Xylopaguridae

Xylopaguridae are a family of hermit crabs of the order Decapoda. It was erected in 2016 to accommodate one new genus, Prexylopagurus, and three existing genera that had previously been placed in Paguridae. They occur in the Atlantic, Indian, and Pacific Oceans.

Some sources do not recognize Xylopaguridae and list the species and genera that were transferred to it under their original family, Paguridae.

Evolution
The oldest record of the family is Paguritergites yvonnecooleae, the only known species of its genus, from the upper Albian (mid-Cretaceous) of northwest Spain. The family appears to have evolved in the Tethys Ocean.

Description and ecology
Xylopagurids have an elongated, subcylindrical carapace. They are adapted to live in cavities such as hollow pieces of bamboo and driftwood, or in empty polychaete tubes. Unlike typical hermit crabs, they inhabit open-ended cavities which they enter head-first. The posterior opening of the cavity is blocked by a strongly calcified portion of the abdomen, whereas a massive, strongly armed right cheliped protects the anterior opening.

Xylopagurids occur from shallow waters to depths of several hundreds of meters, the record being Prexylopagurus caledonicus dredged from a depth of 591 metres.

Genera
There are four genera, two of which are extant: