Thoracotremata
Clade of crabs
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Thoracotremata is a clade of crabs, comprising those crabs in which the genital openings in both sexes are on the sternum, rather than on the legs. It comprises 17 families in four superfamilies .[1]
| Thoracotremata | |
|---|---|
| |
| Leptograpsus variegatus, Grapsidae | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Clade: | Pancrustacea |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Brachyura |
| Section: | Eubrachyura |
| Subsection: | Thoracotremata Guinot, 1977 |
| Families | |
|
See text | |
Evolution
Thoracotremata is the sister group to Heterotremata within the clade Eubrachyura, having diverged during the Cretaceous period. Eubrachyura itself is a subset of the larger clade Brachyura, which consists of all "true crabs". A summary of the high-level internal relationships within Brachyura can be shown in the cladogram below:[2][3]
| Brachyura |
| ||||||||||||||||||
The internal relationships within Thoracotremata are less certain, with many of the superfamilies found to be invalid. The proposed cladogram below is from analysis by Tsang et al, 2014:[2]
Superfamilies and families
However, recent studies have found the superfamilies Grapsoidea and Ocypodoidea to be polyphyletic and invalid.[2][3]
