Graptolites from the Ontikan Limestones (Ordovician) of Öland, Sweden. I: Dendroidea, Tuboidea, Camaroidea, and Stolonoidea

Remains of graptolites have been isolated from blocks of Ontikan (Lower Ordovician) limestone from the localities of Hälludden and Hagudden in the northern part of the island of Öland. A brief introductory section includes a description of the methods of isolation and preparation of this material, notes on terminology and an outline of the stratigraphy of the two localities. The graptolites have been described in two parts; this paper contains the first part and deals with the eighteen species which are attributable to the orders Dendroidea, Tuboidea, Camaroidea and Stalanoidea. The thirteen species of dendraids include six-Callagraptus? perexilis, C. ? perlangus, C. ? sinuosus, Desmagraptus separatus, Dictyanema variabile and Acanthograptus divergens-which are new, whilst one has not been identified specifically; two new subgenera of the genus Callagraptus are proposed. Each of the two tuboid species is accorded to a new genus - Parvitubus and Mullitubus - and one of the species - M. spinasus -is new; two new monotypic families of the order Tuboidea are diagnosed. The two species attributed to the order Camaroidea belong to two genera. One new unnamed species is provisionally placed in the order Stolonoidea. A final section deals with general aspects of dendroid and tuboid morphology, phylogeny and taxonomy.