Ole A. Hoel

University of Oslo · Natural History Museum

Leptaenine brachiopods are common and widespread on Gotland. Lepidoleptaena poulseni and Leptaena rhomboidalis retained a functional apical pedicle throughout ontogeny, and both had strong adductor muscles and robust ornamentation, allowing them to occupy shallow water and high energy environments. A pedicle-shortening muscle is present within the...

Twelve species of Brachiopods are described from the Silurian of Gotland, six furcitellinines and six “strophodontids.” One is new—Strophodonta hoburgensis n. sp. The furcitellinines are moderately common and diverse in the lower part of the succession, but the last species disappears in the middle Hemse beds (~middle Ludlow). Three genera are repr...

The thorax and pygidium of the rare middle Ordovician (clingani graptolite zone) trilobite Prionocheilus narinosus (Siveter, 1977) are described from a nearly complete specimen found at Ringåsen, Norderhov, Ringerike District, Oslo Region. This is the first known association of cranidium, thorax and pygidium of this species and this new record also...

Leptaenine brachiopods are common and widespread in Silurian strata in Gotland. Leptaena sperion, Lept. depressa visbyensis and Lept. depressa lata lived in relatively low-energy environments, but retained a very slender pedicle, whereas Lept. depressa depressa and Lept. parvorugata lived free-lying in deeper water atrophied the pedicle in very ear...

Dorsal valves of the cementing strophomenide brachiopods Leptaenoidea silurica Hedström and Liljevallia gotlandica Hedström are described for the first time, and it is shown that both these species could also live ambitopically. The lower Wenlock Scamnomena rugata (Lindström) represents young individuals of the ambitopic variant of Leptaenoidea sil...

Strophomenid brachiopods belonging to the generaLeptaena andLepidoleptaena are described from the uppermost Llandovery — Ludlow succession of Gotland, Sweden. In Gotland,Lepidoleptaena comprises the single speciesL. poulseni, andLeptaena includes four species:L. rhomboidalis, L. sperion, L. depressa andL. parvirugata n. sp.L. depressa shows a consi...

The occurrence in the Arenig of the Oslo Region of the typically east Baltic trilobite Megistaspis (Rhinoferus) hyorrhina (Leuchtenberg, 1843) is con­ firmed. The Norwegian specimens exhibit a range of variation just as wide as that seen in the east Baltic. The visual field is estimated and found to overlap posteriorly and 20° above horizontal. The...

This is Part II of a two-part description of the trilobite fauna of the Hagastrand Member (Toyen Formation) in the Oslo, Eiker-Sandsvaer, Modum and Mjosa areas. In this part, the non-asaphid trilobites are described, while the asaphid species have been described previously. The history and status of the Tremadoc-Arenig Boundary problem is also revi...

This is part one of a two-part description of the trilobite fauna of the Hagastrand Member of the Toyen Formation. The Toyen Formation (Lower Arenig) of the Oslo Region consists of poorly fossiliferous grey shales and black graptolitic shale. In the basal part of the Formation (i.e. Hagastrand Member) in the Eiker-Sandsvaer, Modum and Oslo district...