丁丁蟲亞目

砂殼纖毛蟲（學名：Tintinnina），又名有鐘纖毛蟲或丁丁蟲，泛指隸屬於纖毛蟲門旋毛綱之下丁丁蟲亞目的物種。丁丁蟲亞目舊屬旋毛綱，現時被重新分類，成為了寡毛綱 Choreotrichida 目之下的五個亞目之一。本分類單元包括有種數在 1000 種左右，大多數在海洋中營浮游生活，屬微型浮游動物（microzooplankton），主要攝食浮游矽藻和鞭毛蟲，是水體微食物環的重要組成部分，在水體中的能量流動和物質迴圈中佔重要地位。

砂殼纖毛蟲的蟲體生活在殼中，其外殼是其獨特的標誌。有部分文獻依從日語文獻，稱呼這種外殼為（Lorica）。

這些外殼大多呈壺形、花瓶形或管形，主要由蛋白質及小量礦物質構成，都有一個開口，有的在反口面還有一個較小的開口，蟲體有一個柄固著在殼的後端，透過身體的伸縮可以將身體伸出和縮排殼內；在環境不利時，蟲體會離開殼。

化石紀錄

形狀和大小類似於丁丁蟲的胴甲的化石，被稱為 Calpionellids（長約 50 到 200 微米，已於中生代滅絕），最早出現在奧陶紀，但由方解石形成，並且由於沒有已知的丁丁蟲會生成含方解石成份的纖毛狀外殼，因此它們不太可能是丁丁蟲的化石 —— 甚至可能根本與纖毛蟲完全無關。能夠與現生丁丁蟲相關連的化石記錄（例如：黏著在一起的胴甲化石）出現於侏羅紀時期，但數量並不多，直到白堊紀才開始大量出現。

xTintinnids are an important part of the fossil record because of the rarity with which most other ciliates become preserved under the conditions of the marine environment. The loricae of some tintinnids are easily preserved, giving them a relatively good fossil record.

形態描述

不同種的砂殼纖毛蟲的殼或胴甲的長度和口徑變化很大。殼長最大的記錄是巨擬網紋蟲（Parafavella gigantea）殼為 750 μm (Marshall, 1969)，最小的殼為極小領細殼蟲（Stenosemella perpusilla），殼長 13 μm (Hada, 1970)。同一個種中，不同海域不同個體間的長度差可達 300 μm。例如，巨擬網紋蟲的最大記錄 750 μm (Marshall, 1969)，但是大多為 337-576 μm (Campbell, 1942)。同一種中不同個體殼的大小可能是年齡的標誌，小殼是幼體，大殼則是成熟的個體 (Gold and Morales, 1976b)。

They were among the many planktonic microorganisms featured in Ernst's 恩斯特・海克爾's classic work popularizing the beauty of the natural world "Art forms in Nature" (自然界的藝術形態).

如同其他原生生物，砂殼纖毛蟲屬於一種複雜的單細胞真核生物。牠們是丁丁是異養水生生物（heterotrophic aquatic organisms）， 以能進行光合作用的藻類和細菌為食，均為 體長介乎 20 到 200 微米的微型浮游生物。Tintinnids are found in marine and freshwaters. However, they are most common in salt water and are usually present in concentrations of about 100 a liter but can reach abundances of several thousand per 公升. Characteristics of their lorica, or shells, are classically used to distinguish the roughly 1000 species described. However, in recent years application of histological and molecular techniques have led to many taxonomic revisions.

Many species appear to have wide distributions (for example from the 切薩皮克灣 to 新喀裡多尼亞) while others are restricted to certain areas, such as arctic waters or coastal seas. Nonetheless, in any given locale dozens of species can be found. Like other members of the microzooplankton (such as ciliates, heterotrophic 雙鞭毛蟲門 s, s, etc.), tintinnids are a vital link in aquatic food chains as they are the ' 食草動物 s' of the plankton. They feed on 浮游植物 (algae and cyanobacteria) and in turn act as food for larger organisms such as 橈腳類 s (small 甲殼亞門 s) and larval fish.

The color image on the right is a specimen of Dictyocysta mitra from the Bay of 濱海自由城 in the Mediterranean Sea. The hair-like projections pointing out of the top of the shell are the cilia of the cell. The cilia generate a water flow across the mouth of the cell, bringing food into contact and move the tintinnid. Their swimming pattern is rather 'jumpy'- or dancing- they are part of the 'choreotrichs' which means dancing hairs from their swimming behaviour and cilia.

分類

丁丁蟲亞目包括下列各個科：

Family Ascampbelliellidae
Family Codonellidae
Family Codonellopsidae
Family Cyttarocylididae
Family Dictyocystidae
Family Epiplocylididae
Family Metacylididae
Family Nolaclusiliidae
Family Petalotrichidae
Family Ptychocylididae
Family Rhabdonellidae
Family Tintinnida incertae sedis
Family Tintinnidae
Family Tintinnidiidae
Family Undellidae
Family Undellidae incertae sedis
Family Xystonellidae

異名：

Coxliellidae 被認為是 Metacylididae 的異名，因為其其模式屬 Coxliella 被認為是 nomen inquirendum，即「尚在研究是否合適的命名」。

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