Potamon fluviatile crabs' unusual size, up to , and longevity (up to 15 years) are also interpreted as evidence of a long-established population, by analogy with island gigantism. On the island of Malta, "Potamon fluviatile" is rare and restricted to a few locations in the west of the island. On Gozo, there is a single population which inhabits a stretch of river only long. In the Balkan Peninsula, "Potamon fluviatile" is known to occur in Croatia, Montenegro, the Republic of Macedonia, Albania and Greece. There are four species of "Potamon" in the Balkans, and "P. fluviatile" is replaced by "Potamon ibericum" in
Equisetum fluviatile Equisetum fluviatile Equisetum fluviatile, the water horsetail or swamp horsetail, is a vascular plant that commonly grows in dense colonies along freshwater shorelines or in shallow water in ponds, swamps, ditches, and other sluggish or still waters with mud bottoms. It is a perennial herbaceous species, growing 30–100 cm (rarely 140 cm) tall with erect dark green stems 2–8 mm in diameter, smooth, with about 10–30 fine ridges. At each joint, the stem has a whorl of tiny, black-tipped scale leaves 5–10 mm long. Many, but not all, stems also have whorls of short ascending and spreading branches 1–5 cm