92 



PH. GREENWOOD 



The nature of the hyoid-mandibular connection in the 

 cirrhitoids, a derived percomorph group (Greenwood, 1995), 

 and that described in other teleosts and in the Lepisosteidae, 

 raises doubts about the strict homology of the connection in 

 these various taxa. 



Functionally, it would seem that a mandibulohyoid connec- 

 tion is of importance both in adults (see Aerts et al. , 1987) 

 and in early larval stages (Verraes, 1977); its phylogenetic 

 history in this context is discussed at length by Lauder (1982). 



Regrettably, the feeding studies on cirrhitoids, from which 

 this anatomical study arose, are not sufficiently advanced or 

 refined to allow informed speculation on any correlation 

 between the morphology and the feeding habits of these 

 fishes. Furthermore, many other cirrhitoid taxa remain to be 

 studied before it will be possible to evaluate what significance 

 the different types of intragroup mandibulohyoid and other 

 linkages (or absence thereof) may have in unravelling the 

 taxonomy and phyletic relationships of the group. Neverthe- 

 less, there are indications from this study, and from informa- 

 tion in the literature on various forms of mandibulohyoid 

 connections, that further investigations may yield insight into 

 the biomechanics of feeding and into historical relationships. 



MATERIALS AND METHODS 



Material 



Clupeidae: 

 Salmonidae: 

 Characidae: 

 Cirrhitidae: 



Etrumeus terres. RUSI 34140 (1 speci- 

 men) 



Oncorhynchus mykiss RUSI 36417 (3 



specimens) 



Hydrocynus vittatus RUSI 19355 (1 



specimen) 



Amblycirrhitus bimacula RUSI 77-20 (3 



specimens) 



Cirrhitichthys oxycephalus RUSI 40526 



(3 specimens) 



Cirrhitops fasciatus RUSI 2375 (1 speci- 

 men; ex Hawaii) 



Cyprinocirrhites polyactis RUSI 12339 



(3 specimens) 



Paracirrhites arcatus RUSI 30975 (2 



specimens) 



Paracirrhites forsteri RUSI 39419 (3 



specimens) 



Acantholatris monodactylus RUSI 



33485 (2 specimens) 



Mendosoma lineatum 



RUSI 33613 (1 specimen) 

 RUSI 33626 (1 specimen) 

 RUSI 26176(1 specimen) 



Cheilodactylus fasciatus DIFS unreg. (2 



specimens) 



Cheilodactylus pixi DIFS unreg. (3 



specimens) 



Chirodactylus brachydactylus DIFS 



unreg. (3 specimens) 



DIFS: Department of Ichthyology and Fisheries Science, 

 Rhodes University, Grahamstown. RUSI: J.L.B. Smith Insti- 

 tute of Ichthyology, Grahamstown. 



Latridae: 



Cheilodactylidae: 



Method 



The entire opercular series, palatopterygoid arch and hyoid 

 arch of one side, together with the mandible, premaxilla and 

 maxilla of that side, were dissected away from the head. 

 Muscles, tendons and ligaments were examined on the dis- 

 sected side, and checked on the contralateral aspect which 

 was left in situ. 



All specimens had been fixed in formalin and preserved in 

 either ethyl or propyl alcohol. 



In the absence of ontogenetical information on the devel- 

 opment of ligamentous and tendinous systems in these fishes, 

 ligaments and tendons in the various taxa are presumed to be 

 homologous if their places of origin and insertion are similar. 



ABBREVIATIONS FOR FIGURES 



Abbreviations for tendons and ligaments are given separately 

 with each figure. 



Muscles: 



Add. mand. 



I u & m: Adductor mandibulae Aj upper and main divi- 

 sions respectively 



Aw: Aw division of adductor mandibulae muscle 



Awt: Tendinous aponeurosis of adductor mandibulae 



Aw 



Geh: Geniohyoideus 



Im: Intermandibularis 



St: Sternohyoideus 





Skeletal elements: 



Ang: 



Anguloarticular 



Bb: 



1st basibranchial 



Ch: 



Ceratohyal 



Dt: 



Dentary 



Ect: 



Ectopterygoid 



Ent: 



Entopterygoid 



Epi: 



Epihyal 



F: 



Raised facet for articulation with epihyal 



Ga: 



Gill arch 



Hyom: 



Hyomandibula 



Hyp: 



Hypohyals 



Ihyl: 



Interhyal 



lop: 



Interoperculum 



Max: 



Maxilla 



Mt: 



Metapterygoid 



Pal: 



Palatine 



Pop: 



Preoperculum 



Q: 



Quadrate 



R: 



Retroarticular 



Sy: 



Symplectic 



V: 



Vomer 



