Chelonibia

Chelonibia is a genus of acorn barnacles in the family Chelonibiidae of the subphylum Crustacea.^[1] Its members are epizootic and live attached to manatees, turtles, marine molluscs, crabs and horseshoe crabs in all tropical and subtropical oceans.^[2] In a few instances, they have been found on sea snakes,^[3] alligators^[4] and inanimate substrates,^[5] but they are not found in the typical habitats of barnacles – on rocks, docks or boats.

Chelonibia Temporal range: Miocene–Recent PreꞒ Ꞓ O S D C P T J K Pg N
Chelonibia patula on the blue crab Callinectes sapidus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Thecostraca
Subclass:	Cirripedia
Order:	Balanomorpha
Superfamily:	Coronuloidea
Family:	Chelonibiidae Pilsbry, 1916
Subfamily:	Chelonibiinae
Genus:	Chelonibia Leach, 1817

Phylogeny

They appear to be the sister group to the Balanidae.^[6]

Fossils

The fossil record of Chelonibia ranges back to the Miocene.^[7]

Species

The genus contains four extant species:^[8][9]

• Chelonibia caretta (Spengler, 1790)
• Chelonibia manati Gruvel, 1903
• Chelonibia patula (Ranzani, 1818)
• Chelonibia testudinaria (Linnaeus, 1758)

Recent molecular genetic work suggests that three of the species, Chelonibia manati, C. patula and C. testudinaria, are all the same species. Depending on the host species, they develop plastically very distinct morphology but cannot be distinguished on the genetic level.^[10]

Three species are only known from the fossil record:

• Chelonibia capellini de Alessandri, 1895
• Chelonibia depressa Seguenza, 1876
• Chelonibia hemisphaerica Rothpletz & Simonelli, 1890