Univ.-Prof. Dr. Jürgen Kriwet Evolution, Ecology and Diversity of Pycnodontiform Fishes Pycnodontiform fishes, which represent an extinct group of ray-finned fishes including more than 1000 nominal species are characterised by a deep, rounded, and laterally compressed body, a frontal flexure and prognathous snout, elongated dorsal and anal fins, which form together with the caudal fin an effective ruder, and distinct dentitions with teeth beimng mainly restricted to the prearticulars and the vomer. The dentition is assumed by most authors to be indicative for durophageous feeding habits. They resemble superficially in their body-shape extant coral reef fishes like the butterflyfishes (Chaetodontidae), doctor fishes (Acanthuridae), and parrotfishes (Balistidae). Their characteristic highly developed and specialised crushing heterodont dentition has long been a leading character in taxonomy and systematics for the last 170 years. Most pycnodontiform taxa are based entirely on characteristics of their prearticular or vomerine dentitions. The squamation pattern of pycnodontiforms fishes ranges from complete (covering the body from the posterior margin of the skull to the beginning of the caudal fin) to completely reduced with different intermediate stages. The scales of pycnodontiforms are rhombic and resemble the lepidosteoid scale type. However, the surfaces of the scales lack the ganoin layer, which is characteristic for this type and the term modified lepidosteoid scale type was introduced for pycnodont scales. The dermal skull bones also lack the ganoin layer. Additionally, these fishes are characterized by the lack of ossified vertebral centra, the significance of which still is not unambiguously established. The monophyly of pycnodontiforms fishes is well-established. The relationships among these fishes and of pycnodontiforms to other actinopterygians, however, have been discussed controversial for a long time and no general agreement has been achieved up to now. This project focuses on the (1) morphology, (2) taxonomy and systematics, (3) evolution, (4) functional aspects of the feeding apparatus, (5) ecology, and (6) palaeobiogeography of pycnodontiform fishes (Neopterygii, Pycnodontomorpha). Related Publications (* = conference abstracts) 1. KRIWET, J. 1997. Pycnodontid fishes from the Upper Barremian (Lower Cretaceous) of Uña (Cuenca Province, E-Spain). – Second International Meeting Mesozoic Fishes - Systematics and the fossil record, Buckow, 1997: 23; Berlin.* 2. KRIWET, J. 1999a. Schädelanatomie und Nahrung pycnodonter Fische (Neopterygii; Pycnodontiformes). – Terra Nostra, 99(8): 46; Zürich.* 3. KRIWET, J. 1999b. Evolutionary trends in the cranial anatomy of pycnodont fishes (Neopterygii, Pycnodontiformes). – Journal of Vertebrate Paleontology, 19 (suppl. 3): 57; Lawrence, Kansas.* 4. KRIWET, J. 1999c. Pycnodont fishes (Neopterygii, †Pycnodontiformes) from the upper Barremian (Lower Cretaceous) of Uña (Cuenca Province, E-Spain) and branchial teeth in pycnodontid fishes. – In: ARRATIA, G. & SCHULTZE, H.-P. (eds.): Mesozoic 1 Univ.-Prof. Dr. Jürgen Kriwet fishes – Systematics and the fossil record: 215–238; Verlag Dr. Friedrich Pfeil, München. 5. KRIWET, J., POYATO-ARIZA, F. & WENZ, S. 1999. A revision of Coelodus subdiscus WENZ, 1989 (Neopterygii, Pycnodontiformes) from the Early Cretaceous of Montsec de Rubies (Lérida). – Treballs del Museu de Geologia de Barcelona, 8: 33–65.* 6. KRIWET, J. 2000a. Revision of Mesturus cordillera MARTILL et al., 1998 (Actinopterygii, Pycnodontiformes) from the Oxfordian (Upper Jurassic) of northern Chile. – Journal of Vertebrate Paleontology, 20(3): 450–455. 7. KRIWET, J. 2000b. Ökomorphologische Aspekte pycnodonter Fische (Neopterygii, Pycnodontiformes. – Terra Nostra, 2000(3): 67; Berlin.* 8. KRIWET, J. 2000c. Evolutionary trends in the cranial anatomy of pycnodont fishes (Neopterygii, Pycnodontiformes). – Terra Nostra, 2000(3): 153; Berlin.* 9. KRIWET, J. 2001a. Palaeobiogeography of pycnodontiform fishes (Actinopterygii, Neopterygii). – Seminario de Paleontología de Zaragoza, 5.1: 121-130. 10. KRIWET, J. 2001b. Feeding mechanisms and ecology of pycnodont fishes (Neopterygii, †Pycnodontiformes). – Mitteilungen aus dem Museum für Naturkunde zu Berlin, Geowissenschaftliche Reihe, 4: 139–165. 11. KRIWET, J. 2002a. Anomoeodus pauciseriale, a new pycnodont fish (Neopterygii, Pycnodontiformes) from the White Chalk Formation (Upper Cretaceous) of Sussex, South England – Paläontologische Zeitschrift, 76(1): 117–123. 12. KRIWET, J. 2002b. Pycnodont fish remains (Neopterygii: Pycnodontiformes) from the Upper Jurassic of the Lusitanian basin. – Neues Jahrbuch für Geologie und Paläontologie, Monatshefte, 10: 577–587. 13. KRIWET, J. 2003. Dental Morphology of the pycnodont fish †Stemmatodus rhombus (Agassiz 1844) (Neopterygii, †Pycnodontiformes) from the Early Cretaceous with comments on its systematic position. – Transactions of the Royal Society of Edinburgh, 94: 145–155. 14. KRIWET, J. 2004. A new pycnodont fish genus (Neopterygii: Pycnodontiformes) from the Cenomanian (Upper Cretaceous) of Mount Lebanon and its interrelationships. – Journal of Vertebrate Paleontology, 24: 525–532. 15. DELSATE, D. & KRIWET, J. 2004. Late Triassic pycnodont fish remains (Neopterygii, Pycnodontiformes) from the Germanic basin. – Eclogae geologicae Helvetiae, 97: 183–191. 16. KRIWET, J. 2005a. A comprehensive study of the skull and dentition of pycnodont fishes (Neopterygii, Pycnodontiformes. – Zitteliana, 45: 135–188. 17. KRIWET, J. 2005b. The cranial and dental morphology of pycnodont fishes (Neopterygii, Pycnodontiformes). – Berichte des Institutes für Geologie und Paläontologie der Karl- Franzens-Universität Graz/Austria, 10: 64.* 18. KRIWET, J. & SCHMITZ, L. 2005. New insight into the distribution and palaeobiology of the pycnodont fish Gyrodus. – Acta Palaeontologica Polonica, 50: 49–56. 19. KRIWET, J. 2008. The dentition of the enigmatic pycnodont fish, Athrodon wittei Fricke, 1876 (Neopterygii; Pycnodontiformes), from the Late Jurassic of NW Germany. – Fossil Record, 11: 77–82. 20. LICHT, M. & KRIWET, J. 2008. Tooth replacement in pycnodontiforms (Actinopterygii, Neopterygii). – Terra Nostra 2009/3: 73-74.* 21. KRIWET, J. & LEHMANN, J. 2013. Turonian pycnodontid fish (Neopterygii, Pycnodontiformes) from northern Germany. – In: SCHWARZ, C. & KRIWET, J. (eds): 2 Univ.-Prof. Dr. Jürgen Kriwet Abstracts 6th International Meeting on Mesozoic fishes: 43; Verlag Dr. Friedirch Pfeil, Munich.* 3 .