Who’s useless at writing a blog: I am!

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As I’m sure some of you may have noticed, I haven’t posted any new things recently — this month in fact.  It has been quite a busy time: I’ve taken visits to both London and Dorchester, acquired an ichthyosaur that I am planning to prepare, and spent an inordinate amount of time thinking about cristi supraorbitali and other obscure but important ichthyosaur features.

I also think that I have discovered my most favourite ichthyosaur yet: Besanosaurus leptorhynchus from the Middle Triassic (Upper Anisian–Lower Ladinian) of Besano, northern Italy.  I thank Christiano Dal Sasso for kindly sending me a copy of his and Giovanni Pinna’s paper (Dal Sasso and Pinna 1996).  It features the most wonderful map of the complete specimen (below; from Dal Sasso and Pinna 1996 fig. 8).

Besanosaurus from Monte San Giorgio
Besanosaurus leptorhynchus from the Besano Formation (Grenzbitumenzone) near Besano, northern Italy. From Dal Sasso and Pinna (1996).

In London, I went to the Natural History Museum (NHM), which is a treasure trove of fossils — a palaeontologist’s paradise.  There I looked through some of the Kimmeridgian ichthyosaur material (there’s too much to do in a day!); particularly looking for bits of Nannopterygius.  Aside from the main skeleton on the wall of the Marine Reptile Gallery, there is very little material for this genus.  The isolated hindpaddle was my main concern (below; layout suggested by SV-POW), but there’s also several vertebrae.

Hind limb of Nannopterygius NHMUK 46497a
Isolated hindpaddle of Nannopterygius enthekiodon, from the Kimmeridgian, in most views as suggested on SV-POW. There has been some slight dorsoventral crushing, hence the significant difference in size of the proximal femoral processes. Abbreviations: car: carpal, dp: dorsal process, fem: femur, fib: fibula, int: intermedium, tbl tibiale, tib: tibia, vp: ventral process.
Vertebvrae of Nannopterygius
Unidentified ‘ichthyosaur’ vertebrae in the collections of the Natural History Museum, London. Still in their plaster wrapping, centra with articulated neural spines.

Whilst in the NHM, I also took a look through the drawers and found a nice set of vertebrae, which were unmarked and only partially removed from their cast, and a very crushed skull of AegirosaurusIchthyosaurus’ leptospondylus from the Solnhofen Limestone of Germany (Bardet and Fernández 2000): the same place the famous ‘missing link’ Archaeopteryx comes from.

Ichthyosaurus leptospondylus in NHMUK
Ichthyosaurus leptospondylus from the Solnhofen Limestone of southern Germany. Significantly crushed, in dorsal view.

References

BARDET, N. and FERNÁNDEZ, M. S. 2000. A new ichthyosaur from the Upper Jurassic lithographic limestones of Bavaria. Journal of Paleontology, 74, 503–511.

DAL SASSO, C. and PINNA, G. 1996. Besanosaurus leptorhynchus n. gen. n. sp., a new shastasaurid ichthyosaur from the Middle Triassic of Besano (Lombardy, N. Italy). Paleontologia Lombarda, New Series, 4, 1–22.

MCGOWAN, C. and MOTANI, R. 2003. Ichthyopterygia. In SUES, H.-D. (ed.) Handbook of Paleoherpetology. Vol. 8. Verlag Dr. Friedrich Pfeil, Munich, 175 pp.

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