Majungasaurinae

Lore & Background

The majungasaurines were mid-sized, bipedal predators, but relatively slow moving. Their stout legs were built for striding, not running. They had tall, deep heads with powerful jaws, but small forearms without carpals in the wrists. Because of their slow gait and small arms, they likely preyed upon the larger, slower sauropods rather than the smaller, faster ornithopods. Their ancestors lived on Gondwana, but by the Early Cretaceous that supercontinent had already fragmented, isolating them from their South American cousins and eventually from each other.

Reader's Guide

The subfamily Majungasaurinae was created in 2014 by paleontologist Thierry Tortosa and colleagues in the description of Arcovenator. It is defined as all abelisaurids more closely related to Majungasaurus than to Carnotaurus. The majungasaurines and their carnotaurine sister group emerged in what is now South America. From there they spread to the rest of Gondwana: modern Africa and India, and presumably Australia and Antarctica as well. Fragmentary evidence of abelisaurs in southern France indicates they may have spread into Europe as well, but the relationship of these species to the rest of Majungasaurinae is not well established. Majungasaurus is known to have preyed upon medium-sized sauropods such as Rapetosaurus, and its teeth marks have been found on the ribs of other Majungasaurus, though whether it actively hunted members of its own species or merely cannibalized their scavenged remains is unknown.

Did You Know?

• Majungasaurinae is named after Majungasaurus, itself named after the city of Mahajanga in Madagascar.
• Majungasaurines had stout legs built for striding, not running, and likely preyed on larger, slower sauropods.
• The first majungasaurine uncovered was Majungasaurus, discovered in Madagascar in 1896, but initially named as a species of Megalosaurus.

From Megalosaurus to Majungasaurinae: A Taxonomic Odyssey

The story of how these enigmatic theropods were recognized as a distinct group spans nearly a century of paleontological work. The very first specimen, unearthed in Madagascar in 1896, was initially slotted into Megalosaurus—a classification that would persist for decades. Meanwhile, in India, Charles Alfred Matley and Friedrich von Huene described Indosaurus and Indosuchus in 1933, placing them among the allosaurids. It was not until 1955 that René Lavocat, examining teeth and a dentary fragment, formally erected the name Majungasaurus, establishing the animal as something entirely separate from Megalosaurus. A brief taxonomic hiccup occurred in 1996 when Majungatholus was proposed for what was thought to be a pachycephalosaurid from Madagascar, only for the material to be reidentified as another Majungasaurus specimen. The pivotal moment came in 1991, when José Bonaparte proposed that these scattered theropods all belonged to a single family, Abelisauridae. Finally, in 2014, Thierry Tortosa and colleagues formalized the subfamily Majungasaurinae, uniting abelisaurids from Madagascar, India, and Europe into one coherent clade.

Skeletal Signatures: What Sets a Majungasaurine Apart

Majungasaurines share a suite of skeletal traits that separate them cleanly from their carnotaurine cousins. All abelisaurids possess vestigial, immobile forelimbs with highly reduced manual phalanges, but the majungasaurines add further diagnostic features: low and wide antorbital fenestrae, a broad triangular bony plate positioned behind the parietal, two small openings for a cerebral vein flanking the sagittal crest, and a pronounced wide groove on the occipital condyle. Vertebrae count also distinguishes the groups—Majungasaurus carries thirteen dorsal vertebrae where Carnotaurus has only eleven. The dentary bone tells another story: in Carnotaurus it is short with an almost vertical ramus, whereas in Majungasaurus the ramus curves backward and bears notable caudal projections. These synapomorphies are not merely catalog curiosities; they form the very criteria by which any newly discovered abelisaurid is sorted into one subfamily or the other. Combined with their mid-sized, bipedal build, stout striding legs, and tall, deep skulls housing powerful jaws, these traits paint a picture of a deliberate, crushing predator rather than a sprinting one.

Crushing Power: Feeding Ecology and Prey Choice

The anatomy of a majungasaurine tells a clear story about how it fed. Bulbous teeth, short deep heads, and exceptionally strong necks gave these predators jaws of tremendous crushing force—capable of shattering a prey animal's trachea or even its vertebrae with a single bite. Their slow, striding gait and tiny, carpal-less forearms made them ill-suited for chasing the smaller, faster ornithopods that populated their ecosystems. Instead, the evidence points toward larger, slower sauropods as primary targets. Majungasaurus is specifically documented as a predator of medium-sized sauropods like Rapetosaurus. Perhaps most striking is the discovery of tooth marks on the ribs of other Majungasaurus individuals, suggesting either active intraspecific predation or the scavenging of fallen conspecifics—though which scenario actually occurred remains unresolved. No other member of the subfamily has shown comparable evidence of this behavior. These animals were carnivorous specialists, built for power over speed, operating in the Upper Cretaceous landscapes of Gondwana's fragmented remnants.

A Young Clade: Phylogeny and the Ongoing Debate

Majungasaurinae is, in taxonomic terms, a remarkably young name. The subfamily was proposed in March 2014 by Thierry Tortosa and colleagues within the description of the Spanish genus Arcovenator, defined operationally as all abelisaurids more closely related to Majungasaurus than to Carnotaurus. The original roster included Arcovenator, Genusaurus, Indosaurus, Majungasaurus, Rahiolisaurus, and Rajasaurus. Yet the boundaries of this group have not settled. In the 2021 description of Llukalkan, both Rahiolisaurus and the Malagasy taxon Dahalokely were repositioned outside Majungasaurinae as basal brachyrostrans. That same analysis confirmed a core clade uniting Majungasaurus, Indosaurus, and Rajasaurus, while also revealing that Arcovenator and Genusaurus form a sister-taxon pair. The broader picture is one of a Gondwanan lineage whose ancestors first appeared in the Middle Jurassic and persisted through the Upper Cretaceous, spreading from South America across Africa, India, and possibly into Europe via fragmentary evidence from southern France.