Comparative diversity of lamellibranch shell morphologies from the Triassic period - Collection of fossilized bivalve mollusks 插畫檔

The provided scientific illustration showcases a diverse assembly of fossilized bivalve mollusks, documenting the significant morphological radiation of "lamellibranchs" across the various marine environments of the Triassic era. The collection highlights a spectrum of shell geometries and surface ornamentations, ranging from the large, thin-shelled form with fine radial ribbing that suggests a pelagic or semi-buoyant lifestyle to robust, heavily-ribbed specimens equipped with prominent "ears" or auricles typical of bottom-dwelling filter feeders. Other figures detail shells with distinct concentric growth lines, triangular profiles, and elongated, wing-like valves adapted for specific ecological niches on the ancient seafloor. By capturing these variations in hinge structure, ribbing density, and overall symmetry, the plate serves as a technical record of the evolutionary success and anatomical specialization of bivalves during the recovery and diversification period following the end-Permian mass extinction.