Stylodactylus sp.

Cleva, Régis, 2004, Stylodactylidae And Bathypalaemonellidae From Taiwan (Crustacea: Decapoda: Caridea), Raffles Bulletin of Zoology 52 (2), pp. 497-511 : 502-504

Stylodactylus sp. aff. pubescens Burukovsky, 1990

( Fig. 3 )

Material examined. – 1 male 14 mm, 1 ov. female 12.5 mm ( NTOU), “ TAIWAN 2003”, st. CD 210, 24 28.99N- 122 12.79E, 500-1183 m, 01 Jun.2003 .

Comparative material. – 2 males 9.5 and 11.5 mm, 3 females 11 to 11.5 mm, paratypes of Stylodactylus pubescens , east Pacific , Sala-y-Gomez and Nasca ridges, 25 09’S- 96 18’W, 545-800 m, 01 May.1987 (Catalogue number 3/81729) ; 1 male 9.5 mm, 1 ov. female 8.5 mm, same data (MNHNNa.15028) . 2 females 13 and 15.5 mm (MNHN-Na.12142), Indonesia, “KARUBAR”, st.CP 17, 05 17’S- 133 00’E, 459- 439 m, 24 Oct.1991 . 1 female 8.5 mm (MNHN-Na.10917), New Caledonia, “BIOCAL”, st.DW 51, 23 05’S- 167 44’E, 680-700 m, 31 Aug.1985 ; 1 female 10.5 mm (MNHNNa.10920), New Caledonia, “CHALCAL 2”, st.DW 72, 24 54’S- 168 22’E, 527 m, 28 Oct.1986 ; 1 male 12.5 mm (MNHN-Na.12159), New Caledonia, “ BERYX 11 ”, st.DW 09, 24 44’S- 170 07’E, 790-825 m, 26 Oct.1992 ; 1 female 11.5 mm (MNHN-Na.14649), New Caledonia, “ BERYX 11 ”, st. CP 53, 23 48’S- 168 17’E, 540-950 m, 21 Oct.1992 ; 1 male 13 mm (MNHN-Na.14647), New Caledonia, “ BERYX 11 ”, st. CP 60, 23 19’S- 168 00’E, 580-600 m, 22 Oct.1992 ; 1 male 10 mm, 1 female carapace damaged (MNHN-Na.14648), same data ; 1 male 9 mm, 2 females 5.5 and 10.5 mm (MNHNNa.14480), New Caledonia, “BATHUS 3”, st. DW 776, 24 44’S- 170 08’E, 770-830 m, 24 Nov.1993 ; 1 female 9 mm (MNHN-Na.12164), New Caledonia, “BATHUS 3”, st. DW 786, 23 54’S- 169 49’E, 699-715 m, 25 Nov.1993 ; 1 female 7.5 mm (MNHN-Na.12163), New Caledonia, “BATHUS 3”, st. DW 794, 23 48’S- 169 49’E, 751-755 m, 26 Nov.1993 .

1 male 10.5 mm, 1 ov. female 12 mm (MNHN-Na.15029), Tonga,“ BORDAU 2 ”, st.CP 1529, 21 13’S- 174 58’W, 688- 710 m, 03 Jun.2000 ; 2 males 8.5 and 10.5 mm, 1 ov. female 11 mm (MNHN-Na.15030), same data ; 1 male 11.5 mm (MNHN-Na.15031), Tonga, “ BORDAU 2 ”, st. CH 1557, 20 10 ’S- 174 42’W, 578 m, 07 Jun.2000 ; 1 male 11.5 mm, 3 females (2 ov.) 11 to 12.5 mm (MNHN-Na.15032), Tonga, “ BORDAU 2 ”, st. CP 1558, 20 10 ’S- 174 43’W, 580-593 m, 07 Jun.2000 .

Remarks. – These 2 specimens clearly differ from S. libratus by the following characters ( Figs. 3a, d ):1/ The carapace/ rostrum ratio: rostrum is shorter than the carapace (0.85 LC on the female; the tip of the rostrum is broken on the male but it can be easily estimated as being shorter than the carapace); 2/ The number and length of the rostral spines: 26 dorsal spines (6 on the carapace proper) and 5 ventral for the female; 3/ The antennal and branchiostegal spines are longer, along with the spinules of the scaphocerite; 4/ The dactyls of the last three pairs of pereiopods are longer; 4 / The eyes are larger.5/ The coloration is also very different: color photograph of the ovigerous female does not indicate special pattern: the body and appendages are pinkish without any trace of stipe or band; eggs are orange.

