Dromiacea

Dromiacea is a group of crabs, ranked as a section. It contains 240 extant and nearly 300 extinct species.^[1] Dromiacea is the most basal grouping of Brachyura crabs, diverging the earliest in the evolutionary history, around the Late Triassic or Early Jurassic. Below is a cladogram showing Dromiacea's placement within Brachyura: ^{[2] [3]}

Brachyura	Dromiacea Raninoida Cyclodorippoida Eubrachyura Heterotremata Thoracotremata

Dromiacea Temporal range: Jurassic–Recent PreꞒ Ꞓ O S D C P T J K Pg N
Dromia dormia (Dromioidea: Dromiidae) feeding on a sea urchin
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Malacostraca
Order:	Decapoda
Suborder:	Pleocyemata
Infraorder:	Brachyura
Section:	Dromiacea De Haan, 1833
Superfamilies
Dakoticancroidea † Dromioidea Glaessneropsoidea † Homolodromioidea Homoloidea

The larvae of Dromiacea resemble those of the Anomura more closely than those of other crabs.^{[citation needed]} This may simply reflect their basal position in the crab phylogeny. The superfamily Eocarcinoidea, containing Eocarcinus and Platykotta, was previously considered to be a member of the Dromiacea, but has since been transferred to the Anomura.^[4]

The fossil record of Dromiacea reaches back at least as far as the Jurassic,^[5] and, if Imocaris is indeed a member, into the Carboniferous.^[6]

Dromiacea primarily consists of two groups of superfamilies - Dromioidea and Homoloidea. See the below cladogram:^[2]

Dromiacea	Dromioidea Dromiidae (may be paraphyletic) Dynomenidae Homoloidea Homolidae (paraphyletic) Latreilliidae

Recent studies have found that some of the families may not be monophyletic, but rather paraphyletic.^[2]

• The Dromioidea family Dromiidae may be paraphyletic with respect to Dynomenidae
• The Homoloidea family Homolidae is paraphyletic with respect to Latreilliidae