Didymograptellus bifidus (Hall, 1865)

1858     Graptolithus bifidus n. sp. — Hall, pp. 130

1865     Graptolithus bifidus J. Hall — Hall, pp. 73, fig. 1:16-18; 3:9-10

1947     Didymograptus bifidus — Ruedemann, pp. 327

1960     Didymograptus bifidus (Hall) — Obut, pp. 152, fig. V 2,2a

1962     Didymograptus bifidus J. Hall — Berry, pp. 294, fig. 1a-e, 2a-b

1982     Didymograptellus bifidus (Hall, 1865) — Cooper & Fortey, pp. 220

1988     Didymograptus (Didymograptellus) bifidus (J. Hall) — Williams et Stevens, pp. 41, fig. 12; 13:8-13

2006     Didymograptus (Didymograptellus) bifidus (J. Hall) — Jackson et Lenz, fig. 8 o-q; u-w