The phylogeographic analysis of these authors indicates that amphidromic
populations have colo-nized various stream systems, giving rise to repeated evolution from amphidromic
coastal populations to strictly freshwater populations (or cryptic species) of Paratya, presumably with some form of ALD.
However, like water spilled from the edge of a shallow dish, tidal effects become more evident in shallowing coastal waters where rotary tidal currents of amphidromic systems are impeded.
The Coriolis effect is joined by the constraining effect of landmasses in imposing amphidromic systems on the tides (Fig.
Note that although in the ocean basins anticlockwise motion of tide waves about amphidromic points occurs in the Northern Hemisphere, and vice versa in the Southern Hemisphere, several exceptions exist.
The waves in fact follow a more complicated distribution, but the repeated basic pattern is easy to understand: The waves rotate around centers of zero height, and the further their radial distance from this central point (called the nodal or amphidromic
point), the taller they are.
The tides which beset its shores are perhaps best described as a degenerate amphidromic system.
So much for the tides of a so-called "degenerate amphidromic system".