raised spiral row of spines.[4]Atlanta echinogyra is a small species (to 2.5 mm shell diameter).[4] The shell is colorless, although the tissues underlying the shell spire give it a red-violet to red-brown color.[4] The spire is low conical and consists of 3-3.25 whorls.[1][4] The spire whorls have incised sutures and bear low spiral ridges on the second through most of the fourth whorls.[4] The outer edge of the third and fourth whorls have a raised ridge (seen best in the larval shell).[4] The fourth whorl (first teleoconch whorl) increases rapidly in width and bears a flange-like keel.[1] The keel is moderately elevated with a slightly truncate leading edge.[4] The keel does not insert between the last two shell whorls.[4] The keel base is either clear or brown.[4] The early whorls are covered with a distinct and relatively coarse ornament consisting of four spirals.[1] This ornament is also visible on the base of the shell, where it is present in the umbilicus, on the last part of the protoconch.[1]Eyes are type a.[4] Operculum is type c, with a gyre that bears a raised spiral row of strong, distally-tapering spines (hence the specific epithet, "echinogyra").[4] Radula is type I, with unlimited numbers of tooth rows and lacking sexual dimorphism.[4] Description overview:
DistributionGeographic distribution of Atlanta echinogyra is Indo-Pacific.[4] In the plankton samples from the Meteor Expedition studied by Richter (1974), Atlanta echinogyra was the fourth most abundant species of heteropod (accounting for 9.1% of the total).[4] By contrast, the species was uncommon off northeastern Australia (ranking ninth, accounting for 1.5% of the total number of heteropods collected) in a study by Seapy et al. (2003).[4] In Hawaiian waters Atlanta echinogyra was variable in its presence and numbers among different collections, ranking eleventh out of thirteen species of atlantids (Seapy, 1990a); from five different sampling periods between 1984 and 1986, it was not collected twice, was represented by a single individual once, and by 27 and 19 individuals in two collections.[4] In eastern Australian waters, Newman (1990) recorded Atlanta echinogyra as rare in northern and central Great Barrier Reef waters.[4] Thus, it would appear that in the Pacific and Indian Oceans, Atlanta echinogyra is only abundant in the northern Indian Ocean.[4] Fossil distributionAtlanta cf. echinogyra is known from the Pliocene of Anda, Pangasinan, Luzon, Philippines.[1]EcologyVertical distribution limited to the upper 100 m in Hawaiian waters.[4] ReferencesThis article incorporates CC-BY-3.0 text from references.[3][4] 1. ^{{de icon}} Richter G. (1972). "Zur Kenntnis der Gattung Atlanta (Heteropoda: Atlantidae)". Archiv für Molluskenkunde 102: 85-91. {{Taxonbar|from=Q4816188}}{{DEFAULTSORT:Atlanta Echinogyra}}2. ^{{WRMS species|430420|Atlanta echinogyra Richter, 1972|||WoRMS (2009). Atlanta echinogyra Richter, 1972. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=430420 on 14 August 2010}} 3. ^1 2 3 4 5 6 {{Cite journal| author=Janssen A. W.| title=Holoplanktonic Mollusca (Gastropoda: Pterotracheoidea, Janthinoidea, Thecosomata and Gymnosomata) from the Pliocene of Pangasinan (Luzon, Philippines)| journal=Scripta Geologica| year=2007| volume=135| url=http://www.scriptageologica.nl/07/nr135/a02}} 4. ^1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 Seapy R. R. (2010). Atlanta echinogyra Richter 1972. Version 28 March 2010 (under construction). http://tolweb.org/Atlanta_echinogyra/28756/2010.03.28 in The Tree of Life Web Project. 2 : Atlantidae|Gastropods described in 1972 |
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