Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Protostomia
Cladus: Spiralia
Cladus: Lophotrochozoa
Phylum: Mollusca
Classis: Gastropoda
Subclassis: Heterobranchia
Infraclassis: Euthyneura
Cohors: Tectipleura
Subcohors: Euopisthobranchia
Ordo: Aplysiida
Superfamilia: Akeroidea
Familia: Akeridae
Genus: Akera
Species (5 + 1†): A. bayeri – A. bullata – A. julieae – A. silbo – A. soluta – †A. spirata
Name
Akera Müller, 1776
Synonyms
Acera Jeffreys, 1867 (unjustified emendation of Akera
Aceras Locard, 1886 (unjustified emendation of Akera)
Bulla (Akera) O. F. Müller, 1776
Eucampe Leach, 1847
Vitrella Swainson, 1840
References
Primary referencesLinks
Akera in the World Register of Marine Species
Akera is a marine genus of sea hare in the family Akeridae, known from the late Callovian (Jurassic) to the recent periods.[2][3]
Akera is the sole genus within the family Akeridae.
Description
Akera bullata
Akera is a primitive genus. Their soft and elongated body does not fit completely in their external shell; it just covers their visceral hump which is positioned at the posterior end of their bodies. Their streamlined bodies are adapted for burrowing.
The shell is large and glossy, globosely cylindrical with a paper-thin, translucent, and flexible texture that provides minimal protection. The spire is truncated, and the whorls are deeply channeled. The protoconch is partially embedded. The upper whorls are blunt. The aperture spans the length of the body whorl or is slightly shorter. It is expanded and deeply sinuated in front, with the outer margin disunited at the suture. The columella is exposed, revealing the inner whorls. The color of the shell is muted, ranging from pale brown to greenish hues.
The head-disc is greatly elongated, wide, and bifid anteriorly, tapering towards the rear. The mantle's hind edge is fimbriated and extends through the fissured shell suture. The foot is expanded and narrow with a rounded anterior end, becoming broad and truncated posteriorly. Using its extended lateral parapodia, the animal swims with considerable agility. [4]
Distribution
Species of this marine genus have a global distribution including temperate and tropical seas, inhabiting soft muddy bottoms, sea grass beds and coral sand. They are herbivorous, feeding on algae and detritus.
Species
Akera bayeri (Marcus & Marcus, 1967) - It can be found along the coast of Colombia and Brazil.
Akera bullata (O. F. Müller, 1776) - type species
Akera constricta Kuroda, 1947
Akera julieae Valdes & Barwick, 2005
Akera silbo Ortea & Moro, 2009
Akera soluta (Gmelin, 1791) - Also called the Solute akera, this species can be found in the Indo-West Pacific. Little is known about this species. Its shell can grow as large as 45 mm in length.
† Akera spirata Staadt, 1913
† Akera striatella Lamarck, 1804 - fossil from the Eocene and Oligocene.
Synonyms
Akera aperta Hedley, 1899: synonym of Oxynoe aperta (Hedley, 1899) (original combination)
† Akera eliai Shalem, 1928 : synonym of † Hamlinia eliai (Shalem, 1928) (original combination)
Akera flexilis T. Brown, 1844: synonym of Akera bullata O. F. Müller, 1776
Akera tasmanica Beddome, 1883 [5] synonym of Diaphana tasmanica (Beddome, 1883)
Akera thompsoni Olsson & T. L. McGinty, 1951: synonym of Akera bayeri Ev. Marcus & Er. Marcus, 1967 (unavailable name, no description)
References
Müller O. F. (1776). Zoologiæ Danicæ prodromus, seu animalium Daniæ et Norvegiæ indigenarum characteres, nomina, et synonyma imprimis popularium. pp. I-XXXII [= 1-32], 1-274. Havniæ. (Hallager). page 242.
Gofas, S. (2012). Akera O.F. Müller, 1776. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=137641 on 2012-03-31
Sepkoski's Online Genus Database. Downloaded 14 October 2008.
Tryon, G.W. (1882). Structural and systematic conchology (vol. 1 ed.).
Schiøtte T. (1998). "A taxonomic revision of the genus Diaphana Brown, 1827, including a discussion of the phylogeny and zoogeography of the genus (Mollusca: Opisthobranchia)". Steenstrupia. 24: 77–140.
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