Discoplax hirtipes ( Dana, 1851 )

Ng, Peter K. L., 2017, On the extant type material of Cardisoma hirtipes Dana, 1851, and Cardisoma obesum Dana, 1851 (Crustacea: Brachyura: Gecarcinidae), Nauplius (e 2017019) 25, pp. 1-7 : 2-4

publication ID	https://doi.org/10.1590/2358-2936e2017019
persistent identifier	https://treatment.plazi.org/id/03B22060-8F06-122E-EA50-FEE3FA68AE6D
treatment provided by	Felipe
scientific name	Discoplax hirtipes ( Dana, 1851 )
status

Treatment

Discoplax hirtipes ( Dana, 1851) View in CoL

( Figs. 1–3 View Figure 1 View Figure 2 View Figure 3 )

Cardisoma hirtipes Dana, 1851: 253 View in CoL (for complete synonymy, see Ng and Shih, 2014: 112).

Type material. Lectotype male (58.2 × 47.4 mm) ( USNM 2356 About USNM ), “Viti” (= Fiji), ca. 17º48’S 178º00’E, coll. U.S. Exploring Expedition. GoogleMaps

Remarks. Cardisoma hirtipes was described by Dana (1851: 253) from “ Viti ” (= Fiji), who listed only one specimen (sex not specified) measuring 28 × 22.5 lines (see also Dana, 1852: 376). Dana (1852: 377) redescribed the species, noting that the specimen was a male from the “Feejee Islands”. This was apparently the same specimen figured by him later ( Dana, 1855: pl. 24, fig. 2). The line was an English unit of measure that has been variously equivalent to 1 ⁄ 10, 1 ⁄ 12, 1 ⁄ 16 or 1 ⁄ 40 of an inch (= 25.4 mm). In the older literature, Englishspeaking biologists usually equated a line with 1 ⁄ 12 of an inch (or 2.1 mm). That would put the dimensions of Dana’s male specimen at 58.8 × 47.3 mm. Evans (1967) had listed a type specimen of the Pacific land crab C. hirtipes ( Gecarcinidae ) in the Natural History Museum, London (see also Türkay, 1974). Ng and Clark (2014) examined the specimen and argued that this was actually not a type, belonging to another species, Cardisoma carnifex (Herbst, 1796) , instead. They commented that since there were no extant types of the species, the neotype male specimen from Fiji designated by Ng and Davie (2012) therefore remained the valid type of C. hirtipes .

The present specimen ( USNM 2356) is a male 58.2 × 47.4 mm and agrees well with the size given by Dana (1851): 58.8 × 47.3 mm. There is no doubt this is the specimen examined and figured by Dana (1851; 1852; 1855). Although Dana (1851; 1852; 1855) mentioned and figured only this one specimen, he did not state it was the holotype or make it clear he only had one specimen (see Ng and Clark, 2014). As such, it is preferable to designate USNM 2356 as the lectotype of C. hirtipes .

The present lectotype is interesting as the left male first gonopod (G1) had been detached ( Figs. 2D View Figure 2 , 3I View Figure 3 ). The G1 was subsequently rehydrated and was shelved in the wet collections of the USNM ( Fig. 3J–M View Figure 3 ). Who did this is not known as neither the box with the dried body or the bottle with the G1 had any labels to this effect.

Interestingly, Türkay (1974: 233) listed among his material examined for D. hirtipes (as a Cardisoma Latreille in Latreille, Le Peletier, Serville & Guérin, 1828) as follows:“Südsee, Viti (1 Go/1 des Holotypus von Cardisoma hirtipes DANA 1851 )”. He did not indicate where the specimen was from and which museum it was kept in,and was not discussed anywhere else in his paper. Ng and Clark (2014: 596) was advised by the late Michael Türkay that he had actually not examined the holotype of the species and the type he had referred to was the specimen recorded by Evans (1967). Could the detached G 1 in USNM be the one he had actually examined instead and then inadvertently forgot in the ensuing years?

The discovery of the present lectotype means that the neotype selected by Ng and Davie (2012) is now no longer a type specimen. The species is currently classified in the genus Discoplax A. Milne-Edwards, 1867 (see Ng and Guinot, 2001; Ng and Shih, 2014).