Kroppcarcinus siderastreicola Badaro, Neves, Castro & Johnsson, 2012

(Figs. 43A–E, 44B, E)

Kroppcarcinus siderastreicola Badaro et al., 2012: 520 .

Trindade and Martin Vaz specimens. 1 ovigerous female (MZUSP 40212), 1 ovigerous female (MZUSP 40219), Brazil, off Espírito Santo, Trindade Island, Enseada da Cachoeira, Farrilhões, 2031’29.8’S, 2919’52.0” W, J.B. Mendonça coll., 21.xi.2017, 11.3 m, associated with Siderastrea . 1 male, 2 ovigeous females (MZUSP 40813), ibidem, 4.iv.2014, 12.2 m, associated with Siderastrea . 1 male, 1 ovigerous female, 1 female parasitized by Rhizocephala (MZUSP 39589), ibidem, Praia do M, 20º30’53.8”S, 29º20’19.2”W, J.B. Mendonça coll., 8.vii.2013, 15 m, associated with Siderastrea . 1 male, 1 female (MZUSP 40794), 1 male (MZUSP 39599), 1 ovigerous female (MZUSP 39867), ibidem, Praia dos Portugueses, Rampa Nova, 20º30’17.7’’S, 29º18’56.7”W, J.B. Mendonça coll., 23.iv.2014, 10.7 m, associated with Siderastrea . 1 male, 1 female (MZUSP 40388), ibidem, Ponta da Calheta, 20º30’18.72’’S, 29º18’31.6”W, J.B. Mendonça coll., 9.vii.2015, 16.3 m. 1 male, 1 female (MZUSP 39595), ibidem, Praia da Calheta, 20º30’29.5’’S, 29º18’37.0”W, J.B. Mendonça coll., 21.vi.2016, 12.5 m, associated with Siderastrea . 2 males, 2 ovigerous female (MZUSP 40802), ibidem, Enseada das Orelhas, 20º29’40.2’’S, 29º20’32.9”W, J.B. Mendonça coll., 1.vii.2016, 9.2 m, associated with Siderastrea . 1 male, 1 female (MZUSP 39590), ibidem, 6.vii.2013, 14 m, associated with Siderastrea . 1 male, 2 ovigerous females, 1 juvenile female (MZUSP 40817), ibidem, Ponta Norte, 20º29’18.7’’S, 29º20’18.3”W, J.B. Mendonça coll., 18.vii.2013, 13.9 m, associated with Siderastrea . 1 male, 1 ovigerous female, (MZUSP 40819), ibidem, Ilha Sul, 20º31’34.3’’S, 29º19’27.9”W, J.B. Mendonça coll., 10.vii.2015, 22.2 m, associated with Siderastrea . 1 male, 1 female (MZUSP 40792), ibidem, 21.x.2014, 17.8 m, associated with Siderastrea . 1 male, 1 female (MZUSP 39586), 1 male (MZUSP 39587), 1 male, 1 female (MZUSP 40774), ibidem, Ilha da Racha, 20º30’26.5’’S, 29º20’48.0”W, J.B. Mendonça coll., 16.vii.2013, 20.8 m, associated with Siderastrea . 3 males, 1 female (MZUSP 40822), ibidem, Parcel das Tartarugas, 20º31’11.86’’S, 29º18’0.6”W, J.B. Mendonça coll., 3.ii.2019, intertidal, 1.0 m, associated with Siderastrea . 1 male, 2 females (MZUSP 40787), ibidem, Praia das Tartarugas, 20º31’01.3’’S, 29º17’56.9”W, J.B. Mendonça coll., 12.vii.2013, intertidal, 10.8 m, associated with Siderastrea . 1 male (MZUSP 42513) Enseada da Cachoeira, Farrilhões, 20º31’26.67’’S, 29º19’55.94’’W, J.B. Mendonça coll., 22.vi.2019, 13.6 m, associated with Montastraea cavernosa . 1 male, 3 females (MZUSP 40778), ibidem, Ponta do Monumento, 20º30’10.3’’S, 29º20’36.1’’W, J.B. Mendonça coll., 2.xi.2014, 15 m. 1 male, 2 females (MZUSP 40777), ibidem, 2.iv.2014, 8.4 m, associated with Siderastrea . 1 male, 3 females (MZUSP 40385), ibidem, Praia do Lixo, 2031’29.8’S, 2919’43.9” W, J.B. Mendonça coll., 15.vii.2013, 17 m, associated with Siderastrea . 1 male, 1 female (MZUSP 40795), ibidem, Ponta Norte, Crista do Galo, 20º29’14.84’’S, 29º20’13.95”W, J.B. Mendonça coll., 21.v.2014, 15 m, associated with Siderastrea . 1 male (MZUSP 39591), 1 male, 4 females (MZUSP 40821), Martin Vaz Archipelago, 20º30’45.7’’S, 29º18’21.9”W, J.B. Mendonça coll. 23.vii.2013, 13 m, associated with Siderastrea .

