Pampaluctor

Pampaluctor Temporal range: Late Pliocene–early Pleistocene Miocene Plio. Plei.
Diagram showing known remains compared to a human
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	†Sparassodonta
Family:	†Thylacosmilidae
Genus:	†Pampaluctor del Campo et al., 2026
Species:	†P. calibar
Binomial name
†Pampaluctor calibar del Campo et al., 2026

Pampaluctor is an extinct genus of metatherian mammal in the Thylacosmilidae, a family of carnivorous, saber-toothed sparassodonts. The genus contains a single species, Pampaluctor calibar, known from a partial skeleton. It is known from the Vorohué Formation of Argentina, which is assigned to the Vorohuean subage of the Marplatan South American land mammal age (SALMA), which is correlated to the late Pliocene to early Pleistocene epochs. With an estimated body mass of around 100 kilograms (220 lb), Pampaluctor is among the largest known mammalian predators from South America. Due to its geologic age, Pampaluctor also represents the youngest known thylacosmilid currently known to science.

Discovery and naming

P. calibar type locality in Buenos Aires Province, Argentina

The Pampaluctor fossil material was discovered in outcrops of the Vorohué Formation on a coastal cliff north of Miramar in Buenos Aires Province, Argentina. The specimen is housed in the paleontology collections of the Punta Hermengo Municipal Museum in Miramar, where it is permanently accessioned as specimen MPH P0730. It consists of a partial postcranial skeleton, comprising the first six cervical (neck) vertebrae, a partial right scapula, the distal end of the right humerus, the shaft of the right radius, most of the left femur, the shaft of the left tibia, two caudal (tail) vertebrae, and a small unidentified distal limb bone fragment.

In 2026, Eric N. del Campo and colleagues described Pampaluctor calibar as a new genus and species of thylacosmilid mammal based on these fossil remains, designating MPH P0730 as the holotype specimen. The generic name, Pampaluctor, combines a reference to the Argentina Pampas region in which the holotype was found, with the Latin word luctor, meaning 'to wrestle'. The specific name, calibar, references Calibar, the 19th century thief-tracking gaucho of Central Argentina.

A single humerus and two associated molars (specimen CCA-196) were found in the Argentine El Polvorín Formation, which has been paleomagnetically dated to ~3.55 to 2.59 million years ago. Given their comparable age, as well as the anatomical similarities of this humerus to that of the P. calibar holotype, it is possible that CCA-196 represents another specimen of this taxon.

Classification

To test the affinities and relationships of Pampaluctor, del Campo et al. (2026) included it in an updated version of the phylogenetic matrix of Suarez et al. (2025), a publication that had described the more basal thylacosmiliform Dimartinia. Pampaluctor was recovered as the sister taxon to Thylacosmilus, with the other two named thylacosmilids, Anachlysictis and Patagosmilus, forming their own clade. The result of their analysis using implied weighting (k = 3) are displayed in the cladogram below:

†Borhyaenoidea	†Lycopsis spp. †Thylacosmiliformes †Dimartinia pristina IGM 251108 (unnamed La Venta taxon) †Thylacosmilidae †Pampaluctor calibar †Thylacosmilus atrox †Anachlysictis gracilis †Patagosmilus goini UF 27881 (unnamed Honda Group taxon) †Prothylacynus patagonicus †Pharsophorus lacerans †Eomakhaira molossus †Proborhyaenidae †Borhyaenidae