Molpadiodemas atlanticus ( Perrier, 1898 ) O'Loughlin & Ahearn, 2005

O'Loughlin, P. Mark & Ahearn, Cynthia, 2005, A review of pygal-furrowed Synallactidae (Echinodermata: Holothuroidea), with new species from the Antarctic, Atlantic and Pacific oceans, Memoirs of Museum Victoria 62 (2), pp. 147-179 : 153

publication ID

https://doi.org/ 10.24199/j.mmv.2005.62.5

persistent identifier

https://treatment.plazi.org/id/116087F5-FFAE-FFE6-FF3D-7B8BFAE21986

treatment provided by

Felipe

scientific name

Molpadiodemas atlanticus ( Perrier, 1898 )
status

comb. nov.

Molpadiodemas atlanticus ( Perrier, 1898) View in CoL comb. nov.

Figures 3a, b View Figure 3 , 4a–d View Figure 4 , 6a, b View Figure 6

Pseudostichopus atlanticus Perrier, 1898: 1665 .— Perrier, 1902: 333–338, pl. 17 figs 15–20.— Mortensen, 1927: 386–387.— Deichmann, 1930: 87–88.— Deichmann, 1940: 209, 211.— Heding, 1942: 5.— O’Loughlin, 2002: 315.

Molpadiodemas acaudum Heding, 1935: 78–80 View in CoL , pl. 6 figs 1–2.— Heding, 1940: 354–357.— Deichmann, 1940: 209, 211.— Heding, 1942: 4–5.

Molpadiodemas atlanticus View in CoL .— Heding, 1940: 353–359.

Meseres atlanticus .— O’Loughlin, 1998: 497.— Thandar, 1999: 376–379, fig. 4.

Meseres acaudum .— O’Loughlin, 1998: 497, fig. 1g –h.

Material examined. Pseudostichopus atlanticus Perrier, 1898 . Holotype. North Atlantic   GoogleMaps , off the Azores, 42°19'N, 23°31'W, 4060 m, Talisman stn 134, 1883, MNHN EcHh 2772. Paratype. 42°19'N, 23°36'W, 4060– 4010 m, MNHN EcHh 658.

Molpadiodemas acaudum Heding, 1935 View in CoL . Paratype. North Atlantic   GoogleMaps , 60°17'N, 54°5'W, 3230 m, Ingolf stn 37, 1885, ZMUC.

Other material. Pacific Ocean , New Zealand, Chatham Is, 2610–2668 m, USNM E49319 About USNM (1) ; Chile, 34°07’S (incorrectly recorded as N in Théel, 1886), 73°56'W (incorrectly as E), 4069 m, Challenger stn 298, BMNH 1886.10 GoogleMaps . 2.149 (1); 33°31'S, 74°43'W, 3950 m, Challenger stn 299, BMNH 1886.10 GoogleMaps . 2.185 (1); Peru, 3500 m, USNM 1020067 About USNM (1) ; California , off Point Conception, 4100 m, 1073654 (1); Oregon, 3021 m, USNM E16475 About USNM (1) ; 3700 m, E16488 (3); Clipperton Fracture Zone , 13°08'– 13°53'N, 129°51'– 129°55'W, 4801–4923M, E31100–E31102 (3); E31107, E31108 (2); E31121– E31123 (3); E31125 (1); E53278 (1); NMV F101845 About NMV GoogleMaps (1).

Atlantic Ocean , Bahamas, 4828–4873 m, USNM 1021592 About USNM (10) ; NE of Bahamas, 4930–4940 m, E49466 (9); West European Basin , 4780–4795 m, E38320 (1); Caribbean Sea, Venezuelan Basin, 13°30'– 14°50'N, 64°45'– 67°30'W, 3411–5062 m, E38789– E38791 (20); E38798 (1); E39266 (20); 1023352 (1); NMV F101846 About NMV GoogleMaps (2).

