| 1. |
- Alvarez, Maria Eugenia Dies, et al.
(författare)
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Bradoriid arthropods from the lower-middle Cambrian of Scania, Sweden
- 2008
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Ingår i: Acta Palaeontologica Polonica. - 0567-7920. ; 53:4, s. 647-656
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Tidskriftsartikel (refereegranskat)abstract
- Three species of bradoriid arthropods from the lower to middle Cambrian transitional interval of Scania, southern Sweden, are described and illustrated: Beyrichona tines from the top of the traditional lower Cambrian (Gislov Formation: Ornamentaspis? linnarssoni Zone), and Hipponicharion eos and Alutella sp. from the basal portion of the traditional middle Cambrian (lowermost part of the Alum Shale Formation). The bradoriid fauna compares most closely with others previously described from western and eastern Avalonia (New Brunswick and England). The record of B. tinea suggests a correlation between the "Protolenus Zone" (Hupeolenus Zone) of western Avalonia and the O.? linnarssoni Zone of Scandinavia. Hipponicharion eos appears to be a fairly long-ranging species as it has previously been recorded from upper lower Cambrian or lower middle Cambrian strata in New Brunswick, Poland, and probably Sardinia. The record of H. eos from the lowermost part of the Alum Shale Formation suggests that this largely unfossiliferous interval in the Scanian succession is not younger than the Acadoparadoxides oelandicus Superzone. The genus Alutella has not previously been recorded from the Acado-Baltic Province.
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| 2. |
- Cederstrom, Peter, et al.
(författare)
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Morphology, ontogeny and distribution of the Cambrian Series 2 ellipsocephalid trilobite Strenuaeva spinosa from Scandinavia
- 2012
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Ingår i: GFF. - : Informa UK Limited. - 2000-0863 .- 1103-5897. ; 134:3, s. 157-171
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Tidskriftsartikel (refereegranskat)abstract
- The ellipsocephalid trilobite Strenuaeva spinosa occurs widely in Scandinavia in the lower part of the Ornamentaspis? linnarssoni Zone (Cambrian Series 2). Its first appearance is a readily recognisable, widespread biohorizon in Scandinavia. During ontogeny, intergenal spines are lost and the librigenae develop from a generative zone in the genal region. The palpebro-ocular ridges are distinct and connected to the posterior part of the frontal glabellar lobe in the early meraspid period, but eye ridges become separate from the palpebral lobes and the glabella in the late meraspid period. S. spinosa is characterised by large genal spines, distinct axial spines and falcate pleural tips. The spines may have functioned in predation resistance. S. spinosa also has a small pointed projection at the anterolateral corners of some thoracic pleurae, the function of which is unknown. The presence of five furrows in the cephalic axial lobe of S. spinosa, best expressed in meraspides, suggests that the head of this ellipsocephalid trilobite was composed of six fused primary segments.
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| 3. |
- Cederstrom, Peter, et al.
(författare)
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Moulting, ontogeny and sexual dimorphism in the Cambrian ptychopariid trilobite Strenuaeva inflata from the northern Swedish Caledonides
- 2011
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Ingår i: Palaeontology. - : Wiley. - 1475-4983 .- 0031-0239. ; 54, s. 685-703
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Tidskriftsartikel (refereegranskat)abstract
- Three thousand seven hundred disarticulated remains together with several articulated specimens of the Cambrian Series 2 ptychopariid trilobite Strenuaeva inflata Ahlberg and Bergstrom, 1978 have been collected from the Tornetrask area, northern Sweden. The material provides significant new data on the morphology, ontogeny, moulting and enrolment of the species. Two distinct morphotypes, possibly an expression of sexual dimorphism, are recognized. The morph with a pair of bulbs in the frontal area, interpreted as brood pouches, is considered to represent females. Statistical treatment of the length/width ratio in cranidia reveals isometric growth during ontogeny for both morphotypes. The transition from the meraspid to holaspid ontogenetic period has been established through recognition of the successive development of the number of thoracic segments in articulated late meraspides. Throughout its life cycle, S. inflata went through 11 meraspid degrees and at least 17 holaspid growth stages. Inferred moult ensembles and exuviae reveal the successive opening of cephalic sutures and the function of the rostral plate during exuviation. As in other ellipsocephalid trilobites in which enrolment is known, the pygidium and two or three thoracic segments of S. inflata are concealed beneath the cephalon (spiral enrolment) during complete enrolment.
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| 4. |
- Ebbestad, Jan Ove R., 1967-, et al.
