Grapsus adscensionis (Osbeck 1765)

Grapsus adscensionis (Osbeck, 1765)

Cancer retusus Linnaeus, 1754: [about p. 28), fig. 10 on pl.—Holm, 1957:39.

Cancer Adscensionis Osbeck, 1757:297; 1765:389; 1771:97.—Herbst, 1790:256.

Cancer adscensionis Osbeck, 1757: third [unnumbered] page of register at end of book; 1765: third [unnumbered] page of “Zweites Register” at end of book.

Cancer Grapsus Linnaeus, 1758:630 [part, only the material from “Insula Adscensionis”]; 1759:252, pl. 3: fig. 10; 1760:252, pl 3: fig. 10; 1767:1048 [part.only the material from “Insula Adscensionis”]; 1788:252, pl. 3: fig. 10.

Cancer ruricola.—Linnaeus, 1759:260, pl. 3: fig. 10; 1760:260, pl. 3: fig. 10; 1788:260, pl. 3: fig. 10. [Not Cancer ruricola Linnaeus, 1758 = Gecarcinus ruricola.]

Cancer graphicus Houttuyn, 1769:350 [only the material from “het Eiland Adscension”].

Cancer graphus Statius Müller, 1775:1016 [only the material from “der Insul Adsension”].

Grapsus Webbi H. Milne Edwards, 1853:167.

Grapsus pictus var. ocellatus Studer, 1883:14.

Grapsus maculatus.—Miers, 1886:255 [part].—Benedict, 1893:538.— Stebbing, 1914:254,265. [Not Grapsus maculatus H. Milne Edwards, 1853 = Cancer grapsus Linnaeus, 1758.]

Grapsus grapsus.—Ortmann, 1893:57.—Lenz and Strunck, 1914:283,338.— Rathbun, 1918:227, pls. 53, 54 [part].—Chace, 1966:640.—Monod, 1956:407, fig. 561.—Chace and Manning, 1972:3.—Manning and Holthuis, 1981:232. [Not Grapsus grapsus (Linnaeus, 1758).]

crabs [Grapsus maculatus) Slonehouse,1960:96,118,137,209.

Grapsus webbi—Türkay, 1982:122.

MATERIAL.—Manning 1971 Collection: Sta ASC-3, McArthur Point: 4 males [39.1–49.2],2 ovig. females [47.2–50.7], 1 juvenile [6.7].—Sta ASC-5, North East Bay: 1 male [55.4].— Sta ASC-11.English Bay: 2 juveniles [8.0–8.5].—Sta ASC-12, McArthur Point 2 females [28.0–36.6].—Sta ASC-18, Shelly Beach: 4 juveniles [5.0–8.0].—Sta ASC-20, south of Collyer Point 1 juvenile [4.5].

Smithsonian 1976 Collection: Sta 1B–76, McArthur Point: 1 male [50.9], 1 ovig. female [38.4].—Sta 4, McArthur Point 24 males [14.7–56.1],8 females [15.7–54.3], 1 ovig. [41.4].—Sta 5A–76, Shelly Beach: 3 males [9.4–16.3], 2 females [10.7– 11.3], 1 juvenile [5.7].—Sta ASC-8, McArthur Point: 1 ovig. female [49.5].

Other Collections: Ascension Island, shore, H.M.S. Challenger: 1 male [19.7] (BMNH 84–31).—Ascension Island: 1 dry male [59.1] (BMNH 84–19).—Ascension, Gazelle, type of Grapsus pictus var. ocellatus Studer 1 ovig. female [54.4] (ZMB 4556).—Deutsche Sudpolar Expedition 1901–1903, Ascension Island, 12 Sep 1903: 2 males [15.1–47.9], 1 female [27.7] (ZMB 17924).—U.S. Eclipse Expedition, 1889–1890, Ascension Island: 4 males [17.0–42.1], 4 females [17.7– 25.6].—Vickrey (1964), South West Bay: 2 males [17.1– 23.2].—Olson (1970), Turtle Shell Beach (= Clarke’s Beach), rocky tide pools: 1 female [29.4].

SIZE.—Carapace lengths of males.9.4–59.1 mm; of females, 10.7–54.4 mm; of ovigerous females, 38.4–54.4 mm; of juveniles,4.5–8.5 mm.

COLOR.—Red or black, covered with white spots increasing in size posteriorly on carapace; spots on carapace not organized into transverse lines; walking legs spotted; chelae uniform bright red, fingers white distally, spooned tips of fingers dark.

Zeiller (1974, figs, on p. 96) gave colored figures of Grapsus grapsus in which there are white lines across the branchial regions and the posterior part of the carapace.and the chelae are dark brown with much less white on the fingers. Chace and Hobbs (1969, fig. 50) also showed that there were lines of white spots across the carapace in G. grapsus from Dominica.

HABITAT.—Usually supratidal, in splash zone, on rocks. On Ascension Grapsus was seen at night roaming over open sand beaches.much like the ghost crab Ocypode.

Stebbing (1914) reported this species from Scotia sta 507, a trawling station in 40 fathoms; it is unlikely that it was taken there.

DISTRIBUTION.—Eastern Atlantic; and central Atlantic at Ascension and St. Helena islands; splash zone.

Grapsus adscensionis is a species of crab found in the eastern Atlantic Ocean.