Claes F. Bergman

Symmetroprion spatiosus (Hinde), a jawed polychaete showing preference for reef environments in the Silurian of Gotland

Abstract Jawed polychaetes formed an important part of the fauna in the Silurian tropical shelf sea of the Gotland region (Sweden) as shown by the presence of abundant and diversified jaw elements (scolecodonts) in the strata of the island. Fluctuating sea‐levels in combination with a variety of bottom sediments produced environments suitable to the benthic annelids. Symmetroprion, a monospecific genus within the Eunicea labidognatha taxa, is recorded hitherto only from the Silurian in the Baltic region. Symmetroprion spatiosus evolved slowly from early Wenlock (Sheinwoodian) through late Ludlow (Ludfordian). It is recorded from 9 of the 13 major stratigraphical units on Gotland. However, it has been found at only about 10% of the studied localities and is not one of the more common species. It is concentrated in the vicinity of some reefs or in areas with isolated stromatoporoids and it has also been found in high abundance in marly pockets in a patch reef and tidal pools. The habitat of S. spatiosus was...

LATE ORDOVICIAN JAWED POLYCHAETE FAUNAS OF THE TYPE CINCINNATIAN REGION, U.S.A

Abstract Late Ordovician jawed polychaete (Annelida) faunas from the type Cincinnatian region in the tri-state area of Indiana, Ohio, and Kentucky, North America, are discussed on the basis of an extensive and unique collection of more than 50,000 well-preserved scolecodonts. Approximately 40 to 50 multi-element species belonging to a dozen families are identified. Scolecodonts of polychaetes with prionognath, and particularly labidognath, type of jaw apparatus markedly dominate, whereas those of placognath and ctenognath taxa are very rare. The most common and/or characteristic genera include Oenonites Hinde, 1879; Kettnerites Žebera, 1935; Atraktoprion, Kielan-Jaworowska, 1962; Ramphoprion Kielan-Jaworowska, 1962; Protarabellites Stauffer, 1933a; Kalloprion, Kielan-Jaworoska, 1962; Leptoprion, Kielan-Jaworowska, 1966; Hadoprion Eriksson and Bergman, 1998; Mochtyella Kielan-Jaworowska, 1961; and Tetraprion? Kielan-Jaworowska, 1966. Members of the family Polychaetaspidae, particularly Oenonites species, generally dominate in abundance and number of species. The second most abundant family typically is either Ramphoprionidae or Paulinitidae. Overall, the taxonomic diversity seems to increase from the deeper water, shale-dominated, Edenian Kope Formation and upward in the succession to the shallower water, limestone-dominated, Richmondian Whitewater Formation. Five more or less distinct scolecodont associations were identified that are of potential biostratigraphic utility. Most families and genera identified have intercontinental distribution and can be identified also in approximately coeval strata of the Baltic paleocontinent. However, the faunal composition differs between these regions, especially at the species level.

Revision of some Silurian paulinitid scolecodonts from western New York

WEST, R. M., M. R. DAWSON, L. J. HICKEY, AND A. D. MIALL. 1981. Upper Cretaceous and Paleogene sedimentary rocks, eastern Canadian Arctic and related North Atlantic areas, p. 279-298. In J. W. Kerr and A. J. Ferguson (eds.), Geology of the North Atlantic Borderlands. Canadian Society of Petroleum Geologists, Memoir 7. -, -, AND J. H. HUtrHISON. 1977. Fossils from the Paleogene Eureka Sound Formation, N.W.T., Canada: occurrence, climatic and paleogeographic implications, p. 77-93. In R. M. West (ed.), Paleontology and Plate Tectonics. Milwaukee Public Museum, Special Publications in Biology and Geology, 2. -, -, AND P. RAMAEKERS. 1975. Paleontologic evidence of marine sediments in the Eureka Sound Formation of Ellesmere Island Arctic Archipelago, N.W.T., Canada. Canadian Journal of Earth Science, 12:574-579. WRIGLEY, A. 1938. English Eocene and Oligocene Strombidae and Aporrhaidae. Proceedings of th Malacological Society of London, 23:61-88.

Ripple marks in the Silurian of Gotland, Sweden

Abstract Twenty-three exposures with ripple marks are listed, 14 of which are in the Slite Beds. Oscillation has formed at least some of the ripple marks. The wavelength ranges from a few centimetres to one metre. One major and two minor ripple-crest directions are observed, viz. NE-SW, E-W and N-S respectively. It is concluded that the wave marks in the Halla Beds and the Hogklint Beds on Faaro are parallel to the contemporaneous coastline.

JAWED POLYCHAETES FROM THE UPPER SYLVAN SHALE (UPPER ORDOVICIAN), OKLAHOMA, USA

Abstract A jawed polychaete fauna from the upper 30 m of the Upper Ordovician Sylvan Shale (Richmondian, Ashgill) of Oklahoma is described, based on recovered scolecodonts (polychaete jaws). The fauna includes members of six families: Paulinitidae, Ramphoprionidae, Polychaetaspidae, Atraktoprionidae, Hadoprionidae, and Kalloprionidae. Ten species are identified and one new paulinitid species, Kettnerites (Aeolus) sylvanensis, dominates. The low-abundance and relatively low-diversity Sylvan Shale fauna differs from approximately coeval ones of both Laurentia and Baltica, particularly by its high relative frequency of paulinitids. The scolecodonts are associated with chitinozoans, as well as some enigmatic organic-walled microfossils. Conodonts are extremely rare, with Plectodina tenuis, Amorphognathus sp., and Dapsilodus sp. identified.

