2011 Finished projects of the Ulm Team on 'Orsten' fossils

Pentastomids

The first paper on this enigmatic and still controversially discussed group of parasitic arthropods was published by Müller and Dieter way back in 1994. Since then 2 more papers had appeared on more species, one from Sweden and one from Newfoundland, togetehr with John Repetski.

The investigations for our fourth paper on Cambrian pentastomids dealt with the ontogeny of fossil material of almost 70 specimens from a trip to Västergötland, Sweden, collected in 2004 by Andreas Braun, Martin Stein and Dieter Waloszek. It was not found during search in the various quarries we explorated but in a piece of rock given to us by John Ahlgren. The paper is out now, published in the monograph series Palaeontographica, and can be accessed from our references page (click on publications above).

Hopefully soon we shall add a few data from this paper here.

Crustacea

A manuscript on phosphatocopines from China prepared by Andreas Maas in collaboration with Prof. Dong from Nanjing has been finally published this year 2011.

Studies of larval sequences

Joachim Haug, who joined the Ulm team in late fall 2005, and his wife Carolin, continue to study fossil and Recent crustaceans and their ontogenies, also larvae of Rhynie Chert and Solnhofen limestones, and larval series in the Burgess-Shale material. In a wider sense Joachim aims at combining data available from 'Orsten' larvae with the ontogenies in Arthropoda in general. He also looks for heterochronic events during evolution of Crustacea and Arthropoda, apparently one of the driving forces to modify morphologies.

1. During this study he has, for example, found a possibility to discriminate the one-eyed twins Goticaris longispinosa (left) and Cambropachycope clarksoni, often known oly from isolated eyes (paper on these published in summer 2009). He also learnt to use the 3D reconstruction software BLENDER, which turned out to be an excellent tool in our studies (see here). Our comparisons also benefitted from models Joachim produced from other 'Orsten' and also from extant animals, such as of the predatory water flea Bythotrephes (e.g. longimanus) (left).

2. The second go was on Martinssonia elongata. Joachim discovered that the material was inhomogenous and part of the larvae had to be removed to another form, known from a large specimen, now named Musacaris gerdgeyeri. The paper appeared in 2010, see list of publications.

3. When studying Oelandocaris oelandica, on e of the "stem crustaceans", Joachim discovered that in Henningsmoenicaris scutula the "Proximal Endite" (PE), which in Oelandocaris was developed only on the 3rd appendage (mandible of labrophoran crustaceans), does not appear in the first instar, but much later. If this is an ontogenetic feature of Crustacea sensu lato, it may provide us with a further tool to discriminate between the different early stem taxa. It also gives a further proof that the PE is new to Crustacea and that Eucrustacea neither had such a PE, nor a coxa, which is a modification of this endite! The article also includes the description of a new form, called Sandtorpia vestrogothiensis. The paper on Henningsmoenicaris appeared in TRSE in 2010, see list of papers.