Scotoplanes

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Scotoplanes
Scotoplanes globosa
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Echinodermata
Class: Holothuroidea
Order: Elasipodida
Family: Elpidiidae
Genus: Scotoplanes
Théel, 1882[1]

Scotoplanes is a genus of deep-sea sea cucumbers in the family Elpidiidae. The species in this genus are commonly known as sea pigs.

Species

The genus includes the following species:[2]

Ventral view of Scotoplanes globosa showcasing its tube feet
  • Scotoplanes clarki
  • Scotoplanes globosa
  • Scotoplanes hanseni
  • Scotoplanes kurilensis
  • Scotoplanes theeli

In 2024, a bright pink sea pig was discovered in the Clarion–Clipperton zone, belonging to an undescribed species. Due to its coloration, it was nicknamed the "Barbie Pig" in reference to the 2023 Barbie film.[3][4]

Description

Members of Scotoplanes grow 4 to 6 inches (10 to 15 centimeters) long.[5] They are bilaterally symmetrical with six pairs of tube feet, which are largest at mid-body and smallest near the anus. Scotoplanes have ten buccal tentacles lining the oral cavity. Papillae are found on their dorsum.

Scotoplanes share many morphological features with echinoderms, including their respiratory, vascular, and nervous systems. Scotoplanes have a poorly developed respiratory system, with gas exchange occurring through the anus. Their bodies are adapted to the high pressure of the benthic zone of the ocean, and bringing them too close to the surface causes them to disintegrate.[6] Scotoplanes have a water vascular system. The dorsal papillae are histologically similar to their tubular feet, as both contain a large muscular water vascular canal in the center. Hydraulic pressure in these canals is responsible for the efficacy of the vascular system.[7] Scotoplanes' nervous system consists of a network of nerves without ganglia.[7]

Histological examination shows that these deep-sea-dwelling sea pigs are similar to other Holothuroidea with a few notable differences. Most holothurians are sexually dioecious. Unlike other echinoderms, holothuroids possess only a single gonad. The water vascular system of holothurians is similar to other echinoderms, except the madreporite opens in the perivisceral coelom instead of in the external body wall.[8] Like other holothuroids, Scotoplanes possess a single gonad—an ovary in females or a testis in males. Unlike most elasipodids, Scotoplanes exhibits active gametogenesis in both females and males, suggesting a distinct reproductive strategy. As detritivores, Scotoplanes feed on organic matter that falls to the bottom of the sea, gathering and ingesting this detritus with their tube feet. The gut is highly efficient, extracting maximum nutrition from meager resources in their immediate environment. Male Scotoplanes have protozoa inside the cyst cavities of their aboral intestines.[8]

Locomotion

Members of the Elpidiidae have particularly enlarged, leg-like "feet" that use water cavities within the skin to inflate and deflate, thereby causing the appendages to move.[9] These appendages differ from the standard tube feet of the order Elasipodida, as ampullae are replaced by dermal cavities to accommodate the larger size of the Elpidiidae tube feet. Scotoplanes move through the top layer of seafloor sediment and disrupt both the surface and the resident infauna as they feed.[10] This type of movement is thought to be an adaptation to life on the soft floor of the deep sea. These creatures, however, can swim when disturbed. Some species of Scotoplanes are benthopelagic and spend considerable time in the water column. The frontal lobe and the two anal lobes propel the sea pig through the water. Their tentacles help detect their surroundings while moving.[11]

Ecology

Scotoplanes live on deep ocean bottoms, specifically on the abyssal plain in the Atlantic, Pacific and Indian Oceans, typically at depths of over 1,200 to 5,000 meters (3,900 to 16,400 feet).[12][13] Some related species can be found in the Antarctic. Scotoplanes, as all other deep-sea holothurians, is a deposit feeder and obtains food by extracting organic particles from deep-sea mud. Scotoplanes globosa has been observed to demonstrate strong preferences for rich, organic food that has freshly fallen from the ocean's surface,[14] using olfaction to locate preferred food sources such as whale falls.[15] Scotoplanes possess distinctive mitochondrial genomes whose encoded proteins are involved in energy production. Scotoplanes, like other sea cucumbers, often occur in huge densities, sometimes numbering in the hundreds. Early collections have recorded groups of 300–600 individuals.

A living Scotoplanes from Monterey Bay with a juvenile Neolithodes diomedae king crab sheltering beneath it at a depth of approximately 1,260 meters. Monterey Bay Aquarium Research Institute, 2016.

