To date, there are more than a hundred reported mtDNAs from crustaceans, including 86 from
Malacostracans, which is the largest of the six classes of crustaceans and includes extinct and living species, such as shrimp, lobsters, crabs, krill.
Some believe that insects evolved from the an ancestor that gave rise to the
malacostracans, a group of crustaceans that include crabs and shrimp, while others point to a lineage of less commonly known crustaceans called branchiopods, which include, for example, brine shrimp.
Hermaphroditism and gynandromorphism in
Malacostracan Crustacea.
Data were analyzed considering the following categories: 1) All crustacean species, 2) Branchiopoda and Copepoda species, and 3)
Malacostracan species.
This phenomenon applies to most
malacostracan Crustacea, which begin reproduction before somatic growth is completed (Hartnoll, 1985), similar to apterygote insects and myriapods.
We found that crab antennules, like those of other
malacostracan crustaceans, take a discrete water sample during each flick by having a rapid downstroke, during which water flows into the aesthetasc array, and a slow recovery stroke, when water is trapped in the array and odorants have time to diffuse to aesthetascs.
The zooplankton comprised the copepods Temora longicornis, Paracalanus parvus, Pseudocalanus elongates, Centropages typicus, Calanus finmarchicus, and Oithona nana; and the
malacostracan crustaceans Crangon crangon, Corophium volutator, N.
These characteristics are highly divergent from the body plan of other
malacostracan crustaceans; therefore, Caprellidea are of great interest for understanding the evolution of morphological novelty.
In a phylogenetic comparison of an 1100-bp region conserved in seven crustacean prophenoloxidases, the enzymes from the Branchiopoda are distinguished from those of the
malacostracan Decapoda (Fig.
The origin and biogeography of
Malacostracan crustaceans in the deep sea.
The names refer to the involvement or otherwise of the giant axon, or fiber, systems that run the length of the ventral nerve cord in many
malacostracan crustaceans.
Apart from the established role of PDH in controlling pigment migration in
malacostracan crustaceans, the physiological significance of PDH-like peptides in arthropods has remained obscure.