Zygothuria lactea (Théel, 1886)

Gebruk, Andrey V., Solis-Marin, Francisco A., Billett, David S. M., Rogacheva, Antonina V. & Tyler, Paul A., 2012, Review of the genus Zygothuria Perrier, 1898 and the Atlantic group of species of the genus Mesothuria Ludwig, 1894 (Synallactidae: Holothuroidea) with description of the new species Mesothuria milleri sp. nov., Journal of Natural History 46, pp. 265-348 : 310-321

Zygothuria lactea (Théel, 1886)

( Figures 13 , 14 )

Holothuria lactea – Théel, 1886a: 183–184, pl. 9, fig. 15; 1886b: 6–7.

Zygothuria lactea (Théel, 1886) – Perrier, 1898: 1665.

Mesothuria lactea (Théel, 1886) – Sluiter, 1901b: 25; Hérouard, 1902: 21–23, pl. 1, figs. 17–19; 1923: 13–15, pl. 4, figs. 1–3; Mortensen, 1927: 382–383 (partim), fig. 227.

Mesothuria (Zygothuria) lactea (Théel, 1886) – Heding, 1940: 340–341, fig. 7.

Mesothuria (Zygothuria) lactea lactea (Théel, 1886) – Heding, 1942a: 9–10, fig. 9.

Mesothuria lactea (Théel, 1886) – Perrier, 1902: 322–327 (partim), pl. 17: 1–6; Deichmann, 1930: 108–111, pl. 8, figs. 8–9; 1940: 190–191; 1954: 386.

Material examined

See Table 11.

Type material

Syntypes, NHM 86.10.2.174 (one specimen), HMS Challenger, St. 169, 10 July 1874, 37 ◦ 34 ′ S, 179 ◦ 22 ′ E, depth 1280 m; NHM 86.10.2.175 (two fragments), HMS Challenger, St. 78, 10 July 1873, 37 ◦ 26 ′ N, 25 ◦ 13 ′ W, depth 1830 m.

Type locality

Atlantic and Pacific Oceans, off the Azores and New Zealand, 1280–1830 m.

Diagnosis

Modified from Deichmann (1954): body oval, rather flat, marginal fringe present, ventral surface evidently flatter than dorsal; skin soft, usually wrinkled, colour whitish. Maximum known size 150 mm (preserved). Mouth ventral, anus almost terminal. Tentacles small, about 20, usually retracted. Ventrolateral tubefeet large, arranged in two simple rows along each side, up to 15–20 in row, placed at some distance from each other. Odd ambulacrum naked. Dorsal papillae minute, easily lost, arranged in two simple rows along each ambulacra, placed about 10 mm from each other. One ventral Polian vesicle and dorsal stone canal that reaches dorsal side.

Ossicles fragile tables of triradiate type, similar in dorsal and ventral sides. Disks rounded or stellate with six angles, but often irregular in outline, with six large holes around small central hole; usually 0.15–0.18 mm in diameter, but may reach 0.20 mm or more ( Figure 13A–C ). Hexagonal disks ( Figure 13D ), 0.20–0.23 mm in diameter, more common on ventral side. Spire high, usually with three long, slender, usually equal in length, smooth arms on top, 0.20–0.24 mm high; one transverse beam between base and top present; occasional minute spines may occur on arms, more common on ventral side ( Figure 14A,B ). Occasionally four arms develop. Spire often singlepointed; strong central single spine may be directed somewhat laterally ( Figure 14D,E ). No terminal plates in tubefeet. Ossicles in tubefeet smooth rods varying in shape and reduced tables. Radial pieces of calcareous ring have nearly triangular outline; ‘wings’, typical of M. milleri sp. nov. for instance, are missing ( Figure 13E ).

