Fig. 4From: Pseudoinversion of septal sutures in Middle Jurassic–Lower Cretaceous non-heteromorph ammonitesIndosphinctes mutatus (Trd.) with sutural pseudoinversion of the transitional type. Specimen no. PIN 3664/5477, lateral view; Lower/Middle Callovian transitional beds; Nikitino, Ryazan region, Russia; a—big-sized septated specimen; b—suture lines of the inner whorl, enlargedBack to article page