Njalila (named after a local tributary of the Ruhuhu River) is a genus of gorgonopsian (extinct predatory therapsids and relatives of modern mammals) that lived during the Late Permian of East Africa, known from fossils found in what is now Tanzania. The type and only species, Njalila nasuta, was originally named in 1950 as a species of the gorgonopsian genus Dixeya (now considered either a junior synonym of Aelurognathus or incertae sedis). Njalila was subsequently recognised as distinct from Dixeya and other gorgonopsians following repeated revisions of gorgonopsian taxonomy during the rest of the 20th century, but it did not receive its own genus name until 2007. However, because this name was first proposed in a PhD thesis, it remained a nomen nudum ("naked name") until its formal validation in an official publication in 2026. With a skull reaching up to 20 centimetres (7.9 in) in length, Njalila is a medium-sized gorgonopsian characterised by a distinctive straight snout profile with an upturned and "pinched" nose. It may have been a close relative of Arctognathus, to which it was tentatively assigned to in the past, but can readily be distinguished as a distinct genus. The fossil record of the Usili Formation where it was discovered shows that Njalila was contemporaneous with many other gorgonopsians, including much larger representatives such as Inostrancevia and rubidgeines.
Discovery and naming
As "Dixeya" nasuta Njalila has a complicated taxonomic history, with the taxon being assigned to various different genera over the years. It was originally described in 1950 by the German palaeontologist Friedrich von Huene on the basis of two skulls collected from the Usili Formation (formerly known as K6 or the Kawinga Formation), exposed in the Ruhuhu Basin of southern Tanzania. The two specimens now represent the lectotype specimen GPIT-PV-117100 (originally "K 52 B") and paralectotype GPIT-PV-117095 (originally "K 96"), now catalogued in the palaeontological collection of the University of Tübingen. Von Huene regarded these specimens as representatives of a second species of Dixeya—a genus previously erected in 1927 by the South African palaeontologist Sidney H. Haughton with the type species D. quadrata—that he named D. nasuta. In 1970, French paleontologist Denise Sigogneau-Russell re-assigned the type species of Dixeya (D. quadrata) to the genus Aelurognathus (as Ae. quadrata) in her systematic revision of gorgonopsian taxonomy, thus synonymising the two genera. However, she did not consider D. nasuta to also belong to Aelurognathus, instead tentatively referring the species to Arctognathus as Arctognathus? nasuta. Furthermore, Sigogneau-Russell only considered the holotype of D. quadrata from Malawi to belong to Aelurognathus, and she did not consider two additional specimens referred to D. quadrata by von Huene in 1950 from Tanzania (GPIT/RE/117105 (formerly GPIT/RE/7120) and GPIT/RE/117099 (formerly GPIT/RE/7121)) to belong to the same species. Instead, she suggested that they may also be referable to Ar.? nasuta—in addition to three other Tanzanian specimens (MZC 876, MZC 886, and MZC 887) referred to D. quadrata by British palaeontologist Francis Rex Parrington in 1955. Nonetheless, Sigogneau-Russell was cautious in assigning "D." nasuta to Arctognathus, and had previously acknowledged that it was not a resolved matter, especially as—in her opinion— that the roof of the skull of this species was not well preserved enough for comparison.
Naming Njalila The genus name Njalila was first proposed for "D." nasuta in 2007 by the German palaeontologist Eva Gebauer in her unpublished PhD thesis. The name comes from the Njalila tributary of the Ruhuhu River in Tanzania. However, because the International Code of Zoological Nomenclature does not recognise theses as validly published works, Njalila was consequently regarded as a nomen nudum ("naked name", i.e. it was not available as a valid genus name). Nonetheless, Njalila was acknowledged as likely representing a distinct taxon in the following years, such as by American paleontologist Christian Kammerer in 2015, though acknowledging that it required re-evaluation and so recommended provisionally leaving its taxonomy open as "Dixeya" nasuta. In an article published in early 2026, Gebauer and her German colleague Michael Maisch formally redescribed the fossils of Njalila. In doing so, they officially established and diagnosed the genus Njalila as the valid and available name for "D." nasuta, in the new combination N. nasuta. Gebauer also proposed the existence of a second species of Njalila in her 2007 thesis that she named "N. insigna", based on another Tanzanian skull that had previously been referred to the South African gorgonopsian Scylacops capensis (MZC 885). She distinguished "N. insigna" from N. nasuta by the presence of thicker arches between its skull openings, a posteriorly wider skull, and a slightly more rounded snout profile. The specific epithet of this proposed taxon is a Latin term meaning "remarkable" or "conspicuous", in reference to the differences noted between it and N. nasuta. However, in their 2026 publication, Gebauer and Maisch did not follow this interpretation and instead cautiously assigned the specimen to N. cf. nasuta. Gebauer and Maisch refrained from erecting a second species due to the individual variation present in the limited number of known N. nasuta specimens, and could not rule out that MZC 885 falls within the possible range of variation of a single species.
Description
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