Inocaulis Hall, 1851

Inocaulis Hall, 1852, p. 176 [*I. plumulosa; M] ?Ordovician–Silurian: worldwide. The genus has long been identified as a dendroid graptolite and in the family Inocaulidae, established by Ruedemann (1947). Furthermore, Bouček (1957) referred to the group as the order Inocaulida Bouček, 1957. Mierzejewski (1986, p. 166) doubted the graptolitic nature of Inocaulis and discussed the genus as a hydroid. Maletz (2014b) suggested that Inocaulis plumulosa is an alga, but LoDuca and others (2017, p. 599) illustrated I. plumulosus as a “hemichordate with an alga-like tubarium.” Because fusellar construction has not been identified in the type species of the genus, its inclusion in the graptolites is uncertain, and the preference herein is to keep it as an alga. However, most species referred to Inocaulis may represent species of the Callograptidae and should be referred to a number of other genera. Muir, Zhang, and Lin (2013) discussed a single fragment as Inocaulis sp., in which fusellar construction was detected.——Fig. 310,4a–b. *I. plumulosa; 4a, illustration of type (Hall, 1865, fig. 26); 4b–c, commonly illustrated typical specimens; scale bars, 10 mm (Bassler, 1909, fig. 59, 61).