OLNEY: LAMPRIFORMES 



371 



Development 



Walters and Fitch (1960), Breder and Rosen (1966), Palmer 

 (1973), Nielsen (1973) and Moser (1981) have summarized the 

 state of knowledge of the early life history of lampriform fishes. 

 Eggs and larvae of the Veliferidae, Radiicephalidae and Style- 

 phoridae are unknown, although Karrer (1976) has mentioned 

 ripe ovarian eggs of Radiicephalus clongatus. Harrison and 

 Palmer (1968) presented meristic and morphometric data on a 

 154 mm SL R. elongatus termed a postlarva and Regan (1924) 

 figured a 26 mm SL larval Stylephorus chordatus. Little data on 

 young stages of the Lampridae are available. Ehrenbaum ( 1 905- 

 1 909) and Gudger ( 1 930) presumed pelagic eggs based on ovar- 

 ian examination; Gudger (1930), D' Ancona (1933b) and Oelsch- 

 lager (1976b) figured juvenile stages of Lampris giutatus; and 

 Parin and Kukuyev (1983) illustrated a young specimen of L. 

 irnmaculatus. Within the Lophotidae, larvae of Eumecichthys 

 are unknown while Fitch (1966) reported on ovarian eggs in E. 

 fiskt and Parin and Pokhilpkaya (1968) figured juvenile stages. 

 Sanzo ( 1 939b, 1 940) and Sparta (1954) have described eggs and 

 early larvae of a species oi Lophotus considered by Oelschlager 

 (1979) to be L. lacepedei. Eggs and larvae of trachipterid and 

 regalecid fishes have received considerable attention although 

 early life history stages of Agrostichthys and Desmodema are 

 unknown. Eggs and early larvae of Zu cristatus were described 

 by Sanzo (1918), Sparta (1933) and Olney and Naplin (1980). 

 Eggs and larvae of Trachipterus, probably representing several 

 species, were described by Emery (1879), Lo Bianco (1908a), 

 Jacino (1909), Ehrenbaum (1905-1909), Sparta (1933), Mito 

 (1961b) and Sardou ( 1 966). Eggs and larval stages of Regalecus 

 were figured and described by Sanzo (1925), Sparta (1933) and 

 Robertson (1975a). In summary, published information on the 

 development of eggs and larvae of four of the 1 2 lampriform 

 genera is available. In the following discussion, these published 

 data as well as additional material are utilized to summarize 

 the important characteristics of eggs, larvae and young of lam- 

 priform fishes and provide illustrations of larvae of four addi- 

 tional genera. 



Egg and embryonic morphology. — Data on morphology and de- 

 velopment of lampriform eggs are incomplete (Table 99) but 

 indicate that eggs are large (1.7-4.0 mm egg diameter, range 

 excludes measurements of ovarian eggs,-see Table 99), spherical, 

 pelagic, often brightly colored (generally in amber, pink or red 

 hues) and possess thick, resilient chorions. Up to three weeks 

 may be required in incubation ( 1 8-20 days for R. glesne, Sparta, 

 1933). As a result, eggs are distinctive and easily recognized in 

 plankton collections (Fig. 1 93B, C) especially in advanced stages 

 of development (Orton, 1955a; Olney and Naplin, 1980). 

 Sanzo (1940) reported both homogeneous (Lophotus) and 

 segmented yolks (Zu and Regalecus) but recent observations 

 indicate homogeneous yolks in all known forms (Robertson, 

 1975a; Olney, unpublished data). Egg diameters, presence or 

 absence of oil droplets, chorionic ornamentation and micro- 

 structure may delimit some species (Table 99). Scanning elec- 

 tron micrographs of cross-sections of the chorions of Zu cris- 

 talus and an unidentified trachipterid species (Fig. 194) indicate 

 variability in chorion thickness and layering which may be of 

 systematic value. In general, however, confirmed identification 

 of lampriform eggs requires late stages with advanced embryos 

 (Olney and Naplm, 1980). 



Fig. 1 94. Scanning electron micrographs of chorionic microstructure 

 in lampriform eggs. (A) trachipterid, chorion thickness 1 1.04 ^m. (B) 

 Zu cristatus, chorion thickness 13.3 ^m. 



Lampriform embryos exhibit precocious development. In 

 Trachipterus. Zu, Lophotus and Regalecus. anterior dorsal rays, 

 pelvic rays, distinctive pigment and total myomeres are appar- 

 ent and distinguish these forms (Sparta, 1933; Mito, 1961b; 

 Sanzo, 1940; Olney and Naplin, 1980). Some disparity exists, 

 however, in descriptions of late embryos. Sparta (1933) depicts 

 late embryonic R. glesne with anterior elements reduced but the 

 fourth elongate while Robertson (1975a) figures R. glesne em- 

 bryos off New Zealand with an elongate first element followed 

 by three reduced rays. 



Larval morphology. — Al hatching, larvae of lampriform fishes 

 possess a number of distinctive characteristics including; well 

 developed, protrusible jaws; diflierentiated guts with an open 

 lumen and little or no yolk material; elongate anterior dorsal 

 elements which insert between the posterior eye margin and the 

 shoulder and are usually ornamented with broad, spatulate and 



