Australian Fritillary (Argynnis hyperbius ssp. inconstans)
The Australian- or laced Fritillary was described in 1873, originally as a distinct species, but is now regarded as a subspecies of the Indian Fritillary (Argynnis hyperbius (L.)) (see photo). It is endemic to eastern Australia, where it is restricted to coastal areas of southern Queensland and northern New South Wales.
The species inhabited damp areas where the host plants of its larvae, Banks’ Violet (Viola banksii K. R. Thiele & Prober) and the Arrow-leaved Violet (Viola betonicifolia Sm.), were found growing abundantly.
Most of the sites that this species was known to inhabit, have been destroyed due to human activities, thus the populations broke down and disappeared completely; the very last known specimen was finally caught on April 17th, 2001, the Australian Fritillary is now most likely totally extinct.
 Trevor A. lambkin: Argynnis hyperbius inconsistans Butler, 1873 (Lepidoptera: Nymphalidae: Heliconiinae): a review of its collection history and biology. Australian Entomologist 44(4): 223-268. 2017
The Sharp-nosed Torrent Frog, also known as Sharp-snouted Day Frog, was described in 1916 and is resp. was endemic to the upland rainforests of northeastern Queensland, Australia.
The species was locally abundant, but its population begun to decline rapidly in 1988 certainly due to the spread of the deadly chytridiomycosis fungal disease that killed and still kills amphibian species all over the world.
The Prostrate Persoonia is, or maybe was, endemic to the northern tip of Fraser Island in Queensland, Australia, where it was found growing in sand dunes as well as in woods.
The species was described in 1810, it is known from only two collections and may in fact just be a prostrate form of another species, the Broad-leaved Persoonia (Persoonia stradbrokensis Domin) (see photo), which, however, is not known to grow on Fraser Island. 
The Prostrate Persoonia was a prostrate shrub with elliptic to spathulate, up to 5 cm long leaves.
The species is probably extinct.
 Peter H. Weston; L. A. S. Johnson: Taxonomic changes in Persoonia (Proteaceae) in New South Wales. Telopea 4(2): 269-306. 1991
Batianoff’s Paspalum Grass was described in 1992, it was collected in the Statue Bay, about 6,5 km southeast of the town of Yeppon in the Gladstone District (formerly Port Curtis District) in Queensland, Australia.
The species had 20 to 40 cm long, creeping stems.
Batianoff’s Paspalum Grass inhabited a very narrow foredune with open wood land consisting of some common, widely distributed plant species, it was found growing directly above the flood mark, acting as a sand stabilizer.
The species is apparently extinct today, however, the reasons for this appear to be unknown.