跳转到内容

File:Sargassum Triggerfish (Xanthichthys ringens).jpg

页面内容不支持其他语言。
這個文件來自維基共享資源
维基百科,自由的百科全书

原始文件 (1,600 × 1,067像素,文件大小:317 KB,MIME类型:image/jpeg


描述

Triggerfishes are members of the family Balistidae, sometimes considered one of the more evolutionarily advanced families of marine fish. A dozen genera comprise the family, which totals less than 40 species. Certain characteristics are shared by all members of the family, notably two dorsal fins but no pelvic fins, eight teeth on the front jaw followed immediately by an additional six teeth and a large, well-developed pharyngeal plate which is well-suited for crushing various hard-shelled crustaceans.

Four species are represented in Indo-Pacific waters, yet Xanthichthys ringens is known only from the Atlantic Ocean. Specimens have been collected from as far north as South Carolina and extending as far south as Brazil. St. Lucia, Florida and Cuba all have healthy populations. Perhaps the largest geographical distribution of the genus occurs in X. caeruleolineatus, which is present from the Tuamotu Archipelago to the St. Brandon's Shoals. Another distribution point worth mentioning is the anti-tropical distribution of X. mento and how both pre-juveniles of X. mento and X. ringens have been found up to 500 miles off the coast.

Like its Indo-Pacific brethren, X. ringens prefers deeper waters near steep dropoffs and is "rarely encountered at depths of less than 100 feet" (Randall, 1968). At least one submarine observation has noted X. ringens patrolling about 400 feet deep off the Jamaican coast. No specimens of X. caeruleolineatus have been collected using traditional SCUBA equipment, probably because most individuals have been found at depths of 600 feet or more.

A slightly upturned mouth, which remains very small throughout the fish's lifespan, does not allow Xanthichthys to consume the same foods as many other triggerfishes. Instead, species of the genus Xanthichthys concentrate their diet on free-floating zooplankton, which they eagerly pluck from the water column. In fact, stomach contents of X. auromarginatus revealed the fish fed exclusively on zooplankton (Hobson, 1974). Additional notes from this study indicated the vast majority of the zooplankton were calanoid copepods.

Two species are known to display distinct sexual dichromatism between the adult males and females. This led to some confusion about species classification, but that was nevertheless worked out more easily than in most other dichromatic genera. Xanthichthys auromarginatus and X. mento each have beautiful male colorations while the females are certainly less attractive and flashy

<a href="http://reefkeeping.com/issues/2005-05/hcs3/index.php">reefkeeping.com/issues/2005-05/hcs3/index.php</a>
日期
来源 originally posted to Flickr as Sargassum Triggerfish (Xanthichthys ringens)
作者 Cliff
授权
(二次使用本文件)
此张图片原发布于Flickr,在Haplochromis管理员审查员Flickr upload bot检查后,确认检查时图片在Flickr的版权声明与维基共享资源的版权使用方针相符。
w:zh:知识共享
署名
本文件采用知识共享署名 2.0 通用许可协议授权。
您可以自由地:
  • 共享 – 复制、发行并传播本作品
  • 修改 – 改编作品
惟须遵守下列条件:
  • 署名 – 您必须对作品进行署名,提供授权条款的链接,并说明是否对原始内容进行了更改。您可以用任何合理的方式来署名,但不得以任何方式表明许可人认可您或您的使用。

说明

添加一行文字以描述该文件所表现的内容

此文件中描述的项目

描繪內容

摄影器材 简体中文(已转写)

38°53'40.6"N, 77°1'56.6"W

文件历史

点击某个日期/时间查看对应时刻的文件。

日期/时间缩⁠略⁠图大小用户备注
当前2009年3月22日 (日) 06:532009年3月22日 (日) 06:53版本的缩略图1,600 × 1,067(317 KB)Flickr upload botUploaded from http://flickr.com/photo/28567825@N03/3366490231 using Flickr upload bot

以下页面使用本文件:

全域文件用途

以下其他wiki使用此文件:

元数据