Synalpheus brooksi Coutière, 1909

Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas & Almeida, Alexandre Oliveira, 2025, Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region, Zootaxa 5666 (1), pp. 1-52 : 16-17

Synalpheus brooksi Coutière, 1909

Material examined: Maranhão—Turiaçu : 4 M, Almirante Saldanha Expedition, St. 1749 A, 06.xi.1967, 00°03.0′S 44°32.3′W, 63.0 m depth, MOUFPE 8746 ; Ceará—Acaraú : 3 M, 1 OV , 1 F, Almirante Saldanha Expedition , St. 1710, 27.x.1967, 02°39.5′S 39°46.0′W, 17.0 m depth, MOUFPE 8743 ; 5 M, same data as MOUFPE 8743, MOUFPE 8756 ; Fortaleza : 1 M, Parque Estadual Marinho da Pedra da Risca do Meio , 15.vii.2004, in Monanchora arbuscula, MOUFPE 21868; Paracuru : 1 M, Almirante Saldanha Expedition, St. 1708 A, 22.x.1967, 02°44.3′S 39°04.0”W, 54.0 m depth, MOUFPE 8762 ; 1 OV, Almirante Saldanha Expedition , St. 1701, MOUFPE 8741 ; 49 M, Pavasas Expedition - DG 03, 19.vii.1987, MOUFPE 8749 ; Pernambuco—Fernando de Noronha : 1 M, Buraco do Inferno, 18.vi.2019, 03°48.968′S 32°23.577′W, 13.0–15.0 m depth, in sponge, DZ / UFRGS 6712 ; 1 M, same data as DZ/ UFRGS 6712 , DZ / UFRGS 6713 ; 1 M, 2 OV, Cagarras , 25.vi.2022, 03°50.933′S 32°26.178′W, 13.0 m depth, in sponge, DZ / UFRGS 7026 ; 4 M, 2 OV, Buraco do Inferno , 26.vi.2022, 03°48.968′S 32°23.577′W, 12.0 m depth, in sponge, DZ / UFRGS 7030 ; 2 M, 2 F, Ilha do Meio , 26.vi.2022, 03°49.015′S 32°23.549′W, 11.0 m depth, in sponge, DZ / UFRGS 7036 ; 1 M, Ponta da Sapata , 30.vi.2022, 03º51.892′S 32º27.965′W, 11.0 m depth, in sponge, DZ / UFRGS 7042 ; 1 M, Laje Dois Irmãos , 30.vi.2022, 03°51.859′S 32°27.934′W, 17.0 m depth, in sponge, DZ / UFRGS 7045 ; Continental Shelf off Recife: 45 M, 7 F, 2 NI , 27.ii.2018, 8°13′33.0′′S 34°37′40.3′′W, 50.6 m depth, in sponge, MOUFPE 21816 ; 2 M, 10.v.2018, 08°23′04.3′′S 34°40′07′′W, 80.0 m depth, in sponge, MOUFPE 21818 ; 1 M, same data as MOUFPE 21818, MOUFPE 21825 ; 2 M, same data as MOUFPE 21818, MOUFPE 21826 ; 2 M, same data as MOUFPE 21818, MOUFPE 21842 ; 1 M, same data as MOUFPE 21818, MOUFPE 21855 ; 1 M, 07.ii.2018, 8°08′43.7′′S 34°34′22.6′′W, 54.0 m depth, MOUFPE 21559 ; 1 M, same data as MOUFPE 21559, in rhodoliths, MOUFPE 21564 ; 1 M, 10.v.2018, 08°21′34.9′′S 34°41′53.3′′W, 50.8 m depth, in sponge, MOUFPE 21791 ; 1 M, 27.ii.2018, 8°13′52.1′′S 34°37′41.2′′W, 51.8 m depth, MOUFPE 21549 ; Ilha de Itamaracá : 11 M, 17.i.1969, 7°49′S 34°49′13′′W, 0.8 m depth, MOUFPE 8753 ; Recife : 18 M, 4 F, 2 NI , Boa Viagem , 24.xi.1964, in sponge, MOUFPE 8757 .

Description: Macdonald & Duffy (2006) and Anker et al. (2012).

