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. Author Gebruk, Andrey V. Author Solis-Marin, Francisco A. Author Billett, David S. M. Author Rogacheva, Antonina V. Author Tyler, Paul A. text Journal of Natural History 2012 2012-02-29 46 265 348 http://dx.doi.org/10.1080/00222933.2011.638423 journal article 10.1080/00222933.2011.638423 1464-5262 5202428 Mesothuria cathedralis Heding, 1940 ( Figure 7 ) Mesothuria ( Allantis ) cathedralis – Heding, 1940: 336–338 , text fig. 5, figs. 1–10. Mesothuria ( Penichrothuria ) cathedralis – Heding, 1942a: 8–9 , text fig. 8, figs. 1–5. Mesothuria cathedralis Heding, 1940 – Gage et al ., 1985: 196 . Table 5. Examined specimens of Mesothuria bifurcata Hérouard, 1901 .

Museum and	No. of	TL / W (mm)	Locality	Date	Depth (m)
catalogue number	specimens
USNM E49271	1	54 / 20	Islas Orcadas , St. 37, Scotia Sea, South	22-05-1975	1652–1684
Sandwich Islands, 56◦58′42′′S, 26◦30′36′′W
NHM 1953.8.21.43	1	178 / 30	Discovery, St. 1648, Antarctic, 78◦18′ 00′′S,	01-1936	550
174◦24′ 00′′ W
NHM 1953.8.21.44	3	86 / 23	Discovery, St. 1648, Antarctic, 78◦18′ 00′′S,	01-1936	520
174◦24′ 00′′ W
NOCS	5	–	ANDEEP II, PS61 / 143-2, Antarctic,	25-03-2002	752.7
58◦44.35′ S, 25◦10.48′ W
NOCS	1	–	ANDEEP II, PS61 / 133-30, Antarctic,	07-03-2002	1122
65◦20.15′ S, 54◦14.35′ W
NOCS	1	–	Discovery, St. 10111 #8, 49◦32.7′–49◦33.5′N,	09-09-1979	1630–1690
13◦7.1′–13◦5.9′W
SBS, BIOICE 2914	1 incompl.	–	BIOICE, St. 476, 64.54◦N, 29.59◦W	25-08-1996	2005–2007
SBS, BIOICE 3077	4	–	BIOICE, St. 308, 62.16◦N, 16.42◦W	13-07-1997	2046–2042
SBS, BIOICE 3572	1	–	BIOICE, St. 391, 63.30◦N, 29.38◦W	05-09-2003	2238–2242
SBS, BIOICE 3574	2	–	BIOICE, St. 392, 63.22◦N, 29.55◦W	05-09-2003	2355–2366

Figure 6. Distribution of a group of Mesothuria and Zygothuria species. Material examined See Table 6 . Type material Syntypes , cat. no. ZMUC HOL39 , two specimens , Valdivia , St. 56, 13 September 1898 , 3 ◦ 10 ′ N , 5 ◦ 28.5 ′ E , 2278 m . Type locality South-east Atlantic, 2278 m . Diagnosis After Heding (1940) : mouth ventral or subventral, anus terminal. Tentacles 20. Calcareous ring well developed. One Polian vesicle. Ossicles quadriradiate tables (rarely triradiate) with four, rarely three, long spinous arms on top of spire and disks with one or two crowns of eight perforations in each; spire relatively high (150 µm on plate 100 µm in diameter); arms from two-thirds to four-fifths of spire length ( Figure 7 ). Feet with end plate and small tables of same type as those in skin, sometimes deformed. Figure 7. Mesothuria cathedralis Heding, 1940 . Ossicles. (A–E) specimen from St. 72 / 386; (F–I) specimen from St. 71-A-8-10. Remarks Mesothuria cathedralis was well defined and carefully described by Heding. It is characterized by quadriradiate tables with four, rarely three, spinous arms on top of the spire and disks with one or two crowns with eight perforations in each; ossicles with the first full crown and few smaller additional perforations in the second crown are most common ( Figure 7A,B ). The juvenile specimen reported by Gage et al. (1985) ( 23 mm long) has tubefeet all over the body, small ventrally and larger laterally. The ossicles are tables generally with eight holes in the base and with a tall spire ending in four points, which are almost smooth and not as thorny as figured by Heding (1940) . Reduced tables are found in the tubefeet. Table 6. Examined specimens of Mesothuria cathedralis ( Heding, 1940 ) .

Museum catalogue	No. of	Type	TL / W (mm)	Locality	Date	Depth (m)
number	specimens	material
ZMUC HOL39	2	Syntypes	–	Valdivia , St. 56, 3◦10′ N, 5◦28.5′ E	13-09-1898	2278
ZMUC	1	–	–	Dana, St. 78, SE Atlantic, 8 miles W of	01-11-1930	2400–2780
Sugarloaf, St. Helena
ZMUC	5	–	–	Valdivia , St. 33, NE Atlantic, 24◦35.3′N,	25-08-1898	2480
17◦4.7′W
ZMUC	2	–	–	Ingolf , St. 18, NE Atlantic, 61◦44′N,	10-01-1896	2337
30◦29′W
USNM E26065	1	–	55 / 7	Alaminos , St. 71-A-8-10, north Atlantic,	30-07-1971	1998
Gulf of Mexico, off coast of Louisiana,
26◦07′ 30′′N, 92◦42′W
NHM 1998.770	1	–	14 / 4	RRS Challenger, St. 10, NE Atlantic, 56o 37′	07-01-1973	–
N, 11o 04′ W
NHM 1978.3.17.109	1	–	23 / 9	RRS Challenger, St 10, NE Atlantic, 56o37′	07-01-1973	2540
N, 11o 04′ W
NOCS	1	–	–	Discovery, St. 9754 #3, 51◦804′–51◦9.5′N,	09-04-1978	1484
12◦1.5′–12◦1.8′W
NOCS	1	–	–	RRS Challenger, St. 50605 #1,	05-07-1979	2930–2820
50◦11.6′–50◦11.2′N, 13◦32.4′–13◦29.0′W
NOCS	1	–	–	Discovery, St. 10113 #1, 50◦16.1′–50◦16.3′N,	10-09-1979	2755–2760
13◦31.6′–13◦32.3′W
NOCS	2	–	–	RRS Challenger, St. 51403 #1,	25-03-1982	1292–1314
51◦37.7′–51◦36.6′N, 12◦59.8′–13◦00.0′W
NOCS	1	–	–	RRS Challenger, St. 51403 #4,	26-03-1982	1319–1333
51◦36.7′–51◦36.0′N, 12◦59.6′–12◦59.8′W
1	–	–	RV G.O. Sars , MAR-ECO St. 72 / 386,	27-07-2004	2548–2567
53◦16′N, 35◦31′W

Distribution In the east Atlantic ( Figure 6 ), including the Gulf of Guinea , off Cape Bojador ( Morocco ), also in the Irminger Basin off southern Greenland and Gulf of Mexico. Bathymetric range Depth 1292–4930 m .