Biology:Akharhynchus

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Akharhynchus (meaning "another snout") is an extinct genus of tropeognathine pteranodontoid pterosaurs possibly from the Cretaceous Kem Kem Group of Morocco. The genus contains a single species, A. martilli, known from a small fragment of the premaxillae.

Discovery and naming

Fossils of Akharhynchus were first unearthed in an unknown locality near the town of Tafilat in Errachidia Province, southern Morocco. The remains found consist of an isolated premaxilla (upper jaw tip) fragment of a pterosaur, which was found by a commercial fossil dealer who sold it to the Faculté des Sciences Aïn Chock. There it was deposited under specimen number FSAC-KK 12500. Based on the matrix it is preserved in and comparisons with other specimens, it presumably originates from the upper Ifezouane Formation, like many other pterosaurs.[1] The Ifezouane Formation is a formation in the Kem Kem Group, which dates to the Cenomanian and perhaps Albian stages of the Cretaceous period.[1][2]

In 2024, an international team of paleontologists including British researcher Megan Jacobs, British researcher Roy Smith & Moroccan researcher Samir Zouhri described this fossil as belonging to a new genus and species of pterosaur, which they named Akharhynchus martilli. The generic name, Akharhynchus, combines the Arabic word akhar, meaning "another", with the Greek word rynchus, meaning "snout". The specific name, martilli, references paleontology researcher David Martill.[1]

Akharhynchus is one of at least ten purportedly distinct pterosaur genera recovered from the Kem Kem Group. About half of these are ornithocheirids. Besides Akharhynchus, these include Anhanguera, Coloborhynchus, Ornithocheirus, and Siroccopteryx.[1] Discussions on Kem Kem pterosaurs have noted the problematic practice of naming taxa based on such fragmentary remains, even in the presence of seemingly diagnostic characters. As every pterosaur from these localities is established based on fragmentary rostral and mandibular remains, detailed comparisons are limited. Consequently, the effects of sexual dimorphism and ontogenetic and interspecific variation on perceived diversity are challenging to identify.[2]

Photograph (left) and line drawing (right) of the holotype

Description

The holotype consists of the anteriormost portion of both premaxillae, preserving three pairs of alveoli (tooth holes) and an incomplete fourth pair. The first pair and the left alveolus of the second pair have broken tooth crowns. As for measurements, the specimen is 53 millimetres (2.1 in) tall at its highest point, 62 millimetres (2.4 in) long, and a maximum width of 37 millimetres (1.5 in).[1]

Classification

In their phylogenetic analyses, Jacobs, Smith & Zouhri (2024) recovered Akharhynchus as a tropeognathine member of the Anhangueria, as the sister taxon to the contemporary Siroccopteryx, which is anatomically alike and similarly fragmentary. These two genera form a clade with the South American Tropeognathus.[3] In turn, the clade formed by these genera is sister to one comprising a polytomy of Australian tropeognathines typically referred to as the Mythungini.[4] The results of their analyses are displayed in the cladogram below:[1]

Anhangueria
 

Ornithocheirus

 
 
 

Targaryendraconia

 
 
 

Hamipteridae

 
Anhangueridae
 
 

Anhanguerinae

 
 

Coloborhynchinae

 
 
Tropeognathinae
 
 

Thapunngaka

 
 

Ferrodraco

 
 

Mythunga

 
 
 
 

Tropeognathus

 
 
 

Siroccopteryx

 
 

Akharhynchus

 
 
 
 
 
 
 
 

Paleoecology

During the Early to Middle Cretaceous, North Africa bordered the Tethys Sea, which transformed the region into a mangrove-dominated coastal environment filled with tidal flats and waterways.[5][6][7] The Kem Kem beds are a sequence of fluvial and lacustrine sediments, though it has some marine sediments. Isotopes from fossils of the dinosaurs Carcharodontosaurus and Spinosaurus suggest that the Kem Kem beds witnessed a temporary monsoon season rather than constant rainfall, similar to modern conditions present in sub-tropical and tropical environments in Southeast Asia and Sub-Saharan Africa.[8][9] The Izefouane Formation, the unit of the Kem Kem beds from which Leptostomia is known, has been interpreted as a braided river system, similar to that found in the Bahariya Formation.[10][11] This river system was freshwater based on the presence of lungfishes and other typically freshwater vertebrates. This indicates that the Izefouane Formation had a wide variety of features, including river channels,

river banks, sandbars, and more.[12][6] These riverine deposits bore large fishes, including the sawskate Onchopristis, coelacanth Mawsonia, and bichir Bawitius.[13] The Kem Kem beds also preserve many piscivorous crocodyliformes, such as the genera Elosuchus, Laganosuchus, and Aegisuchus.[14][6][15]

