磷沙蚕科

磷沙蚕科
科学分类
界：	动物界 Animalia
门：	环节动物门 Annelida
纲：	多毛纲 Polychaeta
亚纲：	隐居亚纲 Sedentaria
科：	磷沙蚕科 Chaetopteridae

磷沙蚕科（学名：Chaetopteridae）是多毛纲隐居亚纲之下的一个海洋滤食蠕虫科，终生管栖，居住在海底沉积物或硬基层内挖掘的垂直或U形栖管内。虫体本身亦已高度适应于在它们分泌的栖管内生活：栖管的两端开口露出泥沙表面，而其身体分为三段，负责身体的不同功能（异律分节）。这三段为：

• 前段：背腹扁平，有9对圆锥形突起,围口节为一宽领状,背面有1对围口触手,口前叶退化；
• 中段由5节组成,第一节两侧有1对大的翼状突起；
• 后段约有30多个体节组成。

另外，疣足的腹须转变为吸盘，用以附着在管壁上；而其背须则转变成肌肉质的鼓动器，能鼓动水流，以获得食料和氧气。

Inside the tube the animal is segmented and regionally specialized, with highly modified appendages on different segments for cutting the tunnel, feeding, or creating suction for the flow of water through the tube home. The modified segments for feeding are on the 12th segment from the head for members of this family.

该管是分段和区域专业的，具有高度修改的附件用于切割隧道，给水或通过管道产生水流。 饲养改良的部分在这个家族的成员头上的第12段。

若虫

本科物种的若虫在所有多毛纲的物种来说体型最大，从 0.4 mm 到 2.5 mm不等；有纪录最大的长达 12 mm; the late stage of an unknown phyllodicid species). Chaetopteridae larvae are barrel-like in form with one to two ciliated bands at the midsection. They also have a large buccal funnel. These larvae are often long lived and effectively disseminate, although are constrained geographically to their appropriate ranges for successful adult growth. The most common form of larval developmental plan for polychaetes is the trochophore larvae. The trochophore will add segments sequentially from a posterior growth zone to produce a nectochaete larva. Chaetopterus represents a distinct deviation from this general design. At no point in larval growth stages does the metatrochophore take on the clearly segmented form of the typical nectochaete larva. The 15 segments of Chaetopterus are formed by subdivision of existing anlage.

Feeding

The Chaetopteridae have several genera with peculiar and well-studied filter feeding mechanisms. The genera Chaetopterus, Mesochaetopterus, and Spiochaetopterus feed using a thin mucus net suspended across the upper portion of their tube. The mucus net is secreted by a hooplike structure called the aliform notopodia arch. The net can grow at a rate as great as one millimeter per second as water currents generated by the notopodial fans pass plankton through the net. When the net grows large enough it contacts the ciliated cup, which rolls up the net. When the roll becomes large the net is disconnected from the aliform notopodia and is rolled into a ball before the ciliated mid-dorsal groove transports it to the mouth.

分类

本科物种包括下列三个属：

• 磷沙蚕属 Chaetopterus
• Phyllochaetopterus属
• Spiochaetopterus属

另外，分子生物学研究表明，本分类单元是环节动物的基底，位处星虫动物门之下。

外部链接

• Some relevant images of adult Chaetopteridae （页面存档备份，存于互联网档案馆）