(författare)
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Shell injuries, repair and malformation in the early Cambrian mollusc Helcionella antiqua from Scania, Sweden
- 2022
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Ingår i: GFF. - : Taylor & Francis. - 1103-5897 .- 2000-0863. ; 144:3-4, s. 203-209
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Tidskriftsartikel (refereegranskat)abstract
- Three cases of repaired injuries and malformation in specimens of the helcionelloid mollusc Helcionella antiqua (Ki & UAELIG;r, 1917) from the lower Cambrian (Cambrian Series 2, Stage 4) Gislov Formation of southern Sweden document some of the oldest known durophagous attacks on Palaeozoic molluscs. Two of the injuries are developed as clefts, of which one had a severe effect on the continued growth of the shell. The third example is a large embayment removing large portions of the supra-apical part of the shell. A similar repaired injury is known in the slightly older mollusc Marocella mira Geyer, 1986. from Antarctica and Australia. The morphology of the injuries and the hydrodynamically quiet depositional setting suggests that the shell damage was caused by failed predatory attacks. The location of the repaired injuries suggests that the attacks may have targeted the head region of the molluscs, thus supporting an endogastrically coiled orientation of the shell in Helcionella. Only three repaired injuries in 252 Helcionella specimens were found, giving a shell repair frequency of 1.2%. All three examples occur in the larger size classes. The size-frequency distribution (N = 182) is strongly right skewed, which could suggest high input of juvenile specimens into the assemblage. The assemblage is interpreted as a time averaged and mixed death assemblage, albeit with good correspondence with the living shelly assemblage, due to a relatively thin, homogenous unit that may suggest within-habitat time averaging.
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| 5. |
- Lindgren, Johan, et al.
(författare)
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The first neoceratopsian dinosaur remains from Europe
- 2007
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Ingår i: Palaeontology. - : Wiley. - 1475-4983 .- 0031-0239. ; 50:4, s. 929-937
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Tidskriftsartikel (refereegranskat)abstract
- Shallow marine, nearshore strata of earliest Campanian (Gonioteuthis granulataquadrata belemnite Zone) and latest Early Campanian (informal Belemnellocamax mammillatus belemnite zone) age in the Kristianstad Basin, southern Sweden, have yielded isolated leptoceratopsid teeth and vertebrae, representing the first record of horned dinosaurs from Europe. The new leptoceratopsid occurrence may support a European dispersal route for the Leptoceratopsidae, or may represent an entirely endemic population. The presence of leptoceratopsid teeth in shallow marine deposits contradicts previous hypotheses suggesting that basal neoceratopsians mainly preferred and and/or semi-arid habitats far from coastal areas.
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| 6. |
- Siversson, Mikael, et al.
(författare)
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Cenomanian-Campanian (Late Cretaceous) mid-palaeolatitude sharks of Cretalamna appendiculata type
- 2015
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Ingår i: Acta Palaeontologica Polonica. - : Polska Akademia Nauk Instytut Paleobiologii (Institute of Paleobiology, Polish Academy of Sciences). - 0567-7920. ; 60:2, s. 339-384
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Tidskriftsartikel (refereegranskat)abstract
- The type species of the extinct lamniform genus Cretalamna, C. appendiculata, has been assigned a 50 Ma range (Albian-Ypresian) by a majority of previous authors. Analysis of a partly articulated dentition of a Cretalamna from the Smoky Hill Chalk, Kansas, USA (LACM 128126) and isolated teeth of the genus from Cenomanian to Campanian strata of Western Australia, France, Sweden, and the Western Interior of North America, indicates that the name of the type species, as applied to fossil material over the last 50 years, represents a large species complex. The middle Cenomanian part of the Gearle Siltstone, Western Australia, yielded C. catoxodon sp. nov. and "Cretalamna" gunsoni. The latter, reassigned to the new genus Kenolamna, shares several dental features with the Paleocene Palaeocarcharodon. Early Turonian strata in France produced the type species C. appendiculata, C. deschutteri sp. nov., and C. gertericorum sp. nov. Cretalamna teeth from the late Coniacian part of the Smoky Hill Chalk in Kansas are assigned to C. ewelli sp. nov., whereas LACM 128126, of latest Santonian or earliest Campanian age, is designated as holotype of C. hattini sp. nov. Early Campanian deposits in Sweden yielded C. borealis and C. sarcoportheta sp. nov. A previous reconstruction of the dentition of LACM 128126 includes a posteriorly situated upper lateroposterior tooth, with a distally curved cusp, demonstrably misplaced as a reduced upper "intermediate" tooth. As originally reconstructed, the dentition resembled that of cretoxyrhinids (sensu stricto) and lamnids. Tooth morphology, however, indicates an otodontid affinity for Cretalamna. The root is typically the most diagnostic feature on an isolated Cretalamna tooth. This porous structure is commonly abraded and/or corroded and, consequently, many collected Cretalamna teeth are indeterminable at species level.
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