The Chemoreceptive Lattice Organs in Cypris Larvae Develop from Naupliar Setae (Thecostraca: Cirripedia, Ascothoracida and Facetotecta)
The Chemoreceptive Lattice Organs in Cypris Larvae Develop from Naupliar Setae (Thecostraca: Cirripedia, Ascothoracida and Facetotecta)
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鲤鱼幼虫的化学感受性格子器官由无节幼体刚毛发育而来（囊壳类：Ciripedia、Ascothoracida 和 Facetotecta）
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发表时间：
2003
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通讯作者：
G. Kolbasov
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作者：
A. Rybakov;J. Høeg;P. Jensen;G. Kolbasov
摘要 格子器官是仅在甲壳纲 Thecostraca（Facetotecta、Ascothoracida、Cirripedia）中发现的特殊化学感受器。在这些类群中，有五对出现在终末幼虫龄（y-cyprid、ascothoracid larva、cyprid）的头盾（甲壳）中，这是定居阶段。格子器官代表了壳甲纲的自体变体，但它们的进化起源和其他甲壳纲中可能的同源物仍然不清楚。我们使用扫描电子显微镜来描述一种 Ascothoracida 物种、一种 Facetotecta 物种以及几种 Cirripedia Thoracica、Acrothoracica 和 Rhizocephala 物种晚期无节幼体的头盾的设置模式。无节幼体头盾总是带有两对位于中线附近的刚毛。这些刚毛中的每一个都带有一个孔，位置、结构和个体发育证据表明，这些刚毛在所有被检查的物种中都是同源的，并且它们代表了随后的幼虫阶段的两对前格器官的前体，即Ascothoracid幼虫（Ascothoracida）、y-cyprid（Facetotecta）和cyprid（Cirripedia）。这使我们推断，格子器官是所有甲壳纲动物中修饰程度最高的感器之一，并且在大多数情况下它们已经失去了与刚毛的所有外部相似性。根头动物的无节幼体携带额外的三对刚毛，位于头盾的更靠后的位置，它们可能是后三对晶格器官的前身。所有其他被检查的物种都缺乏这些后刚毛，除了 Facetotecta 之外，它有一对位于后面的刚毛。
Abstract Lattice organs are peculiar chemoreceptors found only in the Crustacea Thecostraca (Facetotecta, Ascothoracida, Cirripedia). In these taxa, five pairs occur in the head shield (carapace) of the terminal larval instar (y-cyprid, ascothoracid larva, cyprid), which is the settlement stage. Lattice organs represent an autapomorphy for the Thecostraca but their evolutionary origin and possible homologues in other Crustacea remain obscure. We have used scanning electron microscopy to describe the setation pattern of the head shield in late nauplii of one species of Ascothoracida, one species of Facetotecta and several species of the Cirripedia Thoracica, Acrothoracica, and Rhizocephala. The naupliar head shield always carries two pairs setae situated anteriorly near the midline. Each of these setae carry a single pore, and positional, structural and ontogenetic evidence show that these setae are homologous in all the examined species and that they represent precursors of the two anterior pairs of lattice organs of the succeeding larval stage, viz., the ascothoracid larva (Ascothoracida), y-cyprid (Facetotecta), and cyprid (Cirripedia). This leads us to infer that lattice organs are among the most highly modified sensilla in all Crustacea and they have in most cases lost all external resemblance to a seta. The nauplii of the Rhizocephala carry an additional three pairs of setae situated more posteriorly on the head shield and they could be precursors of the three posterior pairs of lattice organs. All other species examined lack these posterior setae, except the Facetotecta which have one posteriorly situated pair.