Dastilbe

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Dastilbe
Dastilbe crandalli

Dastilbe crandalli

Temporal occurrence
Aptium
126.3 to 112.9 million years
Locations
Systematics
Clupeocephala
Otomorpha
Ostariophysi
Sandfish (Gonorynchiformes)
Chanidae
Dastilbe
Scientific name
Dastilbe
Jordan , 1910
Art
  • Dastilbe crandalli
Largely complete, juvenile specimen

Dastilbe is an extinct genus of bony fish fromthe Chanidae family within the sandfish species . Dastilbe crandalli is the type species and at the same time the only generally recognized representative of the genus. Fossil finds come from the Lower Cretaceous ( Aptian ) of Brazil and Equatorial Guinea .

Etymology and history of research

The first description of the genus and type species was carried out in 1910 by David Starr Jordan . In his first description, Jordan gives no indication of the meaning of the generic name Dastilbe . The additional species crandalli , however, is clearly shown as an honor for Roderic Crandall .

The evidence for the first description came from a collection of fossil fish from Brazil , which had been created in 1907 by Roderic Crandall on behalf of the American geologist John Casper Branner for the Carnegie Museum in Pittsburgh . Branner himself reports that he had become aware of the fossil-rich, bituminous slate in the area around Riacho Doce as early as 1899 and commissioned his assistant Crandall to collect relevant evidence. In addition to numerous other fish fossils, the collection contained more than 53 complete and 94 fragmentary specimen copies of Dastilbe crandalli from the Muribeca formation of Riacho Doce in the Brazilian state of Alagoas .

1947, 1955 and 1972, Rubens da Silva Santos with Dastilbe elongatus , Dastilbe moraesi and Dastilbe minor three more kinds of other sites of Brazil in the genre Dastilbe . The validity of these species, however, was strongly questioned by later authors.

In 1989 the genus with Dastilbe batai was first detected outside of Brazil. In this case, too, the validity as an independent species was questioned by later authors.

features

Dastilbe was a medium-sized fish that could reach a standard length of up to 210 mm. The premaxillary , maxilla and dentals are edentulous. Of the otoliths of the organ of equilibrium , the asteriscus is always larger than the sagitta .

Specimen copies of Dastilbe show a relatively large amount of phenotypic variation even within the population of a single site. Classic meristic (“countable”) features such as the number of fin rays are therefore not suitable for differentiating between individual species within the genus Dastilbe .

Characteristics typical of the species are the large, egg-shaped and smooth gill cover , the position of the anal fin closer to the caudal fin than to the pelvic fins and the deeply forked caudal fin itself.

Systematics

 Gonorynchiformes  
 Gonorynchidae  

 Notogoneus †


   


 Gonorynchus abbreviatus


   

 Gonorynchus greyi



   


 Charitosomus †


   

 Charitopsis †



   

 Hakeliosomus †


   

 Judeichthys †


   

 Ramallichthys †







 Chanoidei  
 Kneriidae  

 Phractolaemus ansorgii


 Kneriinae  

 Mahengichthys †


   

 Kneria paucisquamata


   

 Parakneria spekii


 Cromeriini  

 Grasseichthys gabonensis


   

 Cromeria nilotica







 Chanidae  


 Rubiesichthys †


   

 Gordichthys †



   

 Aethalionopsis †


   


 Chanos chanos


   

 Tharrhias †



   

 Dastilbe †


   

 Parachanos †








Template: Klade / Maintenance / Style
Systematic position of dastilbe within the sandfish-like (Gonorynchiformes) according to Near et al., 2014.

species

In addition to the type species Dastilbe crandalli , several other species of the genus Dastilbe were described between 1947 and 1989 , but their validity is not recognized equally by all authors.

