词条 | Semaeostomeae |
释义 |
| image = Sea nettles.jpg | image_caption = Sea nettles, Chrysaora fuscescens | taxon = Semaeostomeae | authority = L. Agassiz, 1862 | subdivision_ranks = Families | subdivision = See text }}Semaeostomeae (literally "flag mouths") is an order of large jellyfish characterized by four long, frilly oral arms flanking their quadrate mouths. The umbrella is domed with scalloped margins, and the gastrovascular system consists of four unbranched pouches radiating outwards from the central stomach; no ring canal is present. They usually possess eight tentacles; four are per-radical and four are inter-radical.[1] TaxonomyThe order consists of four families.
DifferentiationThe three traditional families, Pelagiidae, Cyaneidae, and Ulmaridae, are distinguishable by these characteristics:
In addition, members of the Pelagiidae have no ring canal, and the marginal tentacles arise from umbrella margin. Three genera are in this family. GalleryReferences1. ^{{cite book |author= Barnes, Robert D. |year=1982 |title= Invertebrate Zoology |publisher= Holt-Saunders International |location= Philadelphia, PA|page= 149|isbn= 0-03-056747-5}} 2. ^Bayha, K. M., and M. N. Dawson (2010). New family of allomorphic jellyfishes, Drymonematidae (Scyphozoa, Discomedusae), emphasizes evolution in the functional morphology and trophic ecology of gelatinous zooplankton. The Biological Bulletin 219(3): 249–267
2 : Semaeostomeae|Cnidarian orders |
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。