Samlinger Lokaliteter TidstavleFaunalister Blin


Basinotopus tricornis

 Faktiske data om fund 
Katalognummer:
750
Accessionsnummer:
DK 763
Samling:
Danekræsamlingen
Samler:
Statens Naturhistorisk Museum
Finder:
Mette Hofstedt
Bestemt af:
Barry van Bakel
Lokalitet:
Trelde Næs
Stratigrafi:
Lillebælt Ler Formationen
Periode:
Eocæn [Ypresien/Lutetien]
Type:
Konkretion
Sediment:
Mangancarbonat

Billede

Foto ©: Sten Lennart Jakobsen


 Beskrivelse:   af  Barry van Bakel 
Evaluering af DK 763 Krabbe Basinotopus tricornis i mangancarbonat konkretion

Meget velbevaret eksemplar af krabben Basinotopus tricornis fra Lillebælt Ler Formation ved Trelde Næs. Krabbefaunaen blev beskrevet af englænderen Joe Collins og undertegnede i 2003 baseret på et meget stort antal krabber (ca. 4000) fra private samlinger. Af disse er ca. 300 eksemplarer af Basinotopus tricornis overvejende isolerede skjolde. Kun i få tilfælde er undersiden bevaret, men ikke som i det foreliggende eksemplar. Som det fremgår af Barry Bakels beskrivelse, er netop disse morfologiske karakterer af stor betydning i klassifikationen.

Konklusion:
Krabben er for det første det mest velbevaret af arten og tilmed flot præpareret af finderen.

Kommentar af Barry van Bakel:
Recently you showed me images of a lower Eocene crab, Basinotopus tricornis.
The primitive crabs (Podotremata : Driomioidea) to which this species belongs, is my specialty since many years, which you can deduce from some selected publications (see below).

The new specimen shows very particular details which in this state are rarely seen: the thoracic sternum, with spermathecal apertures; the basis of the legs (coxae) with the last two legs preserved (which are reduced, important character for correct classification), the mouthparts (third maxillipeds) and the claws. The carapace is also exquisitely preserved, but the real scientific value is the ventral side.

The above characters described are not well represented in the type series of this species, and this specimen would greatly complement the type series.
Hopefully this particular specimen can be saved for science. In fact: if it would be housed in a public collection I could immediately use it for publication in a larger revision of dromioid crabs, currently in preparation.

Selected publications

Bakel, B.W.M. van, P. Artal, R.H.B. Fraaije & J.W.M. Jagt, 2009. A new Oligocene crab (Decapoda, Brachyura, Dromiacea) from Northwest Belgium, with comments on its palaeobiology. Geologica Belgica, 12: 45-57, 3 figs, 1 table.

Bakel, B.W.M. van, Artal, P., Fraaije, R.H.B. and Jagt, J.W.M. 2010. Loerenthopluma danielae, a new crab (Decapoda, Brachyura, Retroplumidae) from the lower Eocene of northwest Belgium. In: Castro, P., P.J.F. Davie, P.K.L. Ng, and B. Richer de Forges (eds.) Studies on Brachyura: a Homage to Danièle Guinot. Crustaceana Monographs. Fransen, C.H.J.M. and J.C. von Vaupel Klein (series eds.) Vol. 11. Leiden: Brill. 41–49 pp.

Van Bakel, B.W.M., Guinot, D., Artal, P., Fraaije, R.H.B. & Jagt, J.W.M., 2012. A revision of the Palaeocorystoidea and the phylogeny of raninoidian crabs (Crustacea, Decapoda, Brachyura, Podotremata). Zootaxa, 3215: 1-216.

Van Bakel, B.W.M., Guinot, D., Carmelo Corral, J. & Artal, P., 2012. Graptocarcininae n. subfam., an extinct subfamily of Dynomenidae Ortmann, 1892 (Crustacea, Brachyura, Podotremata). Zootaxa, 3534: 40–52.

Van Bakel, B.W.M. 2013. Preservation of internal pleurites in a new palaeocorystid crab (Crustacea, Brachyura, Raninoidia) from the Cenomanian (Upper Cretaceous) of Poitou-Charentes, France. Zootaxa, 3701 (3): 322–328.

Collins, J.S.H. & Jakobsen, S.L., 2003: New Crabs (Crustacea, Decapoda) from the Eocene (Ypresian/Lutetian) Lillebælt Clay Formation of Jutland, Denmark. Bulletin of the Mizunami Fossil Museum, no. 30, p63-96, 8 pls, 8 figs.

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