Heterotremata
Clade of crabs
From Wikipedia, the free encyclopedia
Heterotremata (from Ancient Greek ἕτερος (héteros), meaning "different", and τρῆμα (trêma), meaning "hole") 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 | |
|---|---|
| |
| Xantho poressa (Xanthoidea: Xanthidae) | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Brachyura |
| Section: | Eubrachyura |
| Subsection: | Heterotremata Guinot, 1977 |
| Superfamilies | |
|
See text | |
Evolution
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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Superfamilies
- Aethroidea
- Bellioidea
- Bythograeoidea
- Calappoidea
- Cancroidea
- Carpilioidea
- Cheiragonoidea
- Corystoidea
- Dairoidea
- Dorippoidea
- Eriphioidea
- Gecarcinucoidea
- Goneplacoidea
- Hexapodoidea
- Leucosioidea
- Majoidea
- Orithyioidea
- Palicoidea
- Parthenopoidea
- Pilumnoidea
- Portunoidea
- Potamoidea
- Pseudothelphusoidea
- Pseudozioidea
- Retroplumoidea
- Trapezioidea
- Trichodactyloidea
- Xanthoidea
However, recent studies have found the following superfamilies and families to not be monophyletic, but rather paraphyletic or polyphyletic:[2][3]
- The superfamilies Calappoidea, Eriphioidea, and Goneplacoidea are polyphyletic
- The superfamily Potamoidea is paraphyletic with respect to Gecarcinucoidea, which is resolved by placing Gecarcinucidae within Potamoidea
- The Majoidea families Epialtidae, Mithracidae and Majidae are polyphyletic with respect to each other
- The Xanthoidea family Xanthidae is paraphyletic with respect to Panopeidae
