Xylopaguridae

Xylopaguridae are a family of hermit crabs of the order Decapoda.^[2][3] 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.^[1]

Xylopaguridae Temporal range: Upper Albian–recent, 100.5–0 Ma[1] PreꞒ Ꞓ O S D C P T J K Pg N
Xylopagurus rectus
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Malacostraca
Order:	Decapoda
Suborder:	Pleocyemata
Infraorder:	Anomura
Superfamily:	Paguroidea
Family:	Xylopaguridae Gašparič, Fraaije, Robin & de Angeli, 2016[1]
Type genus
Xylopagurus A. Milne-Edwards, 1880

Some sources do not recognize Xylopaguridae and list the species and genera that were transferred to it under their original family, Paguridae.^[4]

Evolution

The oldest record of the family is Paguritergites yvonnecooleae,^[1] the only known species of its genus,^[5] from the upper Albian (mid-Cretaceous) of northwest Spain.^[1] The family appears to have evolved in the Tethys Ocean.^[1]

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.^[1] 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.^[6]

Xylopagurids occur from shallow waters to depths of several hundreds of meters, the record being Prexylopagurus caledonicus dredged from a depth of 591 metres.^[1]

Genera

There are four genera, two of which are extant:^[2]

• †Lessinipagurus Beschin, De Angeli, Checchi & Zarantonello, 2012
• †Paguritergites Fraaije, Artal, Van Bakel, Jagt & Klompmaker, 2013
• Prexylopagurus Gašparič, Fraaije, Robin & de Angeli, 2016
• Xylopagurus A. Milne-Edwards, 1880