摘要:Strata with cyanobacterial-sponge buildups of Middle to Late Oxfordian (Late Jurassic) age in the southern Polish Uplands document the earliest known members of the Pylochelidae. Two new Late Jurassic species of “symmetrical” hermit crabs, Ammopylocheles robertboreki and Jurapylocheles iwonae, are described.Anew term, the massetic region, is introduced to describe the equivalent in paguroids of the hepatic region in brachyuran carapaces, because in the former, this region does not reflect the position of the liver but rather an attachment zone of the mandibular muscles.