Stylodactylus A. Milne-Edwards, 1881

Cleva, Régis & Wormhoudt, Alain Van, 2006, On two rare and poorly known species, Stylodactylus discissipes Bate, 1888, and S. serratus A. Milne-Edwards, 1881 (Crustacea, Decapoda, Stylodactylidae), Zoosystema 28 (2), pp. 347-358 : 349-354

publication ID

https://doi.org/ 10.5281/zenodo.5401564

persistent identifier

https://treatment.plazi.org/id/03D787FA-FFAC-FFA9-7A8B-78922CDDFAB8

treatment provided by

Marcus

scientific name

Stylodactylus A. Milne-Edwards, 1881
status

 

Genus Stylodactylus A. Milne-Edwards, 1881 View in CoL

Stylodactylus discissipes Bate, 1888 View in CoL ( Figs 1 View FIG ; 2 View FIG ; 4A View FIG ; Table 1)

Stylodactylus discissipes Bate, 1888: 851 View in CoL , pl. 138, fig. 1. Stylodactylus orientalis Bate, 1888: 854 View in CoL , pl. 138, fig. 2.

Non Stylodactylus discissipes View in CoL – Rathbun 1906: 927, fig. 75, pl. 23, fig. 1 (= Stylodactylus kauaiensis Figueira, 1971 View in CoL ).

MATERIAL EXAMINED. — Kermadec Islands (North of New Zealand). Challenger, stn 171, 28°33’S, 177°50’W, trawl, 1097 m, 15.VII.1874, 1 ♀ c. 8 mm (holotype), 1 ♀ 11 mm (holotype of S. orientalis ) (NHM 88-22).

New Caledonia, Norfolk Ridge. NORFOLK 2, stn DW 2054, 23°40’S, 168°15’E, 736-800 m, 24.X.2003, 1 ♀ 6 mm (MNHN-Na 15728). — Stn DW 2065, 25°16’S, 168°56’E, 750-800 m, 26.X.2003, 1♀ 13.5 mm (MNHN-Na 15729). — Stn DW 2072, 25°21’S, 168°57’E, 1000-1005 m, 26.X.2003, 2 ovig. ♀♀ 13 and 14 mm (MNHN-Na 15730). — Stn DW 2080, 25°20’S, 168°19’E, 764-816 m, 27.X.2003, 1♀ c. 12 mm (carapace damaged) (MNHN-Na 15731).

French Polynesia, Austral Archipelago, E of Rapa.

Specimen, Locality CL RL/CL Rostral Scapho/ Telson/ Telson/ Telson P3: P3: P4: P4: P5: P5: sex, depth (m) formula CL CL abd. 6 L/w Merus P/C Merus P/C Merus P/C coll. no. spines P/D spines P/D spines P/D ♀, NHM 88- Kermadec Is. 11 1.3 30(6)/15 0.46 0.62 – 2.5 11-11 2.1 13- 1.9 – – 22, holotype 1097 4.8 5.1

♀, NHM 88- Kermadec Is. 8 1.4 28(6)/14 – – – – 10- – 11- – 11- – 22, holotype 1097

of S.orientalis

♀ ov.,MNHN- N. Caledonia 14 1.35 28 + (6)/16 0.45 0.70 1.6 2.6 8- 2.0 12- – 10-11 2.1 Na 15730 1000-1005 tip missing 6.0 9.0 ♀ ov.,MNHN- N. Caledonia 13 – – (6) – – 0.68 1.7 2.7 – – – – – – Na 15730 1000-1005

♀, MNHN- N. Caledonia c. 12 – – (6) – – – 1.8 2.7 10-10 2.2 12- 2.2 10-12 2.2 Na 15731 764-816 5.5 6.7 7.5 ♀, MNHN- N. Caledonia 13.5 – – (6) – 0.46 0.68 1.8 2.6 – – – – – – Na 15729 750-800

♀, MNHN- N. Caledonia c. 6 – – (4) – 0.48 – – – 4- 1.8 12- – 11- – Na 15728 736-800 4.8

♀, MNHN- Austral Is. c. 13.5 1.2 27(5)/20 0.45 0.67 1.8 2.6 12-12 2.2 12-13 1.9 12-12 1.8 Na 15725 840-1200 4.7 4.9 6.3 ♀, MNHN- Austral Is. 10 1.6 33(5)/19 0.52 0.68 1.6 2.7 12-13 2.1 14-14 2.0 – – Na 15726 840-1200 4.8 5.5