  • Dastilbe batai Gayet , 1989: only evidence of the genus from Africa; is considered a junior synonym of Dastilbe crandalli .
  • Dastilbe crandalli Jordan , 1910: type species and only generally recognized species of the genus.
  • Dastilbe elongatus Santos , 1947: Crato formation ; is considered a junior synonym of Dastilbe crandalli .
  • Dastilbe minor Santos , 1972: 2008 counted as noun nudum ; was placed in its own genus ( Nanaichthys ) in 2012 as Nanaichthys longipinnus .
  • Dastilbe moraesi Santos , 1955: Areado formation ; 2008 rated as junior synonym of Dastilbe crandalli . However, some authors still regard the taxon as a valid, independent species.

External system

Jordan interpreted the genus Dastilbe in its first description as a representative of the herring family (Clupeidae) and assumed a close relationship with the genus Halecopsis from Eocene Europe. The French vertebrate palaeontologist Camille Arambourg contradicted this interpretation in 1935 and placed Dastilbe in the milkfish family ( Chanidae ). This assignment was confirmed by later editors.

The milk fish are, next to the sand fish (Gonorynchidae) and the slender fish (Kneriidae), a family within the order of the sand fish- like (Gonorynchiformes). The milk fish family is recently represented by only one genus ( Chanos ) with a single species, the milk fish ( Chanos chanos ). In addition to Dastilbe , however , several fossil genera of the family are known with Parachanos , Tharrhias , Aethalionopsis , Gordichthys and Rubiesichthys . The cladogram on the right shows the systematic position of Dastilbe within the sandfish species based on a phylogenetic analysis of a combination of molecular genetic and morphological features.

Paleecology

Paleogeographical distribution

Fossil records of Dastilbe are available from the aptium of the following sedimentary basins :

These sedimentary basins are part of the initial rift system that later led to the breaking up of West Gondwana and the opening of the South Atlantic .

Habitat

Dastilbe is by far the most common macrofossil of the Nova Olinda member within the Crato formation. The rocks of this preserve deposit were deposited in an extensive lake or lagoon in the northeast area of ​​the Araripe Basin. The current distribution of the finely laminated, microcritical plate limestone of the Nova Olinda member shows that the water body is at least 75 × 50 km in size. The lithology and geochemistry of the plate limestone suggest a stably stratified body of water with a well-aerated, near-surface freshwater layer and stagnant, anoxic and / or hypersalinous deep waters. The British paleontologist David Martill estimated in 2011 that in the plate limestone of the Nova Olinda member, on average, one individual of Dastilbe per square meter of bed surface is preserved and puts the total number of specimens in the outcrops of the fossil deposit at around 136 million individuals.

Way of life

Example in typical preservation with the ventral part of the skull already detached from the trunk

For Dastilbe one is anadromous or catadromous lifestyle suspected. Hundreds, if not thousands, of specimens of approximately the same size are often found on individual strata of the Nova Olinda member, which speaks not only for a mass occurrence in this deposit area, but also for occasional mass deaths . However, densely packed masses of Dastilbe do not appear to occur in the Nova Olinda member. In many specimens, the skull is already partially detached from the trunk. This suggests that the dead fish drifted in the water for a long time before they sank to the bottom and were embedded in the sediment.

The vast majority of specimens from the Nova Olinda member have a standard length of less than 65 mm. Most of these are young fish. In contrast, large specimens with a standard length of over 150 mm, which are interpreted as sexually mature adults , appear only sporadically and medium-sized specimens with a standard length between 65 and 150 mm seem to be largely absent. The overall findings from the Nova Olinda member are interpreted to the effect that sexually mature specimens of Dastilbe visited the lake or the lagoon to spawn here . The juvenile fish stayed in the relatively protected habitat until they reached a certain size and were able to migrate to their actual habitat. Mass deaths, which may have been triggered by storm events and the resulting collapse of the stable water stratification (fresh water over anoxic and / or hypersaline deep water), accordingly mainly affected young fish and occasionally scattered adult animals that had failed to leave the spawning grounds in time.

Fossil evidence shows that adult specimens with a standard length of more than 150 mm ate piscivor and preyed on smaller fish, whereby juvenile fish of their own species were not spurned. The finding is remarkable because even adult specimens of Dastilbe did not have any teeth on the jaw margins that would have made it easier to grasp and fixate the prey. There is no fossil evidence of a predatory way of life for juvenile specimens. They presumably fed on microorganisms.

