Ammodytoidei: Development and Relationships 

 E. G. Stevens, A. C. Matarese and W. Watson 



THE suborder Ammodytoidei consists of one family. Am- 

 modytidae, with 5 genera and about 1 8 species. These are 

 small (less than 100-350 mm SL), elongate fish occurring in the 

 littoral and neritic waters of the Atlantic, Indian, Pacific, and 

 Arctic Oceans. Adults form schools but also bury themselves 

 in the sand. They are commercially valuable in the North Sea 

 and off Japan. 



The systematic position of Ammodytoidei. reviewed by 

 Duncker and Mohr ( 1 939). is unresolved, although the suborder 

 is considered a perciform derivative by Berg ( 1 940), Greenwood 

 et al. ( 1 966), and Gosline ( 1 97 1 ). A second family. Hypoptych- 

 idae. has been included in this suborder by these authors and 

 by Robins and Bohlke ( 1 970), but was removed to the suborder 

 Gasterosteoidei by Ida (1976), who considered it a preperco- 

 morph family on the basis of jaw and caudal osteology, egg size, 

 and reproductive behavior (see Fritzsche, this volume). 



Development 



The ammodytid genera, Gymnammodytes, Hyperoplus, and 

 Ammodytes (11 species) are temperate and boreal; Bleekeria 

 and Embolichthys (7 species) are more tropical in distribution. 

 The confused nomenclature of the North Atlantic species was 

 clarified by the synonomies in Reay (1970) and Russell (1976), 

 where summaries of early life history data were also given. Other 

 larval descriptions were given by Fage (1918) for Gymnam- 

 modytes; by Altukhov (1978), Kobayashi (1961c), Norcross et 



al. (1961). Richards (1965). Scott (1972). and Senta (1965) for 

 Ammodytes; and by Macer (1967) for North Atlantic species. 

 To date, eggs of 6 species and larvae of 9 species of these genera 

 have been described. No early life history data are available for 

 the tropical genera. 



Eggs 



Eggs of the six species that have been described are demersal 

 and adhesive, forming clumps on sandy substrates in shallow 

 water. Eggs, probably loosened by tidal currents, have been 

 collected in plankton nets (Williams et al. 1964; Senta, 1965). 

 Russell (1976) summarized studies made on eggs resulting from 

 artificial fertilization. Incubation time ranges from 2.0 to 12.5 

 weeks. Eggs are irregularly shaped, but generally spherical, from 

 0.67 to 1.23 mm in diameter, with a single yellow oil globule. 

 0.17 to 0.42 mm. Embryos develop specific dorsal and ventral 

 pigment, pigmented eyes, a moderate finfold. and pectoral buds 

 prior to hatching at about 3.6 mm. 



Larvae 



Morphology. — harvdiC of Ammodytidae typically are elongate, 

 with rounded snouts which become pointed with age, and pre- 

 anal length slightly more than 50% body length (Fig. 304). Newly 

 hatched larvae range from 3.0 to 4.6 mm body length. In newly 

 hatched and preflexion larvae the anus does not extend to the 

 edge of the moderately wide finfold but opens to the side. No- 

 tochord flexion occurs at 10 to 12 mm body length in most 





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Fig. 304. Larvae of: (upper) Hyperoplus lanceolalus. 16 mm, redrawn by H. Orr from Einarsson (1951); (middle) Ammodytes hexaplerus. 16 

 mm; and (lower) Ammodytes marimis, 16 mm. redrawn by H. Orr from Einarsson (1951). 



574 



