# 棘魚綱[编辑]

| †棘魚綱 化石时期：早志留紀–二疊紀末期
 |
| --- |
|  |
| 科学分类  |
| 界： | 动物界 Animalia |
| 门： | 脊索动物门 Chordata |
| 演化支： | 嗅球類 Olfactores |
| 亚门： | 脊椎动物亚门 Vertebrata |
| 下门： | 有颌下门 Gnathostomata |
| 演化支： | 真有颌类 Eugnathostomata |
| 並系群： | **†棘魚綱 **Acanthodii Owen, 1846 |
| 目
 |
| * †柵棘魚目 Climatiiformes
* †銼棘魚目 Ischnacanthiformes
* †棘魚目 Acanthodiformes
* †双棘鱼目 Diplacanthiformes
 |

**棘魚綱**（學名：Acanthodii）是一類早已絕滅、僅存在於古生代的有頜魚類。有頜魚類在漫長的歷史演化中形成了兩大主支一真口魚類和板鰓類。过去，鱼类学家认为，棘魚類和硬骨魚類共同組成了真口魚類，牠們有著共同的祖先，在真口魚類中代表了兩條獨立的進化路線，然而，近年的研究发现棘鱼纲更接近传统定义上的软骨鱼纲，属于软骨鱼幹群，为并系群。来自贵州石阡大约4.39亿年前的新塑梵净山鱼（*Fanjingshania renovata*）是迄今最古老的具有关联身体构造的棘鱼属种，指示软骨鱼类干群在志留纪兰多维列世就已经演化出典型的栅棘鱼形态。同层位的双列黔齿鱼（*Qianodus duplicis*）也隶属软骨鱼幹群，保存了最古老的牙齿。来自中国重庆秀山大约4.36亿年前的蠕纹沈氏棘鱼（*Shenacanthus vermiformis*）是迄今所知最早的保存完好的软骨鱼，确证了鲨鱼是从“披盔戴甲”的祖先演化而来。

## 形态

同其他所有的原始有頜魚類一樣，棘魚具有偶鰭，耳內有三個半規管，腦顱和咽顱是分開的兩部分，鰓長在鰓弓的外側，領是由頗弓骨骼形成的。棘魚類通常是較小的魚，長度很少超過20釐米，然而一些種類可超過兩米。棘魚具有似鲨的外形，兩對偶鰭，一個歪形尾，除了尾鰭以外，所有鰭的前方都具棘刺，這也是棘魚名字的來源。

棘魚身體披有特殊的鱉皮狀的密集鱗片，但不呈覆瓦狀排列。鱗片呈方冠狀，由緻密的齒質和骨質形成，沒有髓腔，根據這一點可以很容易地區分棘魚鱗片與花鱗魚鱗片。

棘魚綱的系統發育關係：

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  |

|  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
|  |

|  |  |
| --- | --- |
|  |
盔甲魚綱 Galeaspida  |
|  |
|  |
骨甲魚綱 Osteostraci  |
|  |

 |
|  |
|  |

|  |  |
| --- | --- |
|  |
"盾皮魚綱" Placodermi  |
|  |
|  |

|  |  |
| --- | --- |
|  |
硬骨魚  |
|  |
| 軟骨魚類總群
 |

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  |

|  |  |
| --- | --- |
|  | *Tetanopsyrus*  |
|  |
|  |

|  |  |
| --- | --- |
|  | *Nerepisacanthus* |
|  |
|  |

|  |  |
| --- | --- |
|  |
銼棘魚屬 *Ischnacanthus*  |
|  |
|  |
孔棘魚屬 *Poracanthodes* |
|  |

 |
|  |

 |
|  |
|  |

|  |  |
| --- | --- |
|  | *Culmacanthus* |
|  |
|  |

|  |  |
| --- | --- |
|  | *Uraniacanthus* |
|  |
|  |

|  |  |
| --- | --- |
|  |
雙棘魚屬 *Diplacanthus*  |
|  |
|  | *Rhadinacanthus* |
|  |

 |
|  |

 |
|  |

 |
|  |

 |
|  |
|  |

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  |

|  |  |
| --- | --- |
|  | *Cassidiceps* |
|  |
|  |

|  |  |
| --- | --- |
|  |
中棘魚屬 *Mesacanthus* |
|  |
|  |

|  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
|  |

|  |  |
| --- | --- |
|  |
洛德棘魚屬 *Lodeacanthus* |
|  |
|  | *Triazeugacanthus* |
|  |

 |
|  |
|  |

|  |  |
| --- | --- |
|  |
原中棘魚屬 *Promesacanthus* |
|  |
|  |

|  |  |
| --- | --- |
|  |
棘刺鮋屬 *Acanthodes*  |
|  |
|  |

|  |  |
| --- | --- |
|  |
掌棘魚屬 *Cheiracanthus* |
|  |
|  |
平棘魚屬 *Homalacanthus* |
|  |

 |
|  |

 |
|  |

 |
|  |

 |
|  |

 |
|  |

 |
|  |
|  |

|  |  |
| --- | --- |
|  | *Euthacanthus*  |
|  |
|  |

|  |  |
| --- | --- |
|  |
屍棘魚屬 *Ptomacanthus*  |
|  |
|  |

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  |

|  |  |
| --- | --- |
|  |
短刺棘魚屬 *Brachyacanthus* |
|  |
|  |

|  |  |
| --- | --- |
|  |
柵棘魚屬 *Climatius* |
|  |
|  |
异形鱼属 *Parexus* |
|  |
|  | *Vernicomacanthus* |
|  |

 |
|  |

 |
|  |
|  |

|  |  |
| --- | --- |
|  | *Lupopsyrus* |
|  |
|  |

|  |  |
| --- | --- |
|  | *Obtusacanthus* |
|  |
|  |

|  |  |
| --- | --- |
|  | *Kathemacanthus* |
|  |
|  |

|  |  |
| --- | --- |
|  | *Brochoadmones*  |
|  |
|  |

|  |  |
| --- | --- |
|  | *Gyracanthides*  |
|  |
|  |
軟骨魚綱 (傳統定義上) |
|  |

 |
|  |

 |
|  |

 |
|  |

 |
|  |

 |
|  |

 |
|  |

 |
|  |

 |
|  |

 |
|  |

 | "棘魚綱"
 |
|  |

 |
|  |

 |
|  |

 |
|  |