Fig. 1 in A Clade of Non-Sexually Dimorphic Ponyfishes (Teleostei: Perciformes: Leiognathidae): Phylogeny, Taxonomy, and Description of a New Species

Fig. 1. Comparison of light organs (circled) and associated features of the LOS in male leiognathids exhibiting both sexually dimorphic and nondimorphic states. Leiognathus elongatus, extreme sexual dimorphism: (A) external anatomy illustrating expansive transparent lateral flank patch characteristic of males, which is located just external to the clear gasbladder wall and enlarged dorsal lobes of the male light organ; (B) internal anatomy illustrating lateral clearing of the silvery gasbladder lining (arrow) and hypertrophied dorsal lobes of the light organ, which lie internal to the gasbladder lining (removed). Leiognathus aureus, moderate to extreme sexual dimorphism: (C) external anatomy illustrating transparent pectoral­axil patch characteristic of males, which lies just exterior to the hypertrophied dorsolateral light­organ lobes; (D) internal anatomy illustrating enlarged dorsolateral light­organ lobes that abut lateral clearing of the integument just internal to the pectoral­fin axil. Leiognathus equulus, nondimorphic: (E) external anatomy; (F) internal anatomy. In members of the L. equulus species complex the light organ is not enlarged in males and there is no corresponding lateral clearing of the silvery gasbladder lining (arrow indicates posterior clear region common to all leiognathids) or integument proximal to the light organ.