Afrikan Nikolaevich Krishtofovich was a Soviet paleobotanist. His name be abbreviated as "Krysht." When attributing him as the author of botanical names. He was a fossil hunter specializing in Mesozoic flora. (wikipedia entry)
A crater is a circular depression likely created by an impact event. On Mars large craters are named after deceased scientists, writers and others who have contributed to the lore of Mars. Small creaters (less than 60km) are named after small towns and villages.