Rapipontonia paragalene Marin, 2007

Marin, Ivan, 2009, A review of the pontoniine shrimp genus Rapipontonia Marin, 2007 (Decapoda: Caridea: Palaemonidae), with the description of a new species from the Indo-West Pacific, Zootaxa 2289, pp. 1-17 : 8

Rapipontonia paragalene Marin, 2007

( Fig. 4 )

Rapipontonia paragalene Marin, 2007: 777 [partim], figs. 1, 5 [type locality – Vietnam].

Material. 1 ovigerous Ƥ pcl 2.5 mm (holotype, MNHN-Na16395), 1 3 pcl 1.8 mm (allotype, MNHN-Na 16396), Pacific Ocean, Vietnam, Nhatrang Bay, on pile under pier of Marine Military Academy (MMA), depth 2 m, on hydroid Lytocarpia sp., 17 July 2006, coll. Marin; 2 ovigerous ƤƤ (pcl 2.3, 2.6), 1 3 (pcl 1.7 mm) ( ZMMU), Nhatrang Bay, on pile under pier of MMA, depth 2 m, on hydroid Lytocarpia sp., 23 July 2006, coll. Marin.

Diagnosis. Epigastric tooth clearly divided from carapace by a suture. Rostrum ( Fig. 4 A) slender, rostral formula 1+6–7/0; proximal rostral crest with 4–5 large teeth, distal part of rostrum slender with dorsal tooth separated from subapical tooth with a distinct gap. Antenna ( Fig. 4 B) with distolateral margin of basal segment bearing sharp distolateral tooth and rounded median lobe. First pereiopod slender, fingers with spoon-like tips. Second pereiopods unequal in size in females and equal in males. In females, major second pereiopod ( Fig. 6 C) overreaching distal margin of antennular peduncle by twice of its length, with merus about 11 times longer than wide, carpus about 4.5 times longer than maximal width, flaring distally, palm ( Fig. 4 D) about 4.5 times longer than wide, ratio of merus: carpus: propodus: dactylus is 4: 2.5: 2.5: 1; minor second pereiopod ( Fig. 4 E) with merus about 9.5 times longer than wide, carpus about 5 times longer than maximal width, flaring distally, palm ( Fig. 6 F) about 3 times longer than wide, ratio of merus: carpus: propodus: dactylus is 3: 2: 1.3: 1. In males, second pereiopods equal in size and shape, reaching to the distal margin of antennular peduncle, slender, with merus about 10 times longer than wide, carpus about 8 times longer than maximal width, flaring distally, palm about 4 times longer than wide, ratio of merus: carpus: propodus: dactylus is 4.5: 3: 2.8: 1. Third pereiopod with distoventral margin of propodus bearing 2–3 long unpaired and a pair of long distoventral spines ( Fig. 4 G); third proximal spine, if present, about half of the length of the next ventral spine ( Fig. 4 H).

Remarks. Rapipontonia paragalene is clearly separated from R. platalea geographically and by a longer rostrum reaching to distal margin of antennular peduncle. The species can be clearly distinguished from the Indo-West Pacific R. galene by the unequal second pereiopods in females and the different proportions of distal segments of the second pereiopods in males (see present paper and original description in Marin, 2007); for differences from R. hydra n. sp. see below.

Coloration. Body, appendages and eyestalks translucent, with numerous white chromatophores along dorsal margin of the body, telson and uropods; long reddish-brown thin line crossing through all ventral surface of the body from distal margins of antenna to telson; second to fourth abdominal pleurae with oblique red thin lines; fingers of major second pereiopod in female reddish. Gonads and eggs white (see Hoover, 2006). The coloration is similar to the new species, R hydra n. sp. (see below).

Hosts and distribution. The species has been recorded only from the type locality, Nhatrang Bay, Vietnam; photo of Mike Roberts with ovigerous female of Rapipontonia aff. paragalene is published in WWW (http://www.flickr.com/photos/reeflections/53258899/). Associated with hydroid Lytocarpia sp. (Cnidaria. Hydroidea) ( Marin, 2007); in Hawaii was photographed ( Hoover, 2006) on the introduced hydroid Pennaria disticha (Goldfuss, 1820) (Cnidaria, Hydroidea, Thecaphora).

Figures

FIGURE 4. Rapipontonia paragalene Marin, 2007, female, ZMMU: A—carapace and rostrum, lateral view; Bantennula; C—antenna; D—major second pereiopod; E—minor second pereiopod; F—same, distal segments; G, Hgrasping mechanism of third pereiopod. Scale bar: 1 mm.

FIGURE 6. Rapipontonia hydra n. sp., paratype female, (RMNH, D 48164): A—first pereiopod; B—same, chela; Cmajor second pereiopod; D—same, chela; E—minor second pereiopod; F—same, chela; G—third pereiopod; H—same, grasping mechanism. Scale bar: 1 mm.