Brachyura Linnaeus, 1758

Campos, Ernesto, Peláez-Zárate, Víctor Arturo & Solís-Marín, Francisco A., 2012, Rediscovery, hosts and systematics of Holothuriophilus trapeziformis Nauck, 1880 (Crustacea, Brachyura, Pinnotheridae), Zootaxa 3528, pp. 57-62 : 58-61

Infraorder Brachyura Linnaeus, 1758

Section Eubrachyura de Saint Laurent, 1980

Family Pinnotheridae De Haan, 1833

Genus Holothuriophilus Nauck, 1880

Holothuriophilus trapeziformis Nauck, 1880

( Figs. 1A, B, 2A–D)

Holothuriophilus trapeziformis Nauck 1880: 24 , 66; De Man 1887: 721–722; Takeda & Masahito 2000: 103; Ng & Manning

2003: 903, 916–918, fig. 7C–F (lectotype); Ahyong & Ng 2007: 213–214 (lectotype); Ng et al. 2008: 249 (list). Pinnixa banharti — Caso 1958: 329; 1964: 379 (not P. banharti Rathbun 1918 ); Campos et al. 1998: 337. Holothuriophilus sp — Campos et al. 1998: 337. Pinnotheres trapeziformis — Bürger 1895: 380–381, pl. 9: fig. 26, pl. 10, fig. 25; Adensamer 1897: 107; Tesch 1918: 285 (list);

Garth 1948: 55; Silas & Alagarswami 1967: 1211, 1216, 1221 (list); Balss 1956: 1417; Schmitt et al. 1973: 5, 13, 89.

Diagnosis. Female: Carapace transversally elongated, widest anterior to middle portion, broader than long, thin but firm exoskeleton, almost smooth, anterolateral margin cristate; front below postfrontal ridge, deflexed, emarginated, its margin scarcely visible in dorsal view. Third maxilliped with ischium merus indistinguishably fused, palp 3-segmented; carpus subequal in length to subtrapezoidal propodus, spoon-shaped dactylus articulated on medial ventral third of propodus; tip of dactylus slightly overreaching tip of propodus; exopod with onesegment flagellum. Cheliped merus, carpus densely setose; propodus setose on inner distal margin; propodus, dactylus almost meeting when closed. Walking legs robust, similar in shape, segments compressed, carpi, propodi subequal; dactili shorter than preceding articles, similar and subequal, last pair shorter than preceding. Abdomen with 6 somites plus free telson.

Male. Unknown.

Material examined and host. Three females, Punta Tiburón, Mazatlán, Sinaloa, Mexico, rocky intertidal, June 29, 2010, in Holothuria lubrica Selenka, 1867 ; 3 females, same locality, in H. inornata Semper, 1868 ; 1 female, Ixtapa, Zihuatanejo Bay, Guerrero, Mexico, January 7, 1968 in H. kefersteini Selenka, 1867 (= Paraholothuria riojai Caso, 1964 ); 1 female, same locality, March, 1982, in H. inornata Semper, 1868 .

The names of the hosts herein recorded were transcripted from each sample’s label. Because the taxonomic confusion of the species Holothuria in the Mexican Pacific (see, Solís-Marín et al. 2009) the identities of the hosts need to be confirmed. Holothuria inornata is the only host confirmed by us.

Measurements of the type material in millimeters (wc x lc). Female on which the original description was based (lost), 13.8 x 10.5 (after De Mann 1887); 14 x 10 (after Bürger 1895). We consider that both of these authors described the same female and that the minor differences in size is the result of the accuracy of the measurements. Male specimen from Mazatlán measure 8.5 x 5.0 (after Bürger 1895). The female lecotype, SMF-ZMG 170 (Go565a), selected by Ng & Manning, 2003, measuring 7.7 × 4.8, is probably Bürger’specimen, erroneously identified as a male by him (see below).

Type locality and host. Unknown in Holothuria maxima Semper (after Nauck 1880); Mazatlán, Sinaloa, Mexico, from the cloaca of a H. inornata Semper (after Bürger 1885).

