Rapipontonia paragalene, Marin, 2007
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publication ID |
https://doi.org/ 10.5281/zenodo.4525695 |
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persistent identifier |
https://treatment.plazi.org/id/038587B0-FFC8-FFB0-FCCA-F9904AE2E497 |
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treatment provided by |
Felipe |
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scientific name |
Rapipontonia paragalene |
| status |
sp. nov. |
Rapipontonia paragalene View in CoL n. sp.
( Figs 1-5 View FIG View FIG View FIG View FIG View FIG )
TYPE MATERIAL. — Holotype: Vietnam , South China Sea, Nhatrang Bay, on pile under pier of Marine Military Academy ( MMA), depth 2 m, on hydroid Lytocarpia sp., 17.VII.2006, 1 ovigerous ♀ pcl 2.5 mm (MNHN-Na 16395).
Allotype: same locality as for holotype, 1 ♂ pcl 1.8 mm (MNHN-Na 16396).
Paratypes: Vietnam , South China Sea, Nhatrang Bay, on pile under pier of MMA, depth 2 m, on hydroid Lytocarpia sp., 23.VII.2006, 4 ovigerous ♀♀ pcl 2.3, 2.6 (dissected), 3.2, 3.4 mm (photo), 1 ♂ pcl 1.7 mm ( ZMMU).
ETYMOLOGY. — The new species is closely related to Rapipontonia galene n. comb. (para, Latin for similar, resembling).
TYPE LOCALITY. — Nhatrang Bay, Vietnam .
DISTRIBUTION. — Known from the type locality, Nhatrang Bay, Vietnam .
DESCRIPTION (based on female holotype) Medium-sized shrimps with slender body ( Fig. 1 View FIG ). Carapace swollen, smooth, with well developed antennal, hepatic and epigastric teeth; hepatic tooth smaller than antennal, situated posterior and slightly above level of antennal tooth; epigastric tooth well marked, slightly smaller than proximal dorsal tooth, clearly separated from rostral teeth, separated from carapace by a well marked suture. Rostrum ( Fig. 2A, B View FIG ) long and slender, with well developed dorsal carina bearing six teeth, ventrally unarmed; proximal half of rostrum with crest-like carina bearing four large acute teeth; distal half of rostrum slender, with two small teeth. Inferior orbital angle strongly produced, rounded.
Abdominal somites smooth; tergites non-carinate, not posteriorly produced; pleura of first to fifth abdominal somites posteroventrally rounded. Telson ( Fig. 4I View FIG ) slender, four times as long as wide, tapering distally, with two pairs of small dorsal spines at 0.5 and 0.7 of telson length, respectively; posterior margin with three pairs of spines, mostlateral spines shortest, intermediate spines longest, mesial spines more slender than others, about half length of intermediate spine.
Eyes large, cornea rounded.
Antennules ( Fig. 2C View FIG ) with basal segment about three times as long as wide, with distinct ventromesial tooth; lateral portion depressed, well defined (individualized from rest of basal segment), bearing large acute distolateral tooth; stylocerite acute, reaching to about mid-length of basal segment; intermediate segment robust, about 1.5 times as long as wide; distal segment about twice as long as wide; upper (lateral) flagellum long, slender, shorter ramus with more than seven segments, with eight groups of aesthetascs; main ramus with more than 10 segments; lower (mesial) flagellum filiform, with more than 30 segments.
Antenna ( Fig. 2D View FIG ) with distolateral margin of basicerite, with distolateral tooth; carpocerite about 1.5 times as long as wide; scaphocerite slender, exceeding antennular peduncle and rostrum, about three times as long as maximum width, with well developed distolateral tooth, latter not exceeding blade.
Mouthparts without specific features. Mandible ( Fig. 3A View FIG ) without palp; incisor process slender, tapering distally, with three to four distal teeth; molar process well developed.Maxillula ( Fig. 3B View FIG ) with well developed, bilobed palp; upper lacinia larger than lower lacinia, slightly tapering distally, with strong distal spines; lower lacinia slender, distally rounded, with distal setae. Maxilla ( Fig. 3C View FIG ) with well developed, simple palp; basal endite simple, furnished with stiff, elongated setae; coxal endite absent; scaphognathite relatively broad. First maxilliped ( Fig. 3D View FIG ) with distinct endites; palp well developed, without distal setae; exopod with expanded caridean lobe bearing plumose setae marginally; epipod subtriangular. Second maxilliped ( Fig. 3E View FIG ) with normal exopod; distolateral margin of propodus broadly rounded, with slender setae; dactylus about three times as long as broad, with numerous spines along distal margin; epipod poorly developed; podobranch absent.
Third maxilliped ( Fig. 3F View FIG ) relatively slender; coxa with rounded lateral plate and several long plumose setae; basis and ischiomerus fused to single antepenultimate segment, about six times as long as wide, suture between basis and ischiomerus well marked; penultimate segment slender, about four times as long as wide; ultimate segment about four times as long as wide; exopod well developed; single arthrobranch small.
