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Temporal range: Pliensbachian
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Decapoda
Infraorder: Anomura
Superfamily: Eocarcinoidea
Family: Eocarcinidae
Withers, 1932
Genus: Eocarcinus
Withers, 1932
Species: E. praecursor
Binomial name
Eocarcinus praecursor
Withers, 1932

Eocarcinus praecursor is a Jurassic species of decapod crustacean, sufficiently distinct from its relatives to be placed in its own family (Eocarcinidae).[1] Once considered the oldest true crab, it is now considered to be an early member of the Anomura.


It lived during the Pliensbachian age (Lower Jurassic),[2] and has been found in rocks at two sites in the United KingdomMickelton Tunnel (near Aston Magna), Gloucestershire and Runswick Bay, Yorkshire.[3]


In many of its characters, it represents a transitional stage between the Glypheoidea and the Middle Jurassic crabs in the Prosopidae.[2] Since its ancestors were long-tailed decapods, and its successors were short-tailed crabs, Eocarcinus has been described as "the lobster who decided to become a crab".[4] Previously considered to be the oldest known true crab, a 2010 revision concluded that Eocarcinus could not be accommodated among the Brachyura, and was instead transferred to the Anomura.[5]


  1. ^ Sammy De Grave; N. Dean Pentcheff; Shane T. Ahyong; et al. (2009). "A classification of living and fossil genera of decapod crustaceans" (PDF). Raffles Bulletin of Zoology. Suppl. 21: 1–109. Archived from the original (PDF) on 2011-06-06. 
  2. ^ a b M. Krobicki; M. Zaton (2008). "Middle and Late Jurassic roots of brachyuran crabs: Palaeoenvironmental distribution during their early evolution". Palaeogeography, Palaeoclimatology, Palaeoecology. 263 (1–2): 30–43. doi:10.1016/j.palaeo.2008.01.025. 
  3. ^ Danièle Guinot; Marcos Tavares (2001). "Une nouvelle famille de Crabes du Crétacé, et la notion de Podotremata Guinot, 1977 (Crustacea, Decapoda, Brachyura)" (PDF). Zoosystema. 23 (3): 507–546. 
  4. ^ Anonymous (1932). "The Royal Society Conversazione". British Medical Journal. 1 (3724): 946–947. doi:10.1136/bmj.1.3724.944.  JSTOR: 1st page, 2nd page
  5. ^ Rodney M. Feldmann; Carrie E. Schweitzer (2010). "Is Eocarcinus Withers, 1932, a basal brachyuran?". Journal of Crustacean Biology. 30 (2): 241–250. doi:10.1651/09-3230.1.