Well spotted. Merocroca automima has the yellow extend further along the costa to the apex, beside the brown patch. In Echinocosma catachrysa it does not. https://inaturalist.ala.org.au/observations?place_id=6744&quality_grade=research&taxon_id=789423 https://inaturalist.ala.org.au/observations?place_id=6744&quality_grade=research&taxon_id=425906