Common name: none
Latin Origins: Concave
Distribution:Eastern Africa, China, Japan, Malaysia, Taiwan, Micronesian, Polynesia, India
Habitat: Mangrove forests are the preferred home of the cavipes species.
Ecology: Mostly nocturnal, supratidal, terrestrial, shelters in mangrove trees, in most regions prefers sea water in it's shell, except colonies in Quirimba who are reported to prefer fresh water. 1 Feed at lowtide.1 Shield longer than broad; rostrum triangular. Ocular peduncles half shield length or slightly less, corneas only faintly dilated; ocular acicles each with small submarginal spine. Antennular and antennal peduncles overreaching ocular peduncles. Chelipeds grossly unequal, both provided with numerous tufts of short or moderately short setae, often concealing armature, palms and carpi also with numerous capsulate setae on dorsal and lateral surfaces; dorsomesial and dorsolateral margins of palm of right cheliped each with row of small spines, dorsal surface with scattered small, often capsulate spines, one more prominent in midline; carpus with row of prominent spines on dorsomesial margin, dorsal surface with scattered capsulate tubercles and small spines, dorsolateral margin not delimited. Left cheliped with chela elevated in midline but not forming distinct ridge, but armed with row of moderately large spines extending onto proximal half of fixed finger, dorsolateral surface with numerous capsulate tubercles, dorsomesial surface with scattered small spines; dorsomesial margin of carpus with row of large spines, dorsolateral margin only weakly delimited by few small spines. Ambulatory legs similar; dactyls very slightly shorter to somewhat longer than propodi, ventral margins each with row of 7–10 prominent corneous spines; propodi unarmed but with transverse rows of long setae; carpi each with dorsodistal spine and tufts of long plumose setae. Telson with posterior lobes separated by small median cleft; terminal margins almost straight to very slightly concave, each with row of small spines, interspersed with minute spinules.
Characteristics: Prefers to climb and shelter in mangrove trees,where it also will use water in holes to replenish shell water and shell swap, up to 30 individual hermit crabs have been witnessed congregating together in the same hole. 1 Has been viewed cannabilizing other cavipes and rugosus. 1 No stitch marks on large claw. Large crabs regularly immerse themselves in sea water. 1 Preferred shells: thinoclavis sinesis, thais svigny, volema paradiscia, turbo cornoatus, and especially terebralia palustris and general tall spired shells.2 Feed on human faeces, fruit, rotting vegetation, dead fish and bird droppings.3 Has been until mid 2007, misidentified. Coenobita violascens were being called cavipes. Eyes are elongated and the stalks are mostly black. Bottom section of second antenna are orange. Third left leg is armored. Size: Maximum reported shield length 16.0 mm. Coloration–Shield mottled brown and blue-gray. Ocular peduncles generally white with broad dark band at midlength and dark brown patch and tinge of blue at base of cornea. Distal two segments of antennular peduncles each with broad band of reddish-brown and tinge of blue distally. Fifth segment of antennal peduncle transparent with brown mesial and lateral stripe. Chelipeds generally brown with capsulate tubercles gray to blue-gray and spines brown to yellowish-brown; meri brown with spots of blue-gray. Ambulatory legs with dactyls brown proximally, white distally; propodi reddish-brown proximally, blue-gray distally; carpi brown to reddish-brown, spotted with blue-gray; meri each brown proximally with large dorsal white patch and blue-gray distally with large dorsal brown patch. Body color is basically brown with large pincher in a lighter color.
References: 1 David K. A. Barnes on Tree Migration 1997 2 David K.A. Barnes on Shell Characteristics and Utilization 1999 3 David K.A. Barnes on locally important food source 1997
Eupagurus japonicus Stimpson, 1858: 250; Stimpson, 1907: 226, pl. 25, fig. 2; Nakazawa 1927: 203, fig. 1045; Nakazawa, 1947: 739, fig. 2138; Nakazawa, 1949: 737, fig. 2132; Kamita 1955: 34, fig. 13. Eupagurus barbatus Ortmann, 1892: 311. Pagurus japonicus – Miyake 1960: 90, pl. 45, fig. 4; Kim 1963: 300, fig. 18; Miyake, 1965: 648, fig. 1096; Suzuki 1971: 97, pl. 34, fig. 3; Kim, 1973: 239, fig. 58, pl. 71, fig. 38; Miyake, 1975: 323, pl. 115, figs. 7, 10; Miyake, 1978: 94 (in part), fig. 35, pl. 2, fig. 2; Miyake, 1982: 125, pl. 42, fig. 1; Takeda, 1982: 68, fig. 202; Takeda, 1986: 124, unnumbered fig.; Yu & Foo, 1991: 64, unnumbered fig.; Takeda, 1994: 228, fig. 3; Asakura, 1995: 362, pl. 97, fig. 3; Kobayashi, 2000: 186, unnumbered fig.; Minemizu,2000, 149, unnumbered fig.; Park & Choi, 2001: 138, unnumbered fig.; Komai, 2003: 379, figs. 1–5. Pagurus barbatus – Miyake, 1978: 105, fig. 41. Not Eupagurus japonicus? – Miers, 1880: 375, pl. 14, figs. 6, 7 [= Pagurus hirtimanus Miers, 1880]. Not Eupagurus barbatus – Balss, 1913: 55 [= Pagurus similis (Ortmann, 1892)]. Not Eupagurus japonicus – Ortmann, 1892: 309, pl. 12. fig. 16 [= Pagurus rubrior Komai, 2003]