First pereiopod ( Fig. 4A View FIG ) slender, segments unarmed; basis about 1.5 times as long as wide; ischium about three times as long as wide; carpus slender, six times as long as wide; propodus about 4.5 times as long as maximum width, widening distally; palm ( Fig. 4B, C View FIG ) twice as long as wide, subcylindrical; fingers slender, about six times as long as wide, with spoon-like tips and straight cutting edges.
Second pereiopods unequal in size, symmetrical in shape ( Fig. 4D, E View FIG ); basis rectangular; ischium about five times as long as maximal width; merus about ten times as long as maximal width; carpus about three times as long as maximum width, broadening distally; palm subcylindrical ( Fig. 4E View FIG ), about three times as long as maximal width; fingers robust, about two times as long as wide, about one third of the palm length, curved, with acute tips; dactylus simple, round in cross section, without sharp cutting edge; pollex with well developed lateral carina, without sharp cutting edge ( Fig. 4F View FIG ); ratio dactylus:propodus:carpus approximately equal to 1:3:3.
Third pereiopod ( Fig. 4G View FIG ) slender; basis about twice as long as wide; ischium about four times as long as wide; merus about 10.5 times as long as wide; carpus about five times as long as maximum width, with slightly projecting distodorsal margin; propodus six times as long as wide, with broadened distal third, bearing three pairs of long spines; dactylus ( Fig. 4H View FIG ) simple, about five times longer than wide, slender, curved, forming together with long propodal spines a grasping mechanism. Fourth and fifth pereiopods similar to third.
Pleopods without specific features. Uropods ( Fig. 4J View FIG ) slender, exceeding telson; lateral margin of uropodal exopod with small subdistal tooth and adjacent spine.
Allotype male smaller in size but otherwise similar to holotype female; body somewhat more slender; endopod of first pleopod oval-shaped ( Fig. 5A View FIG ); endopod of second pleopod with well developed appendix masculina bearing two long plumose terminal setae and one simple submarginal seta ( Fig. 5B View FIG ).
Colour
Body, appendages and eyestalks translucent, with numerous large white chromatophores ordered in longitudinal bands along carapace and abdomen; first to fourth abdominal pleurae with oblique black bands; additional broad black bands present along ventral margin of posterior abdominal segments; four narrow longitudinal black stripes on upper surface of gonads; antennules, distal uropods and telson black; distal part of propodus and fingers of second pereiopod reddish. Gonads and eggs white ( Fig. 6 View FIG ).
ECOLOGY
All specimens were found clinging onto plumulariid hydroid, Lytocarpia sp. ( Hydroidea, Thacaphora ,
Plumulariidae ) ( Fig. 6 View FIG ), growing on harbour piles, at depths of 2- 5 m.
VARIATION
In two paratype ovigerous females, largest in the type series (pcl. 3.2; 3.4 mm), the major chela is similar in proportions to the holotype, while the minor chela is comparatively more slender, with the carpus being about twice as long as the palm. Nevertheless, the proportion between the dactylus and the palm remains the same (1:3).
REMARKS
The new species is closely related to Rapipontonia galene n. comb., but can be clearly separated from the latter species by the shorter fingers and different proportions of distal segments in the second pereiopod, with the ratio dactylus:propodus:carpus of about 1:3: 3 in the holotype R. paragalene n. sp. (vs. 1:2: 4 in R. galene n. comb.; cf. Holthuis 1952: fig. 24f). In the large specimens of R. paragalene n. sp., the second pereiopods are slightly dissimilar in size, with this ratio in the minor chela being about 1: 3: 6. Rapipontonia paragalene n. sp. also differs from R. galene n. comb. by the finger tips of the first pereiopod being less distinctly scoop-shaped (vs. clearly scoop-shaped in R. galene n. comb.; cf. Bruce 1976: fig. 3d, e); and the number of distal propodal spines on the third pereiopod: three pairs of equally long spines in R. paragalene n. sp. vs. five pairs of unequal spines in R. galene n. comb. (cf. Holthuis 1952: fig. 24g), although Bruce (1976: fig. 3g) illustrated three pairs of equally long spines in R. galene n. comb. from Kenya. The colour pattern of R. paragalene n. sp. also differs from that of R. galene n. comb.; the latter species presents numerous broad black and narrow yellow longitudinal on the carapace and abdomen ( Debelius 2001: 185).
The remaining species, Rapipontonia platalea n. comb., differs from R. paragalene n. sp. by the significantly shorter, simple distal portion of the rostrum; and the second pereiopod with larger fingers, about half as long as palm (cf. Holthuis 1951: fig. 32); further, this species is distributed in the Eastern Atlantic ( Holthuis 1951; Wirtz & d’Udekem d’Acoz 2001).
| ZMMU |
Zoological Museum, Moscow Lomonosov State University |
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.