Remarks. According with Nauck (1880) the ovigerous female on which the original description was based ( Fig. 1B, lost) was collected in an unknown locality in Holothuria maxima . Bürger (1985) redescribed this female and pointed out that a second specimen, not yet described, is much smaller than the ovigerous female and is a male (not a female as pointed out by Ng & Manning 2003: 917), collected by Semper in Mazatlan (Sinaloa, Mexico), in H. inornata . Regarding the host recorded by Nauck (1880) for this species, H. maxima Semper , it is important to point out that Semper did not describe H. maxima Delle Chiaje, 1823 , which actually is a junior synonym of H. tubulosa Gmelin, 1791 , a species that is found in the northwest Atlantic ( Hansson 2001). Because the identity of the H. maxima , erroneously allocated to Semper by Nauck, cannot be established, all the geographical and ecological information for the described crab female is uncertain. Even so, in the absence of additional data, we are assuming that this lost female, along with the female lectotype selected by Ahyong & Ng (2003), were collected in H. inornata in Mazatlán, Sinaloa.

Taxonomic and host records for Holothuriophilus trapeziformis . Nauck (1880: 24, 66) described H. trapeziformis very briefly and did not state the location or sex, only stating that it was a ¨parasite in Holothuria maxima Semper ”. De Man (1887: 721–722) who re-examined Nauck’s material, commented on the affinities of the species and noted he had one female specimen measuring 13.8 x 10.5 mm. He also did not indicate where it was collected. Bürger (1895) was the first to describe and to figure this female in more detail and for the first time he recorded a second specimen assigned to this species from “Mazatlan” collected in Holothuria inornata . He also commented that this second specimen was a male which was not yet described (“ Ein zweites, noch nicht beschriebenes Exemplar ist viel kleiner als das vorige und ein ♂ ”) and measuring 8.5 x 5.0 mm ( Bürger 1895: 381). Assuming Nauck’s material included several specimens, it is clear that he did not select a holotype, and as such, all the presumed material he examined when he named the species (1880) would be syntypes (Article 72.1.1 of the 1999 ICZN Code). Ng & Manning (2003) checked on the possible depositories of Nauck’s material and indicated it was in the Senckenberg Museum (SMF) (where the bulk of the Göttingen University collections, where Nauck originally gave his specimens, are currently deposited), Zoologisches Museum, Museum für Naturkunde, Humboldt Universität, Berlin, and the U.S. National Museum of Natural History (USNM). In the case of Holothuriophilus trapeziformis , there is only one Nauck specimen that still is extant. Ng & Manning (2003) observed this and selected this female specimen as the lectotype of Holothuriophilus trapeziformis Nauck, 1880 (see also Ahyong & Ng 2007). In this context, the “male” specimen (8.5 x 5.0 mm) mentioned by Bürger (1895) is likely to be the same specimen as the lectotype female (7.7 x 4.8 mm) designated by Ng & Manning (2003). The two sets of measurements are very close and can easily be accounted by the poor current state of the soft lectotype female specimen, which looks to have suffered from shrinkage. Bürger (1895) indication that this was a male is probably a lapsus. Two species are currently included in Holothuriophilus in the eastern Pacific, its type species, H. trapeziformis and H. pacificus (Poeppig, 1836) (= Pinnotheres silvestri Nobili, 1901 = Pinnaxodes meinerti Rathbun, 1904 ) ( Nauck 1880: Garth 1958; Manning 1993). Females of both species are morphologically very similar sharing transversally elongated carapace ( Fig. 1A–B) that is broader than long, widest anterior to the middle portion, smooth; a spoon-shaped third maxilliped dactyl (Fig, 2C–D) that is larger than the propodus; and a large carpus more robust than the propodus (Fig., 1 and 2). They can be separated because the fingers of the chela of H. trapeziformis meet when closed, instead of leaving a gape in H. pacificus ( Rathbun 1918: 178) . Two other species have also been included in the genus, H. mutuensis (Sakai, 1939) , from Amori Bay, northern Japan, and H. tomentosus (Ortmann, 1894) , from the West Atlantic, ( Takeda & Masahito 2000; de Melo 2004). The taxonomy and systematics of these species is currently being studied by the first author and will be published elsewhere.