MyopsidaMichael Vecchione and Richard E. Young
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The root of the current tree connects the organisms featured in this tree to their containing group and the rest of the Tree of Life. The basal branching point in the tree represents the ancestor of the other groups in the tree. This ancestor diversified over time into several descendent subgroups, which are represented as internal nodes and terminal taxa to the right.
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Myopsid squids are, neritic, often in very shallow water, or upper slope demersal species. Many species are strong swimmers, occur in large schools and are fished commercially for food. The Loliginidae contains many species some of which reach a rather large size (at least 90 cm ML in Loligo forbesii) but those in Pickfordiateuthis, are dwarf species where males may mature at less than 14 mm ML (Brachoniecki, 1996). The Australiteuthidae contains a single species that is also a dwarf with males that mature as small as 17 mm ML (Lu, 2005).
A decapodiform ...
- with corneal membranes covering eye lenses.
- without secondary eyelids.
- with well-developed gladius.
- Suckers of arms (and tentacles) with circularis muscles (unknown in Australiteuthidae).
- Club without proximal (= carpal) locking-apparatus.
- Buccal crown
- Buccal supports with or without suckers.
- Head with tentacle pocket.
- Eyes with corneal membranes covering lenses.
- Eyes without secondary (= ventral) eyelid.
- Funnel without lateral adductor muscles.
- Mantle locking-apparatus extends to mantle edge (except Australiteuthidae)
- Fins with or without posterior lobes.
- Shell a gladius.
- Gills with branchial canal (except Pickfordiateuthis, unknown in Australiteuthis).
- Right oviduct absent.
- Females with accessory nidamental glands.
- Eggs, where known, attached to substrate.
- Embryo with large external yolk sac.
The two families of the Myopsida appear to be closely related. The Australiteuthidae differs from the Loliginidae primarily in the structure of the funnel/mantle locking-apparatus and the position of the mantle component which does not reach the mantle margin. A number of features of phylogenetic importance in the Australiteuthidae, however, are not known: the presence or absence of a branchial canal, an anterior eye pocket, circularis muscles in the suckers, an interstellate connective; the location of spermathecae; the symmetry of the gills; the type and place (pelagic or benthic) of deposition of egg masses and the position of the intestine relative to the cephalic vein and the vena cavae.
Brakoniecki, T. F. 1996. A revision of the genus Pickfordiateuthis Voss, 1953 (Cephalopoda; Myopsida). Bull. Mar. Sci., 58: 9-28.
Lu, C. C. 2005. A new family of myopsid squid from Australasian waters (Cepahlopoda: Teuthida). P. 71-82. In: Chotiyaputta, C., E. M. C. Hatfield and C. C. Lu (editors). Cephalopod biology, recruitment and culture. International Cephalopod Symposium and Workshop, 17-21 Feb. 2003. Research Bulletin, Phyuket Marine Biological Center, No. 66, Published by the Center Phuket, Thailand, July 2005, 365 pp.
Naef, A. 1921-1923. Die Cephalopoden. Fauna e Flora del Golfo di Napoli, Monographie 35, Vol I, Parts I and II, Systematik, pp 1-863.
National Marine Fisheries Service
National Museum of Natural History
Washington, D. C. 20560
Richard E. Young
Dept of Oceanography
University of Hawaii
Honolulu, Hawaii 96822
Page copyright © 2005 and Richard E. Young
- First online 20 September 2005
Citing this page:
Vecchione, Michael and Young, Richard E. 2005. Myopsida http://tolweb.org/Myopsida/52670/2005.09.20 in The Tree of Life Web Project, http://tolweb.org/. Version 20 September 2005 (complete).