Macrofossils of the Wenlockian Slite Siltstone of Gotland

Abstract The Slite Siltstone, the uppermost unit in the Wenlockian Slite Beds of Gotland, Sweden, is fairly unfossiliferous as a whole, but the silty beds are intercalated with a few calcareous beds which contain a diverse and abundant fauna. The brachiopods Strophochonetes cingulatus and Plagiorhyncha cordata are the characteristic fossils of the siltstone. The preferred orientation of high-spired gastropods (Holopella sp.) and orthoconic nautiloids, recorded at two localities, was probably caused by sediment-sliding. Disarticulated Cypricardinia specimens occur in convex-up position and thus indicate a turbulent environment. An assemblage of Strophochonetes cingulatus has been found in life position, which shows that a rapid burial and a less turbulent environment are probable. The oriented fossils and the faunal composition show that the siltstone was deposited in a shallow marine environment, below the normal wave-base in the central area. In the north-cast and south-west of the siltstone extension, a...

The jawed annelid Rhytiprion magnus Kielan-Jaworowska, 1966 - a muddy bottom dweller

Abstract The Ordovician jawed polychaete annelid Rhytiprion magnus has hitherto been recorded in erratic boulders of probable East Baltic provenance and in drill cores from Poland and North Estonia. In this study the stratigraphical range and geographical distribution are extended as R. magnus is recorded from the Silurian of Gotland (Sweden) and Indiana (U.S.A.). Hence, R. magnus is now known from the Middle Ordovician to the middle Silurian (lower Ludlow; Kockelella v. variabilis conodont Zone) and comprises one of the few Palaeozoic polychaete species with a documented intercontinental distribution. The species is generally very rare but is abundant at a few localities; on Gotland, in the offshore setting of the Late Wenlock (K. ortus absidata conodont Zone; Colonograptus? praedubeli graptolite Zone) Djupvik Member of the Halla Formation. The distribution pattern shows that R. magnus thrived in low energy, distal platform environments, in which marly and muddy terrigenous sediments accumulated.

Paranomenclature and the rules of zoological nomenclature; with examples from fossil polychaete jaws (scolecodonts)

Names of zoological taxa are governed by a set of laws, the International Code of Zoological Nomenclature or ICZN. In contrast to taxonomy, where decisions are based on interpretations, the laws of nomenclature are explicit and must be obeyed. One of the consequences, as discussed herein, is that paranomenclature, that reflects parataxonomic classifications based on parts of organisms independently of other parts, is not recognized under the ICZN and thus cannot be applied to formally diagnosed taxa. In the case of jawed polychaete annelids, parataxonomic treatments of the jaw elements as well as ICZN-governed naming of the reconstructed apparatus has divided their fossil record into separate but biologically overlapping groups of element-based and apparatus-based taxa. The independent treatment of groups created in this way has the potential for much confusion, if their names are used in formal systematics. Other recommendations of ICZN for effective diagnosis and illustration should also be considered in proposing names within groups such as this, where paranomenclature has been customary in the past.

Kingnites diamondi gen. et sp nov., an exceptionally large Silurian paulinitid (Annelida; Polychaeta) from shallow marine settings of Baltoscandia

The polychaete annelid Kingnites diamondi, a new paulinitid genus and species, is described from the Silurian of Baltoscandia. Its large maxillae differ morphologically from those of all other known paulinitids, particularly in being very elongate and having conspicuous myocoele openings and posterior portions of the first maxillae (MI). Albeit rare, this polychaete taxon is highly characteristic and appears to be confined to the Wenlock–Ludlow transitional interval on Gotland, Sweden, and ranges into the upper Ludlow on Saaremaa, Estonia. All samples yielding this species derive from strata formed in proximal carbonate platform environments. The temporal and geographical distribution indicates that it first appeared in Gotland and subsequently spread north-eastwards to the present-day Saaremaa. Kingnites diamondi adds to the list of known members of the Paulinitidae and reinforces the importance of this family, in terms of abundance and diversity, in Silurian polychaete faunas of Baltica. This is the biggest paulinitid recorded from the Silurian with an inferred body length of approximately half a metre and its diagnostic jaws may serve as a proxy for shallow water, backreef (marginal marine to lagoonal) environments.

Scolecodonts from the Upper Danian (Paleocene) of Skane, Sweden

Abstract Jaws of fossil marine polychaete annelids, scolecodonts, from Sweden have chiefly been reported from Silurian strata. The specimens described in this paper come from Upper Danian (Paleocene) strata of the Limhamn quarry in Skåne (Scania), the southernmost province of Sweden. The jaws are assigned to the Recent genera Glycera and Drilonereis, but their state of preservation did not allow species identification. The low diversity fauna is almost exclusively composed of Glycera sp. It differs conspicuously in taxonomical composition from Palaeozoic assemblages and exhibits close affinity to other Mesozoic and Cenozoic faunas as well as and modern ones.