♀ MNHN- Austral Is. 15 – – (5) – – 0.70 1.6 2.5 – – – – – – Na 15726 840-1200

♀ ov.,MNHN- Austral Is. 16 1.2 30(7)/17 0.46 0.68 1.7 2.6 9- 2.1 – – – – Na 15726 840-1200 tip missing 5.2

♂, MNHN- Austral Is. 15 – – (6) – 0.45 0.64 1.6 2.7 – – – – – – Na 15726 840-1200

♀ ov.,MNHN- Austral Is. 16.5 c. 1.25 26 + (5)/17 + 0.44 0.72 1.7 2.8 10-11 2.1 12- 2.1 11- 2.0 Na 15727 900-1300 tip missing 5.9 6.9 8.3 ♂, MNHN- Austral Is. 12-13 – – (5) – – – – 2.8 – – 13- – – – Na 15727 900-1300 damaged

BENTHAUS, stn CP 1910, 27°38.2’S, 144°15.4’W, 840-1200 m, 10.XI.2002, 1 ♀ 13.5 mm, photographed (MNHN-Na 15725); 1 ♂ 15 mm, 3 ♀♀ (1 ovig.) 10-16 mm (MNHN-Na 15726). — Stn CP 1911, 27°37.9’S, 144°15.2’W, 900-1300 m, 10.XI.2002, 1 ♂ c. 12 or 13 mm (carapace damaged), 1 ovig. ♀ 16.5 mm (MNHN-Na 15727).

DISTRIBUTION. — Kermadec Is., 1097 m; New Caledonia, 736-1005 m ; French Polynesia, Austral Is. (Rapa Is.), 840-1300 m .

DIAGNOSIS. — Carapace with small supra-orbital spine. Antennal and branchiostegal spines well developed. Rostrum 1.2 to 1.6 times longer than carapace, bearing from 27 to 33 dorsal spines (four to seven on carapace proper, usually five or six), and from 14 to 20 ventral spines. Telson 0.62 to 0.72 carapace length and 1.6 to 1.8 longer than sixth abdominal somite. All abdominal pleura rounded. Antennal scale with outer edge entire except for terminal spine, about half length of carapace. Merus of last three pairs of pereiopods bearing series of strong external spines as follows: P3: eight to 13 (four for smallest specimen MNHN-Na 15728); P4: 12 to 14; P5: 10 to 12. Ratios P/C and P/D of last three pereiopods ranging as follows: P3: 1.8 to 2.2 and 4.7 to 6.0; P4: 1.9 to 2.2 and 4.9 to 6.9; P5: 1.8 to 2.2 and 6.3 to 9.0.

COLORATION ( FIG. 4A View FIG ) The colour photograph of a specimen collected from Rapa during BENTHAUS cruise (female 13.5 mm, MNHN-Na 15725) reveals no special pattern: general colour of body yellowish with anterior part of cephalothorax reddish; rostrum translucent; Mxp3, P1, P2 pinkish, other pereiopods pale yellowish; parts of telson and pleopods pale pinkish.

REMARKS A summary of morphological data for the specimens studied is provided in Table 1.

As previously mentioned, only two specimens of Stylodactylus discissipes were known, both from

Challenger station 171. The synonymy of S. orientalis with S. discissipes was evident to Kemp (1925: 258) and Crosnier & Forest (1973: 131). We have reexamined Bate’s two females (8 and 11 mm CL), both in poor condition, and have illustrated them ( Fig. 1 View FIG ). The telson of the smallest female is incomplete. The telson of the largest female is abnormal, having four dorsal spines on one side and three on the other; there are four pairs of spines at its extremity, which appears enlarged, whereas three pairs are usually present in all species of the genus.

A

Stylodactylus serratus A. Milne-Edwards, 1881 ( Figs 3 View FIG ; 4B View FIG ; Table 2)

Stylodactylus serratus A. Milne-Edwards, 1881: 11 View in CoL ; 1883: pl. 36. — Faxon 1896: 160. — Figueira 1971: 2, fig. 1. — Crosnier & Forest 1973: 129, fig. 36a-f. — Cleva 1990: 166. — Fransen 1991: 191. — Forest & Holthuis 1997: 102 (pl. 36): 113, 116 (pl. A, appendix 1). — d’Udekem d’Acoz 1999: 92.

Non Stylodactylus serratus View in CoL – Stebbing 1914: 51, pl. 12 (= Stylodactylus stebbingi Hayashi & Miyake, 1968 View in CoL ).

