Raninidae

Raninidae Temporal range: Albian–Recent PreЄ Є O S D C P T J K Pg N
Lyreidus tridentatus
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Order:	Decapoda
Infraorder:	Brachyura
Section:	Raninoida
Superfamily:	Raninoidea
Family:	Raninidae De Haan, 1839
Genera
See text

Raninidae is a family of unusual crabs, sometimes known as "frog crabs", on account of their frog-like appearance. They are taken by most scientists to be quite primitive among the true crabs. They closely resemble the (unrelated) mole crabs, due to parallel evolution or convergent evolution. In both groups, the claws are modified into tools for digging, and the body is a rounded shape that is easy to bury in sand. Unlike most other true crabs, the abdomens of raninids are not curled under the cephalothorax.

The earliest fossil attributable to the family Raninidae dates from the Albian.^[1]

Taxonomy

Ranina ranina

The 46 extant and 183 extinct species in the famila Raninidae are arranged among 34 genera in 7 subfamilies:^[2]

Subfamily Cyrthorhininae Cyrtorhina Subfamily Lyreidinae †Hemioon †Lyreidina Lyreidus Lysirude †Rogueus †Macroacaena †Tribolocephalus Subfamily Notopodinae Cosmonotus †Eumorphocorystes †Lianira †Lovarina Notopus †Ranidina †Raniliformis Ranilia Umalia Subfamily Ranininae †Lophoranina Ranina †Raninella

Subfamily Raninoidinae †Bicornisranina †Cenocorystes †Cristafrons Notopoides Notosceles †Quaslaeviranina Raninoides Subfamily Palaeocorystinae †Cretacoranina †Eucorystes †Heus †Notopocorystes Subfamily Symethinae Symethis incertae sedis †Araripecarcinus †Sabahranina

References

1. Andreas Brösing (2008). "A reconstruction of an evolutionary scenario for the Brachyura (Decapoda) in the context of the Cretaceous–Tertiary boundary" (PDF). Crustaceana 81 (3): 271–287. doi:10.1163/156854008783564091.
2. Sammy De Grave, N. Dean Pentcheff, Shane T. Ahyong; et al. (2009). "A classification of living and fossil genera of decapod crustaceans" (PDF). Raffles Bulletin of Zoology. Suppl. 21: 1–109.