Acteonoidea

Acteonoidea is a superfamily of sea snails, or bubble snails, marine gastropod mollusks.

Acteonoidea
Live Hydatina physis
Scientific classification
Kingdom:
Animalia
Phylum:
Mollusca
Class:
Gastropoda
(unranked):
clade Heterobranchia
informal group Lower Heterobranchia
Superfamily:
Acteonoidea

d'Orbigny, 1843
Diversity[1]
about 150 species

Taxonomy
Acteon tornatilis shell.

In the taxonomy of Bouchet & Rocroi (2005), the superfamily Acteonoidea has been included into the informal group "Lower Heterobranchia" (Heterostropha sensu Ponder & Warén, 1988), also known as the Allogastropoda.[2]

Only one of analyses by Jörger et al. (2010)[3] indicates the Acteonoidea sister to Nudipleura.[3] This clade that had resulted repeatedly in molecular studies with still limited "lower heterobranch" taxon sampling, either in a derived position or as a basal offshoot within Euthyneura.[3] A recent molecular phylogeny on Acteonoidea suggest a common origin with lower heterobranch Rissoelloidea and a sister group relationship to Nudipleura.[1][3] While the basal position of Acteonoidea was commonly accepted, some authors doubted the basal position of Nudipleura, which was originally considered as a highly derived taxon, and suspect rate heterogeneity and deviant base composition as causing this unnatural grouping.[3] Based on potential synapomorphies in the reproductive system (presence of a ciliary stripe within the ampulla, androdiaulic or triaulic pallial gonoduct), Ghiselin already suggested a relationship between Acteonoidea and Nudipleura.[3] However, Acteonoidea form a well-supported "lower heterobranch" clade with Rissoelloidea, confirming results by Aktipis et al. and Dinapoli and Klussmann-Kolb.[3] The latter authors also recovered Nudipleura as the first offshoot of Euthyneura, which is confirmed by Jörger et al. (2010) study. Salvini-Plawen and Steiner grouped Umbraculoidea with Nudipleura, but none of the recent molecular or morphological studies support such a relationship.[3]

Families

The following five families have been recognized in the taxonomy of Bouchet & Rocroi (2005):[2]

Description

All acteonoids have a shell that resembles that of many prosobranchs. Some of the members are able to withdraw completely into the shell and to close the shell with an operculum, e.g. Acteon tornatilis.[4]


Anatomy

No defensive strategies are known from these animals although histological investigations show a highly glandular area in the mantle cavity and the mantle rim. The mantle rim glands, for example, are very conspicuous. These comprise large epithelial cells that are filled with a non-staining vacuole. The glandular area is highly folded. The cells appear to lie subepithelially due to their size. They alternate with small ciliated cells. The hypobranchial gland in the roof of the mantle cavity is small and consists of violet-staining epithelial cells indicating acid mucopolysaccharides.[4]

Feeding habits

Acteonidae and Aplustridae are carnivorous and mainly feed on polychaetes.[4]

gollark: And I think `as` is a keyword for the sole purpose of `with ... as x`
gollark: I really don't see why `in` and `is` need to be dedicated keywords.
gollark: ``` and as assert async[note 1] await[note 1] break class continue def del elif else except exec[note 2] False[note 3] finally for from global if import in is lambda None nonlocal[note 3] not or pass print[note 2] raise return True[note 3] try while with yield```Oh, and I found this list of keywords here.
gollark: To someone who just wants to parse XML, that makes absolutely no sense.
gollark: ```Structured Markup Processing Tools html — HyperText Markup Language support html.parser — Simple HTML and XHTML parser html.entities — Definitions of HTML general entities XML Processing Modules xml.etree.ElementTree — The ElementTree XML API xml.dom — The Document Object Model API xml.dom.minidom — Minimal DOM implementation xml.dom.pulldom — Support for building partial DOM trees xml.sax — Support for SAX2 parsers xml.sax.handler — Base classes for SAX handlers xml.sax.saxutils — SAX Utilities xml.sax.xmlreader — Interface for XML parsers xml.parsers.expat — Fast XML parsing using Expat```

References

This article incorporates CC-BY-2.0 text from references.[3][4]

  1. Gbbeler K. & Klussmann-Kolb A. (2010). "The phylogeny of the Acteonoidea (Gastropoda): molecular systematics and first detailed morphological study of Rictaxis punctocaelatus (Carpenter, 1864)". Journal of Molluscan Studies 76(4): 303-316. doi:10.1093/mollus/eyq014.
  2. Bouchet, Philippe; Rocroi, Jean-Pierre; Frýda, Jiri; Hausdorf, Bernard; Ponder, Winston; Valdés, Ángel & Warén, Anders (2005). "Classification and nomenclator of gastropod families". Malacologia. Hackenheim, Germany: ConchBooks. 47 (1–2): 1–397. ISBN 3-925919-72-4. ISSN 0076-2997.
  3. Jörger K. M., Stöger I., Kano Y., Fukuda H., Knebelsberger T. & Schrödl M. (2010). "On the origin of Acochlidia and other enigmatic euthyneuran gastropods, with implications for the systematics of Heterobranchia". BMC Evolutionary Biology 10: 323. doi:10.1186/1471-2148-10-323.
  4. Wägele H. & Klussmann-Kolb A. (2005). "Opisthobranchia (Mollusca, Gastropoda) – more than just slimy slugs. Shell reduction and its implications on defence and foraging". Frontiers in Zoology 2:3. doi:10.1186/1742-9994-2-3.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.