Description. Large, up to 210 mm long; body rounded in section, sometimes sac-like, sometimes with slight brim, usually no detrital attachments; body wall moderately thick, soft leathery or firm gelatinous, frequently smooth surface, frequently wrinkled ventrally; uniform cover of very small tube feet, frequently not evident or in pits, most evident ventrally and pygally, from 0.1 mm long, 0.2 mm diameter up to 1.0 mm long, 0.3 mm diameter, cylindrical and firm if extended; ossicles frequently abundant in tentacles and gonads, sometimes rare or absent; tentacle ossicles frequently irregular thin rods slightly to strongly curved with ends intertwined to create small perforations, less frequently irregular straight to curved, narrow to wide, smooth to laterally spinous, variably perforated rods, ossicles variable in length, up to 500 µm long; gonad ossicles irregular rods, frequently with thin lateral branches joined to create extensive irregular lace-like mesh, non-spinous, up to 420 Μm long.

Colour. Body and tube feet brown to grey-brown to off-white; frequently some residual mauve markings.

Distribution. North Atlantic, 3230–4060 m ( Perrier, 1902, as P. atlanticus ; Heding, 1935, as M. acaudum ); south-east Atlantic, 3155–3255 m ( Thandar, 1999); West European Basin, 4780–4795 m (this paper); Venezuelan Basin, 3411–5062 m (this paper); Pacific Ocean, off Chile, 3950–4069 m ( Théel,1886; see below); Pacific Ocean, 2610–4923 m (this paper).

Remarks. In agreement with the opinions of Deichmann (1940) and Heding (1942), M. acaudum was made a junior synonym of P. atlanticus by O’Loughlin (2002). That decision is confirmed here.

Théel (1886) noted that two Challenger specimens, taken in the Pacific Ocean off Chile at stations 298 and 299, closely resembled Pseudostichopus villosus but lacked tube feet. Both specimens were examined in this study, and determined as P. atlanticus . Théel (1886) reported sizes up to 280 mm long. The larger specimen is now only 150 mm long.

The very small dark brown attachments on the body which were noted by O’Loughlin (2002) and Théel (1886) are judged to be epibiotes. O’Loughlin (2002) judged the “mulberry” bodies in the body wall of P. atlanticus , illustrated by Perrier (1902) and Thandar (1999), and referred to by Théel (1886) as present in some specimens of P. villosus , to be detrital accretions and not holothurian ossicles. That opinion is maintained here.

The presence of P. atlanticus in the Pacific Ocean is confirmed by the numerous USNM specimens determined in this study. O’Loughlin (2002) summarised P. atlanticus distribution records as Atlantic Ocean only. This work extends the distribution to the Pacific Ocean, and to greater depths (at least 5062 m).

Amongst Molpadiodemas species the distinguishing characters of M. atlanticus are: large, sac-like form; even cover of small tube feet, frequently inconspicuous; frequent presence of large, irregular, open mesh-like gonad ossicles.

MNHN

Museum National d'Histoire Naturelle

USNM

Smithsonian Institution, National Museum of Natural History

NMV

Museum Victoria

Kingdom

Animalia

Phylum

Echinodermata

Class

Holothuroidea

Order

Persiculida

Family

Molpadiodemidae

Genus

Molpadiodemas

Loc

Molpadiodemas atlanticus ( Perrier, 1898 )

O'Loughlin, P. Mark & Ahearn, Cynthia 2005
2005
Loc

Meseres atlanticus

Thandar, A. S. 1999: 376
O'Loughlin, P. M. 1998: 497
1998
Loc

Meseres acaudum

O'Loughlin, P. M. 1998: 497
1998
Loc

Molpadiodemas atlanticus

Heding, S. G. 1940: 353
1940
Loc

Molpadiodemas acaudum

Heding, S. G. 1942: 4
Heding, S. G. 1940: 354
Deichmann, E. 1940: 209
Heding, S. G. 1935: 80
1935
Loc

Pseudostichopus atlanticus

O'Loughlin, P. M. 2002: 315
Heding, S. G. 1942: 5
Deichmann, E. 1940: 209
Deichmann, E. 1930: 87
Mortensen, T. 1927: 386
Perrier, R. 1902: 333
Perrier, R. 1898: 1665
1898
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