Biology:Thoracotremata

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Short description: Clade of crabs

Thoracotremata
Purple rock crab444.jpg
Leptograpsus variegatus, Grapsidae
Scientific classification e
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Malacostraca
Order: Decapoda
Suborder: Pleocyemata
Infraorder: Brachyura
Section: Eubrachyura
Subsection: Thoracotremata
Guinot, 1977
Families

See text

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]

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

Dromiacea

Raninoida

Cyclodorippoida

Eubrachyura

Heterotremata

Thoracotremata

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]

Thoracotremata

Pinnotheridae

Dotillidae

Percnidae

Xenograpsidae

Cryptochiridae

Ocypodidae

Glyptograpsidae

Grapsidae

Plagusiidae

Gecarcinidae

Sesarmidae

Mictyridae

Varunidae

Macrophthalmidae

Superfamilies and families

However, recent studies have found the superfamilies Grapsoidea and Ocypodoidea to be polyphyletic and invalid.[2][3]

References

  1. Sammy De Grave et al. (2009). "A classification of living and fossil genera of decapod crustaceans". Raffles Bulletin of Zoology Suppl. 21: 1–109. http://rmbr.nus.edu.sg/rbz/biblio/s21/s21rbz1-109.pdf. 
  2. 2.0 2.1 2.2 Ling Ming Tsang; Christoph D. Schubart; Shane T. Ahyong; Joelle C.Y. Lai; Eugene Y.C. Au; Tin-Yam Chan; Peter K.L. Ng; Ka Hou Chu (2014). "Evolutionary History of True Crabs (Crustacea: Decapoda: Brachyura) and the Origin of Freshwater Crabs". Molecular Biology and Evolution (Oxford University Press) 31 (5): 1173–1187. doi:10.1093/molbev/msu068. 
  3. 3.0 3.1 Wolfe, Joanna M.; Breinholt, Jesse W.; Crandall, Keith A.; Lemmon, Alan R.; Lemmon, Emily Moriarty; Timm, Laura E.; Siddall, Mark E.; Bracken-Grissom, Heather D. (24 April 2019). "A phylogenomic framework, evolutionary timeline and genomic resources for comparative studies of decapod crustaceans". Proceedings of the Royal Society B 286 (1901). doi:10.1098/rspb.2019.0079. PMID 31014217. PMC 6501934. https://royalsocietypublishing.org/doi/10.1098/rspb.2019.0079. 

Wikidata ☰ Q1813320 entry