Schaefer’s Spiny-jawed Snake was described in 1995; it is, however, known from a single specimen that was collected in Hutan Lipur Templer, a forest reserve in the Gombak District of Selangor, Malaysia.
The species was apparently never found since; it is officially treated as “Data Deficient” but, given the ongoing destruction of many forests around the world, might well be already extinct.
King’s Alphonsea is known only from the type material which was collected in the Kinta District of Perak, Malaysia, a region that today is heavily mined over, thus the survival of this species appears to be very doubtful.
De Crespigny’s Karst Snail (Opisthostoma decrespignyi)
This minute species, whose shell hardly reaches 0,2 cm, was described in the year 1865.
De Crespigny’s Karst Snail inhabited small islets like Pulau Burung, Pulau Daat, and Pulau Papan offshore the island state of Labuan, which again lies offshore Borneo’s northwest coast, where it was strictly restricted to limestone rocks.
The limestone (of all these islands ?) was removed in the 1960s by quarrying, and thus the habitat of this snail species was destroyed. 
De Crespigny’s Karst Snail is now considered possibly extinct – however, there have been no recent surveys to confirm this assumption.
References:  Reuben Clements; Navjot S. Sodhi; Menno Schilthuizen; Peter K. L. Ng: Limestone Karsts of Southeast Asia: Imperiled Arks of Biodiversity. BioScience 56(9): 733-742. 2006
The Lesser Pygmy Flying Squirrel was described in 1908 based on a single specimen that was collected in 1901 in Sabah, northern Borneo.
It is the smallest of the three species within its genus, reaching a full size of about 14 cm (including the tail).
The species was never found since its description and, probably being restricted to intact forest habitats, may now be extinct since large areas in the region have been converted into oil palm plantations.