Pterosaurs known from the Kem Kem beds include the azhdarchoid Alanqa, the possible azhdarchoids Leptostomia and Xericeps, indeterminate azhdarchoids, the tapejarid Afrotapejara, the possible chaoyangopterid Apatorhamphus, and the ornithocheirids Akharhynchus,[16] Anhanguera, Coloborhynchus, Nicorhynchus, Ornithocheirus, and Siroccopteryx. However, all of these pterosaurs are known from fragmentary and/or isolated remains, making their classification difficult to confirm. Many fossils have been found without overlap, such as vertebrae or limb bones, that may belong to these taxa.[12] Dinosaurs are also known from the Kem Kem beds, including the sauropod Rebbachisaurus and the theropods Deltadromeus, Carcharodontosaurus, and Spinosaurus, in addition to unnamed ankylosaurs, titanosaurs, and noasaurid theropods.[17][6]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Jacobs, Megan L.; Smith, Roy E.; Zouhri, Samir (2024). "A new ornithocheirid pterosaur (Pterosauria: Ornithocheiridae) from the mid-Cretaceous Ifezouane Formation, Kem Kem Group of Morocco" (in en). Cretaceous Research 166. doi:10.1016/j.cretres.2024.106015. 
  2. ↑ 2.0 2.1 Smith, Roy E.; Ibrahim, Nizar; Longrich, Nicholas; Unwin, David M.; Jacobs, Megan L.; Williams, Cariad J.; Zouhri, Samir; Martill, David M. (2023-02-04). "The pterosaurs of the Cretaceous Kem Kem Group of Morocco" (in en). PalZ 97 (3): 519–568. doi:10.1007/s12542-022-00642-6. ISSN 0031-0220. Bibcode: 2023PalZ...97..519S. 
  3. ↑ Holgado, Borja; Pêgas, Rodrigo (2020). "A taxonomic and phylogenetic review of the anhanguerid pterosaur group Coloborhynchinae and the new clade Tropeognathinae". Acta Palaeontologica Polonica 65. doi:10.4202/app.00751.2020. 
  4. ↑ Richards, Timothy; Stumkat, Paul; Salisbury, Steven (6 October 2023). "A second specimen of the pterosaur Thapunngaka shawi from the Lower Cretaceous (upper Albian) Toolebuc Formation of North West Queensland, Australia". Cretaceous Research 154. doi:10.1016/j.cretres.2023.105740. 
  5. ↑ Hamed, Younes; Al-Gamal, Samir Anwar; Ali, Wassim; Nahid, Abederazzak; Dhia, Hamed Ben (March 1, 2014). "Palaeoenvironments of the Continental Intercalaire fossil from the Late Cretaceous (Barremian-Albian) in North Africa: a case study of southern Tunisia". Arabian Journal of Geosciences 7 (3): 1165–1177. doi:10.1007/s12517-012-0804-2. Bibcode: 2014ArJG....7.1165H. 
  6. ↑ 6.0 6.1 6.2 6.3 Ibrahim, Nizar; Sereno, Paul C.; Varricchio, David J.; Martill, David M.; Dutheil, Didier B.; Unwin, David M.; Baidder, Lahssen; Larsson, Hans C. E. et al. (2020). "Geology and paleontology of the Upper Cretaceous Kem Kem Group of eastern Morocco". ZooKeys (928): 1–216. doi:10.3897/zookeys.928.47517. ISSN 1313-2989. PMID 32362741. Bibcode: 2020ZooK..928....1I. 
  7. ↑ Cavin, Lionel; Boudad, Larbi; Tong, Haiyan; Läng, Emilie; Tabouelle, Jérôme; Vullo, Romain (2015-05-27). "Taxonomic Composition and Trophic Structure of the Continental Bony Fish Assemblage from the Early Late Cretaceous of Southeastern Morocco" (in en). PLOS ONE 10 (5). doi:10.1371/journal.pone.0125786. ISSN 1932-6203. PMID 26018561. Bibcode: 2015PLoSO..1025786C. 
