The oldest described eurypterid: a giant Middle Ordovician (Darriwilian) megalograptid from the Winneshiek Lagerstätte of Iowa

Table 1 Pentecopterus decorahensis prosomal ventral plate measurements

Specimen	Total length	Maximum width	Rostrum width	Main body length	Posterior process		Lateral projections
Specimen	Total length	Maximum width	Rostrum width	Main body length	Length	Width	Length	Width
SUI 139914	42^a	22^a	–	–	–	–	42^a	22
SUI 139915	64^a	23^a	–	–	–	–	64^a	8
SUI 139916	144^a	42^a	–	61^a	–	–	97	21
SUI 139917	60	62	29	28	5	4	32	7
SUI 139921	28^a	24^a	–	–	28	24	–	–
SUI 139936	66^a	76^a	35^a	43	13	10	23^a	19
SUI 139941	89^a	111^a	28^a	57	19	14	16^a	8^a
SUI 139978	102^a	40^a	–	29^a	–	–	72	13
SUI 139979	94^a	122^a	63^a	52^a	–	–	27^a	21
SUI 139982	69^a	33^a	–	15^a	–	–	54^a	17
SUI 140009	54^a	12^a	–	–	–	–	54^a	12^a
SUI 140011	61^a	21^a	–	–	–	–	61^a	21

ISSN: 2730-7182