These specimens could be related with Stylodactylus pubescens Burukovsky, 1990 , as are the specimens from Indonesia, New Caledonia, and Tonga mentionned above (Indonesian and New Caledonian specimens have been left unidentified by Cleva, 1997, page 393, under the name Stylodactylus sp. ). We have examined or reexamined all this material, along with 7 paratypes of Burukovsky species ( Figs. 3b, c ), in order to try understanding the relationships of these different groups between each other and with S pubescens . Due to rather important individual variations, their status is not easy to establish: do they belong to one species different from S. pubescens , or to several different species, or are they different populations of the same species, this species being S. pubescens or another one?

Comparison between specimens of the same size leads to the following conclusions:

1) Ovigerous female from Taiwan (CL 12.5 mm) appears to be very closed to ovigerous female from Indonesia (MNHN-Na.12142, CL 13 mm): rostral formula, size and disposition of rostral teeth, size of carapace spines, size of abdominal somites, of telson, and of articles of P1 to P5, are perfectly close, all except the dactyls of P3 to P5, being pretty longer on the Taiwanese specimen (propodus/ dactyl ratio of P3 to P5 are respectively: 3.7, 4.5 and 6.0 for taiwanese specimen, versus 4.6, 5.9 and 6.8 for indonesian specimen).

2) Comparison of ovigerous female from Taiwan (CL 12.5 mm) with males of close size from New Caledonia (MNHN-Na. 14647, male 13 mm and Na.12159, male 12.5 mm) show differences indicating that they probably belong to different species: the taiwanese specimen has got longer rostral teeth, larger abdominal somites; articles of mxp3, P1, P2, comparable, but P3 to P5 longer, especially propodus and dactyls.

3) Comparison of ovigerous female from Taiwan (CL 12.5 mm) with ovigerous females of the same size from Tonga (MNHN-Na.15029 and Na.15032) reveals more or less the same differences observed with New Caledonia specimens: the rostral teeth are here only a little shorter than those of taiwanese specimen, but the latter has got a stronger body and longer P3 to P5 (mainly due to longer propodus and dactyls), articles of mxp3, P1, P2 being of equal length. Moreover, the coloration of the former differs from the latter: on the photograph the Tawanese specimen is pinkish uniform, whereas coloration of ovigerous female Na.15029 is summurized as follows: cephalothorax pale pinkish, abdomen greenish, some red stripes on P1 and P2.

4) Comparison between specimens from New Caledonia and specimens from Tonga reveals that they could belong to the same species. The variations observed while comparing specimens of the same size seems to be not relevant, at the most indicating 2 populations of the same species.

5) Comparison between paratypes of Stylodactylus pubescens and specimens of the same size from New Caledonia and Tonga lead to the conclusion that the last two belong to a different species: S. pubescens has got generally: smaller eyes, rostral teeth a little smaller and thinner, and longer appendages (mxp3 to P5).

6) Comparison between ovigerous female from Taiwan (CL 12.5 mm) and larger paratypes of S. pubescens (male and female 11.5 mm) indicates that while all articles of P3 to P5 are logically longer on the former which is larger, on the other hand articles of mxp3, P1, P2 are of the same size or even shorter on the taiwanese specimen, leading to the conclusion that they probably belong to different species.

To conclude at this stage, one can think that we could have 3 different species: S. pubescens , and two related species, one from Taiwan and Indonesia, the other from New Caledonia and Tonga. Molecular analysis could be an important tool to clear up the problem.

Figures

Fig. 3. (a),(d), Stylodactylus sp. aff. pubescens Burukovsky, 1990, female ov. 12.5 mm,“TAIWAN 2003”, st. CD 210: (a), anterior part of cephalothorax; (d), right third pereiopod; (b),(c), Stylodactylus pubescens Burukovsky, 1990: (b), male 11.5 mm, Paratype, anterior part of cephalothorax; (c), female 10.5 mm, Paratype, anterior part of cephalothorax. Scale bars = 5 mm.