Hanyusuchus

Hanyusuchus sinensis was a large long-snouted crocodilian that lived in southern China during the late Holocene. Four skulls and portions of the skeleton provide a rare fossil record for an animal that shared river landscapes with people. Several directly dated individuals lived about 3,300–2,900 years ago, and two specimens carry marks interpreted as cuts from metal weapons.

The species was named in 2022. Its anatomy combines features that help connect the living gharial and false gharial lineages, while archaeological and historical evidence suggests that long-snouted crocodiles persisted in the region later than the directly dated bones. The profile appears in the ancient crocodylomorph catalogue.

Quick facts

A Holocene crocodilian named from a historical story

Masaya Iijima, Yu Qiao, Wenbin Lin, Youjie Peng, Minoru Yoneda and Jun Liu described Hanyusuchus sinensis in 2022. The generic name honours Han Yu, a Tang-dynasty official and writer. In 819 CE, Han Yu composed an address asking crocodiles in the river near Chaozhou to leave. The fossils named for him predate that account by millennia; the name connects the extinct animal with later historical memory rather than dating the species to Han Yu's lifetime.

The material includes four skulls and portions of associated skeletons collected from archaeological contexts in southern China. The record is unusual because it can be read alongside dated human settlement and historical texts. Those sources answer different questions: bones show anatomy and individual encounters, radiocarbon measurements date particular remains, and written accounts describe what people believed or reported about regional crocodiles.

Specimens and direct dates

The holotype XM 12-1558 came from Dalincun village in Jiangmen, Guangdong. It includes a skull, lower jaw and postcranial portions. Radiocarbon analysis gave a calibrated age of 3,327 ± 53 years before present. Paratype XM 12-1557, a skull from the same locality, dates to 3,297 ± 48 years. SM E1623 includes another skull, jaw and skeletal remains and is dated to 2,942 ± 55 years. The fourth skull, SM S01812, has not been directly dated.

All four studied individuals were skeletally mature based on closure of vertebral neurocentral sutures. This does not mean that every bone had identical preservation or that the sample captures the full size range of the species. The fossils belong to museum collections in China, and the associated material provides more information about body proportions than a skull-only record would.

Archaeological records of long-snouted crocodilians extend across Guangdong, Guangxi, Fujian and Hainan. The dated specimens establish a late Holocene presence in this region, while the wider archaeological record and historical documents suggest persistence beyond the oldest radiocarbon dates. Individual accounts cannot always be assigned to Hanyusuchus with the certainty available for a diagnosed skull.

Large size estimated from skeletal proportions

The researchers estimated total lengths of 5.43–6.19 metres for the four adult individuals. These values were calculated by scaling preserved measurements against crocodilian proportions; they were not obtained from complete carcasses. The range shows that several animals were large, but it should not be converted into a single maximum size for every member of the species.

The long, narrow muzzle carried many teeth and is consistent with taking fish and other aquatic prey. As with other longirostrine crocodilians, this is a functional inference. No stomach contents or associated prey identify a usual diet. Large individuals could have captured larger animals, but historic reports of attacks on livestock are not direct observations of a fossil taxon unless they can be securely connected to its remains.

Some cranial features are shared with living gharials, while others resemble the false gharial Tomistoma schlegelii. The combination was important because morphology had often separated the two living species, whereas DNA-based studies placed them as close relatives. The fossil anatomy provides an independent set of characters for examining that relationship.

Two cut-marked crocodilians

Two specimens show deep cut or chop marks interpreted as damage from metal weapons. One includes a severe cut around the junction of the head and neck. Their shape, placement and archaeological context support a human interaction rather than ordinary wear or a bite from another animal. This is direct evidence that people struck at least two crocodilians represented in the sample.

The marks do not establish every step in the event. They do not show whether an individual was killed immediately, whether the animal was hunted for food or protection, or how frequently people encountered crocodiles. They are also not enough on their own to demonstrate the cause of extinction. To address population disappearance, the study compared the bones with settlement expansion, changes to river landscapes and historical accounts of efforts to drive out or kill crocodiles.

Written sources from southern China describe dangerous crocodilians and attempts at control, including Han Yu's famous address. Such texts add historical context but were not field notes identifying a fossil species. The strongest account keeps the two evidence types separate: weapon damage is observed on bones, while long-term persecution is inferred from a broader archaeological and historical pattern.

Gharial relationships and distinctive skull anatomy

The 2022 study placed Hanyusuchus among gavialids and described it as a morphological link between the two living gharials. Its skull combines characters not all pointing toward the same familiar modern form. The analysis therefore tests how the living lineages evolved and whether their apparent differences hide a more complex shared history.

One notable feature is a pair of cavities in the pterygoid region, considered in relation to the cranial structures of living gharials. Cranial anatomy can inform hypotheses about vocal or sensory systems, but fossil bone does not preserve the sound produced or the exact function of a soft-tissue space. The presence of a bony feature is direct; its behavioural meaning requires comparison and remains qualified.

The species was not an ancestor of either living gharial simply because its traits are intermediate. A fossil can preserve a combination of ancestral and derived characters without sitting on the direct line to a modern species. Phylogenetic analyses place it on a branching tree; they do not turn that tree into a ladder.

Why the lineage disappeared

Archaeological crocodilian remains and historical descriptions suggest that large long-snouted crocodiles persisted in southern China into much later periods, perhaps into the second millennium CE. Exact dates for those later records and their species-level identity vary. The directly dated skeletons prove late Holocene animals; the literary record broadens the timeline but has less taxonomic precision.

Iijima and colleagues argued that human pressure and the transformation of river valleys likely contributed to the species' disappearance. Expanding settlements, rice cultivation, dams and other changes altered floodplains and rivers while people deliberately tried to remove dangerous crocodilians. Climate alone does not readily explain the late survival indicated by historical accounts. Still, the relative importance of hunting, habitat change and other pressures cannot be quantified from four directly dated individuals.

The end of Hanyusuchus is therefore a strong human-impact hypothesis supported by several independent lines, not one cut-mark interpreted in isolation. Its remains show that large gavialids survived in southern China alongside people long after many other fossil crocodilians had vanished. The ancient crocodylomorph catalogue includes this unusually recent branch of crocodilian history.