432 



ONTOGENY AND SYSTEMATICS OF FISHES-AHLSTROM SYMPOSIUM 



Fig. 235. Egg (A) and larvae (B — 4.5 mm SL, C— 6.3 mm SL, ventral view) of Eumicrotremiis orbis from Matarese and Borton (in prep.) and 

 larvae of Cycloplerus lumpus (D— 5.0 mm SL. Damariscotta River, Maine, HML H-24029). 



toral fin has numerous melanophores (Fig. 237) and during de- 

 velopment the fin may become bilobed (Fig. 238). The gill open- 

 ing decreases in size during development. 



Disk size varies within each subfamily and may be related to 

 habitat. Pelagic forms such as the cyclopterine Pelagocychis vi- 

 tiazidind the liparidine L. fabricii (¥i%. 237) have small orgreatly 

 reduced disks. Some pelagic forms, such as Nectoliparis pclag- 

 icus and Lipanscus nanus lack disks entirely. 



The arrangement of the cranium may offer useful insights into 

 cyclopterid phylogeny. Svetovidov ( 1 948) noted that the cranial 

 cavity extends into the interorbital space in Liparis but only 

 reaches the hind margin of the orbit in Cycloplerus. Our material 

 indicates that this character state changes ontogenetically in 

 Cycloplerus with the earliest stages showing the liparidine state. 



Able and McAllister (1980) suggested that tooth shape ex- 

 hibits polarity, with trilobed teeth with equal lobes representing 

 the primitive condition, trilobed teeth with a larger central lobe 

 an intermediate condition, and simple teeth the derived con- 

 dition. The ontogeny of teeth in Liparis supports this statement. 

 All Liparis examined to date possess trilobed teeth early in 

 development. With continued growth the oldest teeth may be- 

 come simple, as in L. fabricii (Able and McAllister. 1980). 



Caudal morphology and ontogeny show variation that may 

 prove useful for identification and phylogenetic studies. Within 

 liparidines caudal elements vary. For example. Stein (1978) 

 noted a lack of epurals in Careproclus longifilis, whose caudal 

 structure he considered typical of deepwater eastern Pacific li- 

 paridines he examined, while we note the typical presence of 