Scotoplanes, like other sea cucumbers, host parasitic and commensal organisms, including gastropods and small tanaid crustaceans.[16] For example, they provide shelter to juvenile crabs, Neolithodes diomedeae. This relationship benefits the crabs by reducing their predation risk while sheltering beneath the sea pig.[17]

Scotoplanes are known to exhibit behavioral patterns of aggregation, where large numbers will gather together either to feed or mate.[18]

References

  1. Théel, Johan Hjalmar (1886). Report on the Holothurioidea dredged by HMS Challenger during the years 1873-76.
  2. MarineSpecies.org – Scotoplanes
  3. Hunt, Katie. "'Barbie-pig': Scientists capture stunning images of ocean life in proposed deep-sea mining zone". www.ksl.com. Retrieved 2024-10-22.
  4. Funnell, Rachael (2024-03-25). ""Barbie Pigs" Among Strange And Possibly New-To-Science Species Discovered In The Pacific". IFLScience. Retrieved 2024-10-22.
  5. Bates, Mary (2014-06-16). "The Creature Feature: 10 Fun Facts About Sea Pigs". Wired. ISSN 1059-1028. Retrieved 2020-05-21.
  6. Barry, James; Taylor, Josi; Kuhnz, Linda; De Vogelaere, Andrew (October 15, 2016). "Symbiosis between the holothurian Scotoplanes sp. A and the lithodid crab Neolithodes diomedeae on a featureless bathyal sediment plain". Marine Ecology. 38 (2) e12396. Bibcode:2017MarEc..38E2396B. doi:10.1111/maec.12396.
  7. LaDouceur, Elise E. B.; Kuhnz, Linda A.; Biggs, Christina; Bitondo, Alicia; Olhasso, Megan; Scott, Katherine L.; Murray, Michael (2021-08-06). "Histologic Examination of a Sea Pig (Scotoplanes sp.) Using Bright Field Light Microscopy". Journal of Marine Science and Engineering. 9 (8): 848. Bibcode:2021JMSE....9..848L. doi:10.3390/jmse9080848. ISSN 2077-1312.
  8. LaDouceur, Elise E. B.; Kuhnz, Linda A.; Biggs, Christina; Bitondo, Alicia; Olhasso, Megan; Scott, Katherine L.; Murray, Michael (August 2021). "Histologic Examination of a Sea Pig (Scotoplanes sp.) Using Bright Field Light Microscopy". Journal of Marine Science and Engineering. 9 (8): 848. Bibcode:2021JMSE....9..848L. doi:10.3390/jmse9080848. Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License.
  9. Hansen, B. (1972). "Photographic evidence of a unique type of walking in deep-sea holothurians". Deep-Sea Research and Oceanographic Abstracts. 19 (6): 461–462. Bibcode:1972DSRA...19..461H. doi:10.1016/0011-7471(72)90056-3.
  10. Blake, James A.; Maciolek, Nancy J.; Ota, Allan Y.; Williams, Isabelle P. (2009-09-01). "Long-term benthic infaunal monitoring at a deep-ocean dredged material disposal site off Northern California". Deep Sea Research Part II: Topical Studies in Oceanography. 56 (19–20): 1775–1803. Bibcode:2009DSRII..56.1775B. doi:10.1016/j.dsr2.2009.05.021.
  11. Gebruk (1995): 95-102., A. V. (1995). "Locomotory organs in the elasipodid holothurians: functional-morphological and evolutionary approaches". Echinoderm Research: 95–102. ISBN 978-90-5410-596-1.{{cite journal}}: CS1 maint: numeric names: authors list (link)
  12. Barry, James P.; Taylor, Josi R.; Kuhnz, Linda A.; De Vogelaere, Andrew P. (2016-10-01). "Symbiosis between the holothurian Scotoplanes sp. A and the lithodid crab Neolithodes diomedeae on a featureless bathyal sediment plain". Marine Ecology. 38 (2) e12396. Bibcode:2017MarEc..38E2396B. doi:10.1111/maec.12396. ISSN 1439-0485.
  13. Llano, George Biology of the Antarctic Seas III, Volume 11 of Antarctic research series, Volume 3 of Biology of the Antarctic seas, Issue 1579 of Publication (National Research Council (U.S.))) American Geophysical Union, 1967, p. 57
  14. Miller, R. J.; Smith, C. R.; Demaster, D. J.; Fornes, W. L. (2000). "Feeding selectivity and rapid particle processing by deep-sea megafaunal deposit feeders: A 234Th tracer approach". Journal of Marine Research. 58 (4): 653. doi:10.1357/002224000321511061.
  15. Pawson, DL; Vance, DJ (2005). "Rynkatorpa felderi, new species, from a bathyal hydrocarbon seep in the northern Gulf of Mexico (Echinodermata: Holothuroidea: Apodida)". Zootaxa. 1050: 15–20. doi:10.11646/zootaxa.1050.1.2.
  16. Miller, Robert J.; Smith, Craig R.; Demaster, David J.; Fornes, William L. (April 4, 2000). "Feeding selectivity and rapid particle processing by deep-sea megafaunal deposit feeders: A 234Th tracer approach". Journal of Marine Research. 58 (4): 653–673. doi:10.1357/002224000321511061. Retrieved January 6, 2026.
  17. Barry, James P.; Taylor, Josi R.; Kuhnz, Linda A.; De Vogelaere, Andrew P. (2017). "Symbiosis between the holothurian Scotoplanes sp. A and the lithodid crab Neolithodes diomedeae on a featureless bathyal sediment plain". Marine Ecology. 38 (2) e12396. Bibcode:2017MarEc..38E2396B. doi:10.1111/maec.12396.
  18. Gutt, J.; Piepenburg, D. (1991). "Dense aggregations of three deep-sea holothurians in the southern Weddell Sea, Antarctica". Marine Ecology Progress Series. 68 (3): 277–285. doi:10.3354/meps068277. ISSN 0171-8630. JSTOR 44634754.

Further reading