Continent world ultimately persisted with these being regarded as separate continents. From the late 18th century, some geographers started to regard North America and South America as two parts of the world, making five parts in total. Overall though, the fourfold division prevailed well into the 19th century. Europeans discovered Australia in 1606, but for some time it was taken as part of Asia. By the late 18th century, some geographers considered it a continent in its own right, making it the sixth (or fifth for those still taking America as a single continent). In 1813, Samuel Butler wrote of Australia
Smallest organisms "Megaphragma caribea" from Guadeloupe, measuring 170 μm long, is another contender for smallest known insect in the world. Beetles of the tribe Nanosellini are all less than 1 mm long; the smallest confirmed specimen is of "Scydosella musawasensis" at 325 μm long; a few other nanosellines are reportedly smaller, in historical literature, but none of these records have been confirmed using accurate modern tools. These are among the tiniest non-parasitic insects. The western pygmy blue ("Brephidium exilis") is one of the smallest butterflies in the world. The smallest sea cucumber, and also the smallest echinoderm, is "Psammothuria ganapati", a synaptid