Ossicles of similar size and type were found in small specimens 4 mm long and large specimens greater than 100 mm. Single-pointed tables occur already in juveniles <10 mm long. Some juveniles possess tables with disks that resemble in shape those from the genus Mesothuria (e.g. Mesothuria maroccana Perrier, USNM E2333 , (Continued)

Museum catalogue No. of Type TL / W (mm) Locality number specimens material

Date Depth (m)

– – NHM 96.5.18.20 1 – – Bay of Biscay NHM 1966.1.20.76 2 – – Albatross, St. 2206, west Atlantic, south of

Block Dol, 39 ◦ 35 ′ 00 ′′ N, 71 ◦ 24 ′ 30 ′′ W NHM 1938.8.23.17 1 – – SW coast of Ireland NHM 89.9.2.90 1 – – SW coast of Ireland MNHN 1818 1 – – Prince de Monaco, St. 575 MNHN 1644 1 – – Travailleur, St. 40, 33 ◦ 9 ′ N, 11 ◦ 58 ′ W MNHN 1645 1 – – Talisman, St. 31, coast of Morocco, 32 ◦ 37 ′ N,

12 ◦ 07 ′ W MNHN 1646 1 – – Talisman, St. 59 , 27 ◦ 32 ′ N, 16 ◦ 29 ′ W MNHN 1647 1 – – Talisman, St. 31, coast of Morocco , 32 ◦ 37 ′ N,

12 ◦ 07 ′ W MNHN 1939 4 – – Talisman, St. 20 , 33 ◦ 43 ′ N, 11 ◦ 22 ′ W MNHN 1942 1 – – Talisman, St. 34 , 32 ◦ 27 ′ N, 12 ◦ 15 ′ W MNHN 1643 1 – – Talisman, St. 31, coast of Morocco , 32 ◦ 37 ′ N,

12 ◦ 07 ′ W USNM E2009 ∗∗ 4 – – Albatross, St. 2923, north Pacific, off

California, 32 ◦ 40 ′ 30 ′′ N, 117 ◦ 31 ′ 30 ′′ W USNM E2013 ∗∗ 1 – – Albatross, St. 3603, north Pacific, Bering Sea,

SW of Pribilof Islands, 55 ◦ 23 ′ N, 170 ◦ 31 ′ W USNM E2015 ∗∗ 2 – – Albatross, St. 3345, north Pacific, off Oregon,

Cape Falcon, 45 ◦ 39 ′ N, 124 ◦ 53 ′ W USNM E2024 ∗∗ 3 – – Albatross, St. 2923, north Pacific , off

California, 32 ◦ 40 ′ 30 ′′ N, 117 ◦ 31 ′ 30 ′′ W USNM E2025 ∗∗ 1 – – Albatross, St. 2929, north Pacific , California,

San Diego, 32 ◦ 27 ′ 30 ′′ N, 117 ◦ 26 ′ 30 ′′ W

– 20-08-1884

– – 1895 31-07-1882 16-06-1883

07-07-1883 16-06-1883

16-06-1883 17-06-1883 16-06-1883

19-01-1889

11-08-1895

22-09-1890

19-01-1889

26-01-1889 1300 1908

1820 1820 1165 1900 1103

2013 1103

1105 836 1535–1100

1503

3239

1388

1503

1139

USNM E9914 ∗∗ 1 – – Albatross, St. 4658, south Pacific, Peru, SW of 14-11-1904 Lobos de Afuera Island, 8 ◦ 30 ′ S, 85 ◦ 36 ′ W

USNM E16459 ∗∗ 1 – – North Pacific , 45 ◦ 56 ′ 36 ′′ N, 127 ◦ 31 ′ 36 ′′ W –

USNM E16477 ∗∗ 1 – – North Pacific , 44 ◦ 42 ′ 48 ′′ N, 124 ◦ 31 ′ 12 ′′ W –

USNM E16500 ∗∗ 2 – – Cayusa, north Pacific, 44 ◦ 34 ′ 30 ′′ N, 03-11-1973 128 ◦ 21 ′ 30 ′′ W

