Trapezia bidentata Forskål, 1775

PETER CASTRO, PETER K. L. NG & SHANE T. AHYONG, 2004, Phylogeny and systematics of the Trapeziidae Miers, 1886 (Crustacea: Brachyura), with the description of a new family, Zootaxa 643, pp. 1-70 : 48-50

Trapezia bidentata Forskål, 1775

Cancer bidentatus Forskål, 1775: 90 .

Trapezia ferruginea Latreille, 1828: 695 .

Grapsillus subinteger Macleay, 1838: 67 .

Trapezia miniata Jacquinot, in Hombron & Jacquinot 1846 : pl. 4, figs. 10 (colour)—13; Jacquinot in Lucas 1853: 43.

Trapezia subdentata Gerstaecker, 1857: 127 . Trapezia bidentata — Davie 2002: 498.

Remarks. Forskål (1775) described Cancer bidentatus from an unspecified number of specimens from the Gulf of Suez, in the Red Sea. In his brief description, Forskål (1775: 90) wrote " Color rubro­flavescens… Thorax…depressus, glaber…Dentes duoab urroque hatere... chelae glabra ... color rubro­flavescens " [depressed, smooth carapace (orange colour; carapace depressed, smooth; teeth on both sides). Although brief, Forskål’s description clearly refers to T. ferruginea Latreille, 1828 , as currently understood, even if clear, obtuse anterolateral teeth are typically observed among smaller individuals. Specimens were collected between shells (“ inter conchylia ”) but it is possible that the reference was to corals. Klunzinger (1913: 307) placed Forskål's species in the genus Trapezia and relegated T. ferruginea Latreille, 1828 , to a junior synonym. Klunzinger obviously worked with live or fresh material, referring to the red spot at the distal end of the propodi of the ambulatory legs, which is diagnostic for T. ferruginea . Many authors, however, have incorrectly regarded T. bidentata as Klunzinger's species; and have synonymised it with T. ferruginea Latreille, 1828 . Since T. ferruginea Latreille, 1828 , was supposedly senior to " T. bidentata Klunzinger, 1913 ", the latter name has been conveniently forgotten. Davie (2002) used the name “ T. bidentata ( Forskål, 1775) ” for his Australian material but he based this on an early unpublished manuscript of the present paper by the first two authors. Since T. bidentata is a now attributed to Forskål (1775), this name has priority over T. ferruginea Latreille, 1828 .

Trapezia cymodoce , which is also common in the Red Sea, has often been confused with T. ferruginea . Unlike T. cymodoce (Plate 2C), however, C. bidentatus has smooth chelipeds which lack a conspicuous tomentum. Forskål based his descriptions on fresh specimens he obtained during his stay in Suez, and as such, probably would not have missed this character. As such, we are confident T. bidentata ( Forskål, 1775) is not T. cymodoce .

Trapezia ferruginea Latreille, 1828 , was described from the Red Sea on the basis of a female specimen. It has since been reported throughout the Indo –West Pacific and eastern Pacific regions. The type, supposedly in the Muséum national d'Histoire naturelle, Paris, is no longer extant.

Grapsillus subinteger Macleay, 1838 , was described from Cape of Good Hope, South Africa on the basis of an unspecified number of specimens. The description was inadequate and no figures were provided. The name has long been regarded as a synonym of T. digitalis Latreille, 1828 (see Serène 1984: 278), but Ng & Ahyong (2000), who re­examined and re­figured Macleay's specimen (a dried lectotype male) in the Macleay Museum in the University of Sydney, showed that this was incorrect. This was later verified by the first author. Grapsillus subinteger Macleay, 1838 , is actually conspecific with T. ferruginea (present T. bidentata ).

Trapezia miniata Jacquinot, 1846 , was described from Nuku Hiva, Marquesas Islands, French Polynesia, and from his description (in Lucas 1853: 43) and colour figure (Jacquinot, in Hombron & Jacquinot 1846: pl. 4, fig. 10) and apparent type material (a dried male and female [MNHN­B 2956] and two dried males [MNHN­B 2959]), there is little doubt that it is conspecific with T. bidentata (also see Castro 1997b: 120).

Trapezia subdentata Gerstaecker, 1857 , was described (but not figured) from two specimens from the Red Sea. Its description leaves little doubt that T. subdentata is conspecific with T. bidentata . Photographs of Gerstaecker's specimens in the Zoologisch Museum, Humboldt­Universität, Berlin (ZMB 195) confirm this.

Trapezia cymodoce var. edentula Laurie, 1915 , was described from one specimen from Ceylon (= Sri Lanka). Lauries description of the specimen (location unknown) shows that this variety is identical with T. bidentata .

Since the types of the two earliest names, Cancer bidentatus Forskål, 1775 , and Trapezia ferruginea Latreille, 1828 , are lost, a neotype is necessary to stabilise the use of these names as presently discussed. Since both species were described from the same area, we hereby designate a male specimen (MNHNB 27680 [ex B 13925]; cl 11.6 mm, cw 13.6 mm) from Abu Latt Island (19º57’N, 40º07’E), Red Sea as the simultaneous neotype of both species. It was collected by the research vessel Calypso from Pocillopora at an unknown depth and date in 1952. The diagnostic red spot on the distal edge of the propodi of the ambulatory legs is still clearly visible.