Kai Ingemann Schnetler
Startside Op

 

  United Kingdom Flag

The Catalogue of the gastropods from the Baunekule facies (nose-limestone) is now available

Lauridsen, B.W. & Schnetler, K.I. 2014. A catalogue of Danian gastropods from Baunekule facies. Geological Survey of Denmark and Greenland Bulletin 32, 117 pp.

Abstract

The present catalogue of 194 gastropod taxa is based on the Danian collection of gastropods from the Baunekule facies, Faxe Formation in eastern Denmark. The gastropod fauna is extremely rich and well preserved. Most of the gastropods (106 species) are referred to genus level only, 9 morphotypes to even higher taxonomical levels and 79 gastropods are referred to species level. The gastropods are classified following Bouchet & Rocroi (2005) as 4 different clades: Vetigastropoda (represented by 26 species and 10 superfamilies); Caenogastropoda (represented by 142 species and 17 superfamilies); Heterobranchia (represented by 23 species and 5 superfamilies) and Opisthobranchia (represented by 1 species and 1 superfamily). The new species Zaclys? nuetzeli n. sp. is introduced.

The Faxe Formation is recognized as a cold-water coral ecosystem with interfingering smaller bryozoan mounds. The Baunekule facies is found in the upper part of the coral mound complex of the Faxe Formation, where it forms isolated lensoidal bodies in the flanks of some of the coral mounds. It is characterized by a high diversity invertebrate fauna set in weakly consolidated coral-dominated floatstone to rudstone. The diagenesis of the Baunekule facies is of special significance because a high proportion of the originally aragonite-shelled fauna is preserved by recrystallization to calcite during early burial diagenesis. Most of the gastropods are not known from other parts of the Faxe Fm. The fauna is very important for evolutionary comparative studies of the fossil and modern gastropods on cold-water coral mounds. Many of the genera were not known from Danian strata before. No gastropod species found in the Baunekule facies are known for certain to have passed the K/Pg boundary. The fauna is comparable to gastropods found on modern cold-water coral mounds in the North Atlantic.

The gastropod fauna from Baunekule facies is characterized by a very high diversity of rather small millimeter sized gastropods having a preference for hard substrate and with more than 63.9% belonging to the browsing carnivore trophic group feeding mainly on sedentary animals. Surprisingly, the fauna contains some common occurrence of typically warm water species. The fauna consists mostly of Cenozoic genera and up to 87% of the species could be endemic to the cold-water coral ecosystem of the Faxe Fm. The diverse and rather unusual gastropod fauna from Baunekule facies is undoubtly linked to the evolution of cold-water coral ecosystems.

A full-text pdf can be downloaded from the website of GEUS on this link: http://www.geus.dk/UK/publications/geol-survey-dk-gl-bull/32/Pages/default.aspx

 

New species from the Gram Clay

The German collector and amateur palaeontologist  Andreas Grant found an unknown gastropod in the clay-pit at Gram in 2004. He sent it to me in 2014 and the gastropod was unknown for the Gram Clay and also for science. A study resulted in an assignment to the genus Pseudocochlespira Schnetler, 2001 and in a new paper the new species Pseudocochlespira gramensis Schnetler & Grant, 2014 is now established.

The genus Pseudocochlespira was established by me fpr three species from the Selandian (Paleocene) of København and the type species was Surcula (Cochlespira) boeggildi Ravn, 1939. The two other species are Pseudocochlespira koeneni (Arkhanguelsky, 1904) and Pseudocochlespira rosenkrantzi Schnetler, 2001. Schnetler & Palm (2008) recognized a representative of the genus in the late Oligocene Branden Clay and established the species Pseudocochlespira schwarzhansi Schnetler & Palm, 2008. The occurence of the genus in the late Miocene Gram Clay is surprising, as the genus until now not have been encountered in deposits from Eocene and older parts of the Oligocene and Miocene elsewhere.

Schnetler, K.I. 2001. The Selandian (Paleocene) mollusc fauna from Copenhagen: the Poul Harder 1920 Collection. Geology of Denmark Survey Bulletin 37: 85 pp.

Schnetler, K.I. 2005. The Mollusca from the stratotype of the Gram Formation (Late Miocene, Denmark). In:: Roth, F. & Hoedemakers, K. (eds) The geology and palaeontology of the Gram Formation (Late Miocene) in Denmark, 1. Palaeontos 7: 62–190.

