Hippolyte catagrapha, Cédric, 2007

Cédric, 2007, New records of Atlantic Hippolyte, with the description of two new species, and a key to all Atlantic and Mediterranean species (Crustacea, Decapoda, Caridea), Zoosystema 29 (1), pp. 183-207 : 185-193

Hippolyte catagrapha n. sp.

( Figs 1-4 )

TYPE MATERIAL. — South AFrica. False Bay , 6-8 m depth, from the crinoid Tropiometra carinata (Lamarck, 1816) , collected by the scuba divers Georgina Jones, Peter Southwood and Guido Zsilavecz and made available for study by Charles L. Griffiths, 1.V.2005, ovigerous ♀ holotype (MNHN-Na16258) ; 1 ovigerous ♀ dissected paratype (MNHN-Na16259); 1 immature ♀ paratype (MNHN-Na16260).

ETYMOLOGY. — Catagrapha is the feminine of the Latin adjective catagraphus, which means painted, coloured, figured. The name alludes to the complex and variable colour pattern of the species.

DISTRIBUTION. — False Bay ( South Africa).

DESCRIPTION

Carapace moderately stout. Rostrum moderately high, straight, about as long as carapace, much longer than antennular peduncle. Rostrum without postrostral tooth, with a single dorsal teeth at 0.4 of rostrum length; two or three ventral teeth, distant from tip of rostrum. Hepatic tooth overreaching or not reaching anterior edge of carapace. Pterygostomial angle not protruding ( Fig. 1A, B ).

Third pleonite barely curved in lateral view. Ratio dorsal length/height of sixth pleonite: 1.8 in holotype ( Fig. 1A ). Distal border of telson with 10 well developed spines in dissected paratype (outer spines much shorter than others). First pair of dorsolateral spines on 0.5 or 0.6 of telson and second pair on 0.8 ( Fig. 1E, F ).

Unpigmented part of cornea slightly longer than broad ( Fig. 1C ). Cornea not reaching stylocerite apex ( Fig. 1A ). First article of antennular peduncle without distolateral tooth; stylocerite long, reaching or just overreaching tip of first article of antennular peduncle. Second article of antennular peduncle distinctly longer than broad in dorsal view, distinctly longer than third article in dorsal view. Inner antennular flagellum longer than outer flagellum ( Fig. 1C ). Scaphocerite 3.2 times as long as wide; distolateral spine of scaphocerite not reaching tip of blade; distolateral spine and blade separated by a distinct notch ( Fig. 1D ).

Mandibular incisor process with seven teeth ( Fig. 2B ). Third maxilliped reaching about 0.5 of scaphocerite ( Fig. 1A ). Ultimate article of third maxilliped with many long apical setae (looking like a paintbrush), with 10 conical spines on its apex and the distal third of its mesial border (the apical ones are difficult to see in dorsal view, being hidden by setae); 3 times as long as wide when dorsally measured; 1.5 times as long as penultimate; exopod of third maxilliped not reaching half of antepenultimate segment of endopod ( Fig. 3 A-D).

P1 ( Fig. 3E, F ) with outer edges of fingers of chela not denticulate (but with marginal tiny setules).

P2 ( Fig. 3G, H ) with first segment of carpus 2.1 times as long as third segment, 1.2 times as long as second and third segments combined; first segment 8.6 times as long as wide; second segment 3.6 times as long as wide; third segment 3.7 times as long as wide.

P3-P5 stout ( Fig. 4 ). Merus of P3-P4 with a single spine, in subdistal position; merus of P5 without spine; carpus of P3-P5 with spine; propodus with about two or three slender spinules on distal third, hidden by dense tufts of setae; dactylus short and very stout, with two terminal spines much shorter than dactylus (most anterior spine 2.5 times as long as next one), and with four or five more slender but rather well developed spines on flexor border.

No specimens with plumose setae on body (“fascigerous” specimens) were recorded.

A B

A

Colour pattern

Colour pattern very vivid but variable (photographs given by C. Griffiths).Some specimens have a colour pattern made up of longitudinal red and yellowish stripes, some stripes being interrupted and forming longitudinal series of spots. Others are spotted like a panther: black spots on a yellow background with a few small whitish marks. The different colour patterns mimic those (also varied) of the feather star Tropiometra carinata (Lamarck, 1816) .

Size

Total length up to 22 mm.

ECOLOGY

6-8 m depth, associated with the crinoid Tropiometra carinata , mimicking its various colour patterns.

REMARKS

Hippolyte catagrapha n. sp. can be distinguished at first glance from the other South African Hippolyte described by Barnard (1950) and Kensley (1970, 1972) by the whorl of setae of the tip of its third maxilliped. This character is shared with the rare European species H. leptometrae . The two species are very similar but H. catagrapha n. sp. lives in shallower waters than H. leptometrae . Hippolyte catagrapha n. sp. has only one dorsal rostral tooth (on the middle of the rostrum), whilst H. leptometrae has in addition a subdistal tooth on the dorsal part of the rostrum. Hippolyte catagrapha n. sp. is also stouter than H. leptometrae , especially in the last three pereiopods and their dactyli.

The validity of the rostral ornamentation as a diagnostic character is variable within the genus Hippolyte . There are species in which this character is very constant, e.g., H. varians , and others, such as Hippolyte leptocerus (Heller, 1863) , in which it is exceedingly variable (d’Udekem d’Acoz 1996). Griffiths (in litt.) who examined more specimens of H. catagrapha n. sp. confirmed that there was one single dorsal rostral tooth in all his specimens, confirming the validity of this character for the species.

