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[dinosaur] Elosuchus and Fortignathus (Crocodyliformes) from Cretaceous of Niger (free pdfs)




Ben Creisler
bcreisler@gmail.com


Both these papers were posted in advance versions on the DML. They're now officially published and have free pdfs, so I'll post them again. Also, the publisher and the links have changed.



Louise M. V. Meunier &  Hans C. E. Larsson (2017)
Revision and phylogenetic affinities of Elosuchus (Crocodyliformes). 
Zoological Journal of the Linnean Society  179 (1): 169-200
DOI: https://doi.org/10.1111/zoj.12448
https://academic.oup.com/zoolinnean/article/179/1/169/2870024/Revision-and-phylogenetic-affinities-of-Elosuchus

Elosuchidae is a clade of longirostrine Crocodyliformes currently confined to Barremian through Cenomanian deposits in north-west Africa and Great Britain. The clade is currently composed of Elosuchus cherifiensis (Lavocat, 1955), Elosuchus felixide Lapparent de Broin, 2002, Sarcosuchus imperator Broin & Taquet, 1966, Sarcosuchus hartii Buffetaut & Taquet, 1977, Vectisuchus leptognathus Buffetaut & Hutt, 1980 and, by some authors, Stolokrosuchus lapparenti Larsson & Gado, 2000. We redescribe Elosuchus from assigned and new material. This genus occurs in terrestrial Cenomanian deposits in Morocco and Algeria and known from multiple relatively complete skulls. The holotype is unknown but the assigned lectotype in the Muséum National d'Histoire Naturelle (Paris, France) is composed of a fragmentary ventral braincase. Referred paralectotype material housed in the same museum includes multiple fragmentary specimens and two nearly complete skulls. These and additional material in the Canadian Museum of Nature and Royal Ontario Museum were used to re-examine the genus. The original and new material show a number of autapomorphies among crocodyliforms: a unique contribution of the squamosal and jugal to the postorbital anterolateral process and a highly modified suborbital fenestra that displaces the antorbital cavity anteriorly and forms a bony wall separating the cavity from the orbit. Two diagnosable morphotypes are revealed, one from the Kem Kem beds, Morocco, and the other from Gara Samani, Algeria. We retain Elosuchus cherifiensis for the Kem Kem form and erect a new species Elosuchus broinae sp. nov. for the Algerian form. The revised diagnosis for Elosuchus questions the validity of E. felixi. Elosuchus is incorporated into a phylogenetic analysis that includes extensive revisions to character scores for relevant taxa. The resulting topologies recover Elosuchus sister to Meridiosaurus vallisparidisiMones, 1980, within a complex of ‘Pholidosauridae’ that includes elosuchids and dyrosaurids but excludes Stolokrosuchus. This phylogenetic revision is used to discuss the evolution of this clade and its contribution to crocodyliform diversity during the Cretaceous.



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Mark T. Young,  Alexander K. Hastings,  Ronan Allain & Thomas J. Smith (2017)
Revision of the enigmatic crocodyliform Elosuchus felixi de Lapparent de Broin, 2002 from the Lower–Upper Cretaceous boundary of Niger: potential evidence for an early origin of the clade Dyrosauridae.
Zoological Journal of the Linnean Society  179 (2): 377-403. 
DOI: https://doi.org/10.1111/zoj.12452
https://academic.oup.com/zoolinnean/article/179/2/377/2957726/Revision-of-the-enigmatic-crocodyliform-Elosuchus


The enigmatic crocodyliform ‘Elosuchus’ felixi from the Echkar Formation (upper Albian to lower Cenomanian, Early–Late Cretaceous boundary) west of In Abangharit, Agadez District, Niger, is here re-described. Our assessment of the material shows that there are at least two taxa amongst the referred material: ‘E.’ felixi, including the holotype (an incomplete lower jaw) and two larger incomplete lower jaws; and an incomplete premaxilla, which we refer to Elosuchus sp. All other referred material is herein considered Crocodyliformes indeterminate. Based on our study of ‘E.’ felixi we refer it to a new genus, Fortignathus. A comparative study and updated phylogenetic analyses both suggest that F. felixi comb. nov. is a non-hyposaurine dyrosaurid or a dyrosaurid sister taxon. This is supported by four characteristics, including: inferred double festooned maxillae, a large gap between the D2 and D3 alveoli, gladius-shaped anterior dentary, and enlarged D4 alveoli that have a subrectangular cross section. The paucity of material means we refrain from referring F. felixi comb. nov. to Dyrosauridae. This species and suggestive material from the Cenomanian of Sudan allows us to formulate two hypotheses, however: (1) basal dyrosaurids were either freshwater or could live in both freshwater and saltwater ecosystems; and (2) Africa was their place of origin and dispersal.