USNM E16504 ∗∗ 2 – – Cayusa, north Pacific, 45 ◦ 00 ′ 42 ′′ N, 03-11-1973 127 ◦ 28 ′ 48 ′′ W

USNM E16753 ∗∗ 1 – – North Pacific, off Oregon, SW of Mouth of 29-05-1964 Columbia River , 45 ◦ 55 ′ N, 125 ◦ 9 ′ W

USNM E16754 ∗∗ 1 – – North Pacific, off Oregon, SW of Mouth of 29-05-1964 Columbia River , 45 ◦ 45 ′ N, 125 ◦ 9 ′ W

USNM E16755 ∗∗ 2 – – Comando , north Pacific, 45 ◦ 36 ′ N, 124 ◦ 54 ′ W 09-06-1962

USNM E27540 ∗∗ 2 – – Eltanin , St. 514, Antarctic , Weddell Sea, 24-02-1963 Antarctica, South Orkney Islands, 63 ◦ 21 ′ S ,

44 ◦ 51 ′ W

USNM E27903 ∗∗ 2 – – Eltanin , St. 334, south Pacific, Chile, Los 27-11-1962 Lagos, SW of Valdivia , 42 ◦ 57 ′ S, 75 ◦ 3 ′ W

USNM E2324 2 – – Albatross, St. 2117, north Atlantic, Caribbean 27-01-1884 Sea, Venezuela, Aves Island, 15 ◦ 24 ′ 40 ′′ N,

63 ◦ 31 ′ 30 ′′ W

USNM E2333 1 – – Albatross, St. 2117, north Atlantic, Caribbean 27-01-1884 Sea, Venezuela, Aves Island, 15 ◦ 24 ′ 40 ′′ N,

63 ◦ 31 ′ 30 ′′ W

USNM E2577 5 – – Albatross, St. 2392, north Atlantic, Gulf of 13-03-1885 México, United States, Louisiana, east of

Mississippi Delta, 28 ◦ 47 ′ 30 ′′ N, 87 ◦ 27 ′ W

USNM E10534 1 – – Comando , north Pacific, United States , 15-05-1963 Washington, SW Mouth of Colombia

River, 45 ◦ 37 ′ 6 ′′ N, 124 ◦ 54 ′ 36 ′′ W

USNM E10535 3 – – Comando , north Pacific, United States , 17-05-1962 Washington, SW Mouth of Colombia

River, 45 ◦ 54 ′ N, 125 ◦ 9 ′ W

4334

2763 150 2820

2848

1554

1646

1371 3587–3660

3651

1249

1249

1324

1371

1554

(Continued)

Museum catalogue No. of Type TL / W (mm) Locality number specimens material

Date Depth (m)

USNM E15112 4 – – Albatross, St. 2706, north Atlantic, Canada, Nova Scotia, south of Browns Bank , 41 ◦ 28 ′ 30 ′′ N, 65 ◦ 35 ′ 30 ′′ W

USNM E28709 1 – – Columbus Iselin, St. 2706 , north Atlantic , Bahamas, Tongue of the Ocean, 23 ◦ 57 ′ N, 77 ◦ 16 ′ W

USNM E46759 1 – – Oregon II, St. 10955, north Atlantic , Gulf of Mexico, Mexico, Veracruz, Northwest part of Campeche Bay, 21 ◦ 41 ′ N, 96 ◦ 55 ′ W

USNM E46761 1 – – Oregon II, St. 10880, north Atlantic, Gulf of Mexico, east of Boca de Sandoval , 24 ◦ 57 ′ N, 96 ◦ 13 ′ W

NOCS 7 – – Discovery, St. 13919#1, NE Atlantic, 51 o 08.89 ′ N, 11 o 03.92 ′ W

NOCS 9 – – Discovery, St. 9754 #3, 51 ◦ 8.4 ′ – 51 ◦ 9.5 ′ N, 12 ◦ 1.5 ′ – 12 ◦ 1.8 ′ W