  8. ↑ Goedert, J.; Amiot, R.; Boudad, L.; Buffetaut, E.; Fourel, F.; Godefroit, P.; Kusuhashi, N.; Suteethorn, V. et al. (2016). "Preliminary investigation of seasonal patterns recorded in the oxygen isotope compositions of theropod dinosaur tooth enamel.". PALAIOS 31 (1): 10–19. doi:10.2110/palo.2015.018. Bibcode: 2016Palai..31...10G. 
  9. ↑ Amiot, Romain; Buffetaut, Eric; Lécuyer, Christophe; Wang, Xu; Boudad, Larbi; Ding, Zhongli; Fourel, François; Hutt, Steven et al. (February 2010). "Oxygen isotope evidence for semi-aquatic habits among spinosaurid theropods". Geology 38 (2): 139–142. doi:10.1130/G30402.1. Bibcode: 2010Geo....38..139A. 
  10. ↑ Smith, Joshua B.; Lamanna, Matthew C.; Lacovara, Kenneth J.; Dodson, Peter; Smith, Jennifer R.; Poole, Jason C.; Giegengack, Robert; Attia, Yousry (2001). "A Giant Sauropod Dinosaur from an Upper Cretaceous Mangrove Deposit in Egypt". Science 292 (5522): 1704–1706. doi:10.1126/science.1060561. PMID 11387472. Bibcode: 2001Sci...292.1704S. https://www.science.org/doi/10.1126/science.1060561. 
  11. ↑ Kellermann, Maximilian; Cuesta, Elena; Rauhut, Oliver W. M. (2025-01-14). "Re-evaluation of the Bahariya Formation carcharodontosaurid (Dinosauria: Theropoda) and its implications for allosauroid phylogeny" (in en). PLOS ONE 20 (1). doi:10.1371/journal.pone.0311096. ISSN 1932-6203. PMID 39808629. Bibcode: 2025PLoSO..2011096K. 
  12. ↑ 12.0 12.1 Smith, Roy E.; Ibrahim, Nizar; Longrich, Nicholas; Unwin, David M.; Jacobs, Megan L.; Williams, Cariad J.; Zouhri, Samir; Martill, David M. (2023-09-01). "The pterosaurs of the Cretaceous Kem Kem Group of Morocco" (in en). PalZ 97 (3): 519–568. doi:10.1007/s12542-022-00642-6. ISSN 1867-6812. Bibcode: 2023PalZ...97..519S. 
  13. ↑ Ibrahim et al. 2020, p. 184.
  14. ↑ Holliday, Casey M.; Gardner, Nicholas M. (January 31, 2012). "A New Eusuchian Crocodyliform with Novel Cranial Integument and Its Significance for the Origin and Evolution of Crocodylia". PLOS ONE 7 (1). doi:10.1371/journal.pone.0030471. PMID 22303441. Bibcode: 2012PLoSO...730471H. 
  15. ↑ Ibrahim et al. 2020, p. 180, 189.
  16. ↑ Jacobs, Megan L.; Smith, Roy E.; Zouhri, Samir (2025-02-01). "A new ornithocheirid pterosaur (Pterosauria: Ornithocheiridae) from the mid-Cretaceous Ifezouane Formation, Kem Kem Group of Morocco". Cretaceous Research 166. doi:10.1016/j.cretres.2024.106015. ISSN 0195-6671. https://www.sciencedirect.com/science/article/pii/S0195667124001885. 
  17. ↑ Wilson, Jeffrey A.; Allain, Ronan (July 4, 2015). "Osteology of Rebbachisaurus garasbae Lavocat, 1954, a diplodocoid (Dinosauria, Sauropoda) from the early Late Cretaceous–aged Kem Kem beds of southeastern Morocco". Journal of Vertebrate Paleontology 35 (4). doi:10.1080/02724634.2014.1000701. Bibcode: 2015JVPal..35E0701W. 

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