Calvactaea

{{Short description|Genus of crabs}}

{{Speciesbox

| image =

| image_caption =

| genus = Calvactaea

| parent_authority = Ward, 1933

| species = tumida

| authority = Ward, 1933

}}

Calvactaea tumida is a species of crabs in the family Xanthidae, the only species in the genus Calvactaea.{{cite journal |last1=Ng |first1=Peter K. L. |last2=Guinot |first2=Danièle |last3=Davie |first3=Peter J. F. |date=January 2008 |title=Systema Brachyurorum: Part I. An annotated checklist of extant Brachyuran crabs of the world |url=https://lkcnhm.nus.edu.sg/wp-content/uploads/sites/10/app/uploads/2017/04/s17rbz.pdf |url-status=live |journal=Raffles Bulletin of Zoology |volume=17 |pages=1–286 |archive-url=https://web.archive.org/web/20110606061453/http://rmbr.nus.edu.sg/rbz/biblio/s17/s17rbz.pdf |archive-date=6 June 2011 |access-date=8 June 2011 |via=the National University of Singapore}}{{cite WoRMS|last=Ahyong|first=Shane T.|author-link=Shane T. Ahyong|year=2024|title=Calvactaea Ward, 1933|id=439936|access-date=29 September 2024}}

Found primarily off the coast of New South Wales, Australia, as well as, Sri Lanka, China, Taiwan, and Japan.[http://species-identification.org/species.php?species_group=crabs_of_japan&id=1193 Marine Species Identification List]