MATERIAL EXAMINED. — Western Atlantic, West Indies. U.S. Coast Survey, Caribbean Islands Exploration, Blake, stn 190, off Dominique Island , 958 m, 1878- 1879, A. Agassiz coll., 1 ovig. ♀ 17.5 mm, holotype (MNHN-Na 7992). — U.S. Coast Survey , Caribbean Islands Exploration , off Martinique Island, Blake, stn 205, 14°25.15’N, 60°56.35’W, 611 m, 10.II.1879, A. Agassiz coll., 1 ♂ 13 mm (MNHN-Na 1850) GoogleMaps ; 1 ♂ 17 mm (MNHN-Na 11276). — SE of St. Vincent, Pillsbury, stn P-881, 13°20.8’N, 61°02.5’W, 576-842 m, Blake trawl, 6.VII.1969, 1 ♂ 17.5 mm; 1 ♀ 20.5 mm ( RMNH D 38033 View Materials ). — N of Monserrat, Pillsbury, stn P-954, 16°55.0’N, 62°43.0’W, 686-1043 m, Blake trawl, 18.VII.1969, 1 ♂ 12.5 mm GoogleMaps ; 1 ovig. ♀ 18 mm ( RMNH D 38034 View Materials ). Eastern Atlantic , off south Portugal ( Banc Joséphine ). SEAMOUNT I ATLANTIQUE, stn CP 50, 36°47.4’N, 14°31.7’W, 1360-1380 m, 6.X.1988, 1 ovig. ♀ 21 mm (MNHN-Na 15732). Canary Islands. CANCAP 2, stn 131, SW of Hierro, off Punta de Orchilla, 27°40’N, 18°10’W, 1200-1800 m, Agassiz trawl, 8.IX.1977, 2 ♀♀ 18 and 19.5 mm (ovig.) ( RMNH D 38035) GoogleMaps .

ably belonging to P3; 4, appendages detached, may belong to P4 or P5. Abbreviations: see Table 1.

Rio de Oro, Spanish Sahara (currently Morocco). Talisman , stn 73, 25°39’N, 16°06’W, 1435 m, 9.VII.1883, 1 ♂ 12.5 mm (MNHN-Na 1851).

DISTRIBUTION. — Western Atlantic : West Indies, 576- 1043 m. Eastern Atlantic: off south Portugal (Banc Joséphine), 1360-1380 m ; Canary Is., 1200-1800 m; Rio de Oro (Spanish Sahara), 1435 m .

DIAGNOSIS. — Carapace with very small supra-orbital spine, antennal and branchiostegal spines well developed. Rostrum 1.25 to 1.7 times longer than carapace, with 38 dorsal and 28 ventral spines on the unique specimen with intact rostrum; seven or eight spines on carapace proper, behind orbit.Telson 0.66 to 0.75 carapace length, and 1.6 to 1.8 longer than sixth abdominal somite. Abdominal pleurae rounded. Antennal scale with outer edge entire except for terminal spine, about half length of carapace. Merus of last three pairs of pereiopods bearing series of strong external spines: P3: 13 to 15; P4: 13 to 17; P5: 12 to 15. Ratios P/C and P/D of last three pereiopods ranging as follows: P3: 2.1 to 2.2 and 4.5 to 5.5 (6.4?); P4: 2.0 to 2.2 and 6.8 to 8.2; P5: 1.9 to 2.2 and 7.6 to 10.5.

COLORATION ( FIG. 4B View FIG )

A.Milne-Edwards’s illustration published by Forest & Holthuis (1997: 116), reproduced herein ( Fig. 4B View FIG ), indicates that coloration of this species is very similar to that of S. discissipes .

REMARK

A summary of morphological data for the specimens studied is provided in Table 2.

RMNH

National Museum of Natural History, Naturalis

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Stylodactylidae

Loc

Stylodactylus A. Milne-Edwards, 1881

Cleva, Régis & Wormhoudt, Alain Van 2006
2006
Loc

Stylodactylus serratus

STEBBING T. R. R. 1914: 51
1914
Loc

Stylodactylus discissipes

RATHBUN M. J. 1906: 927
1906
Loc

Stylodactylus serratus

FOREST J. & HOLTHUIS L. B. 1997: 102
FRANSEN C. H. J. M. 1991: 191
CLEVA R. 1990: 166
CROSNIER A. & FOREST J. 1973: 129
FIGUEIRA A. J. G. 1971: 2
FAXON W. 1896: 160
1896
Loc

Stylodactylus discissipes

BATE C. S. 1888: 851
BATE C. S. 1888: 854
1888
Darwin Core Archive (for parent article) View in SIBiLS Plain XML RDF