| Labocania | |
|---|---|
 | |
| Known remains ofL. anomala | |
.jpg) | |
| Known remains ofL. aguillonae | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Superfamily: | †Tyrannosauroidea |
| Family: | †Tyrannosauridae |
| Clade: | †Teratophoneini (?) |
| Genus: | †Labocania Molnar, 1974 |
| Type species | |
| †Labocania anomala Molnar, 1974 | |
| Other species | |
Labocania is an extinctgenus oftheropod dinosaur of disputed affinities, known from theLate Cretaceous of Mexico. Initially regarded as an indeterminate theropod, later studies have mentioned possible affinities withtyrannosaurids,abelisaurids, orcarcharodontosaurids. More recent research based on additional fossil material found support for a position within thetyrannosaurine cladeTeratophoneini. Two species have been proposed:L. anomala (the type species), likely from theLa Bocana Roja Formation, andL. aguillonae from theCerro del Pueblo Formation.
In the summer of 1970, theNational Geographic Society and theLos Angeles County Museum of Natural History organized a jointpaleontological expedition, led bygeologist William J. Morris, to theArroyo del Rosario inBaja California, Mexico. While prospecting, volunteer Harley J. Garbani discovered the fragmentary skeleton of a theropod north ofPunta Baja nearCerro Rayado.[1]
The collected specimen, IGM 5307 (formerly LACM 20877), was found in a layer of what is likely theLa Bocana Roja Formation, originally thought to date from the lateCampanian, about 73 million years old. More recent research has provided conflicting dates, possibly as old as around 93.6 million years old (Cenomanian–Turonian),[2] but vertebrate remains suggest a younger age.[3] The specimen consists of a very fragmentary skeleton withskull elements, including a rightquadrate, a leftfrontal, a piece of the leftmaxilla, a fragment of thedentary, achevron, the upper parts of bothischia, the middle shaft of the rightpubis, most of the second rightmetatarsal, atoe bone and several looseteeth. The elements were found disarticulated and strongly weathered, dispersed over a surface of about two square meters. The remains were mixed with the ribs of ahadrosauroid.[1]
In 1974,Ralph Molnardescribed thetype species,Labocania anomala, based on these remains. Thegeneric name references the La Bocana Roja Formation, named afterla Bocana Roja, "the redestuary". Thespecific name means "anomalous" inLatin, in reference to the distinctive morphology.[1]
In 2024, Rivera-Sylva & Longrich described a second species,Labocania aguillonae, based on fragmentary remains found in the Campanian-agedCerro del Pueblo Formation ofCoahuila, Mexico. The specific name honors the discoverer of the specimen, Martha C. Aguillon, a long-time paleontologist based in Coahuila. The holotype, CPC 2974, comprises parts of a maxilla, the frontals, left lacrimal, nasals, left squamosal, cervical, dorsal, sacral, and caudal vertebrae, lefthumerus, partialpelvic girdle, and partial left hindlimb. CPC 3077, a partial left dentary belonging to a larger, more mature individual, was tentatively referred toL. aguillonae.[3]
Labocania was a medium-sized carnivore. In 2010,Gregory S. Paul estimated the length ofL. anomala at 7 metres (23 ft) and its weight at 1.5 long tons (1.7 short tons).[4] In 2016, Molina-Pérez & Larramendi gave a higher estimate of 8.2 metres (27 ft) meters long and 2.6 long tons (2.9 short tons) in weight.[5] The holotype ofL. aguillonae which belongs to either a subadult or a young adult is smaller, at an estimated 6.3 metres (21 ft) long. A tentatively referred specimen belongs to a larger individual.[3]
The cranial elements are very robust, and thefrontals in particular are strongly thickened. The teeth of the maxilla are gradually recurving and rather flat; those of thepremaxilla do not have a D-shaped cross-section.[1]
.png)
BecauseLabocania is based on fragmentary material, its affinities are uncertain. Molnar (1974) noted certain similarities betweenLabocania andtyrannosaurids, especially in the form of theischium which features a low triangular obturator process and a circular lateral scar on the upper end, but he did not assignLabocania to any family, placing it asTheropodaincertae sedis. Molnar especially comparedLabocania with "Chilantaisaurus"maortuensis (later made the separate genusShaochilong) andIndosaurus.[1]Labocania was considered as a possible tyrannosauroid in the 2004 review of the group byThomas R. Holtz Jr., who pointed out that the similarities with the Tyrannosauridae were shared with theCoelurosauria in general—no tyrannosauroidsynapomorphies were present—and thatLabocania also showed someabelisaurid traits such as the thick frontals and a reclining quadrate. The L-shaped chevron and the flattened outer side of the second metatarsal support a position in theTetanurae.[6]
In 2024,Andrea Cau includedL. anomala in a large-scale phylogenetic dataset and recovered it as acarcharodontosaurid forming a clade withShaochilong.[7]
In their description of theropod material assigned to the newLabocania speciesL. aguillonae, Rivera-Sylva & Longrich (2024) found support for a position within thetyrannosaurine cladeTeratophoneini. Theirphylogenetic analyses recoveredLabocania in a clade withBistahieversor,Dynamoterror,Teratophoneus, and two unnamed taxa from theAguja andTwo Medicine formations. Their results are displayed in thecladogram below:[3]
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
In their 2025 description of the early tyrannosauroidKhankhuuluu, Voris and colleagues regardedL. aguillonae as anomen dubium due to a lack of clearly distinguishable traits compared to other southern tyrannosaurids, as they found none of the proposed diagnostic characters to be unique to this taxon.[8]
.png)
{{cite journal}}: CS1 maint: DOI inactive as of July 2025 (link).jpg)
.jpg)
.png)
.jpg)
