Hi David,  Thank you for your comments.  You have raised issues that are beyond my knowledge.  I'll pass on your messages to an expert, and will post a comment when I hear back.

I'm so far unable to find any references to the existence or otherwise,nor written clarification as to what if anything is known about sexual dimorphism in our Clinids(including breeding season gender-dependent transient changes of colouring and patterns of markings such as stripes,bands,blotches)in any of our mainstream fish ID books and also on this ausmus site:If such sexual dimorphism for Clinids has indeed been reported and documented in the literature,then I'd love to read about it,and if it's never even been considered as a possibility in this very poorly researched group(...which as a rank amateur I'd still find surprising-but then if we never ask the obvious questions?!...)then I wish to flag the certainty that,again based on field obs only,it does exist in at least one species:Heteroclinus perspicillatus.I've images of adult pairs in very proximate,almost intimate bonding poses w each ptner bowed head to tail side by side,and the sexual dichromism is very overt.

I'm pretty certain,just from many multiseasonal field observations over recent years mainly at Carrickalinga on Fleurieu Peninsula just south of Adelaide,that the described NSW inshore species Heteroclinus whiteleggi is simply the transient (weeks or at most a few months each late spring/early summer) season dependent male phenotype of Heteroclinus perspicillatus. Note these 2 species' known ranges are disjunct or have minimal overlap,and any supposed separation by habitat preference can be explained by differing inshore wave energy in SA's gulfs vs NSWs' more exposed coasts. Please advise us of seasons/dates of the posted more overtly banded H whiteleggi images to prove I'm wrong!