Razanandrongobe (meaning "ancestor [of the] large lizard" in Malagasy) is a genus of carnivorous ziphosuchian crocodyliform from the Middle Jurassic of Madagascar.

While they clearly belonged to a member of the Archosauria, Maganuco and colleagues refrained from assigning the genus to a specific group because the fragmentary remains resembled lineages among both the theropod dinosaurs and crocodylomorphs.

Measuring 7 metres (23 ft) long, it was the largest member of the Notosuchia and may have occupied a predatory ecological niche similar to theropods.

All known remains of Razanandrongobe originate from strata belonging to the Sakaraha Formation in the badlands (locally called tanety) surrounding the town of Ambondromamy, Madagascar.

[1] Simone Maganuco, Cristiano Dal Sasso, and Pasini described these specimens in 2006 as representing a new genus and species, Razanandrongobe sakalavae, with MSNM V5770 as the holotype.

[1] Between 1972 and 1974, the assistant director of technical services of the Sugar Company of Mahavavy had previously collected a dentary (lower jawbone) and a premaxilla from the area where the holotype of Razanandrongobe was discovered.

Among these fragments, the larger ones are spongy with pieces of the surrounding rock (matrix) attached; the smaller ones are denser, whitish, and polished, suggesting prolonged exposure to air and sunlight.

On the palate, two sub-circular depressions were situated near the front of the snout, where the first pair of teeth from the lower jaw would have been located when the mouth was closed.

The teeth themselves are unusual; they bear large serrations on both the front and rear edges, which are proportionally even larger than those of dinosaurs such as Tyrannosaurus.

[6] Maganuco and colleagues suggested that unfused interdental plates are either a synapomorphy of Archosauriformes, or a plesiomorphic (ancestrally present) characteristic of crocodyliforms, theropods, and poposaurids.

[1][7] Considering these characteristics, Maganuco and colleagues placed Razanandrongobe in the Archosauria, but not as part of any basal (early-diverging) lineages due to its heterodont teeth and tall maxilla.

While it resembles the Prestosuchidae in the depth and shape of its maxilla, heterodont teeth, paradental shelves, and large size, Maganuco and colleagues considered these traits to have been convergently acquired.

Within the Archosauria, they identified two possible positions for Razanandrongobe: Crocodylomorpha and Theropoda, the only lineages of large predatory archosaurs to have survived past the Triassic.

However, the original material of Razanandrongobe, consisting of a maxilla and teeth, was too fragmentary to be included in a phylogenetic analysis of archosauriforms, since it lacks nearly all characteristics used in such analyses.

However, the height of the paradental shelf, the large tooth serrations, the width of the teeth from the side of the jaw, and the relatively flat interdental plates were found to be unusual for crocodylomorphs.

[1] Among theropods, Maganuco and colleagues likened the sub-rectangular tooth sockets, roughened interdental plates, low-crowned teeth, and possible broad contact between the maxilla and jugal in Razanandrongobe to the Abelisauridae; however, they noted that the innervated pits (foramina) on its maxilla were distributed more evenly, and that its teeth differed in their cross-sections and the size of their serrations.

[2] Within the Crocodylomorpha, Dal Sasso and colleagues confirmed previous observations that the palate of Razanandrongobe differed from "sphenosuchians", in addition to having a more robust dentary with a shorter toothless portion and a less conspicuous splenial.

[9] Little is known about the origins and early evolution of notosuchians, but the fact that they are the brother group of the Neosuchia (which contains all living crocodilians) in the Mesoeucrocodylia implies that they must have first appeared during the Jurassic.

Its retention of plesiomorphic characteristics is consistent with its status as an early notosuchian; however, for this reason, Dal Sasso and colleagues noted that its close relation to Sebecosuchia — a much younger lineage, being known from the Santonian forward — must be treated as provisional.

Dal Sasso and colleagues supported the notion that notosuchians primarily lived on the continent of Gondwana through their evolutionary history (although the remaining ghost lineage prior to Razanandrongobe precludes inferences about their origins).

The rest of the skull would have been strengthened by the expansion of the paradental shelves to form a "secondary palate", which would have greatly increased resistance to vertical bending and torsion,[12] while the fused interdental plates would have protected the teeth from transverse forces.

[1][13] In 2017, Dal Sasso and colleagues suggested that these feeding adaptations — along with a large skull and body size — made Razanandrongobe a highly specialized terrestrial predator.

The sandstone surrounding the holotype of Razanandrongobe is fine-grained (0.2–0.3 millimetres (0.008–0.01 in) in diameter) and is mainly composed of quartz, with rarer grains of ilmenite, garnet, and zircon.

[1][2] Based on the sea urchins Nucleolites amplus and Acrosalenia colcanapi as index fossils, the Sakaraha Formation has been correlated to the Bathonian stage (167.7–164.7 million years ago) of the Middle Jurassic epoch.