Case study of the convergent evolution in the color patterns in the freshwater bivalves

• DOI: 10.1038/s41598-022-14469-3
• Publication Date: 2022-07-13T10:03:19Z
• Authors: Kaito Asato; Kentaro Nakayama; Takuya Imai
• Keywords: Convergent evolution

The class Bivalvia (phylum Mollusca) is one of the most successful at survival groups animals with diverse color patterns on their shells, and they are occasionally preserved in fossil record as residual patterns. However, freshwater bivalves could be traced only to Miocene, greatly limiting pattern evolution knowledge. We present Cretaceous belonging three extinct families order Trigoniida (hereinafter Kitadani Freshwater Bivalves) from Japan, which oldest second molluscan Bivalves consists two types patterns: stripes along growth lines radial rays tapered toward umbo, resemble that colored bands extant bivalves. This resemblance between species indicates represent convergent Unionida. To explain this evolution, we advocate conceivable factors: phylogenetic constraints, monotonous habitats typical ecosystems, predation pressure by visual predators sediments.