日本産ワタゾコツキヒガイ類の分類形質

概要

論文の詳細を見る
Various macroscopic and microscopic characters of propeamussiids from Japan were examined, and their taxonomic and evolutionary significances, though preliminarily, were considered. Five species of Propeamussium, two species of Polynemamussium and two species of Cyclopecten from Japanese waters surely share the diagnostic characters of the Propeamussiidae Abbott, 1954 [emend. Waller, 1978], i.e. flexible ventral margin of the right valve (owing to the single layer of prismatic calcite), discrepant surface sculpture and shell microstructure between the two valves, absence of true ctenolium even in early growth stages, and imbedded pallial myostracum in the inner layer of crossed lamellar aragonite. In some species it was clearly observed that each prism of the outer layer of the right valve is internally foliated, and that fibrous prismatic structure gradationally change into foliated structure. The morphological resemblance between Propeamussium and Amusium is only superficial because their internal ribs are genetically unrelated. Diversified species of the Propeamussiidae in the western Pacific may be important for understanding the classification and evolutionary process of the suborder Pectinina, because they seem to retain various primitive characters as "living fossils".
日本貝類学会の論文
1988-07-15