Illegal fossil trade

In Brazil, searching for fossils without permission from the National Department of Mineral Production (DNPM) is prohibited by law. The Brazilian constitution also stipulates that all fossils found on Brazilian territory are automatically state property. Trading in and exporting fossils is therefore illegal under Brazilian law and can be punished with imprisonment of up to 20 years. Regardless of this, the black market is flourishing . In particular, the numerous fossil specimens from Dastilbe are offered for sale worldwide and are part of heated technical debates about the meaningfulness of such regulations.

Individual evidence

  1. ↑ a b c d D. S. Jordan: Description of a Collection of Fossil Fishes from the Bituminous Shales at Riacho Doce, State of Alagôas, Brazil. In: Annals of the Carnegie Museum , Volume 7, Number 1, 1910, pp. 23-34 ( digitized ).
  2. ^ JC Branner: The Geology of the Coast of the State of Alagôas, Brazil - Part I. In: Annals of the Carnegie Museum , Volume 7, Number 1, 1910, pp. 5–22 ( digitized version ).
  3. ↑ a b c d e f g h i j k l S. P. Davis & DM Martill: The Gonorynchiform fish Dastilbe from the Lower Cretaceous of Brazil. In: Palaeontology , Volume 42, Number 4, 1999, pp. 715-740 ( digitized version ).
  4. ↑ R. da Silva Santos: Uma redescricão de Dastilbe elongatus, con algumas consideracoes sobre o genero Dastilbe. In: Notas Preliminares e estudos, Ministerio da Agricultura, Divisao de Geologia e Mineralogia , Volume 42, 1947, pp. 1-7.
  5. ^ R. da Silva Santos: Descrição dos peixes fósseis. In: EP Scorza & R. da Silva Santos (eds.): Ocorrência de folhelho fossilífero cretácico no Município de Presidente Olegário, Minas Gerais. Boletin do Ministerio de Agrirultura, Divisâo de Geologia e Mineralogia, Volume 155, 1955, pp. 17-27.
  6. ^ R. da Silva Santos: Peixes da Formação Marizal, Estado da Bahia. unpublished dissertation, Instituto de Geosciências da Universidade de São Paulo, 1972, 76 pp.
  7. ↑ M. Gayet: Note préliminaire sur le matériel paléoichthyologique éocrétacique du Rio Benito (sud de Bata, Guinée Equatoriale). In: Bulletin du Muséum National d'histoire Naturelle. Section C, Sciences de la terre, paleontologie, géologie, minéralogie , Volume 11, 1989, pp. 21-31.
  8. ↑ a b P. M. Brito & Y. Yabumoto: An updated review of the fish faunas from the Crato and Santana formations in Brazil, a close relationship to the Tethys fauna. In: Bulletin of the Kitakyushu Museum of Natural History and Human History Series A , Volume 9, 2011, pp. 107-136 ( digitized version ).
  9. ↑ FJ Poyato-Ariza, T. & R. Grande Diogo: Gonorynchiform Inter Relationships: Historic Overview, Analysis, and Revised Systematics of the Group. In: T. Grande, FJ Poyato-Ariza & R. Diogo (Eds.): Gonorynchiformes and Ostariophysan Relationships: A Comprehensive Review , Taylor & Francis, 2010, ISBN 978-1-4398-4268-3 , pp. 227-337 . ( Digitized version ).
  10. ↑ a b Th. J. Near, A. Dornburg & M. Friedman: Phylogenetic relationships and timing of diversification in gonorynchiform fishes inferred using nuclear gene DNA sequences (Teleostei: Ostariophysi). In: Molecular Phylogenetics and Evolution , Volume 80, 2014, pp. 297-307 ( digitized version ).
