Williamstimpsonia denticulata (White, 1848)

(Fig. 42A–O)

Xantho denticulatus White, 1848: 225 [Type locality: West Indies].

Olivioxantho denticulatus . — Števčić 2005: 134; Ng et al. 2008: 205; Felder et al. 2009: 1085.

Williamstimpsonia denticulatus – Thoma et al. 2014: 89; Mantelatto et al. 2020: 82; Moraes et al. 2022: 15.

Trindade and Martin Vaz specimens. 1 male (MZUSP 33730), Brazil, off Espírito Santo, Trindade Island, Ponta da Calheta, 20º30’18.72”S, 29º18’31.67”W, J.B. Mendonça coll., 22.x.2014, 15.8 m . 1 male (MZUSP 41306), ibidem, 20.x.2014, 17 m . 1 male (MZUSP 41309), ibidem, 20.x.2014, 17.7 m . 1 juvenile male (MZUSP 40934), ibidem, 16.xi.2017, 17.1 m . 1 male (MZUSP 41304), ibidem, Enseada da Cahoeira, Farrilhões, 20º31’29.6”S, 29º19’52.0”W, J.B. Mendonça coll., 22.vii.2015, 22.6 m . 1 juvenile (MZUSP 41404), ibidem, 20º31’22.4”S, 29º19’52.0”W, J.B. Mendonça coll., 4.vii.2012, 17.9 m . 1 male (MZUSP 41307), ibidem, 20º31’29.8”S, 29º19’52.0”W, J.B. Mendonça coll., 9.viii.2018, 10.5 m . 1 male (MZUSP 40846), ibidem, 21.xi.2017 . 2 females (MZUSP 41318), 20º31’22.4”S, 29º19’52.0”W, J.B. Mendonça coll., 9.vii.2013, 10.4 m . 1 male (MZUSP 41305), 1 juvenile female (MZUSP 41321), ibidem, Enseada dos Portugueses, Farol, 20º29’52.3”S, 29º19’15.6”W, J.B. Mendonça coll., 4.viii.2015, 10 m . 1 male (MZUSP 41308), 1 male (MZUSP 41311), 1 male (MZUSP 41312), ibidem, 24.vi.2016, 11.3 m . 1 ovigerous female (MZUSP 41319), ibidem, 8.iv.2014, 12.9 m . 1 male (MZUSP 41310), 1 ovigerous female (MZUSP 41320), ibidem, Enseada das Orelhas, 20º29’40.2”S, 29º20’32.9”W, J.B. Mendonça coll., 23.vii.2015, 14.6 m . 1 male (MZUSP 41313), 1 female (MZUSP 41316), ibidem, Parcel das Tartarugas, 20º31’11.86”S, 29º18’0.06”W, J.B. Mendonça coll., 2.ii.2019, tide pool, 1 m . 1 male (MZUSP 41315), ibidem, Praia da Calheta, 20º30’29.5’S, 29º18’37.0W, J.B. Mendonça coll., 18.vii.2016, 3.5 m . 1 ovigerous female (MZUSP 41317), ibidem, Enseada dos Portugueses, SECOM/ECIT, 20º30’20.9”S, 29º18’43.7”W, J.B. Mendonça coll., 14.v.2014, 10 m . 1 juvenile male (MZUSP 41322), ibidem, Ilha da Racha, 20º30’26.5”S, 29º20’48.0”W, J.B. Mendonça coll., 1.vii.2016, 21.4 m . 1 juvenile (MZUSP 39680), ibidem, Ponta Norte, 20º29’18.7”S, 29º20’18.3”W, J.B. Mendonça coll., 2.vii.2015, 14.2 m . 2 males, 1 female (MZUSP 41405), 1 male, 4 females (MZUSP 41054), Martin Vaz Archipelago, 20º30’45.7”S, 29º18’21.9”W, J.B. Mendonça coll., 24.vii.2013, 12.3 m. 1 juvenile (MZUSP 41058), ibidem, Enseada dos Portugueses, R/V “Marion Dufresne”, TAAF MD55/Brésil Expedition coll., 22.v.1987, vacuum suction sampler, 10 m.

Size of largest male: cl 14.9 mm, cw 23 mm; largest female: cl 10.9 mm, cw 17 mm.

Comparative material examined. Williamstimpsonia denticulata: United States: 1 juvenile female (MZUSP 13116), Florida, Brower County, Deer Field Beach, P.J.S. de Souza coll., vii.1998, 3–4 m . Brazil: Ceará: 1 male (MZUSP 32711), Parque Estadual Marinho da Pedra da Risca do Meio, L.E.A. Bezerra coll., 15.vii.2004 , associated to the sponge Dragmacidon reticulatum (Ridley & Dendy) . São Paulo: 1 female (MZUSP 16710), Ilha Vitória, 23°44’04”S, 45°01’35”W, Saco da Professora, D.F.R. Alves et al. coll., v.2004 . Central Atlantic: 12 males, 11 females (MZUSP 41774), São Pedro and São Paulo Archipelago, Enseada, W. Santana et al. coll., 18.ii.2009 to 5.iii.2009. Ascension Island: 1 male (USNM 256641), McArthur Point, Stn ASC 1C-76, R.B. Manning et al. coll., 11.vii.1976 . 1 male, 1 female (USNM 256639), English Bay, Stn ASC 3C-76, R.B. Manning et al. coll., 12.vii.1976 .

Distribution. Amphi-Atlantic. Western Atlantic: Bermuda, Bahamas, Florida, Gulf of Mexico, Antilles, Colombia, Venezuela and Brazil (Ceará to Bahia, and São Paulo) (Rathbun 1930; Rodriguez, 1980; Lemaitre 1981; Melo 1996; Alves et al. 2006; Felder et al. 2009). Brazilian oceanic islands: São Pedro and São Paulo Archipelago (Holthuis et al. 1980; this study) and Trindade and Martin Vaz. This is the first record of W. denticulata from TMV. Central Atlantic: Ascension Island (Manning & Chace 1990; De Grave et al. 2017). Eastern Atlantic: Ghana and offshore islands of Gulf of Guinea

Ecological notes. Associated with sand reefs of Phragmatopoma caudata, the sponge D. reticulatum, coral and stone reefs, coralline algae, rubble, under rocks and on sand bottoms from the intertidal to depths of 22 m (Rathbun 1930; Forest & Guinot 1966; Holthuis et al. 1980; Manning & Chace 1990; Bezerra & Coelho 2006; Lane-Medeiros et al. 2021). It has been reported as prey for juveniles of Octopus insularis Leite & Haimovici (Bouth et al. 2011) . It is the commonest xanthid in Trindade where it has been found in tide pools to depths of 22 m.

Remarks. Guinot (1968: 712) briefly mentioned slightly differences in the proportions, convexity, and ornamentation of the carapace between western- and eastern Atlantic specimens of W. denticulata without further specifics. Juveniles and adults vary considerable in the shape of the carapace and denticulation of the anterolateral margin (Fig. 42A, N). An extreme variation in the color pattern occurs in the specimens from Trindade and Martin Vaz (Fig. 42A–O). The form of the body and first male gonopod of the specimens from Trindade and Martin Vaz agree with the illustrations of a male from Ghana provided by Monod (1956: 281, 282, figs 335, 338).