Stimpson, 1860
Diagnosis:
Rostrum very inconspicuous, a wide angle in the anterior margin of the carapace, overreached by the full length of the eyes.
The eyes bluntly triangular or quadrangular. Antennal angle likewise inconspicuously triangular, without antennal spine. Antennular peduncle distinctly longer than the antennal peduncle, reaching beyond it with more than half the last segment.
Third maxilliped with the ischium and merus expanded to form a distinct operculum. Large chela of adult male with a small concavity in the anterior margin of the palm above the fixed finger. Carpus somewhat longer than the palm and longer than high. Merus with a distinct process in the basal half of the lower margin; this process produced forward, ending in a narrowing rounded top. In the females this process is reduced to a small triangular tooth. Telson quadrangular slightly shorter than the uropods. The endopod of the uropod broadly triangular with rounded corners.
Type:
Type locality of C. petalura: "In portu "Simoda" Japoniae" (=Shimoda, Izu peninsula, Shizuoka prefecture, Honshu, Japan). Type material probably lost in the 1871 Chicago fire.
Type locality of C. gigas japonica and C. g. eoa (the latter being a replacement name for the preoccupied former): "Japanisches Meer, Meerbusen Peter der Grosse, Bucht Patrokl" ( = Patrokol Bight (Bukhta Patrokl) in Peter the Great Bay (Zaliv Petra Velikogo)), S.E. Siberian coast of Sea of Japan. Holotype male in Hydrology Institute, Leningrad, USSR.
Geographical Distribution:
S.E. Siberia, N. China, Japan.
Habitat and Biology:
On sand or mud flats of coasts that are more exposed than those where C. japonica is found. The species makes its burrows in the soft substrate.
Size:
The total body length is 1.5 to 5 cm (males), 1 to 5 cm (females), 2.8 to 5 cm (ovigerous females).
Interest to Fisheries:
The only reference known to me, concerning this aspect of the species, is its inclusion in Liu's (1955: 65, pl. 23 fig. 6-9) "Economic shrimps and prawns of North China". It is most likely used as fish bait.