High-level classification of the nautiloid cephalopods: a proposal for the revision of the Treatise Part K

Swiss Journal of Palaeontology

Table 2 Current knowledge of numbers of families where muscle attachment scars have been reported distributed across orders

Subclass	Order/suborder	No. of families per subclass	No. of families per (sub)order	No. of families where attachment pattern is known	Attachment pattern (O, V, P, D)	% of families per subclass where attachment pattern is known	% of families per order where attachment pattern is known
Plectronoceratia	Plectronoceratida	4	2	2	O	50	100
	Yanheceratida		1	0	?		0
	Protactinoceratida		1	0	?		0
Multiceratia	Ellesmeroceratida	48	7	3	O	35	43
	Cyrtocerinida		3	1	O		33
	Bisonoceratida		11	1	O		9
	Oncoceratida		17	9	O		53
	Discosorida		10	3	O		30
Tarphyceratia nov.	Tarphyceratida	12	10	6	V, Pl	67	60
Tarphyceratia nov.	Ascoceratida	12	2	2	V	67	100
Nautilia	Nautilida	24	24	8	Pl	33	33
Orthoceratia	Rioceratida	45	2	1	D	22	50
	Dissidoceratida		9	1	D		11
	Dissidoceratina		7	1	D		14
	Troedssonellina		2	0	?		0
	Orthoceratida		9	4	D		44
	Pseudorthoceratida		3	0	?		0
	Actinoceratida		8	1	D		13
	Astroviida		8	2	D		38
	Lituitina		2	2	D		100
	Pallioceratina		6	0	?		17
	Endoceratida		6	1	D		17

Numbers of families are derived from the Treatise Part K 1964 and a range of subsequent publications. The numbers are inevitably subjective and dependent on opinions regarding the validity of particular family groupings. For sources of data regarding records of muscle attachment scars, see Online Appendix 1
O oncomyarian, V ventromyarian, Pl pleuromyarian, D dorsomyarian