Size of largest male: cl 2.5 mm, cw 2 mm; largest female: cl 2.9 mm, cw 2.1 mm.

Comparative material examined. Kroppcarcinus siderastreicola: Brazil: Paraíba: 3 females (2 ovigerous), 1 male (MZUSP 6089), Tambaú, Quebra-Quilha Reef, P. Young coll. 4.i.1983, associated with the scleractinian coral Siderastrea . 3 females (MZUSP 6090), 2 females (1 ovigerous) (MZUSP 6094), 1 ovigerous female, 1 male (MZUSP 6088), ibidem, P. Young coll., 20.viii.1982, associated with Siderastrea . 3 ovigerous females, 1 male (MZUSP 6086), ibidem, P. Young coll., 17.xi.1982, associated with Siderastrea . 1 male, 2 ovigerous females (MZUSP 6092), 2 ovigerous females (MZUSP 6093), ibidem, P. Young coll., 4.i.1983, associated with Siderastrea . 2 females (MZUSP 6087), Tambaú, Picãozinho Reef, P. Young coll., 6.vii.1982, associated with Siderastrea . Bahia: 1 male, 2 females (1 ovigerous) (MZUSP 40797), 13º37.653’’S, 38º53.475’’W, Morer, Boipeba, M. Tavares and J.B. Mendonça coll., 2.iii.2013, 3 m, associated with Siderastrea .

Distribution. Florida Keys (Klompmaker et al. 2016), Curaçao (Meij 2014a) and Brazil (Paraíba, Bahia) (Badaro et al. 2012; Nogueira et al. 2014; this tudy). This is the first record of K. siderastreicola from farther north on the Brazilian coast (Paraíba) and from the Trindade and Martin Vaz Archipelago.

Ecological notes. Kroppcarcinus siderastreicola was previously only known as an obligate symbiont of the stony corals Siderastrea stellata Verril, S. siderea (Ellis & Solander) and Stephanocoenia interscepta (Esper) (Barado et al. 2012; Nogueira et al. 2014; Meij 2014a; Klompmaler et al. 2016), usually in shallow depths although hosts are also available at greater depths (Tienderen & Meij 2016). It is recorded here for the first time with Montastraea cavernosa (Linnaeus) as a new host. Males are smaller than females (Fig. 43A–E), commonly one pair per coral colony, each crab in its own pit (Trindade). The crabs produce or induce crescent-shaped chambers or pits in the coral host (Fig. 43F), but other domicile morphologies can be created (Nogueira et al. 2014). The potential for suspension feeding by the plumose setae of the third maxillipeds has been suggested by Nogueira et al. (2014). The females from Trindade carry few very large eggs. The female MZUSP 39589 was parasitized by a rhizocephalan. Apparently, rhizocephalans parasitizing gall crabs are rare and such a symbiosis has been described only recently (Boyko & Meij 2020).

Remarks. Kropp (1990) reported that the Cryptochiridae from the Pacific Ocean may have the P3–P5 coxae provided with a forward directed anterior lobe (reduced or absent in some genera). In the male and female Kroppcarcinus siderastreicola the coxae of P2–P5 are likewise provided with a well-developed anterior lobe, somewhat less developed in the P2 coxa.