The existence of a pair of very similar species, one European and one South African is not unique amongst decapods. This is for example the case in Callianassa subterranea (Montagu, 1808) and C. australis Kensley, 1974 . In other cases there is a latitudinal succession of three related species, for example Polybius (Macropipus) tuberculatus (Roux, 1830) in Europe, P. (M.) rugosus Doflein, 1904 in West Africa and P. (M.) australis Guinot, 1961 in South Africa. Therefore it would not be unexpected if a third Hippolyte species of the group leptometrae would occur on crinoids of tropical West Africa.

Unlike H. catagrapha n. sp. and H. leptometrae , the third crinoid-associated Hippolyte species , the European H. prideauxiana Leach, 1815 (syn. H. huntii Gosse, 1877 ), has no dense whorl of setae on the tip of the third maxilliped. However H. prideauxiana shares other characters with H. catagrapha n. sp. and H. leptometrae , such as a very long and narrow first article of the carpus of P2 and the general morphology of the dactylus of P3-P5.

Hippolyte catagrapha n. sp. exhibits either longitudinal stripes or a spotted colour pattern. H. leptometrae is longitudinally striped (in the very few specimens observed alive) ( Noël 1983). Adult females of H. prideauxiana are always transversally striped ( Smaldon et al. 1993). Hippolyte catagrapha n. sp. probably is able to modify its colour pattern to match the variable colour of its host. Free-living Hippolyte species such as H. varians are able to modify their colour pattern to match the substrate, in modifying their chromatophores (Chassard- Bouchaud 1965). So, it could also be the case in some symbiotic species.

Hippolyte leptometrae Ledoyer, 1969 ( Figs 5 ; 6 )

Hippolyte leptometrae Ledoyer, 1969: 342 , pl. 2. — Lagardère 1973: 80, 84. — Noël 1983: 37, fig.1. — D’Udekem d’Acoz 1996: 54, fig. 24.

MATERIAL EXAMINED. — France. Bay of Biscay,TROPHAL cruise, sample E3-TS03-F1 (daytime sampling), 46°56’N 004°30’W, medium-grained sand [“sables moyens”], 130-132 m depth, the occurrence of Leptometra celtica (McAndrew & Barrett, 1858) in the sample was noted (Jean-Claude Sorbe pers. comm.), 13.IX.2002, coll. J.-C. Sorbe, 1 ovigerous ♀ (MNHN-Na16261).

DISTRIBUTION. — Bay of Biscay ( Lagardère 1973; present data); Mediterranean (d’Udekem d’Acoz 1996).

ECOLOGY The species has been recorded between 95 and 130 m depth. It is associated with the crinoids Leptometra phalangium (J. Müller, 1841) in the Mediterranean ( Ledoyer 1969; Noël 1983) and presumably with Leptometra celtica in the eastern Atlantic, as the occurrence of L. celtica in the sample here examined was noted.

REMARKS

Hippolyte leptometrae has rarely been recorded, and all illustrations in the literature are based on Mediterranean specimens. The Biscayan specimen under study proves to be slightly more robust than the Mediterranean shrimp illustrated by d’Udekem d’Acoz (1996). In that paper, I indicated that I was unable to observe spines on the last article of the third maxilliped of the single specimen examined (which was not dissected). The dissection of the maxilliped of the present specimen (from the Bay of Biscay) indicates that such spines are indeed present but cannot be seen in dorsal view ( Fig. 6 A-C).

Figures

FIG. 1. — Hippolyte catagrapha n. sp., ♀♀, South Africa,False Bay: A, holotype; B-D, paratype; A, habitus in lateral view;B, carapace; C, right eye and antennula; D, left scaphocerite; E, telson; F, tip of telson. Scale bar: A, B, 2.9 mm; C-E, 1.24 mm; F, 0.3 mm.

FIG. 2. — Hippolyte catagrapha n. sp., ♀ paratype, South Africa, False Bay: A, right mandible; B, incisor process of right mandible; C, left maxillula; D, left maxilla; E, left Mxp1; F, left Mxp2. Scale bar: A, 0.42 mm; B, 0.10 mm; C-F, 0.30 mm.

FIG. 3. — Hippolyte catagrapha n. sp., ♀ paratype, South Africa, False Bay: A, left Mxp3 in dorsal view; B, distal article of left Mxp3 in dorsal view; C, distal article of left Mxp3 in ventral view; D, tip of distal article of left Mxp3 in dorsal view (setae not shown); E, left P1; F, tip of left P1 in mesial view; G, left P2; H, tip of left P2. Scale bar: A, E, G, 0.84 mm; B, C, 0.42 mm; D, F, H, 0.20 mm.

FIG. 4. — Hippolyte catagrapha n. sp., ♀ paratype, South Africa, False Bay: A, left P3; B, dactylus of left P3; C, left P4; D, left P5. Scale bar: A, C, D, 0.84 mm; B, 0.17 mm.

FIG. 5. — Hippolyte leptometrae Ledoyer, 1969, ♀, Bay of Biscay: A, habitus in lateral view (right P4 used for illustration since left P4 is missing); B, rostrum and dorsal part of carapace; C, carapace and cephalic appendages in dorsal view. Scale bar: A, C, 2.5 mm; B, 1.8 mm.

FIG. 6. — Hippolyte leptometrae Ledoyer, 1969, ♀, Bay of Biscay: A, right Mxp3 in dorsal view;B, distal two articles of Mxp3 in ventral view; C, tip of distal article of right Mxp3 in dorsal view (setae not shown);D, left P2; E, left P3; F, dactylus of left P3; G, right P4. Scale bar: A, B, 0.75 mm; C, 0.21 mm; D, E, G, 0.84 mm; F, 0.17 mm.