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Dorsjil fin small, anteriorly situated to just behind neurocranium and above 

 Weberian complex, first basal inserted above fourth vertebral centrum. First dorsal 

 fin lepidotrichium forming a small, "V'-shaped locking spine. Second dorsal fin 

 lepidotrichium of females and nonbreeding males typically forming a relatively 

 weak, posteriorly serrated spine, except iny4. brevifilis,A. marmoratus, and^l. 

 pofystictus, in which the element forms an unbranched, segmented ray. Dorsal fin 

 spine of nuptial males elongated and hyperossified, smooth on posterior margin, 

 with numerous antrorse serrae along anterior margin. Dermal component of basal 

 radial of second dorsal fin ray completely fused to supraoccipital. Adipose fin 

 relatively small, constricted at base. 



Caudal fin deeply forked, emarginate, or obliquely truncate; upper lobe with 

 8 principal rays, lower lobe with 9-10 principal rays, and a variable but relatively 

 large number of procurrent rays in each lobe. Lower hypural plate consisting of 

 fused parhypural and lower two hypurals; upper hypural plate formed by fused third 

 and fourth hypurals; fifth hypural free or only weakly co-ossified with upper hypural 

 plate. One epural present, closely abutting posterior margin of neural spine of last 

 free vertebra. Primary and secondary hypurapophyses fused to form a shallow 

 horizontal keel that extends midway or beyond the upper margin of the second 

 hypural. < 



Anal fin relatively long, with between 25 and 45 lepidotrichia; first anal 

 pterygiophore generally with one or two very small, deeply embedded splints 

 anteriorly and a longer ray posteriorly. Last anal pterygiophore with a laminar 

 posterior extension, usually supporting two or three branched rays. Anal fin of 

 nuptial males with third through seventh lepidotrichia elongated, thickened, and 

 coalesced, forming an intromittent organ; interradial membranes over thickened 

 rays swollen; gonopore displaced on distal tip of modified anal rays. - 



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