Table 1.

Morphological comparison of Paracatenula and Wallaceago with the most similar genera.

	Paracatenula	Wallaceago	Catenulopsis	Catenula	Amphora	Lunella	Parlibellus
	This study	This study	Kryk et al. (2021)	Mereschkowsky (1902)	Kützing (1844)	Snoeijs (1996)	Cox (1988)
Valves	strongly asymmetric and dorsiventral	strongly asymmetric, dorsiventral, semi–rhombic	strongly asymmetric and dorsiventral	strongly asymmetric and dorsiventral	asymmetric and dorsiventral	semi-lanceolate and dorsiventral	symmetric, bluntly lanceolate
Raphe position	eccentric, near ventral mantle	eccentric, near ventral mantle	eccentric, near ventral mantle	eccentric, near ventral mantle	moderate to strong eccentric toward ventral mantle or valve margin, raphe ledge present	near the ventral margin	on valve face, in the centre
Raphe shape	biarcuate	straight biarcuate	slightly biarcuate or sinusoidal	biarcuate	straight to biarcuate (sigmoid)	slightly biarcuate	straight
Raphe distal Endings	bent to dorsal, distant to poles	curved to ventral, distant to poles	curved to ventral, distant to poles	bent to dorsal, distant to poles	curved to dorsal face	terminating to ventral	terminating to secondary side
Raphe proximal Endings	straight, distant	close and curved to ventral	close and curved to ventral	straight, distant	terminate on ventral; on valve face; close to distant	straight to deflected on ventral; close	straight and distant
Sternum	narrow	none	narrow	narrow	narrow	narrow	narrow
Valve face/ mantle transition	abrupt	abrupt	abrupt	abrupt	abrupt	gradual both ventral and dorsal	gradual
Helictoglossae	well developed	poorly developed	poorly developed	well developed	poor to well-developed	well developed	well developed
Cingulum	open, perforated small pore	unknown	several plain porous copulae	open, non–porous band	plain or perforated, one or more areolae	porous copulae	wide girdle region, perforated