Distribution: USA (Florida), Gulf of Mexico, Bahamas, Caribbean Sea, Suriname and Brazil (Fernando de Noronha, Abrolhos, and from Amapá to Bahia) ( Chace 1972; Christoffersen 1979, 1998; Ríos & Duffy, 2007; Alves et al. 2008; Anker et al. 2012; Soledade et al. 2015).

Ecology: Coral reef areas, associated with coral rubble, calcareous algae, seagrass banks, and sponges (e.g., Agelas sp. , Ircinia sp. , Lissodendoryx sp. , and Spheciospongia sp. ); in heterosexual pairs, associated with H. caerulea ; also forming “subsocial” groups, with densities varying from 10 to 1000 individuals, with few ovigerous females among them ( Ríos & Duffy, 2007); intertidal to 82.3 m, most commonly up to 10 m ( Christoffersen 1979; Dardeau 1984; Ríos & Duffy, 2007; Anker et al. 2012). Ecological notes regarding our material, especially those related to association with sponges, are provided in the remarks and in the Discussion section.

Remarks: Synalpheus brooksi is one of the most widely distributed species of Synalpheus in the western Atlantic ( Macdonald & Duffy 2006; Anker et al. 2012). The specimen from Parque Estadual Marinho da Pedra da Risca do Meio, Fortaleza, Ceará, previously cited by Bezerra & Coelho (2006) as S. townsendi (without access number), actually correspond to S. brooksi (MOUFPE 21868) (this study).

Some morphological variations were observed in our material in comparison to the redescription provided by Dardeau (1984). In three females (1 OV, MOUFPE 8741; 1 OV, and 1 F, MOUFPE 8743), the pleura of the third and fourth segments are rounded (vs. third and fourth pleura subrectangular to tapered) ( Dardeau 1984, Fig. 12C ). One of these females (OV, MOUFPE 8741) exhibited only one pair of dorsal spiniform setae on the telson (vs. typically two pairs; see Dardeau 1984, Fig. 12F ), two distolateral teeth on the uropodal exopod (vs. one distolateral tooth; see Dardeau 1984, Fig. 12F ), and the rostrum and orbital hoods were poorly produced, with the tridentate front being wider than long (vs. produced rostrum and orbital hoods, with tridentate front being longer than wide; see Dardeau 1984, Fig. 12A )

Interestingly, eight males carried embryos on their pleopods (1 M, MOUFPE 8746; 4 M, MOUFPE 8749; 2 M, MOUFPE 8753; 1 M, MOUFPE 21816), a surprising observation given the absence of ovigerous setae and the presence of pleura characteristics typical of Synalpheus males. This behavior has been previously reported for this species by Coutière (1909), Chace (1972), Dardeau (1984), and Anker et al. (2012). Notably, ovigerous females were found in the same jars as these males, suggesting a potential collective caregiving behavior for offspring within “subsocial” groups. Ethological studies are needed to further investigate this phenomenon.

We recorded a possible subsocial group with a total of 54 specimens associated with a sponge ( Fig. 3C ) on the continental shelf off Recife , Pernambuco ( MOUFPE 21816 ) . Among them, two individuals (1 M and 1 F) possessed two pairs of minor chelae. Additionally, one S. herricki specimen (1 M, DZ / UFRGS 7067 ) was found co-occurring within the same sponge host. Parasitism was also observed, with some individuals exhibiting gill chambers infested by bopyrid isopods (1 M and 1 F, MOUFPE 21816 ) and pleons parasitized by rhizocephalans ( MOUFPE 8746 ) .

Figures

FIGURE 3. Substrates where the specimens of Synalpheus Spence Bate, 1888 analyzed in this study were found.A, Rhodoliths; B, Sediment; C, Sponge where the colony of S. brooksi Coutière, 1909 was found; D, Sponge morphotype where the possible communal groups of S. hoetjesi Hultgren, Macdonald & Duffy, 2010 and S. ul (Ríos & Duffy, 2007) were found, arrows indicate the presence of shrimps. Photos A–D: P.H. Paixão.

FIGURE12. Synalpheus corallinusMacdonald,Hultgren &Duffy, 2009:male from thecontinentalshelf off Recife,Pernambuco, Brazil [MOUFPE 21812]. A, pleon, right view; B, right uropod, dorsal view; C, left uropod, dorsal view; D, third maxilliped, right side, lateral view; E, telson, dorsal view. Scale bars: A, 1 mm; B–E, 0.3 mm.