La autora identifica, describe y figura 12 especies de fosiles de invertebrados, de las cuales 3 especies son de la familia Conulariidae; 4 especies son Trilobites: 2 de la Familia Phacopidae y 2 de la Familia Calmoniidae; 3 especies de braquiopodos pertenecen a 3 Familias: Leptocoeliidae, Eatoniidae y Delthyrididae; un foraminifero de la Familia Fusulinidae
y, un briozoo de la Familia Fenestellidae.
They studied the fossils of Fusulinidae, a unicellular organism, in a 40-meter-thick layer of limestone in the southwestern Japanese town of Takachiho, Miyazaki Prefecture.
Isozaki said he and Ota paid close attention to Fusulinidae, which became extinct after living in coral reefs or shallow seas during the Paleozoic era.
The study found that larger Fusulinidae, measuring up to 1 centimeter long, became extinct about 260 million years ago, he said.
It also found that smaller Fusulinidae, measuring less than 1 millimeter, survived at that time, he said.
But the smaller Fusulinidae became extinct about 250 million years ago, underscoring the two-stage theory of extinction.