NOCS 1 – – Discovery, St. 9774 #1, 51 ◦ 4.4 ′ – 51 ◦ 5.2 ′ N, 11 ◦ 59.3 ′ – 12 ◦ 3.4 ′ W

NOCS 5 – – Discovery, St. 9779 #1, 49 ◦ 22.3 ′ – 49 ◦ 20.7 ′ N, 12 ◦ 49.1 ′ – 12 ◦ 49.5 ′ W

NOCS 7 – – RRS Challenger, St. 50510 #1, 51 ◦ 05.3 ′ – 51 ◦ 06.5 ′ N, 13 ◦ 04.5 ′ – 12 ◦ 59.5 ′ W

NOCS 7 – – RRS Challenger, St. 50511 #1, 50 ◦ 32.4 ′ – 50 ◦ 31.4 ′ N, 13 ◦ 01.4 ′ – 12 ◦ 55.6 ′ W

NOCS 3 – – RRS Challenger, St. 50513 #1, 50 ◦ 07.6 ′ – 50 ◦ 04.2 ′ N, 13 ◦ 58.3 ′ – 14 ◦ 02.0 ′ W

27-08-1886

15-09-1980

03-06-1970

23-06-1970

25-10-2000

09-04-1978

21-04-1978

24-04-1978

03-06-1979

04-06-1979

05-06-1979

2172

1378

896

1234

1545

1484

1499–1572

1404–1398

1925–1945

2410–2440

3400–3620

NOCS

NOCS

NOCS

NOCS

NOCS

NOCS

NOCS

NOCS

NOCS

NOCS

NOCS

NOCS

NOCS

NOCS

NOCS NOCS

1 – – RRS Challenger, St. 50517 #1, 07-06-1979 49 ◦ 30.1 ′ – 49 ◦ 27.7 ′ N, 13 ◦ 19.9 ′ – 13 ◦ 17.2 ′ W

8 – – RRS Challenger, St. 50519 #1, 08-06-1979 49 ◦ 29.5 ′ – 48 ◦ 29.9 ′ N, 12 ◦ 48.9 ′ – 12 ◦ 43.6 ′ W

36 – – RRS Challenger, St. 50602 #3, 02-07-1979 51 ◦ 6.8 ′ – 51 ◦ 6.9 ′ N, 13 ◦ 16.7 ′ – 13 ◦ 24.4 ′ W

2 – – Discovery, St. 10108 #1, 49 ◦ 20.6 ′ – 49 ◦ 19.6 ′ N, 05-09-1979 12 ◦ 49.2 ′ – 12 ◦ 48.7 ′ W

15 – – Discovery, St. 10111 #8, 49 ◦ 32.7 ′ – 49 ◦ 33.5 ′ N, 09-09-1979 13 ◦ 7.1 ′ – 13 ◦ 5.9 ′ W

1 – – RRS Challenger, St. 50703 #1, 49 ◦ 33 ′ –N, 13-10-1979 12 ◦ 34 ′ –W

4 – – RRS Challenger, St. 50715 #1, 51 ◦ 19.5 ′ –N, 21-10-1979 12 ◦ 57 ′ –W

1 – – RRS Challenger, St. 50902 #1, 07-11-1980 51 ◦ 17.4 ′ – 51 ◦ 15.74 ′ N, 12 ◦ 45.2 ′ – 12 ◦ 49.19 ′ W

1 – – RRS Challenger, St. 51009 #1, 51 ◦ 34.2 ′ –N, 02-05-1981 12 ◦ 54.2 ′ –W

1 – – RRS Challenger, St. 51307 #1, 51 ◦ 26.4 ′ –N, 19-02-1982 13 ◦ 01.4 ′ –W

1 – – RRS Challenger, St. 51308 #1, 51 ◦ 13.0 ′ –N, 20-02-1982 13 ◦ 02 ′ –W

5 – – RRS Challenger, St. 51403 #1, 25-03-1982 51 ◦ 37.7 ′ – 51 ◦ 36.6 ′ N, 12 ◦ 59.8 ′ – 13 ◦ 00.0 ′ W

