Heterotremata is a clade of crabs, comprising those crabs in which the genital openings are on the sternum in females, but on the legs in males. It comprises 68 families in 28 superfamilies.[1]
Heterotremata | |
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Xantho poressa (Xanthoidea: Xanthidae) | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Malacostraca |
Order: | Decapoda |
Suborder: | Pleocyemata |
Infraorder: | Brachyura |
Section: | Eubrachyura |
Subsection: | Heterotremata Guinot, 1977 |
Superfamilies | |
See text |
Heterotremata is the sister group to Thoracotremata 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 |
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The internal relationships within Heterotremata 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]
Heterotremata |
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However, recent studies have found the following superfamilies and families to not be monophyletic, but rather paraphyletic or polyphyletic:[2][3]