Location
Philadelphia, PA
Start Date
1-5-2024 1:00 PM
End Date
1-5-2024 4:00 PM
Description
Introduction: A new species of giant catfish (Teleostei: Siluriformes) and bowfin fish (Holostei: Amiiformes) were discovered from Eocene rocks of the Tamaguélelt Formation located in the Taoudenit Basin of northern Mali. These unique freshwater species expand our knowledge about life in Western Africa during the Eocene.
Objective: The purpose of this study is to develop an approximate understanding of the phylogenetic position of the new Malian fossil specimens. We recognized a new fossil species belonging to a giant catfish (Teleostei: Siluriformes), which we named and described. Among the isolated remains of these catfish were the first postcranial remains of the giant bowfin, †Maliamia gigas (Holostei: Amiiformes), which we describe as well.
Methods: The specimens were collected during an expedition to Mali conducted by the researchers at Stony Brook University. Morphological features of the specimens were compared to extinct fossils, and skeletons of extant species were prepared from literature and collections located at the Academy of Natural Sciences in Philadelphia and the Museum of Natural History in New York. The specimens, preserved as vertebrae, vertebral complexes, and pectoral fin spines, possess diagnostic claroteid features. We described and plotted the new Malian catfish fossils and other extinct African taxa onto the molecular phylogeny of Lundberg et al. (2007). †Maliamia was also reevaluated using the phylogenetic hypotheses of Grande and Bemis (1998).
Results: These Malian specimens are significantly larger than previously described, and therefore, we hypothesize the specimen to be a new species: †Fajumia bouareensis n. sp. The vertebral complexes possess an open aortic canal that is substantially troughed through the anterior first vertebral centrum and post-Weberian vertebrae to the basioccipital. The basioccipital is sutured to the first centrum, and the first centrum is firmly affixed to the basioccipital. The fin spines have numerous anterior and posterior dentitions. The posterior dentitions are distal to shallow grooves, and there is a deep, triangular, posterior basal recess. The articular processes of the pectoral fin spine in †Fajumia bouareensis are asymmetrical and proportionally larger than the shaft. These characteristics are like †Fajumia.
Conclusion: Many specimens found at this locality were remarkably larger than previously described species known during the Eocene, which may indicate a unique environment and possibly an extremely isolated community pressuring evolution towards optimal body size. The sedimentary composition of the facies of which the specimens were found is interpreted as shallow marine-to-brackish water phosphorites and shallow, normal-to-restricted marine lagoons and open platform settings. However, †Fajumia bouareensis more closely resembled freshwater Clarotidae species instead of marine Baguridae and Ariidae catfish species due to the presence of an open aortic canal in the Weberian apparatus.
Embargo Period
6-17-2025
Tamaguélelt giants: Freshwater fishes from the Eocene of the Sahara Desert, Mali
Philadelphia, PA
Introduction: A new species of giant catfish (Teleostei: Siluriformes) and bowfin fish (Holostei: Amiiformes) were discovered from Eocene rocks of the Tamaguélelt Formation located in the Taoudenit Basin of northern Mali. These unique freshwater species expand our knowledge about life in Western Africa during the Eocene.
Objective: The purpose of this study is to develop an approximate understanding of the phylogenetic position of the new Malian fossil specimens. We recognized a new fossil species belonging to a giant catfish (Teleostei: Siluriformes), which we named and described. Among the isolated remains of these catfish were the first postcranial remains of the giant bowfin, †Maliamia gigas (Holostei: Amiiformes), which we describe as well.
Methods: The specimens were collected during an expedition to Mali conducted by the researchers at Stony Brook University. Morphological features of the specimens were compared to extinct fossils, and skeletons of extant species were prepared from literature and collections located at the Academy of Natural Sciences in Philadelphia and the Museum of Natural History in New York. The specimens, preserved as vertebrae, vertebral complexes, and pectoral fin spines, possess diagnostic claroteid features. We described and plotted the new Malian catfish fossils and other extinct African taxa onto the molecular phylogeny of Lundberg et al. (2007). †Maliamia was also reevaluated using the phylogenetic hypotheses of Grande and Bemis (1998).
Results: These Malian specimens are significantly larger than previously described, and therefore, we hypothesize the specimen to be a new species: †Fajumia bouareensis n. sp. The vertebral complexes possess an open aortic canal that is substantially troughed through the anterior first vertebral centrum and post-Weberian vertebrae to the basioccipital. The basioccipital is sutured to the first centrum, and the first centrum is firmly affixed to the basioccipital. The fin spines have numerous anterior and posterior dentitions. The posterior dentitions are distal to shallow grooves, and there is a deep, triangular, posterior basal recess. The articular processes of the pectoral fin spine in †Fajumia bouareensis are asymmetrical and proportionally larger than the shaft. These characteristics are like †Fajumia.
Conclusion: Many specimens found at this locality were remarkably larger than previously described species known during the Eocene, which may indicate a unique environment and possibly an extremely isolated community pressuring evolution towards optimal body size. The sedimentary composition of the facies of which the specimens were found is interpreted as shallow marine-to-brackish water phosphorites and shallow, normal-to-restricted marine lagoons and open platform settings. However, †Fajumia bouareensis more closely resembled freshwater Clarotidae species instead of marine Baguridae and Ariidae catfish species due to the presence of an open aortic canal in the Weberian apparatus.