Diuqin lechiguanae
- 演化之聲
- Mar 19
- 3 min read
Updated: 2 days ago
Age
Cretaceous（Santonian）
86.3-83.6 Ma
Taxonomy
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Superorder: Dinosauria
Order: Saurischia
Suborder: Theropoda
Family: Unenlagiidae
Genus: Diuqin
Species: Diuqin lechiguanae
Morphological description
Diuqin lechiguanae is represented by a fragmentary yet clearly associated postcranial skeleton, including the neural arch of the last sacral vertebra, the neural arch of an anterior caudal vertebra, an almost complete left humerus lacking its proximal end, and four indeterminate bone fragments (at least two of which likely correspond to vertebral remains).
The deltopectoral crest on the humerus is oriented anteriorly rather than anterolaterally, and there is no longitudinal groove separating it from the humeral shaft. On the distal half of the crest, a distolateral deltopectoral ridge is present; this ridge extends toward the lateral midshaft and projects distally. This condition resembles that seen in some dromaeosaurids such as Deinonychus and certain troodontids, yet differs in its precise position and morphological combination.
The distal end of the humerus curves anteriorly. Above the ectepicondyle, a pronounced crest bearing a small tubercle is present. The ulnar condyle extends farther distally than the radial condyle. The caudal vertebral transverse processes are more robust and differ in inclination compared to those of Buitreraptor.
Overall, the humerus displays a mosaic of features intermediate between Unenlagia and Austroraptor, including anterior orientation of the deltopectoral crest, absence of a medial groove, and distal curvature. This combination suggests a transitional morphology in unenlagiine evolution.
The holotype specimen is catalogued as MUCPv 1401.
Etymology
The genus name Diuqin is derived from Mapuzungun, meaning "bird of prey", honoring the indigenous Mapuche culture of the region where the fossil was discovered.
The species name lechiguanae refers to Lechiguana, a witch character in the 1975 Argentine film Nazareno Cruz y el Lobo, directed by Leonardo Favio, who foretells the protagonist's transformation into a werewolf.
Biological description
Diuqin lechiguanae is an unenlagiine theropod discovered in northwestern Patagonia, Argentina, from the Bajo de la Carpa Formation of Santonian age (Late Cretaceous).
This taxon fills an approximately 15-million-year gap in the regional fossil record of Unenlagiinae. Morphologically, it combines traits seen in earlier forms such as Unenlagia with those of later, larger-bodied taxa such as Austroraptor. Notably, the humeral architecture characteristic of Austroraptor-like forms had already evolved prior to significant increases in body size.
The paleoenvironment in which Diuqin lechiguanae lived was warm and semi-arid, likely dominated by shrublands, grasslands, and sparsely distributed trees. Within such open habitats, it would have foraged for prey. The ecosystem included diverse herbivorous dinosaurs such as titanosaurs and ornithopods, which may have served as potential prey or part of the broader food web.
Two small conical punctures, approximately 10 mm apart, are preserved on the lateral distal end of the humerus. These marks are interpreted as feeding traces, likely produced by a conical-toothed predator such as a crocodyliform, a mammal, or another theropod—including the possibility of conspecific scavenging or cannibalism.
Phylogenetic analyses place Diuqin lechiguanae within Paraves, most consistently within Unenlagiinae, though its exact position varies across equally parsimonious trees, sometimes appearing as a sister taxon to the clade or nested within it.
（Author: Shui-Ye You）
Reference
Porfiri JD et al. (2024). Diuqin lechiguanae gen. et sp. nov., a new unenlagiine (Theropoda: Paraves) from the Bajo de la Carpa Formation (Neuquén Group, Upper Cretaceous) of Neuquén Province, Patagonia, Argentina. BMC Ecology and Evolution.
-38.55, -68.82
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