Akkedops

Akkedops Temporal range: Late Permian PreꞒ Ꞓ O S D C P T J K Pg N
Holotype skull in lateral (side) (A, B) and occipital (braincase) (C, D) views
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Family:	†Younginidae (?)
Genus:	†Akkedops Mooney, Scott & Reisz, 2025
Species:	†A. bremneri
Binomial name
†Akkedops bremneri Mooney, Scott & Reisz, 2025

Akkedops is an extinct genus of early neodiapsid sauropsids known from the Late Permian Cistecephalus Assemblage Zone of South Africa. The genus contains a single species, Akkedops bremneri, known from a single skull.

Discovery and naming

Holotype skull in dorsal (top) (A, B) and ventral (bottom) (C, D) views

The Akkedops holotype specimen, SAM-PK-K6205, was discovered by D. T. Bremner in the 1980s in outcrops of the Beaufort Group (Karoo Supergroup), representing part of the Cistecephalus Assemblage Zone, in South Africa. The specimen consists of a single, nearly complete skull with associated postcranial fragments. The specimen is somewhat crushed and distorted.^[1]

In 2025, Ethan D. Mooney, Diane Scott, and Robert R. Reisz described Akkedops bremneri as a new genus and species of early neodiapsids based on these fossil remains. The generic name, Akkedops, combines the Afrikaans word akkedis, meaning "lizard", with the Greek suffix opsis, meaning appearance, in reference to the superficially lizard-like morphology of the preserved material. The specific name, bremneri, honors the discoverer of the holotype specimen.^[1]

Mooney and colleagues also referred two other specimens to Akkedops based on alleged similarities in their anatomy and discovery locality: BP/1/2614, an additional nearly complete but crushed skull, and SAM-PK-K7710, an aggregation of at least six partial individuals originally described as juveniles of the related Youngina.^[1][2] In their 2025 redescription of Galesphyrus, a fellow Permian South African sauropsid, Buffa and colleauges questioned the referral of SAM-PK-K7710 to Akkedops, and restricted their phylogenetic scoring of this taxon to just the holotype, SAM-PK-K6205.^[3] In 2026, Jenkins and colleagues redescibed SAM-PK-K7710 as belonging to a new genus and species, Scyllacerta creanae. These authors noted that, contrary to statements by Mooney and colleagues that the three 'Akkedops' specimens came from the same locality in the Endothiodon Assemblage Zone (EAZ), the Akkedops holotype is actually from the Cistecephalus AZ, Scyllacerta is from the EAZ, and BP/1/2614 is from the Daptocephalus AZ, separating the three specimens by millions of years.^[4]

Classification

To test the relationships of Akkedops, Mooney, Scott & Reisz (2025) scored this taxon in the data matrix of Buffa et al. (2024).^[5] This phylogenetic analysis placed Akkedops as the sister taxon to Sauria (crown-group reptiles) within the Neodiapsida, diverging after Youngina. These results are displayed in Topology A below.^[1] Later in 2025, Buffa, Jenkins, and Benoit published an extensively updated and expanded version of this phylogenetic matrix, incorporating the A. bremneri holotype and SAM-PK-K7710 as separate OTUs (operational taxonomic units). Their results supported the placement of these two specimens as sister taxa within a monophyletic Younginidae, also including Youngina, with multiple additional lineages between this clade and the reptile crown-group. These results are displayed in Topology B below.^[3]

Topology A: Mooney et al. (2025) tree[1] Neodiapsida Mesosaurus tenuidens Weigeltisauridae ⊞ Coelurosauravus elivensis Rautiania spp. Weigeltisaurus jaekeli ⊟ Claudiosaurus germaini Hovasaurus boulei Acerosodontosaurus piveteaui Youngina capensis Akkedops bremneri Sauria Archosauromorpha Lepidosauromorpha

Topology B: Buffa et al. (2025) tree[3] Neodiapsida Younginidae Youngina capensis Akkedops bremneri SAM-PK-K7710 Tangasauridae ⊞ Kenyasaurus mariakaniensis Acerosodontosaurus piveteaui Thadeosaurus colcanapi Hovasaurus boulei Tangasaurus mennelli ⊟ Claudiosaurus germaini Weigeltisauridae ⊞ Coelurosauravus elivensis Rautiania spp. Weigeltisaurus jaekeli ⊟ Sauria Archosauromorpha Lepidosauromorpha

In their 2026 description of Scyllacerta (SAM-PK-K7710), Jenkins and colleagues similarly recovered this specimen, Akkedops, and Youngina within a monophyletic Younginidae, albeit with the latter two genera as sister taxa.^[4]

References

1. Mooney, Ethan Dean; Scott, Diane; Reisz, Robert Raphael (2025-02-26). "A new stem saurian reptile from the late Permian of South Africa and insights into saurian evolution". Swiss Journal of Palaeontology. 144 (1): 10. doi:10.1186/s13358-025-00351-y. ISSN 1664-2376. PMC 11865139. PMID 40027993.
2. Smith, Roger M. H.; Evans, Susan E. (1996). "New material of Youngina: evidence of juvenile aggregation in Permian diapsid reptiles". Palaeontology. 39: 289–303.
3. Buffa, Valentin; Jenkins, Xavier A.; Benoit, Julien (2025-11-17). "Galesphyrus capensis from the Permian of South Africa and the origin of Neodiapsida". Journal of Systematic Palaeontology. 23 (1) 2563582. doi:10.1080/14772019.2025.2563582. ISSN 1477-2019.
4. Jenkins, Xavier A.; Buffa, Valentin; Marchant, Cy J.; Ford, David P.; Browning, Claire; Fernandez, Vincent; Dollman, Kathleen; Botha, Jennifer; Choiniere, Jonah N.; Benson, Roger B. J.; Peecook, Brandon R. (2026-01-22). "The origin of the tympanic fossa in reptiles revealed by a late Permian neodiapsid". Palaeontology. 69 (1) e70041: 1–15. doi:10.1111/pala.70041. ISSN 0031-0239.
5. Buffa, Valentin; Frey, Eberhard; Steyer, J-Sébastien; Laurin, Michel (2024-05-11). "'Birds' of two feathers: Avicranium renestoi and the paraphyly of bird-headed reptiles (Diapsida: 'Avicephala')". Zoological Journal of the Linnean Society. 202 (4) zlae050. doi:10.1093/zoolinnean/zlae050. ISSN 0024-4082.