Pethia didi markings rather than one. Pethia didi Pethia didi is a species of cyprinid fish which has only been recorded in the vicinity of Myitkyina and Indawgyi Lake in the north of Myanmar. This is a small fish which can reach a length of SL. It is generally brownish with a dark vertical bar just behind the operculum and a round dark blotch on the caudal peduncle. The species "P. tiantian" – with a range close to "P. didi" – is similarly marked, but "P. didi" can be distinguished by its truncated lateral line, deeper body and longer dorsal fin, with
Operculum (fish) over time. The fossil record of the threespine stickleback provide the ancestral shapes of the operculum bone. Overall, the operculum bone became more triangular in shape and thicker in size over time. Genes that are essential in the development of the opercular series is the Eda and Pitx1 genes.These genes are known to be a part of the development and loss of armor plates in gnathostomes. The Endothelin1 pathway is thought to be associated with the development of the operculum bone since it regulates dorsal-ventral patterning of the hyomandibular region. Mutations in Edn1-pathway in zebrafish are known to lead to