Schnetler, K.I. & Palm, E., 2008. The molluscan fauna of the Late Oligocene Branden Clay/Denmark. Palaeontos 15: 1–92.

Schnetler, K.I. & Grant, A. 2014. A new Pseudocochlespira species (Gastropoda, Conoidea, Cochlespiridae) from the Gram Clay Formation (late Miocene, Tortonian) of Gram, Denmark. – Cainozoic Research, 14(2), 135–137.

 

New name for a wellknown gastropoid species from Faxe

Eoatlanta ravni Schnetler, 2013. Holotype, diameter 2.5 mm, height of aperture 0.9 mm.

A very common gastropod species from the 'nose-limestone' in Faxe is a little discoidal gastropod with a trumpet-like aperture. Ravn (1933) identified it with a little hesitation as Eoatlanta spiruloides Lamarck, 1804. Rosenkrantz suggested in his files of drawings that it was a new species and proposed the name Eoatlanta ravni, but he never published it.

The genus Eoatlanta was until recently interpreted as a pelagic heteropod gastropod, belonging to the family Atlantidae, but Lozouet (2012) suggested that the benthic families Capulidae or Hipponicidae were more appropiate.  A new study of the material and literature resulted in the establishment of the name Eoatlanta ravni, which Rosenkrantz never publiced.

 

Lozouet, P. 2012.: Position systématique de quelques gastéropodes de l’Eocène à dernier tour disjoint (Mollusca, Gastropoda, Caenogastropoda): Delphinula conica, Omalaxis, Eoatlanta. Cossmanniana 14: 57-66.

Ravn, J.P.J. 1933. : Études sur les pélécypodes et gastropodes du Calcaire de Faxe. Det Kongelige Danske Videnskabernes Selskabs Skrifter, naturvidenskabelig og mathematisk Afdeling, 9: 1-74.

Schnetler, K.I., 2013: Eoatlanta ravni nov. sp. (Mollusca: Gastropoda, ?Hipponicidae) from the Danian (early Paleocene) of Faxe, Denmark. Cainozoic Research 10 (1-2), 3-7.

 

A new genus and species from the Danian of Faxe

The gastropod family Porcellioidea, previously Cirroidea, is divided into two subfamilies: Porcelliinae and Agnesiinae. The representatives of the Porceliinae are planispiral and known from Trias to Late Cretaceous, while the sinistrally coiled Agnesiinae are known from Silur to late Triassic.

A unique specimen from Faxe was collected by Mrs Alice Rasmussen, and this specimen is the basis for the new genus Faxetrochus. The species name problematicus refers to the difficulties with referring the specimen to the Porcelliidae.

Schnetler, K.I.  & Lozouet, P. : A new genus and species of the Mesozoic superfamily Porcellioidea (Mollusca: Vetigastropoda) from the Danian (early Paleocene) of Faxe, Denmark. – Cainozoic Research 9 (1), 3–7. 

 

 

The molluscan fauna of the Eocene Lillebælt Clay, Denmark

For the first time the molluscan fauna of the latest Ypresian-early Lutetian Lillebælt Clay Formation of Denmark is treated monographically. The assemblage yielded 75 species. Four new species and one new subspecies are introduced, viz. Astarte filigera treldensis n. subsp., Abra madseni n. sp., Thracia barsoei n. sp., Galeodea anderseni n. sp. and Desorinassa tonneseni n. sp. The molluscan assemblage contains species known from different stratigraphic levels of the British Eocene, where the Lillebælt Clay correlates with the Bracklesham Group, based on micropalaeontological and magnetostratigraphical data. The molluscan fauna suggests water depths during deposition to have ranged from lower sublittoral to upper bathyal, probably 100-300 m.

 

Paleocene molluscs from Nuussuaq, West Greenland

In the course of 18 expeditions to West Greenland during the years 1938 - 1939 and 1946 - 1968 a large material of Paleocene molluscs was collected by the late professor Alfred Rosenkrantz and his co-workers. Rosenkrantz (1971) established a few new species. 1983 Kollmann & Peel published an inventory of the gastropod fauna, without establishing new species. Pacaud & Schnetler (1999) established three new species. Schnetler & petit (2010) published a revision of the gastropod family Cancellariidae and established one new genus and 18 new species.

Kollmann, H.A. & Peel, J.S., 1985: Paleocene gastropods from Nûgssuaq, West Greenland. – Grønlands Geologiske Undersøgelse, Bulletin No. 146. 115 pp.

