Hemitaeniochromis Hemitaeniochromis Hemitaeniochromis is a small genus of cichlid fishes endemic to Lake Malawi in east Africa. The genus is distinguished from other genera of Lake Malawi Haplochromini by details of its melanic color pattern and by its dentition. The color pattern includes (1) a midlateral horizontal stripe starting at least an eye length behind the operculum, this stripe broken into separate spots at least on its front half, more nearly continuous on its rear half, extending to the end of the caudal peduncle; (2) a second (supralateral) stripe above the midlateral one that is only on the front part of
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