76 



ONTOGENY AND SYSTEM ATICS OF FISHES- AHLSTROM SYMPOSIUM 



Table 15. Morphological Characters of Ophichthidae (Myrophinae and Ophichthinae). + = All or most species; ( + ) = some species 



only. Refer to Fig. 35. 



Myrophinae 



Ophichthinae 



Characters 



Murae- Neen- Pseudo- Ophich- Sphage- Bascanich- Calle- 



4h!ia mchlhys Myrophis chetys myrophts thini branchini thyini chelyini 



A. Body depth (euryodontic stage) 



1. >10%TL 



2. <10%TL 



B. Gut loops or swellings 



1. Low 



2. Moderate to pronounced 



C. End of nephros 



1. Above or just before anus 



2. 4-14 myomeres before anus 



D. Liver lobes and oesophageal swellings 



1. Two 



2. Three 



E. Caudal fin at metamorphosis 



1. Present, normal 



2. Absent (or much reduced) 



F. Dorsal pterygiophores and rays before 

 metamorphosis 



1 . Well developed; dorsal origin 

 migrates forwards 4-6 myomeres 



2. Weakly developed; origin migrates 

 forwards 5-50 myomeres (or resorbed) 



+ (+) 



+ (+) + 



(+) 



(+) 



+ 



(+) 

 (+) 



of lai-vae, the significance of these has not yet been comprehen- 

 sively reviewed across the Anguiliiformes. Furthermore, the ex- 

 tent of intraspecific variability of pigment patterns has also not 

 been assessed. Any present discussion as to the significance or 

 otherwise of similarities and differences in larval pigmentation 

 must therefore be preliminary. 



The range of pigmentation in genera for which larvae have 

 been identified, and for some other forms, is summarized in 

 Tables 14-23, family by family. These tables, with their accom- 

 panying figures and morphological information, may be used 

 as a guide to generic identification, and also as a synopsis of 

 pigment patterns. Because these are both complex and diverse 

 in some families, they cannot always be simply displayed in 

 keys. In the Ophichthidae also, and other families, further pig- 

 ment patterns are known, probably representing other genera. 

 This is particularly so of Indo-Pacific Anguiliiformes which have 

 not been extensively studied. 



These tables and figures highlight common features of pig- 

 mentation: (1) on the gut or its adjacent body wall, often as a 

 regular, spaced series from throat to anus (Notacanthiformes, 

 Congrinae, Heterocongrinae. Heterenchelyidae, Colocongri- 

 dae), or as an interrupted series (Nettastomatidae. Muraene- 

 socidae. Dysommatidae. Ophichthidae) or in some other form 

 (Bathymyrinae, Heterocongrinae, Muraenidae, Nemichthyidae, 

 Xenocongridae); (2) on the lateral body surface (Dysommatidae, 

 Congrinae, Nettastomatidae, Xenocongridae). often associated 

 in some way with the myosepta (Ophichthidae, Bathymyrinae, 



Heterocongrinae, Serrivomeridae. Derichthyidae); (3) on the 

 spinal cord (Nemichthyidae. Muraenidae); or (4) on the bases 

 of the dorsal, anal and caudal fins. 



The broad perspective on the ontogeny of the Anguiliiformes 

 and Notacanthiformes given by the preceding deserves com- 

 ment. 



As adults, eels have adopted a somewhat conformist body 

 plan notable for reduction and loss of external features, though 

 the component families of the group are more or less discrete 

 osteologically. In contrast, through elaboration of the leaflike 

 body form and pigment patterns their larvae display a diversity 

 which matches that of any other group of teleosts. This diversity 

 involves some distinctive larval characters (morphological and 

 pigmentary) which allow leptocephali to be identified at the 

 family level. These characters have not been comprehensively 

 assessed; further definitive identification of larval forms will aid 

 any future analysis. Within families, larvae are generally similar 

 in body form and pigmentation but there are several remarkable 

 exceptions. There are some discernible character gradients in 

 larvae (e.g., the complexity of gut swellings or loops in Ophich- 

 thidae; pigmentation of Congridae). but these may or may not 

 be matched by adult character gradients. Detailed meristic in- 

 formation, as forthcoming throughout larval development, is 

 the only satisfactory medium for species identification, espe- 

 cially in the larger eel families. 



Zoology Department, Victoria University of Wellington, 

 Wellington, New Zealand. 



