Larval Development of the Australian Devilfish, 

 Gymnapistes marmoratus (Teleostei: Scorpaenidae) 



Francisco J. Neira 



ABSTRACT: The larval development of the devil- 

 fish, Gymnapistes marmoratus, is described from 

 material collected in the Swan and Peel-Harvey 

 Estuaries in southwestern Australia. Larvae of G. 

 marmoratus examined (2.6-9.3 mm BL) are pelagic 

 and characterized by a deep and compressed, light- 

 ly pigmented body; a moderately short gut; 29 

 myomeres; complex head spination; and large, pig- 

 mented fan-shaped pectoral fins which form early 

 in development. Notochord flexion occurs between 

 4.8 and 6.0 mm BL and transformation between 6.8 

 and 10.9 mm BL. 



The majority of head spines in G. marmoratus 

 form before the postflexion stage. These include 

 parietal, supraocular, preopercular, nasal, ptero- 

 tic, posttemporal, and some suborbital spines. The 

 suborbital stay develops after flexion; the nuchal 

 and three of the anterior preopercular spines disap- 

 pear in juveniles. The caudal complex of lar\-al G. 

 marmoratus includes well-fused hypural elements 1 

 and 2 and hypural elements .3 and 4, a reduced fifth 

 hypural bone, and a parhypural element. 



In addition to larval development, comparisons 

 with similar taxa and the occurrence of the larvae 

 in the Swan Estuary are discussed. 



Scorpaeniform fishes are represented in south- 

 western Australia by one marine species of each 

 oiCentropogou, Scorpaena, Maxillicosta, Gym- 

 napistes, and Giyptauchen and three of Neo- 

 sebastes (Hutchins and Thompson 1983; Hutch- 

 ins and Swainston 1986). The larval stages of 

 none of these genera have been described except 

 for those of Scorjmetia, which were described 

 from larvae caught elsewhere (see Moser et al. 

 1977; Washington et al. 1984a). The present 

 paper describes for the first time the larval de- 

 velopment of the sole species of the genus Gym- 

 napistes, G. marmoratus, using material collect- 

 ed in the Swan and Peel-Harvey Estuaries in 

 southwestern Austraha. This paper also includes 

 information on the occurrence and distribution of 

 the larvae in the Swan Estuary. 



Francisco J. Neira, School of Biological and Environmental 

 Sciences, Murdoch University, Murdoch 6150, Perth, West- 

 em Australia. 



The devilfish, Gymnapistes marmoratus, also 

 known as the soldier fish or South Australian 

 cobbler, is a marine species common in seagrass 

 beds of coastal embayments and estuaries of 

 southern Australia. It occurs between southern 

 Sydney in New South Wales and Fremantle in 

 Western Australia and occurs also in Tasmania 

 (Hutchins and Thompson 1983; Last et al. 1983; 

 Hutchins and Swainston 1986). Juveniles are 

 relatively common in both the lower Swan Estu- 

 ary and the Peel Inlet, in southwestern Aus- 

 tralia (Chubb et al. 1979; Potter et al. 1983). 



The population of G. marmoratus studied by 

 Grant (1972) in the D'Entrecasteaux Channel, 

 southern Tasmania, spawned at the beginning of 

 spring at approximately two years of age. In the 

 Gippsland Lakes, Victoria, the adults apparently 

 spawn over an extended period with a peak in 

 winter (Ramm 1986). Larvae of this species have 

 been collected fi'om July to October in Port Phil- 

 lip Bay, Victoria, with peak abundance occurring 

 in August (Jenkins 1986). 



MATERIALS AND METHODS 



Collection of Larvae 



Larvae of G. marmoratus were obtained from 

 plankton samples collected monthly during 1986 

 in the lower Swan Estuary (lat. 32°04'S, long. 

 115°44'E). Samples were obtained at night using 

 0.6 m diameter paired bongo nets, with 0.5 mm 

 mesh, which were towed horizontally 0.5 m 

 below the surface for 10 minutes. Transforming 

 and juvenile G. marmoratus were caught in the 

 Peel-Harvey Estuary (32°35'S, 115°45'E) using a 

 3.0 mm mesh beach seine. Samples were fixed in 

 10% formalin and specimens were stored in 70% 

 alcohol. 



Material Examined 



A total of 22 larvae, ranging in body length 

 (BL) from 2.6 to 6.8 mm, were used to describe 

 pigmentation, morphometries, and meristics. 

 One transforming lai-va (9.3 mm BL) and seven 



Manuscript Accepted March 1989. 

 Fishery Bulletin, U.S. 87: 889^98. 



889 



