Akera
Encyclopedia
Akera is a marine
genus
of sea hare
in the family Akeridae
, known from the late Callovian
(Jurassic) to the recent periods.
; it just covers their visceral hump which is positioned at the posterior end of their bodies. Their streamlined bodies are adapted for burrowing.
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of sea hare
Sea hare
The clade Aplysiomorpha, commonly known as Sea hares or Sea Bags , are medium-sized to very large Opisthobranchia with a soft internal shell made of protein...
in the family Akeridae
Akeridae
Akeridae is a small taxonomic family of sea snails, marine gastropod molluscs belonging to the superfamily Akeroidea, the sea hares. The family, in its original spelling "Aceridae", has previously been attributed in error to Pilsbry, 1893....
, known from the late Callovian
Callovian
In the geologic timescale, the Callovian is an age or stage in the Middle Jurassic, lasting between 164.7 ± 4.0 Ma and 161.2 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the Oxfordian....
(Jurassic) to the recent periods.
Description
Akera is a primitive genus. These sea hares do not fit completely in their external shellGastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
; it just covers their visceral hump which is positioned at the posterior end of their bodies. Their streamlined bodies are adapted for burrowing.
Species
- Akera bayeri (Marcus & Marcus, 1967) - It can be found along the coast of ColombiaColombiaColombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
and BrazilBrazilBrazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
. - Akera bullataAkera bullataAkera bullata is a species of sea snail , a marine opisthobranch gastropod mollusk in the family Akeridae, a family that is related to the sea hares...
O. F. Müller, 1776 - type genus - Akera julieae Valdes & Barwick, 2005
- Akera soluta (GmelinJohann Friedrich GmelinJohann Friedrich Gmelin was a German naturalist, botanist, entomologist, herpetologist and malacologist.- Education :Johann Friedrich Gmelin was born as the eldest son of Philipp Friedrich Gmelin in 1748 in Tübingen...
, 1791) - Also called the Solute akera, this species can be found in the Indo-West PacificIndo-West PacificThe Indo-West Pacific, or IWP, is a zoogeographical region spanning the entire Indian Ocean including the Red Sea and the Pacific Ocean as far as the Caroline Islands but short of the Marshall Islands...
. Little is known about this species. Its shell can grow as large as 45 mm in length. - † Akera striatella Lamarck, 1804 - fossil from the EoceneEoceneThe Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
and OligoceneOligoceneThe Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
. - Akera tasmanica Beddome, 1883