Rapipontonia platalea ( Holthuis, 1951a )

Fransen, Charles H. J. M., 2023, The marine palaemonid shrimps (Crustacea, Deapoda, Caridea) of the Dutch Caribbean, Zootaxa 5387 (1), pp. 1-127 : 110-112

Rapipontonia platalea ( Holthuis, 1951a)

( Fig. 72 )

Material examined. Curaçao: RMNH.CRUS.D.51643 : 1 damaged female, pocl. 1.1 mm, R=4/0; stn CUR.13, south coast, Playa Lagun , 12°19′05.5″N 069°09′02.0″W, depth 14.1 m, 06.vi.2005, scuba diving, on Briareum asbestinum (F374), collected by N. Snijders (fcn. g103). Material for comparison. Eastern Atlantic: RMNH.CRUS.D.51044 : 2 females, 2 males; Cape Verde Islands , Sao Nocolau, SE coast, “Tydeman” Cancap VII Expedition, Stn 7.D.11, 16º34′N 24º17′W, 2–3.ix.1986 . RMNH.CRUS.D.50048 : 2 males, São Tomé , Pedra Hirondino, Rolas Island, 0 ºN 6º31′E, from gorgonians, depth 14 m, viii.2002, collected by P. Wirtz. RMNH.CRUS.D.50047 : 2 males; São Tomé , Pedra de Brago, Rolas Island, from gorgonians, 12 m, viii.2002, collected by P. Wirtz.

Remarks. The present small specimen corresponds to the descriptions by Holthuis (1951a) and Marin (2009) of East Atlantic specimens and by Hale & De Grave (2007) of West Atlantic specimens. The posterior part of the abdomen is missing as well as all pereiopods except for one detached left third, fourth or fifth pereiopod. The rostrum ( Fig. 72A ) has four dorsal teeth and is without ventral teeth, it is not reaching the distal margin of the basal segment of the antennular peduncle which is similar to the small East Atlantic specimen depicted by Marin (2009: fig. 1C) and small specimens recorded by Hale & De Grave (2007). The epigastric tooth is missing although a scar is present. The infraorbital angel is broadly rounded. The antennal spine is situated distinctly below the infraorbital angle. The hepatic spine is situated slightly above the level of the antennal spine. The first pereiopods ( Fig. 72B ) show the spoon-like distal part of the fingers ( Fig. 72C ), typical for the genus. The detached third, fourth or fifth pereiopod ( Fig. 72D ) has the distoventral margin of the propodus ( Fig. 72E ) bearing two unpaired and one pair of long distoventral spines. These spines are minutely bifurcate distally. This feature has not been observed for the East Atlantic specimens.

Ecology. The species was recorded from Antipatharia : Antipathes spp. ( Wirtz & d’Udekem d’Acoz 2001, 2008), Stichopathes gracilis Gray, 1857 ( Wirtz & d’Udekem d’Acoz 2008); Plumapathes pennacea (Pallas, 1766) ( De Grave et al. 2019) ; from Gorgonacea: Leptogorgia gaini Stiasny, 1940 ( Wirtz & d’Udekem d’Acoz 2001), Leptogorgia sp. ( Wirtz, 2003; Wirtz & d’Udekem d’Acoz 2008; Wirtz & De Grave 2010); unidentified Gorgonaria ( Wirtz & d’Udekem d’Acoz 2008; Wirtz et al. 2020); and from Hydrozoa: Gymnangium longicauda (Nutting, 1900) , encrusted with the parazoanthid Parazoanthus tunicans Duerden, 1900 . The species is herein recorded for the first time from the alcyonacean Briareum asbestinum (Pallas, 1766) .

Distribution. The species has an amphi-Atlantic distribution. It has been recorded from scattered locations: Cape Verde Islands ( Holthuis 1951a; Wirtz & d’Udekem d’Acoz 2001); Guinea ( Wirtz & d’Udekem d’Acoz 2001); Senegal ( Wirtz & De Grave 2010); São Tomé Island ( Wirtz 2003; Wirtz & d’Udekem d’Acoz 2008); Gabon ( Wirtz et al. 2020); Ascension Island and St. Helena ( De Grave et al. 2019); Tobago ( Hale & De Grave 2007); northern Yucatan peninsula, Mexico (Santano-Moreno et al. 2013). This is the first record of the species from Curaçao.

Figures

FIGURE 72. Rapipontonia platalea (Holthuis, 1951a), RMNH.CRUS.D.51643: 1 female, pocl. 1.1 mm.A, anterior appendages, lateral; B, first left pereiopod; C, idem, chela; D, third, fourth or fifth left pereiopod; E, idem, dactylus and distal part propodus. Scale bars: A=1.0 mm; B, D=0.5 mm; C, E=0.125 mm.