Pacaud, J.- M. & Schnetler, K.I., 1999: Revision of the gastropod family Pseudolividae from the Paleocene of West Greenland and Denmark. – Bulletin of the Geological Society of Denmark, 46, 53–67, 3 figs, 4 pls.

Rosenkrantz, A., 1970: Marine Upper Cretaceous and lowermost Tertiary deposits in West Greenland. Meddelelser fra Dansk Geologisk Forening 19, 406–453.

Schnetler, K.I., & Petit, R.E., 2010: Revision of the gastropod family Cancellariidae from the Paleocene of Nuussuaq, West Greenland. Cainozoic Research 7(1-2), pp. 3–26.

 

 

New gastropods from Fakse

Previous work
Many gastropod species have been recorded from the classical locality Fakse Chalkpit. In the corallian limestone gastropods as a rule are preserved as external impressions and internal moulds. Previously especially the internal moulds were collected, while the impressions were overlooked. For a determination, however, the impressions are important, because they allow fine silicone rubber casts. 
The great Danish palaeontologist and for many years inspector of the Geological Museum of Copenhagen, Dr J.P.J. Ravn, 1902 described gastropods, bivalves and nautils from the Danish Cretaceous. Ravn considered the chalk from Fakse, as well as the Cerithium Chalk in Stevns, as Cretaceous deposits. Schilder (1928) described the Cypraeacea from Fakse.

An unconsolidated soft chalk, often informally named "nose-chalk", has been encountered several times. It contains well preserved gastropods. The original aragonite has been transformed into calcite. The amateurgeologist K. Brünnich Nielsen was the first to mention this fauna of small gastropods (1919).

Ravn (1933) revided his 1902 paper, and in his paper he treated the "nose-chalk" material, collected by K. Brünnich Nielsen and the later professor Alfred Rosenkrantz. Ravn established many new species.
Sten Lennart Jakobsen and Søren Bo Andersen collected a large material in 1972, and in the 1990es Alice Rasmussen collected much more material. German palaeontologists also studied nose-chalk material, and Alexander Nützel (1997) and Klaus Bandel (1998) established new species from Fakse.

In cooperation with the French palaeontologists Pierre Lozouet and Jean-Michel Pacaud I 2001 published a small paper, treating the family Scissurellidae in Fakse. Now five species of this rare family are known. All representatives are small (1 - 2 mm) with a selenizone. Ravn recognized only one species, and Bandel (1998) established one further species. Thus we could establish three new species.
 

Revision of the Cancellariidae
In 2006 I published a revision of the family Cancellariidae from Fakse, made in cooperation with R.E. Petit, U.S.A.
The superfamily Cancellarioidea contains c. 100 genera with more than 1800 Recent or fossil species (Petit & Harasewych, 1990). Cancellaridae have 2 - 3 folds on the columella and a sculpture of almost equal strong spiral and axial ribs, resulting in a cancellate sculpture. Ravn (1933) referred three species to this family, except for Admete ? biplicata all very rare
During the study of the Selandian (Paleocene) molluscs of Sundkrogen, Copenhagen I was contacted by Mr R.E. Petit, and soon the study of the family Cancellariidae was started. The Sundkrogen fauna contained several common representatives of the Cancellariidae. Richard E. Petit from South Carolina, U.S.A. has for more than 35 years been studying the family Cancellariidae. The revision of the Cancellariidae from Fakse confirms that representatives of this family are rare. Yet 8 species were recognized, 6 of them were undescribed.

                                               

Plesiotriton steni and Unitas aliceae. Left photo by Leif Rasmussen, Fakse. The SEM-photo to the right by Erik Thomsen, Geologisk Institut, Århus. Both specimens collected by Alice Rasmussen.

The illustrated specimens above made an establishment of the new species possible, as other adult specimens had no well preserved protoconchs. The two specimens became paratypes and in 2005 they were designated  "danekræ". A remarkable sinistral gastropod of the family Cirroidea, also collected by Alice Rasmussen, was the first Fakse gastropod among the "danekræ".
 

                

Three specimens of the new species Tatara danica. To the left the holotype, in the middle a specimen from the collection of Alice Rasmussens, Fakse and to the right a silicone rubber cast of a paratype (height 25 mm, two other specimens have a height of c. 10 mm). The holotype and the paratype were collected by Søren Bo Andersen in 1972. The genus Tatara has a very characteristic aperture with denticles on both the columella and the internal of the labrum.

