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1
Content available remote A new occurrence of sharks in the Menilite Formation (Lower Oligocene) from the Outer (Flysch) Carpathians of Poland
Bieńkowska-Wasiluk M.
Acta Geologica Polonica
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2009
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Vol. 59, no. 2
235-243
EN
Two newly recognized sections (Jamna Dolna 2 and Wola Czudecka) of the Lower Oligocene Menilite Shales (Menilite Formation) in the Polish Outer (Flysch) Carpathians have recently yielded a small shark assemblage. It comprises teeth of Heptranchias howelli (Reed, 1946), not hitherto reported from Europe, as well as the remains of other sharks (teeth of ?Mitsukurina, Alopias, gillrakers of Cetorhinus) all contributing to the fish assemblage of the Carpathian Menilite Formation, which has long been famous mostly for its teleost content. The life environment of the studied sharks and the basin bottom conditions are briefly discussed.
2
Content available remote The Late Jurassic neoselachian Macrourogaleus FOWLER, 1947 is a palaeospinacid shark (Elasmobranchii; Synechodontiformes)
Klug S.
Acta Geologica Polonica
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2008
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Vol. 58, no. 2
229-234
EN
The taxonomy of palaeospinacid sharks (Chondrichthyes, Neoselachii) is reviewed. New skeletal material from the famous Late Jurassic lithographic limestones of southern Germany (Solnhofen area and Nusplingen) enables identification of the morphological and dental differences between Synechodus and Paraorthacodus. These taxa were hitherto known mainly by isolated teeth or a few mostly fragmentary skeletal remains from the Early and Late Jurassic and Late Cretaceous. Differences not only include dental features but also the presence of a single dorsal fin in Paraorthacodus compared to two in Synechodus. Fin spines are restricted to Early Jurassic specimens. A detailed examination of the small neoselachian shark, Macrourogaleus hassei, from the lithographic limestones of the Solnhofen area revealed that this taxon displays the characteristic synechodontiform tooth root morphology (pseudopolyaulacorhize) and a single dorsal fin as seen in Paraorthacodus. Consequently, Macrourogaleus is assigned to the Palaeospinacidae. It differs from Paraorthacodus, however, in the presence of a single row of enlarged placoid scales on the caudal crest.
3
Content available remote New information on the Devonian shark Mcmurdodus, based on material from western Queensland, Australia
Burrow C., Hovestadt D., Hovestadt-Euler M., Turner S., Young G.
Acta Geologica Polonica
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2008
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Vol. 58, no. 2
155-163
EN
Histological structure of the type and newly collected teeth of the shark Mcmurdodus whitei TURNER &YOUNG, 1987, from a Devonian (?late Emsian-early Eifelian) limestone outcrop in the Cravens Peak Beds of western Queensland, was determined by immersion in anise oil, thin sectioning, and acid etching of fractured surfaces. The morphology and vascularization of the teeth are comparable to those of modern hexanchiform and echinorhinid squaliform sharks, being most similar to those of Echinorhinus. Amultilayered enameloid layer is not discernible in Mcmurdodus teeth, but a parallel-fibred layer is possibly present. Prismatic calcified cartilage, presumed to be from M. whitei, appears identical to that of all elasmobranchs. Scales and spines and distinctive ring like elements occur in the same horizon, the latter comparable with elements that encircle the lateral line in Echinorhinus, and which are found in no other Recent elasmobranchs.
4
Content available remote Interrelationships of Mesozoic hybodont sharks as indicated by dental morphology - preliminary results
Rees J.
Acta Geologica Polonica
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2008
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Vol. 58, no. 2
217-221
EN
As many hybodont sharks are known solely from their teeth, this investigation approaches the phylogeny of the group with an emphasis on tooth morphology and dentitional patterns. The preliminary results presented here suggest that at least four different lineages of hybodont sharks occurred in the Mesozoic. Dentitional characters imply a close relationship within the Lonchidiidae (Lonchidion, Vectiselachos, Parvodus, and tentatively Hylaeobatis), within the Hybodontinae (Hybodus and Egertonodus) and in another, unnamed subfamily of the Hybodontidae, including Planohybodus, Secarodus and Priohybodus. There is also weak support for a grouping of Acrodus, Asteracanthus and Palaeobates in the Acrodontinae, while Lissodus is left without family designation due to a rather unique dentition and cephalic spine morphology. "Polyacrodus" is considered a nomen dubium as there are no characters to diagnose the genus based on the type species.
5
Content available remote Ctenacanthiform Cladodont Teeth from the Lower PermianWichita Group, Texas, U.S.A.
Johnson G.
Acta Geologica Polonica
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2008
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Vol. 58, no. 2
205-209
EN
Isolated teeth of Glikmanius occidentalis occur in ten vertebrate faunas in the Waggoner Ranch Formation and in one fauna in the underlying Petrolia Formation. They range in size (anteromedial-posterolateral base length) from 1.28 mm to 10.15 mm (n = 12). In addition to the typical teeth, one with an asymmetrical base and one possible posterior tooth (both G. ?occidentalis), and a questionable symphyseal tooth (Glikmanius?), occur in the collection.
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