German New Guinea ended in 1919.

German New Guinea was created in 1884.

German New Guinea Company was created in 1884.

Australia did not "capture" German New Guinea.

The northern half of Papua New Guinea was once known as German New Guinea after it came under German control in 1884, while the southern half was known as British New Guinea, later renamed to Papua in 1904. During WWI, the island was occupied by Australian troops to defend the British half.

When the Treaty of Versailles was established after World War I, and many German-occupied lands were removed from German control, Australia was put in charge of administering German New Guinea. The British part of the island came to be considered an External Territory of the Commonwealth of Australia, though it was still "owned" by Britain. The two territories were, at this stage, regarded as separate territories, known as 'Papua' and 'New Guinea'.

The Papua New Guinea side of New Guinea was divided between Germany and England. The northern half of the country fell to German control in 1884, so it was briefly known as German New Guinea. The southern half was known as British New Guinea, later renamed to Papua in 1904.