The genus Tatara was until now only known from the Eocene and Miocene of New Zealand. The genus Semitriton was until now known from the Eocene of Australia and France only. These two genera have consequently their oldest representatives in the Danian of Fakse. A possible explanation of the appearence of these two genera might be a sea connection between the North Sea Basin and the Australian-New Zealandic region during the Danian time. This connection thus is considerably older than the connection between Tasmania and Crown Prince Frederik!
 

     

Semitriton biplicatus (Ravn, 1902), Admetula faksensis, Admetula rosenkrantzi, Unitas anderseni and Unitas aliceae. Heights 9.8 mm, 10.3 mm, 6.7 mm, 7.5 mm og  8.8 mm respectively.

Frequency of the 6 new species

Species

Number

Plesiotriton steni 3
Unitas anderseni 11
Unitas aliceae 5
Admetula rosenkrantzi 2
Admetula faksensis 2
Tatara danica 26

Semitriton biplicatus (Ravn, 1902) is rather common, whereas only one specimen of the last species of the 8 Cancellariidae (a Unitas) is known.


Acknowledgements
Alice Rasmussen, Fakse, Søren Bo Andersen, Århus and Sten Lennart Jakobsen, København kindly placed their collections at my disposal.
 

Litteratur

Bandel. K. 1998: 
Scissurellidae als Modell für die Variationsbreite einer natürlichen Einheit der Schlitzbandschnecken (Mollusca, Archaeogastropoda). Mitteilungen aus dem Geologisch-Paläontologischen Institut der Universität Hamburg 81, 1-120.

Nielsen, K.B. 1919: 
En Hydrocoralfauna fra Faxe. Meddelelser fra Dansk geologisk Forening 19, 5-63.

Nützel, A. 1997: 
Über die Stammgeschichte der Ptenoglossa (Gastropoda). Berliner Geowissenschaftliche Abhandlungen E 26, 229 pp., 35 plates.

Petit, R.E. & Harasewych, 1990: 
Catalogue of the Superfamily Cancellarioidea Forbes & Hanley, 1851 (Gastropoda: Prosobranchia). The Nautilus, Supplement 1 (Issued with Volume 103): 69 pp.

Ravn, J.P.J. 1902: 
Molluskerne i Danmarks Kridtaflejringer. I. Lamellibranchiater. Det Kongelige Danske Videnskabernes Selskabs Skrifter, 6. Række, naturvidenskabelig og mathematisk Afdeling XI. 4: 70 pp.

Ravn, J.P.J. 1902: 
Molluskerne i Danmarks Kridtaflejringer. II Scaphopoder, Gastropoder og Cephalopoder. Det Kongelige Danske Videnskabernes Selskabs Skrifter, 6. Række, naturvidenskabelig og mathematisk Afdeling XI 4: 5-66 pp., pls. 1-5.

Ravn, J.P.J. 1933: 
Études sur les Pélécypodes et Gastropodes du Calcaire de Faxe. Det Kongelige Danske Videnskabernes Selskabs Skrifter, naturvidenskabelig og mathematisk Afdeling, 9. Række, V 2. 1-74.
 

Schilder, F.A. 1928: 
Die Cypraeacea des Daniums von Dänemark und Schonen. Danmarks geologiske Undersøgelse IV. Række 2(3): 27 pp. 


Schnetler, K.I., Lozouet, P. & Pacaud, J.- M. 2000: 
Revision of the gastropod family Scissurellidae from the Middle Danian (Paleocene) of Denmark. Bulletin of the Geological Society of Denmark 48: 79-90. Copenhagen.

Schnetler, K.I. 2001: 
The Selandian (Paleocene) mollusc fauna from Copenhagen: the Poul Harder 1920 Collection. Geology of Denmark Survey Bulletin 37: 85 pp.

Schnetler, K.I., & Petit, R.E. 2006: Revision of the gastropod family Cancellariidae from the Danian (Early Paleocene) of Fakse, Denmark. – Cainozoic Research 4(1–2), pp.97–108.

 

A new chiton from Fakse

Sigwart, J., Andersen, S.B.,  & Schnetler, K.I. 2007: First record of a chiton from the Palaeocene of Denmark (Polyplacophora: Leptochitonidae) and its phylogenetic affinities. – Journal of Systematic Palaeontology 5 (2), 123–132.