Jump to content

Peracarida

From Wikipedia, the free encyclopedia
(Redirected from Marsupium (Peracarida))

Peracarida
Temporal range: upper Devonian–present, 365–0 Ma
Gammarid amphipods from the Gulf of Naples
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Malacostraca
Subclass: Eumalacostraca
Superorder: Peracarida
Calman, 1904 [1]

The superorder Peracarida[a] is a large group of malacostracan crustaceans, having members in marine, freshwater, and terrestrial habitats. They are chiefly defined by the presence of a marsupium (the "brood pouch"), formed from thin flattened plates (oostegites) borne on the basalmost segments of the legs.

Peracarida is one of the largest crustacean taxa and includes about 12,000 species. Most members are less than 2 cm (0.8 in) in length,[3] but the largest can be quite sizeable, such as the giant isopod Bathynomus giganteus which can reach 76 cm (30 in) in length, and the giant amphipod Alicella gigantea (34 cm (13 in) long). The earliest known peracaridian was Oxyuropoda ligioides, a fossil taxon dated to the Late Devonian of Ireland (more than 360 mya).[4]

Orders

[edit]

There is some disagreement as to which orders should be included within Peracarida.[clarification needed] The World Register of Marine Species WoRMS (2023) includes the following 13 orders:[5]

Of these Bochusacea, Ingolfiellida and Stygiomysida were added to the classification of Martin & Davies (2001).[6] Ruppert et al. (2004) excluded Thermosbaenacea and placed it in a separate order, Pancarida. They also still kept Lophogastrida, Mysida and Pygocephalomorpha in a single order Mysidacea,[3] an arrangement that was disputed by Meland and Willassen (2007) since molecular data shows that the three orders are not closely related (they do not form a clade).[7]

Description

[edit]
Generalized peracarid mandibula[b]

The defining characteristics of the order includes the possession of a single pair of maxillipeds (rarely 2–3), mandibles with an articulated accessory process between the molar and incisor "teeth" in the adults (called the lacinia mobilis), and of carapace which is often reduced in size and is not fused with the posterior thoracic somites.[8] In some orders, the young hatch at a post-larval, prejuvenile stage called a manca which lacks the last pair of legs.[8]

Marsupium

[edit]
Livoneca redmanii; Cymothoidae, young in brood pouch

The marsupium of female peracaridans is a characteristic unique to this group (though males lack this part of their anatomy).[9][10] It is a space on the ventral surface of the animal which functions as a brood pouch,[11] and is enclosed by the large, flexible oostergites, which are bristly flaps (sometimes defined as lamellae) which extend from the basal segments of the pereiopods (the "hip" or coxae),[12] which form the floor of a chamber "roofed" by the animal's sternum.[13] This chamber is where the eggs are brooded; females lay their eggs directly into the brood chamber, and the young will develop there, undergoing several moults before emerging as miniature adults referred to as mancae; the larval development is direct in most cases.[3]

In the underground order Thermosbaenacea, there are no oostergites and the carapace of the female is expanded to form a dorsal marsupium.[3]

References

[edit]
  1. ^ New Latin; from Greek pēra (pouch, bag) + New Latin -carida (from Latin carid-, caris, a kind of sea crab)[2]
  2. ^ 1. Molar process; 2. Spine row; 3. Lacinia mobilis; 4. Incisor process; 5. Palp
  1. ^ W. T. Calman (1904). "On the Classification of the Crustacea Malacostraca". Annals and Magazine of Natural History. 13 (74): 144–158. doi:10.1080/00222930408562451.
  2. ^ "Peracarida". Merriam-Webster.com Dictionary. Merriam-Webster. Retrieved 2025-06-19.
  3. ^ a b c d Ruppert, E. E.; Fox, R. S.; Barnes, R. D. (2004). Invertebrate Zoology, 7th edition. Cengage Learning. pp. 651–652. ISBN 978-81-315-0104-7.
  4. ^ Robin, N.; Gueriau, P.; Luque, J.; Jarvis, D.; Daley, A. C.; Vonk, R. (2021). "The oldest peracarid crustacean reveals a Late Devonian freshwater colonization by isopod relatives". Biology Letters. 17 (6). The Royal Society: 20210226. bioRxiv 10.1101/2021.04.25.441336. doi:10.1098/rsbl.2021.0226. ISSN 1744-957X. PMC 8205522. PMID 34129798.
  5. ^ Peracarida World Register of Marine Species 5 Aug 2023
  6. ^ Martin, J. W. & G. E. Davis (2001). An Updated Classification of the Recent Crustacea (PDF). Natural History Museum of Los Angeles County. pp. 132 pp.
  7. ^ Meland, K.; Willassen, E. (2007). "The disunity of "Mysidacea" (Crustacea)" (PDF). Molecular Phylogenetics and Evolution. 44 (3): 1083–1104. Bibcode:2007MolPE..44.1083M. doi:10.1016/j.ympev.2007.02.009. PMID 17398121.
  8. ^ a b "Peracarida". Guide to the marine zooplankton of south eastern Australia. Tasmanian Aquaculture & Fisheries Institute. June 2008. Archived from the original on October 4, 2011. Retrieved August 30, 2011.
  9. ^ Peter Ax (2000). "Peracarida". The Phylogenetic System of the Metazoa. Multicellular Animals. Vol. 2. Springer. pp. 174–178. ISBN 978-3-540-67406-1.
  10. ^ Sol Felty Light (1974). "Subclass Peracarida". Intertidal Invertebrates of the Central California Coast (2nd ed.). University of California Press. pp. 135–171. ISBN 978-0-520-00750-5.
  11. ^ "Marsupium". research.nhm.org/. Natural History Museum of Los Angeles County » Crustacea Glossary. Retrieved 19 June 2025.
  12. ^ "Oostergites". research.nhm.org/. Natural History Museum of Los Angeles County » Crustacea Glossary. Retrieved 19 June 2025.
  13. ^ G. C. B. Poore (2002). "Superorder: Peracarida Calman, 1905". Crustacea: Malacostraca. Syncarida, Peracarida: Isopoda, Tanaidacea, Mictacea, Thermosbaenacea, Spelaeogriphacea. Zoological Catalogue of Australia. Vol. 19.2A. CSIRO Publishing. pp. 24–25. ISBN 978-0-643-06901-5.
[edit]
Retrieved from "https://en.wikipedia.org/w/index.php?title=Peracarida&oldid=1296304538#Marsupium"