5 – – RRS Challenger, St. 51403 #4, 26-03-1982 51 ◦ 36.7 ′ – 51 ◦ 36.0 ′ N, 12 ◦ 59.6 ′ – 12 ◦ 59.8 ′ W

2 – – RRS Challenger, St. 51403 #5, 26-03-1982 49 ◦ 23.7 ′ – 51 ◦ 37.3 ′ N, 11 ◦ 34.2 ′ – 12 ◦ 59.0 ′ W

1 – – RRS Challenger, St. 51403 #6, NE Atlantic 26-03-1982

1 – – RRS Challenger, St. 51403 #7, 26-03-1982 51 ◦ 36.4 ′ – 51 ◦ 39.2 ′ N, 12 ◦ 59.9 ′ – 12 ◦ 58.8 ′ W

1794–1785

1465–1431

1930–1815

1385–1390

1630–1690

1575–1625

1635–1720

1825–1865

1510–1535

1490–1415

1715–1770

1292–1314

1319–1333

1289–1297

1278–1295 1320–1247

(Continued)

Museum catalogue No. of Type TL / W (mm) Locality number specimens material

Date Depth (m)

NOCS 28 – – RRS Challenger, St. 51409 #1, 51 ◦ 16.5 ′ – 51 ◦ 19.0 ′ N, 13 ◦ 00.2 ′ – 12 ◦ 56.6 ′ W

NOCS 1 – – RRS Challenger, St. 51411 #1, 50 ◦ 27.2 ′ – 50 ◦ 22.4 ′ N, 12 ◦ 59.1 ′ – 13 ◦ 01.3 ′ W

NOCS 25 – – RRS Challenger, St. 51419 #1, 51 ◦ 19.0 ′ – 51 ◦ 16.8 ′ N, 13 ◦ 05.4 ′ – 13 ◦ 07.4 ′ W

NOCS 2 – – RRS Challenger, St. 51420 #1, 51 ◦ 37.3 ′ – 51 ◦ 36.9 ′ N, 12 ◦ 58.6 ′ – 12 ◦ 58.6 ′ W

NOCS 10 – – RRS Challenger, St. 51708 #2, 51 ◦ 31.3 ′ – 51 ◦ 31.0 ′ N, 12 ◦ 58.4 ′ – 13 ◦ 0.3 ′ W

NOCS 6 – – RRS Challenger, St. 52018 #1, 51 ◦ 42.36 ′ – 51 ◦ 31.39 ′ N, 13 ◦ 05.76 ′ – 12 ◦ 46.97 ′ W

NOCS 9 – – RRS Challenger, St. 52019 #1, 51 ◦ 24.81 ′ – 51 ◦ 25.14 ′ N, 12 ◦ 46.17 ′ – 12 ◦ 45.55 ′ W

NOCS 11 – – RRS Challenger, St. 52203 #1, 51 ◦ 25.91 ′ – 51 ◦ 25.48 ′ N, 13 ◦ 00.60 ′ – 13 ◦ 00.38 ′ W

NOCS 2 – – RRS Challenger, St. 52204 #1, 51 ◦ 37.07 ′ – 51 ◦ 37.29 ′ N, 12 ◦ 59.96 ′ – 13 ◦ 00.01 ′ W

NOCS 19 – – RRS Challenger, St. 52211 #1, 51 ◦ 10.57 ′ – 51 ◦ 09.84 ′ N, 13 ◦ 14.71 ′ – 13 ◦ 15.15 ′ W

