Faculteit Academiejaar Wetenschappen 1997/1998 UNIVERSITEIT GENT On how a larva becomes an adult catfish a functional morphological approach to the cranialontogeny of the African catfish, Clarias gariepinus (Siluriformes, Clariidae) Van larvale tot adulte katvis eenfunctioneel-morfologische benadering vande craniale ontogenie van de Afrikaanse katvis, Clarias gariepinus (Siluriformes, Clariidae) PART I TEXT Dominique Adriaens Thesis submitted to obtain the degree of Rector: Prof. Dr. ir. J. Willems Doctor in Sciences (Biology) Decaan: Prof. Dr. W. De Breuck Proefschrift voorgedragen tot het bekomen van de graad van Doctor in de Wetenschappen (Biologie) Promotor: Prof. Dr. W. Verraes Contents i Acknowledgements - Dankwoord Part I - General introduction Chapter I.1 – History and aims..................................................................................................................................1 I.1.1 - HISTORY ............................................................................................................................................ 1 I.1.2 - AIMS ................................................................................................................................................ 2 Chapter I.2 - Material and methods.........................................................................................................................4 I.2.1 - ONTOGENETIC SERIES OF CLARIAS GARIEPINUS ............................................................................... 4 I.2.2 - MORPHOLOGICAL DESCRIPTIONS...................................................................................................... 8 I.2.2.a - In toto clearing and staining .................................................................................... 8 I.2.2.b - Serial sections........................................................................................................ 8 I.2.2.c - Three-dimensional reconstructions ........................................................................... 9 I.2.2.d - Dissections ............................................................................................................ 9 I.2.3 - ABNORMAL DEVELOPMENT ............................................................................................................ 10 I.2.3.a - Teratogens........................................................................................................... 10 1. 2,4-DINITROPHENOL ..................................................................... 11 2. COLCHICINE............................................................................... 11 3. DIAZO-OXO-NOR-LEUCINE ............................................................ 13 4. β-AMINO-PROPIO-NITRIL ............................................................... 14 5. RETINOIC ACID............................................................................ 16 6. MALATHION ................................................................................ 19 I.2.3.b - Induction of dwarfism ............................................................................................ 22 I.2.3.c - Evidence of epigenetic control of skull ontogeny....................................................... 23 Chapter I.3 - Catfishes, a group of specialised Ostariophysi.......................................................................25 I.3.1 - OSTARIOPHYSI................................................................................................................................25 I.3.1.a - The taxon ‘Ostariophysi’ ......................................................................................... 25 I.3.1.b - Ostariophysan interrelationships ............................................................................ 28 I.3.1.c - Ostariophysan zoogeography .................................................................................. 30 I.3.2 - SILURIFORMES .............................................................................................................................. 31 I.3.2.a - Some general specialisations in catfishes............................................................... 31 I.3.2.b - Affinities between catfishes................................................................................... 33 I.3.3 - CLARIIDAE ..................................................................................................................................... 35 I.3.4 - CLARIAS GARIEPINUS Burchell (1822) ....................................................................................... 37 Contents ii Chapter I.4 - Some terminologies used................................................................................................................38 I.4.1 - BIOMETRIC DATA............................................................................................................................. 38 I.4.2 - ONTOGENETIC PERIODS.................................................................................................................. 39 I.4.3 - SCIENTIFIC TERMINOLOGY OF ANATOMICAL STRUCTURES............................................................... 42 I.4.4 - BONE HISTOLOGY .......................................................................................................................... 43 I.4.4.a - Cartilage 43 1. CELL RICH HYALINE CARTILAGE + MATRIX RICH HYALINE CARTILAGE..... 44 2. FIBRO/CELL RICH CARTILAGE + ELASTIC/CELL RICH CARTILAGE ........... 44 3. ‘ZELLKNORPEL’ + SCLERAL CARTILAGE............................................. 45 I.4.4.b - Bone .................................................................................................................... 45 1. CARTILAGE BONE......................................................................... 45 2. DERMAL BONE ............................................................................ 46 3. MEMBRANE BONE........................................................................ 47 4. CHONDROID BONE...................................................................... 47 Part II - Ontogeny of the skull Chapter II.1 - The cranial skeleton........................................................................................................................49 II.1.1 - THE CHONDROCRANIUM................................................................................................................... 49 INTRODUCTION................................................................ 49 RESULTS.......................................................................... 50 DISCUSSION.................................................................... 57 CONCLUSIONS................................................................ 66 II.1.2 - THE OSTEOCRANIUM ...................................................................................................................... 67 INTRODUCTION................................................................ 67 RESULTS.......................................................................... 68 DISCUSSION.................................................................... 82 CONCLUSIONS................................................................ 93 II.1.3 - THE CRANIAL LATERAL-LINE SYSTEM..........................................................................................94 INTRODUCTION................................................................ 94 RESULTS.......................................................................... 95 DISCUSSION.................................................................. 105 CONCLUSIONS.............................................................. 113 Chapter II.2 - The cranial myology ......................................................................................................................114 II.2.1 - THE ADDUCTOR MANDIBULAE COMPLEX........................................................................................ 114 INTRODUCTION.............................................................. 114 RESULTS........................................................................ 115 DISCUSSION.................................................................. 118 CONCLUSIONS.............................................................. 121 II.2.2 - THE TENTACULAR MUSCLES........................................................................................................ 122 INTRODUCTION.............................................................. 122 RESULTS........................................................................ 123 DISCUSSION.................................................................. 125 CONCLUSIONS.............................................................. 129 II.2.3 - THE HYOID MUSCLES .................................................................................................................. 131 INTRODUCTION.............................................................. 131 RESULTS........................................................................ 133 Contents iii DISCUSSION.................................................................. 136 CONCLUSIONS.............................................................. 141 II.2.4 - THE SUSPENSORIAL AND OPERCULAR MUSCLES......................................................................... 142 INTRODUCTION.............................................................. 142 RESULTS........................................................................ 143 DISCUSSION.................................................................