On the extant type material of Cardisoma hirtipes Dana , 1851 , and Cardisoma obesum Dana , 1851 ( Crustacea : Brachyura : Gecarcinidae )

Two boxes in the U.S. National Museum of Natural History, Smithsonian Institution, were found to contain the dried type material of the land crabs Cardisoma hirtipes Dana, 1851, and Cardisoma obesum Dana, 1851 (Gecarcinidae). Th e types of the common Pacifi c land crab, C. hirtipes were believed to have been lost and a neotype had been designated in earlier revisions. Cardisoma obesum Dana, 1851 is currently regarded as a junior subjective synonym of Cardisoma carnifex (Herbst, 1796). key woRds Land crab, type specimens, Dana material, Cardisoma, taxonomy. Recently, two specimens of gecarcinid crabs were found in the dried collection of the U.S. National Museum of Natural History (USNM), Smithsonian Institution, Washington D.C., which have been forgott en by taxonomists working on this family. Th e specimens were identifi ed as the types of Cardisoma hirtipes Dana, 1851, and Cardisoma obesum Dana, 1851. Th eir features and proportions agree well with the measurements given by Dana (1851) in his original description; and together with the labels, leave no doubt to their identities. sHoRT commUnIcaTIon This article is part of the tribute offered by the Brazilian Crustacean Society in memoriam of Michael Türkay for his outstanding contribution to Carcinology CORRESPONDING AUTHOR Peter K. L. Ng peterng@nus.edu.sg SUBMITTED 13 February 2017 ACCEPTED 12 April 2017 PUBLISHED 22 June 2017 Guest Editor Célio Magalhães DOI 10.1590/2358-2936e2017019

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, 3I).The G1 was subsequently rehydrated and was shelved in the wet collections of the USNM (Fig. 3J-M).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 G1 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).Remarks.Cardisoma obesum was described by Dana (1851: 252-253) from "Paumotu" (= Tuamotu) in French Polynesia, and he listed one specimen (sex not specified) measuring 3.67 by 3 inches (93.2 × 76.2 mm).Dana (1852: 376) redescribed the species and figured the carapace, noting that it was from Peacock Island in the Paumotu Archipelago, and that the "... only specimen of this species saved from among the many collected, is a carapax." The front of the carapace was figured in Dana (1855: pl. 24, fig.1).Cardisoma obesum is currently regarded as a junior subjective synonym of C. carnifex (see Türkay, 1974).The whereabouts of the type of C. obesum, was to date not known.
The present specimen (USNM 2356) measures 90.6 × 70.0 mm and the measurements are slightly smaller from that given by Dana (1851) but this can easily be explained by the fact that all that is left of the specimen is the carapace and the left side is broken and in poor condition.As thus, there is doubt this is in fact the holotype specimen of C. obesum.

acknowledgemenTs
The author is grateful to Rafael Lemaitre and Karen Reed (USNM) for helping him find the dried specimens in question.The visit to USNM was facilitated by a travel grant from the National University of Singapore.This note is dedicated to an old friend, Michael Türkay, and the author of so many important papers on Brachyura, including especially the Gecarcinidae, which he always loved.