NOCS 1 – – RRS Challenger, St. 52213 #1, 50 ◦ 33.04 ′ – 50 ◦ 32.41 ′ N, 12 ◦ 59.21 ′ – 12 ◦ 58.53 ′ W

28-03-1982

29-03-1982

01-04-1982

02-04-1982

13-04-1983

21-08-1984

22-08-1984

16-06-1985

16-06-1985

18-06-1985

20-06-1985 1660–1740

2470–2500

1500–1555

1326–1328

1470–1430

1095–1620

1710–1725

1540–1550

1310–1315

1715–1760

2440–2405

SBS, BIOICE 2430 1 – – BIOICE cruise B-9-93, St. 568, 63.08 ◦ N, 03-07-1993 19.57 ◦ W

SBS, BIOICE 2864 1 incompl. – – BIOICE cruise B-13-95, St. 735, 62.04 ◦ N, 31-08-1995 20.36 ◦ W

SBS, BIOICE 3168 1 – – BIOICE cruise B-9-00, St. 439, 60.54 ◦ N, 26-07-2000 22.47 ◦ W

SBS, BIOICE 3260 2 – – BIOICE cruise B-11-01, St. 727, 62.59 ◦ N, 12-09-2001 19.11 ◦ W

1016–1007

1681–1688

1899–1900

1308–1320

Notes: ∗ Specimen(s) very deteriorated.

∗∗ Identified at the USNM as Capheira mollis .

Albatross St. 2117, north Atlantic Ocean, Caribbean Sea; Venezuela, Aves Island, 15 ◦ 24 ′ 40" N, 63 ◦ 31 ′ 30" W, 1229 m, 27 January 1884).

Remarks

The form and the size of ossicles in Z. lactea are characteristic. Some confusion, however, has arisen owing to variation in the number of arms, which is normally three or sometimes just one. Single-pointed ossicles were not indicated by Théel (1886a) in the type material (one station off New Zealand and one in the east Atlantic). However, he added this character later, based on additional material from the north Atlantic ( Théel, 1886b). A new variety ( oxysclera ), based on the specimens from the east Atlantic exclusively with single-pointed tables was described by Perrier (1902). Deichmann (1930) suggested that single-pointed ossicles might become more numerous in older animals, because many of Perrier’s specimens were large. In our material single-spined ossicles were equally common in small (<50 mm) and large (> 100 mm) specimens. Owing to this variation, common in Z. lactea , the variety oxysclera was not recognized by Hérouard (1923) nor Heding (1942a). The co-occurrence of single and three-armed tables was also stressed by Sluiter (1901b) as an argument against a new variety. There are other clear differences between Z. lactea and Z. oxysclera . The latter species is described below as a valid species.

Relationships

This species is most close to Z. candelabri Hérouard, 1923 and Z. connectens Perrier, 1902 , all these forms having triradiate tables with three long arms.

Distribution

Cosmopolitan species ( Figure 15 ). However, some old records may not be reliable because most authors did not recognize the variety oxysclera and these two species could have been confused. This is especially likely with the records from the Gulf of Mexico and the Caribbean ( Deichmann 1930) where Z. oxysclera occurs. Numerous records from the north-east Atlantic, also known from the north-west Atlantic, off west Africa, south-east Atlantic, Indo-Malayan archipelago and New Zealand.

Bathymetric range

Reliable bathymetric range from 694 m ( Sluiter 1901b) to 5278 m ( Hérouard 1902). In the Porcupine Seabight most of the specimens (83%) occurred between 1430 and 1930 m ( Billett 1988).

Figures

Figure 13. Zygothuria lactea (Théel, 1886). Ossicles (A–D) and segments of calcareous ring (E). RRS Discovery St. 51419.

Figure 14. Zygothuria lactea (Théel, 1886). Table spires. RRS Discovery St. 51419.

Figure 15. Distribution of Zygothuria lactea, Zygothruia marginata and Zygothuria oxysclera.