Late Silurian fish microfossils from Helvetesgraven, Skåne (southern Sweden) (I)

Abstract

The fauna from a Late Silurian residue sample from Övedskloster (Skåne) is listed. It comprises scales of ‘Agnatha’ (rare osteostracan scales, and the thelodonts Thelodus parvidens, ‘T. traquairi’, T. sculptilis, T. admirabilis, and ‘Loganellia cuneata’) and of Gnathostomata (the acanthodians Nostolepis striata, Gomphonchus sandelensis, Poracanthodes? lehmani sp. nov., and Poracanthodes cf. punctatus, tesserae of the head and other specialised elements of the squamation; and the osteichthyan Andreolepis hedei). This fauna is considered to be as old as, or slightly younger than that from the complex of sedimentary rocks along the Anglo-Central Urals margin of the Laurussian continent affected by the Ludfordian A. hedei Event. This event marks the transition between the hedei and sculptilis Zones of the Microvertebrate Standard Zonation and can be correlated with the snajdri Conodont Interval Zone. The evidence favours a simultaneous palaeogeographical appearance of the punctatiform and porosiform poracanthodid acanthodians within the Baltica region of Laurussia.