Topic
Stenaster
About: Stenaster is a research topic. Over the lifetime, 2 publications have been published within this topic receiving 5 citations.
Papers
TL;DR: Seventeen specimens representing three of the four asterozoan classes are recorded from Ordovician and Silurian strata of the western United States and northwest France; only the Somasteroidea is not represented.
Abstract: Seventeen specimens representing three of the four asterozoan classes (Stenuroidea, Asteroidea, Ophiuroidea) are recorded from Ordovician and Silurian strata of the western United States and northwest France; only the Somasteroidea is not represented. New taxa are: the stenuroids Lopidiaster jamisoni nov. gen. and sp. and Lehmannaster spinosus nov. gen. and sp.; the asteroids Meturaster belli nov. gen. and sp., Petraster crozonensis nov. sp., and Schuchertia sprinklei, nov. sp.; Lepidactis? sp. also is recognized. The Ophiuroidea is represented by Stenaster sp., Protaster sp., and an arm tip is of unknown familial and generic affinities. Class level assignments of all specimens are clear, and all but Lopidiaster are similar to earlier-known representatives of their respective classes; phylogenetic differentiation within the subphylum was well-established early in the Paleozoic. Ordovician asterozoans are both geographically widely distributed and morphologically clearly separable from modern asterozoans, yet overall structural similarities favor ecologic roles paralleling those known today.
9 citations
1 Jan 2005
TL;DR: Asterozoans have not been described before now from the Lower Palaeozoic rocks of Norway and they are rare in equivalent rocks throughout Baltoscandia (e.g. Rasmussen 1952; Regnell 1960; Rozhnov 2004) as mentioned in this paper.
Abstract: Asterozoans have not been described before now from the Lower Palaeozoic rocks of Norway and they are rare in equivalent rocks throughout Baltoscandia (e.g. Rasmussen 1952; Regnell 1960; Rozhnov 2004). It was therefore of great interest when two amateur collectors, Liv Torgunn Torud Hagen and Ingebjorg Nilsen from Brumunddal, discovered a rich ophiuroid (brittle star) bed in the Caradocian Furuberget Formation in the Hamar district north of Oslo, Norway (Fig. 1). The specimens occur mainly as decalcified moulds in a fine-grained marlstone. They are scarcely deformed and with the aid of latex casts can be studied in detail. Although we have had access to more than 100 specimens, only one species of the widespread form, Stenaster obtusus (Forbes, 1848) has been identified. In addition, during detailed profile logging by one of us (TH) in the uppermost part of the Elnes Formation (Llanvirn) near Slemmestad, Oslo-Asker area, another well-preserved asteroid was found, described herein as Cnemidactis osloensis n.sp. This occurrence is of the oldest hitherto described from Baltoscandia, though Sergei Rozhnov (pers. comm. 2004) informs us that undescribed Arenig asteroid material is known from the Leningrad region. NORWEGIAN JOURNAL OF GEOLOGY Starfish from the Ordovician of the Oslo Region 209
3 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2016 | 1 |
| 2005 | 1 |