And I realized that this brain actually comprises three successive neuropils in the optic regions, which is a trait of malacostracans, not branchiopods," he said.
When Strausfeld traced the fossilized outlines of Fuxianhuia's brain, he realized it had three optic neuropils on each side that once were probably connected by nerve fibers in crosswise pattern as occurs in insects and malacostracans. The brain was also composed of three fused segments, whereas in branchiopods only two segments are fused.
Malacostracans are different: in the present study we found a marked difference between Patagonian species and Northern species in agreement with the panbiogeographical analyses of the amphipod genus Hyalella (De los Rios-Escalante et al., 2012), and of inland water decapods (Morrone & Lopretto, 1994).
Current state of freshwater malacostracans of Chile.
Current state of knowledge of freshwater malacostracans of Chile.
It has long been suggested that when malacostracan crustaceans flick the lateral flagella of their antennules, they increase the penetration of ambient water into the spaces between the aesthetascs, thus bringing odor-carrying water closer to the surfaces of those aesthetascs (e.g., Snow, 1973; Schmitt and Ache, 1979; Atema, 1985; Moore et al, 1991; Gleeson et al., 1993; Koehl, 1995, 1996; Pravin and Reidenbach, 2013; Waldrop et al , 2014).
Malacostracan crustaceans flick the lateral flagella of their antennules through the water in the Re range at which the leakiness of an array of hairs is very sensitive to velocity.
Against this background, I conclude that the composite nature of the terminal (sixth) ganglion and the pattern of its formation by fusion during embryogenesis is part of the malacostracan ground plan.
In addition, some authors report that the embryos of several malacostracan species contain terminal mesodermal somites that might be related to a vestigial seventh pleonic segment and that also fuse with the sixth pleonic somites (e.g., Manton, 1928a; Shiino, 1942).
However, the research, published in the journal Nature, notes that the shape of the fossilised brain matches that of modern malacostracans
4B); and cirripeds, branchiopods, and malacostracans
represent a more advanced stage, with the triads restricted to the periphery of the myofibrils (Fig.
Sex change has also been experimentally induced by androgenic gland grafting and removal in some malacostracans
that are not hermaphroditic in nature (Charniaux-cotton, 1975).