A stratigraphically significant conodont fauna from the base of the Tetragraptus approximatus Zone at Holsbrotten, Mt. Hunneberg, SW Sweden

A diverse conodont collection representing the Oelandodus elongatus–Acodus deltatus deltatus Subzone of the Paroistodus proteus Zone has been retrieved from a sample from the E bed at Holsbrotten on the west side of Mt. Hunneberg. This bed marks the base of the Tetragraptus approximatus Zone at the nearby Diabasbrottet section, the recently ratified stratotype for the base of the Second Global Stage of the Ordovician. The E bed at Holsbrotten is underlain by graptolite-bearing strata of the Hunnegraptus copiosus Zone, and because graptolites are missing in the more calcareous development of this interval at the Diabasbrottet stratotype, the new Holsbrotten data are important for both the graptolite and conodont correlation of the base of the Second Global Stage of the Ordovician.