Oregoniidae, Garth, 1958

GUINOT, DANIÈLE, TAVARES, MARCOS & CASTRO, PETER, 2013, Significance of the sexual openings and supplementary structures on the phylogeny of brachyuran crabs (Crustacea, Decapoda, Brachyura), with new nomina for higher-ranked podotreme taxa, Zootaxa 3665 (1), pp. 1-414 : 128

Family Oregoniidae

The male gonopore is coxal. The penis is very short and is only protected by the abdomen ( Fig. 1A ). See Monophyletic Heterotremata: Superfamily Majoidea ; Affinities between Inachoididae and Inachidae .

It should be noted Chionoecetes is known to include at least five species, with two groups based on vertical distribution: C. opilio (“snow crab”) and C. bairdi (“Tanner crab”) in shallow waters on continental shelves (see Watanabe & Marumaya 1999), C. japonicus Rathbun, 1932 (“red snow crab”), C. angulatus Rathbun, 1893 (“triangle Tanner crab”), C. tanneri Rathbun, 1893 (“grooved Tanner crab”), and C. pacificus Sakai, 1978 ( Sakai 1978, as C. japonicus pacificus ) (see Ng, Guinot & Davie 2008: 124). Recent molecular analyses of the red-snow-crab species complex have shown that C. japonicus must be synonymised with C. angulatus and corroborated that C. pacificus was “an evolutionarily independent species that should be given full species recognition as C. pacificus ” ( Azuma et al. 2011: 291, 292).

Figures

FIGURE 1. A, Anatomical relationships of penis and gonopods in Brachyura exemplified by Chionoecetes opilio (Fabricius, 1788) (Oregoniidae) (modified from Beninger et al. 1991: fig. 1C; G1 basal setae not figured); B–D, schematic representation of the dispositions of male gonopore, penis, and ejaculatory duct (indicated by dotted line) in Brachyura: B, C, perforation of P5 coxa by the ejaculatory duct: B, coxal gonopore, with penis emerging from P5 coxa (Podotremata and Heterotremata pro parte); C, coxo-sternal condition, with coxal gonopore and penis emerging at level of thoracic sternal suture 7/8 (Heterotremata pro parte); D, E, perforation of thoracic sternum by ejaculatory duct: D, sternal gonopore at the suture 7/8 level; E, sternal gonopore far from suture 7/8, in posteriormost location in relation to sternite 8. a1, abdominal somite 1; cx5, P5 coxa; g, gonopore; G1, first gonopod; G2, second gonopod; p, penis; p5, fifth pereopod; 7, 8, thoracic sternites 7, 8; 7/8, thoracic sternal suture 7/8. Scale bar: 1 mm (A).