Stars which have common names often have multiple names, so the common names shown (if any) cannot be considered authoritative. Right ascension and declination are given in 2000.0 coordinates.
β Cet (Deneb Kaitos = Diphda) -- In early Arabic times, this star and Fomalhaut (a first-magnitude star to its west) were called the frogs, which is the source of the name Diphda. After Al Sufi translated ancient Greek texts into Arabic, Greek constellations replaced the Arabic ones, and this star, being on the western or "tail" side of the constellation (as shown in Bayer's map), became "the tail of the whale", or Deneb Kaitos. However, since the mid 20th century, the constellation has often been drawn with its head to the west and its tail to the east, placing "the tail of the whale" in the whale's mouth. As a result, the old Arabic name of the star has come into use again. Whether this serves any purpose save to confuse those trying to learn the name of the star is another matter, and is the reason Bayer created the designation "Beta Ceti".