362 



ONTOGENY AND SYSTEM ATICS OF FISHES -AHLSTROM SYMPOSIUM 



Table 95. 



Derived Developmental Character States in the 

 Atherinomorpha. 



Alhenni- 

 formes 



Cypnno- 

 Beloni- donti- 

 formes formes 



Egg large, demersal with chorionic fila- 

 ments and lipid globules coalescing at 

 vegetal pole 



Separation of embryonic afferent and effer- 

 ent circulations by development of heart 

 in front of the head 



Formation of spermatogonia near the tuni- 

 ca albuginea 



Gut length less than 40% of flexion length 



Single row of melanophores on dorsal sur- 

 face 



Fin rays present at hatching 



X 

 X 



the development of a single dorsal melanophore row in the 

 common ancestor of the Atherinomorpha and separate loss 

 events in the Exocoetoidei and Cyprinodontiformes. 



' After this paper went to press, a report on the relationships of the 

 phallostethid fishes appeared in which Parenti (1984) questions our 

 conclusions on atherinifomi monophyly. The evidence she presents 

 suggests another phylogenetic interpretation but at the present time 

 neither hypothesis can definitely be rejected. 



Aspects of the variable reproductive behavior of the ather- 

 iniform fishes might be useful in determining relationships with- 

 in the order. The habit shared by Leuresthes tenuis and L. sar- 

 dina of spawning on the beach in synchrony with the lunar cycle 

 (Thompson and Thompson, 1919; Clark, 1925; Walker, 1952) 

 is a synapomorphy identifying the two grunion species as each 

 other's closest relative. Another lunar spawner, Menidia men- 

 idia deposits its eggs in detrital mats and on the stems and 

 exposed roots of the cordgrass plant Spartina alternijlora (Moore, 

 1980; Middaugh et al., 1981). Telmatherina ladigesi deposit 

 their eggs over a period of several days, attaching them singly 

 and in a widely spaced pattern to aquatic vegetation. In the 

 Phallostethidae, fertilization is internal and the eggs are attached 

 to a substratum by their adhesive filaments. There is much 

 variation in the reproductive behavior of atheriniform fishes 

 and investigation of their breeding habits might secure infor- 

 mation bearing on their systematic relationships. 



Table 95 summarizes the derived ontogenetic characters that 

 bear on atherinomorph relationships. There is still much that 

 is unknown about the early life history of the atheriniform fishes 

 and it is reasonable to hope that future investigation, particularly 

 of their reproductive habits and egg morphology, will contribute 

 to the elucidation of their evolutionary relationships.' 



Section of Fishes, Natural History Museum, Los Angeles, 

 California 90007. 



Cyprinodontiformes: Development 

 K. W. Able 



THE approximately 800 members of the Cyprinodontiformes 

 (killifishes) are small to medium-sized fishes (8-300 mm 

 SL) that live in shallow fresh and brackish water. They are nearly 

 worldwide in their distribution in temperate and tropical areas 

 (Parenti, 1981). Cyprinodontiformes is considered to be mono- 

 phyletic based on several adult osteological characters and the 

 long embryonic development time (Parenti, 1 98 1 ). I here follow 

 the most recent and extensive revision of the group by Parenti 

 ( 1 98 1 ) in which she rearranges them into two suborders: Aploch- 

 eiloidei with 2 families (Aplocheilidae and Rivulidae) and Cy- 

 prinodontoidei with 7 families (Profundulidae, Fundulidae, 

 Valenciidae, Anablepidae, Poeciliidae, Goodeidae, Cyprino- 

 dontidae). See Nelson (1976) and Parenti (1981, Table 3) for 

 prior classification schemes. Comments on portions of Parenti's 

 reclassification can be found in Klee (1982) and Foster (1982). 

 Reproduction and development within the group is excep- 

 tionally varied, with oviparity, ovoviviparity, viviparity (in- 

 cluding functional states of each) and functional hermaphro- 

 ditism represented. In addition, viviparity may have evolved 

 independently at least four times within the order (Parenti, 1981). 

 Among the viviparous forms occur a vast array of schedules 

 and morphological modifications for internal development such 

 as the trophotaeniae of the goodeids and the intra- and extra- 

 follicular gestation and superfetation in some poeciliids. De- 

 velopment reportedly is long, from four days to more than one 



year (Scheel, 1962) in some of the "annual" killifishes. The 

 rivulid, Rivulus mannoratus, is unique among fishes, and ver- 

 tebrates in general, in that it is a functional hermaphrodite with 

 internal fertilization (Harrington, 1961). Published early life his- 

 tory descriptions are listed in Table 96. 



Eggs 



The eggs of some Cyprinodontiformes are among the smallest 

 known for fishes. Scrimshaw (1946) recorded fertilized eggs of 

 the poeciliid Hcterandria fonnosa. in which development is 

 internal, to average 0.30 mm and Roberts (1970) recorded "ripe" 

 eggs of another poeciliid, Fluviphylax, as 0.1 mm (not substan- 

 tiated). The eggs of other cyprinodontiforms are larger (Table 

 97) with the largest that of Fiindiilus majalis at 2.0-3.0 mm. 

 Egg size varies within some species (i.e., the cyprinodontid 

 Aphanius anatoliae. Grimm, 1979a, b) and judging from the 

 data in Table 97, may vary in other species as well. Other authors 

 have noted differences in the egg size of cyprinodontids of the 

 genus Cyprinodon and considered them to be environmental 

 (Soltz and Hirschfield, 1 98 1) or genetic (Garrett, 1 982). Fecun- 

 dity is correlated with egg size in the aplocheilid Nothohranchius 

 (Bailey, 1972) and with female size in poeciliids (see Thibault 

 and Schultz, 1978). Fecundity also varies between females and 

 populations in the oviparous goodeid, Crentchthys baileyi (Es- 

 pinosa, 1968). Superfetation occurs in several poeciliid genera 



