Abstract
The genus Miosesarma Karasawa (Decapoda : Brachyura : Grapsidae) known from the Miocene of Japan is redefined. A phylogenetic analysis of 22 genera of the family Grapsidae MacLeay is provided based on 41 adult morphological characters. A single tree is produced (length=85, CI=0.565, RI=0.807, RC=0.456). The analysis supports the monophyly of the subfamilies Plagusiinae Dana, Grapsinae MacLeay and Varuninae H. Milne Edwards. The analysis suggests that the Sesarminae Dana is polyphyletic and that Cyclograpsus H. Milne Edwards, Helice De Haan, Metaplax H. Milne Edwards and Miosesarma are derived as sister taxa to varunines. The tribe Cyclograpscaea H. Milne Edwards is treated as a subfamily Cyclograpsinae (nomen. transl.) consisting of Cyclograpsus (type genus), Helice, Heterograpsus Campbell and Griffin, Metaplax, Miosesarma and Paragrapsus H. Milne Edwards, which were previously placed within the Sesarminae. within the Grapsidae, the Varuninae and Cyclograpsinae are sister groups nested as the most derived clade, followed by the Sesarminae, Grapsinae, and the most basal Plagusiinae. Five subfamilies within the Grapsidae are redefined based on the phylogenetic analysis. During a review of fossil records of the Grapsidae, 25 species, 17 genera and four subfamilies are recognized as fossils. Maingrapsus Tessier et al., Palaeograpsus Bittner, and Telphusograpsus Lorenthey, known from the European Eocene, are referred to the family Goneplacidae H. Milne Edwards and Sculptoplax Muller and Collins from the Eocene of Hungary is referred to the Xanthidae MacLeay. Fossil grapsids exhibiting the dorsal carapace only can not confidently be referred to subfamilies.