  11. ^ A b E. Fara, M. Gayet & L. Taverne: The Fossil Record of Gonorynchiformes. In: T. Grande, FJ Poyato-Ariza & R. Diogo (Eds.): Gonorynchiformes and Ostariophysan Relationships: A Comprehensive Review , Taylor & Francis, 2010, ISBN 978-1-4398-4268-3 , pp. 173-226 . ( Digitized version ).
  12. ^ A b P. M. Brito & CRL Amaral: An overview of the specific problems of Dastilbe JORDAN, 1910 (Gonorynchiformes: Chanidae) from the Lower Cretaceous of western Gondwana. In: G. Arratia, H.-P. Schultze & MVH Wilson (Eds.): Mesozoic Fishes 4 - Homology and Phylogeny , Verlag Dr. Friedrich Pfeil, 2008, ISBN 978-3-89937-080-5 , pp. 279-294.
  13. ↑ CRL Amaral & PM Brito: A New Chanidae (Ostariophysii: Gonorynchiformes) from the Cretaceous of Brazil with Affinities to Laurasian Gonorynchiforms from Spain. In: PLoS One , Volume 7, Number 5, 2012, e37247, doi: 10.1371 / journal.pone.0037247 .
  14. ↑ AC Ribeiro, FJ Poyato-Ariza, FA Bockmann & MR de Carvalho: Phylogenetic relationships of Chanidae (Teleostei: Gonorynchiformes) as impacted by Dastilbe moraesi, from the Sanfranciscana basin, Early Cretaceous of Brazil. In: Neotropical Ichthyology , Volume 16, Number 3, 2018, e180059, doi: 10.1590 / 1982-0224-20180059 .
  15. ↑ C. Arambourg: Observations sur quelques poissons fossiles de l'ordre des halécostomes et sur l'origine des clupéidés. In: Comptes rendus hebdomadaires des séances de l'Académie des sciences , Volume 200, Number 25, 1935, pp. 2110-2112.
  16. ↑ . Th CC Parméra, V. Gallo, HMA da Silva & FJ de Figueiredo: Distributional patterns of Aptian-Albian paleoichthyofauna of Brazil and Africa based on Track Analysis. In: Anais da Academia Brasileira de Ciências , 2017, 13 pp. Doi: 10.1590 / 0001-3765201720160456 .
  17. ↑ RM Lindoso, JG Maisey & I. de Souza Carvalho: Ichthyofauna from the Codó Formation, Lower Cretaceous (Aptian, Parnaíba Basin), Northeastern Brazil and their paleobiogeographical and paleoecological significance. In: Palaeogeography, Palaeoclimatology, Palaeoecology , Volume 447, 2016, pp. 53-64 ( digitized version ).
  18. ↑ DM Martill, RF Loveridge, JA Ferreira Gomes de Andrade, AH Cardoso: An unusual occurrence of amber in laminated limestones: The Crato Formation Lagerstätte (Early Cretaceous) of Brazil. In: Palaeontology , Volume 48, Number 6, 2005, pp. 1399-1408 ( digitized version ).
  19. ↑ U. Heimhofer, D. Ariztegui, M. Lenniger, St. P. Hesselbo, DM Martill, AM Rios-Netto: Deciphering the depositional environment of the laminated Crato fossil beds (Early Cretaceous, Araripe Basin, North ‐ eastern Brazil). In: Sedimentology , Volume 57, Number 2, 2010, pp. 677-694, doi: 10.1111 / j.1365-3091.2009.01114.x .
  20. ^ A b D. M. Martill: Protect - and die. In: Geoscientist Online , The Geological Society of London, November 10, 2011, accessed February 7, 2019.
  21. ↑ E. Gibney: Brazil clamps down on illegal trade fossil. In: nature , volume 507, number 20, 2014, doi: 10.1038 / 507020a
  22. ↑ MC Langer, R. Iannuzzi, AAS da Rosa, RP Ghilardi, CS Scherer, VG Pitana & TL Dutra: A reply to Martill - The Bearable Heaviness of Liability. In: Geoscientist Online , The Geological Society of London, March 12, 2012, accessed February 7, 2019.

Remarks

  1. ↑ The village is located on the Brazilian Atlantic coast, a few kilometers northeast of Maceió , the capital of the state of Alagoas.

Web links

Commons : Dastilbe  - collection of images, videos and audio files