Trapezia cymodoce (Herbst, 1801)

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 : 45-47

Trapezia cymodoce (Herbst, 1801) (Plate 2C, D, 3A)

Cancer cymodoce Herbst, 1801: 22 , pl. 51, fig. 2 (colour) (see Plate 2D). Trapezia dentifrons Latreille, 1828: 695 .

Trapezia coerulea Rüppell, 1830: 27 , pl. 5, fig. 7; pl. 6, fig. 22.

Grapsillus dentatus Macleay, 1838: 67 , pl. 3.

Trapezia hirtipes Jacquinot, in Hombron & Jacquinot 1846 : pl. 4, figs. 14 (colour)–16; Jacquinot, in Lucas 1853: 44.

Trapezia dentata var. subintegra Dana, 1852: 259 , pl. 15, figs. 7a (colour), b (see Plate 3A).

Trapezia cymodoce var. ornatus Chen, 1933: 108 , fig. 53.

Remarks. This well­known species has a long synonymy. The above synonymy has been accepted by most workers for many decades, although in many cases, the types of the various taxa have never been checked. Cancer cymodoce Herbst, 1801 , was described on the basis of an unspecified number of specimens from "Ostindien" (Herbst 1801: 23; see Plate 2D). As such, any specimens that may have been reported should be regarded as syntypes. Rathbun (1906: pl. 11, fig. 6) published a photograph of a syntype specimen (also see Castro 1997a: 77) which was deposited in the Zoologisch Museum, Humboldt­Universität, Berlin but this specimen could no longer be located by us during separate visits by the first two authors, and is now regarded as lost (H.E. Gruner in litt., 6 June 1994). Sakai (1999: 41) in compiling the extant Herbst material, also could not locate any specimen of C. cymodoce there.

Trapezia dentifrons Latreille, 1828 , was most probably described from a juvenile specimen (" très petite," anterolateral teeth " très aiguë "; Latreille 1828: 695), but because of this, it is impossible to be sure of its identity. The type specimen(s), supposedly in the Muséum national d’Histoire naturelle, Paris, cannot be located by the first author and is here considered to be lost. Latreille himself (1828: 696) nevertheless noted that it was just a variety of T. cymodoce : " n'est peut­être qu'une variété du Cancer cymodoce d'Herbst ".

Galil (1988b: 161) and Castro (1999b: 104) separately examined the type material of T. coerulea Rüppell, 1830 (type locality Red Sea) from the Senckenberg Museum, Frankfurt and showed that Rüppell's specimens of " T. coerulea " also included T. ferruginea [= present T. bidentata ( Forskål, 1775) , see below]. The lectotype designation by Galil (1988b: 162) ensured that T. coerulea Rüppell, 1830 , remains a junior subjective synonym of T. cymodoce .

The identity of Grapsillus dentatus Macleay, 1838 , and its synonymy with T. cymodoce , is less of a problem as Macleay provided a relatively good colour figure of the species. The dried type specimen (a female) is still extant in the Macleay Museum, University of Sydney, and has been examined by us. Ng & Ahyong (2000) provided a photograph of the lectotype designated by them.

The apparent type of T. hirtipes Jacquinot, 1846 (a dried male, MNHN­B 2953, type locality Nuku Hiva Island, Marquesas Islands, French Polynesia), is still in good condition. Re­examination of this specimen and consideration of the relatively good colour figure, we have no doubt that it is a junior synonym of T. cymodoce (see Castro 1997b: 119).

The identity of T. dentata var. subintegra Dana, 1852 , described from the Tuamotu Archipelago, French Polynesia, is questionable as it was based on a small (cl 3 lines = 7.6 mm) specimen which is no longer extant. Its long accepted synonymy with T. cymodoce is not necessarily correct. On the basis of the very brief description and a colour figure ( Dana 1852: pl. 15, fig. 7a; see Plate 3A), Dana's variety can just as easily be referred to T. bidentata ( Forskål, 1775) . To resolve this matter, we have selected a neotype for this species that maintains the long established synonymy of T. dentata var. subintegra with T. cymodoce (see below).

On the basis of material collected by L. Plate and ultimately deposited in the Phyletisches Museum, University of Jena ( Germany), Chen (1933) described Trapezia cymodoce var. ornatus (type locality Sri Lanka) which agrees very well with what is presently defined as T. cymodoce . Although his figure of Quadrella rufopunctata ( Chen 1933: fig. 55) seemingly depicts T. cymodoce , the description of this taxon demonstrates that it is actually T. rufopunctata (Herbst, 1799) . Chen had five specimens of T. cymodoce var. ornatus on hand, but no holotype was designated. Chen's specimens could not be located in the Jena, Senckenberg or Humboldt­Universität museums (Dietrich von Knorre, Michael Türkay, Oliver Coleman, pers. comm.).

It is somewhat unfortunate that Rathbun (1930: 556) selected Trapezia dentifrons Latreille, 1828 , a somewhat dubious species described on the basis of a juvenile, and which is now lost, as the type species of Trapezia . In addition, the type materials of Cancer cymodoce Herbst, 1801 , T. dentata var. subintegra Dana, 1852 , T. cymodoce var. ornatus Chen, 1933 , and Quadrella rufopunctata Chen, 1933 , are also lost. As such, the taxonomic situation of the species is far from stable. More recently, Castro (1997a) described T. lutea (type locality New Caledonia), a species close to T. cymodoce and with which it has been confused with for over a century. While we are convinced that none of the names of Herbst, Latreille, Dana, and Chen (at least on the basis of their descriptions, colour notes and/or figures) are conspecific with T. lutea , the lack of type material is very troublesome and can potentially cause nomenclatural problems.

In order to stabilise the taxonomy of T. cymodoce , one of the most common and widely distributed species of trapeziids anywhere, neotypes should be designated for all the above names for which type material is not extant. As several of the junior synonyms of what is now regarded as T. cymodoce s. str. (see Galil & Clark 1990; Castro 1997a, b) have been recognised as valid taxa for many decades, we believe that the best solution is to designate a neotype simultaneously for Cancer cymodoce Herbst, 1801 , Trapezia dentifrons Latreille, 1828 , Trapezia dentata var. subintegra Dana, 1852 , and Trapezia cymodoce var. ornatus Chen, 1933 . All four names thus become objective synonyms; with the oldest name, Cancer cymodoce Herbst, 1801 , automatically becoming the type species of Trapezia . Whilst this action seems drastic, it is the one which we feel will present the least problems and confusion in the long term. We hereby select a male specimen ( ZRC 1985.1554; cl 11.7 mm, cw 13.8 mm) collected from Siloso Beach, Sentosa Island, Singapore (01º20’N, 103º50’E), as the neotype of the above five taxa. The specimen was collected by P. K. L. Ng on 25 May 1982 from a colony of Pocillopora .