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ACTA UNIVERSITATIS LATVIENSIS, 2004, Vol. 679, pp. 57-78
Revisiting Lophosteus, a primitive osteichthyan
HANS-PETER SCHULTZE and TIIU MÄRSS
H.-P. Schultze, Institut für Paläontologie, Museum für Naturkunde, Humboldt Universität,
Invalidenstr. 43, D-10115 Berlin, Germany; privat: 2001 Vermont St., Lawrence, Kansas
66046, USA; vrtpaleo@ku.edu
T. Märss, Institute of Geology at Tallinn University of Technology, Estonia Ave. 7, Tallinn
10143, Estonia; marss@gi.ee
Gross (1968) recognized one species of Lophosteus, L. superbus, from a single locality, Ohesaare
Cliff, Saaremaa, and a single time interval, late Pridoli, Late Silurian. Today, six species are
recognized and have a worldwide distribution from early Ludlow to early Pragian. We describe
three new species from the type locality, the Canadian Arctic and the Urals. The systematic
position of the genus is ambiguous. Lophosteus has been placed with sarcopterygians and with
actinopterygians, or basal to both osteichthyan groups and in connection to acanthodians.
Similarities to placoderms are superficial. We identify Lophosteus as a taxon close to acanthodians.
Introduction
Pander (1856) described Lophosteus superbus based on a small bone from the Ohesaare
cliff, Saaremaa (German: Ösel). Rohon (1893) synonymised the species Pterichthys
elegans Pander 1856 with Lophosteus superbus Pander, and treated P. harderi Pander
1856 as a distinct species, L. harderi. He placed Lophosteus in close relationship to
sarcopterygians (Holoptychius, Glyptolepis etc.) based on its histology. A second species
from the same locality (L. harderi (Pander), 1856) was synonymised with L. superbus
by Gross (1969). Gross (1969, 1971) gave the most exhaustive description of the
morphology and histology of Lophosteus superbus Pander 1856. Additional material
has been described by Märss (1986) who proposed a new species, Lophosteus? connexus,
from Vaivere, Saaremaa; Märss (1997) also identified similar Early Devonian scales
from the Central Urals as Actinopterygii gen. et sp. A. Burrow (1995a) proposed another
species, L. incrementus, from the Lower Devonian of Australia, and Märss (2000) shortly
described Lophosteus sp. from Cornwallis Island, Arctic Canada.
Here, we synthesise all data on lophosteids, give diagnoses for all species and
summarise current knowledge of their relationships.
Abbreviations: GIT, Institute of Geology at Tallinn University of Technology, Tallinn,
Estonia; IGB, Institute of Geology, Beijing, China; MMM, Mining and Mineralogical
Museum, Sydney, Australia; QMF, Queensland Museum fossil collection, S. Brisbane,
Queensland, Australia; Tü, Geologisch-Paläontologisches Institut und Museum,
Universität Tübingen, Germany; UALVP, Laboratory of Vertebrate Paleontology,
University of Alberta, Edmonton, Alberta, Canada; UQY, Geology Department,