Pachycheles

Reliable species-level identification within Pachycheles requires examination of cheliped morphology, specifically: pattern of carapace granulation, number and shape of teeth on the anterior margin of the carpus, and presence or absence of setae on the carpus and propodus. Molecular data (16S mtDNA and H3 nDNA sequences) support separation of closely related species. The genus shares fragmented lateral carapace walls with Neopisosoma, though the two genera are phylogenetically distinct.

Marine littoral and sublittoral environments; rocky shores in temperate zones; polychaete sandbanks. Some species occur in estuarine ecosystems.

Tropical and temperate regions of all oceans; originated in the Indo-Pacific with subsequent spread to the American continent during the early Tertiary. Documented from the southwestern Atlantic (Brazil, Argentina), southeastern South America, Sea of Japan, and southern Caribbean Sea.

• Lernaeodiscus rybakovi - parasiterhizocephalan barnacle; prevalence up to 32.3% in P. stevensii; causes feminization of male hosts
• Lernaeodiscus kasyanovi - parasiterhizocephalan barnacle; less common than L. rybakovi in P. stevensii
• Aporobopyrus muguensis - parasitebopyrid isopod; reduces growth and reproduction in P. rudis

Development includes megalopa stage; recruitment observed in fall for some species. Megalopae presence documented exclusively in spring for P. laevidactylus in southern Brazil.

Pachycheles rudis exhibits heterosexual pair bonding with size-assortative pairing; pairs show aggression toward conspecific strangers. Resident males display elevated aggression toward returning mates after separations exceeding 48 hours. Females appear dominant in stable pairs, fitting models for monogamous crustaceans.

Pachycheles pubescens harvested as food from estuarine ecosystems; subject to bacterial contamination including Vibrio, Salmonella, and Shigella, posing health risks if inadequately cooked.

• NeopisosomaShares fragmented lateral carapace walls, but phylogenetically distinct; Pachycheles is monophyletic while Neopisosoma is polyphyletic; Neopisosoma likely arose later in the Caribbean Province with distribution restricted mainly to Central America

• porcelain crab
• Anomura
• marine
• parasitism
• monogamy
• cryptic species
• molecular phylogenetics
• fisheries
• food safety

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Morphological and molecular data support the distinctiveness of Pachycheles laevidactylus Ortmann, 1892 and Pachycheles chubutensis Boschi, 1963 (Anomura, Porcellanidae)
• Description of a new species of Pachycheles (Decapoda, Anomura, Porcellanidae) from the southern Caribbean Sea
• Size-assortative Pairing and Mate Recognition by the Thickclaw Porcelain Crab Pachycheles Rudis Stimpson, 1858 (Anomura, Porcellanidae)
• Inhibition of the growth and reproduction of the porcellanid crab Pachycheles rudis by the bopyrid isopod, Aporobopyrus muguensis
• Porcellanid crab Pachycheles stevensii parasitized by rhizocephalans Lernaeodiscus spp.: population biology in the northwestern Sea of Japan
• Population structure, maturity and relative growth of the porcelain crab Pachycheles laevidactylus Ortmann, 1892 (Decapoda, Porcellanidae) in a temperate zone
• Porcelain crabs of the genera Pachycheles Stimpson and Neopisosoma Haig (Decapoda : Anomura : Porcellanidae): new premises based on molecular data and comments on phylogenetic relationships in the family
• Bacteriological assessment of crab (Pachycheles pubescens) and dog whelk (Nucella lapillus) shellfishes from mesotidal estuarine ecosystem
• Population biology of the porcelain crab Pachycheles laevidactylus Ortmann, 1892 (Anomura: Porcellanidae) in the Southwestern Atlantic