Morphology of Cyprid Attachment Organs Compared Across Disparate Barnacle Taxa: Does It Relate to Habitat?
Morphology of Cyprid Attachment Organs Compared Across Disparate Barnacle Taxa: Does It Relate to Habitat?
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DOI：
10.1086/690092
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发表时间：
2016-10-01
影响因子：
1.6
通讯作者：
Hoeg, Jens T.
中科院分区：
文献类型：
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作者：
Al-Yahya, Hamad;Chen, Hsi-Nien;Hoeg, Jens T.
本研究采用形态测量分析比较的第三触角段，也称为附着器官，在Cyprid幼虫的蔓足类物种代表了不同的分类组的结构。其目的是调查的程度形态变化的多样性的栖息地，解决基质，和生活方式中发现的蔓足类。在所有的Cyprids的第三节具有一个平坦的表面（附着盘）覆盖着小的表皮绒毛，被认为是在粘附功能。分析的参数是这个盘相对于触角的长轴的角度，它的形状（轮廓），表皮绒毛的密度，和包围盘的表皮结构的类型。研究的10个物种来自大多数主要的蔓足类，包括栖息在硬底的浅水形式（Capitulum mitella，Pollanes pollanes，Semibalanus balanoides，Austrominius modestus，Megabalanus rosa），亚沿岸形式（Verruca stroemia，Scalpellum scarpellum），附着在活的软组织上的表生形式（Balanus spongicola，Savigalus crenatum）和寄生虫（Peltogaster paguri）。在物种之间发现了显着的结构变异，但由于有限的分类单元采样，目前还不清楚是否与生态因素或系统发育关系的差异。花盘周边由一系列长而薄的表皮边缘（=帆）或一些低但非常宽的表皮瓣（=裙）保护。帆（在所有岩石海岸的物种）或裙子（所有其他物种）的附件盘周围的存在是唯一的参数，明确与栖息地。第三触角节段的形状从具有面向远端的附接盘的对称钟形变化到在侧视图中伸长的节段，其中具有非常倾斜的腹侧盘表面，腹侧盘表面具有椭圆形盘轮廓。钟形可能是最常见的形式从岩石海岸，但在我们的测试形态参数只有Scalpellum scalpellum（sublittoral），Savigalus crenatum（珊瑚中的epiobiotic），和Peltogaster paguri（寄生）的形状，显着不同于其他物种。附着盘上的绒毛密度差异显著，但也没有表现出明确的相关性与基质或栖息地。附着器官的结构显然是最多变的功能，在蔓足类。为了评估附着器官结构与栖息地、定居基质和生活方式的相关程度，未来的研究应该在扩大的数据集上采用更精细的统计分析，增加分类单元采样和更多方面的生态变量定义。
This study used morphometric analyses to compare the structure of the third antennular segment, also called the attachment organ, in cyprid larvae from cirripede species representing a diverse set of taxonomic groups. The aim was to investigate the degree of morphological variation in view of the diversity of habitats, settlement substrata, and modes of life found in the Cirripedia. In all cyprids the third segment features a flat surface (the attachment disc) covered with small cuticular villi thought to function in adhesion. The parameters analyzed were the angle of this disc relative to the long axis of the antennule, its shape (outline), the density of cuticular villi, and the type of cuticular structure encircling the disc. The 10 species studied came from most major groups of cirripedes, and comprised shallow-water forms inhabiting hard bottoms (Capitulum mitella, Pollicipes pollicipes, Semibalanus balanoides, Austrominius modestus, Megabalanus rosa), sublittoral forms (Verruca stroemia, Scalpellum scalpellum), epibiotic forms settling on live, soft tissues (Balanus spongicola, Savignium crenatum), and a parasite (Peltogaster paguri). Significant structural variation was found among the species, but due to limited taxon sampling it was unclear whether the differences relate to ecological factors or phylogenetic affiliation. The disc perimeter is guarded by either a series of long and thin cuticular fringes overreaching the rim of the disc (= a velum) or a few low, but very broad cuticular flaps (= a skirt). The presence of a velum (in all rocky-shore species) or a skirt (all other species) around the attachment disc was the only parameter that was clearly correlated with habitat. The shape of the third antennular segment varied from a symmetrical bell shape with a distally facing attachment disc having a circular disc outline, to segments that were elongated in side view, with a very tilted ventral disc surface having an elliptical disc outline. The bell shape may be most common in forms from rocky shores, but in our test of morphometric parameters only Scalpellum scalpellum (sublittoral), Savignium crenatum (epibiotic in corals), and Peltogaster paguri (parasitic) had shapes that differed significantly from the other species. The density of villi on the attachment disc varied significantly, but also showed no clear-cut correlation with substratum or habitat. Attachment organ structure is clearly the most variable feature in cirripede cyprids. To evaluate the degree to which attachment organ structure is correlated with habitat, settlement substratum, and mode of life, future studies should employ a more refined statistical analysis on an enlarged dataset, with much increased taxon sampling and a more multifaceted definition of ecological variables.