Drive north from Guangzhou toward the border with Jiangxi and the landscape shifts. The subtropical lowlands give way to folded hills, and the soil turns a vivid, almost rusty red. That color tells the geological story: the Nanxiong Basin formed when Mesozoic rifting split the underlying Jurassic granite apart, creating a graben — a sunken block of crust bounded by faults — that trapped sediment from ancient rivers for millions of years. The result is a thick accumulation of siliciclastic red beds, the kind geologists call continental deposits because they formed not beneath an ancient sea but on land, along floodplains and river channels where dinosaurs lived and died. The formation has been dated to approximately 66.7 million years ago, placing it right at the boundary between the Cretaceous and the Paleogene — the moment the asteroid struck, the skies darkened, and the non-avian dinosaurs disappeared.

The Nanxiong Formation has produced a fauna strikingly rich in variety. Sauropods lumbered through — titanosaurian giants whose fossilized remains include several newly described species, among them Gandititan cavocaudatus, formally named in 2024, which extended the known diversity of long-necked dinosaurs right to the end of the Cretaceous. Theropods prowled alongside them: oviraptorosaurs with elaborate crests, therizinosaurs with scythe-like claws, and tyrannosaurs — including a deep-snouted species described as recently as 2024 — that represent a distinct Asian lineage quite different from their North American cousins. Ornithopods left tracks pressed into ancient mud, now lithified and studied alongside pterosaur footprints from the same beds. Large predatory lizards — some reaching impressive size — rounded out an ecosystem that in broad outline resembled the Nemegt Formation of Mongolia, suggesting similar ecological conditions across a wide band of Late Cretaceous Asia.

If one discovery has made the Nanxiong Formation famous beyond specialist circles, it is the eggs. Thousands of dinosaur eggs have emerged from these red beds, many of them elongatoolithid eggs produced by oviraptorids — crested, beaked theropods that sat on their nests like birds. The eggs are often found in clutches, sometimes with the brooding adult preserved directly atop the nest. More remarkable still, some eggs contain embryonic skeletons inside, giving paleontologists a rare window into how these animals developed before hatching. Research published in 2019 even suggested that oviraptorids hatched asynchronously — meaning eggs in the same clutch hatched at different times, a reproductive strategy previously unknown in non-avian dinosaurs. A 2005 study added another layer: a female oviraptorid preserved with two shelled eggs still inside her body, caught in the act of laying. Each season of fieldwork seems to produce another chapter in the oviraptorid life story.

The formation's richness extends well beyond the famous headline animals. Crocodyloids of the genus Jiangxisuchus — known from a nearly complete skull and mandible — inhabited the ancient waterways. Turtles of the family Nanhsiungchelyidae left their shells behind, along with trionychid soft-shelled turtles. Large lizards of the platynota group, relatives of today's monitor lizards, hunted through the undergrowth. Taken together, this community of animals resembles in some ways the world being documented today from the roughly contemporaneous deposits of Central Asia — a world that, within a geological instant of these sediments being deposited, would vanish entirely. The red beds of the Nanxiong Basin record not just individual species but the texture of a world at its terminus.

Research on the Nanxiong Formation accelerated sharply after the 1980s, as Chinese and international paleontologists gained greater access to the region around Ganzhou city in Jiangxi Province — where many of the formation's most productive exposures lie — and the Nanxiong Basin in Guangdong itself. New species continue to be described at a pace that reflects both the richness of the deposits and the growing capacity of Chinese paleontology. Two new titanosaur species were named in 2023 and 2024 respectively. A new deep-snouted tyrannosaur was published in 2024. The oviraptorid diversity from Ganzhou now numbers among the highest concentrations of that group anywhere in the world. For anyone who looks at the terracotta-colored hillsides of northern Guangdong and sees only eroded rock, a closer look at what lies within them reframes the view entirely.