Archive of Some of the Projects on 'Orsten' Fossils and Living Crustaceans of the Ulm Team, including those with, mainly,
C.O.R.E.-Group Collaborators

2011 – 1994

Pentastomida, the oldest known arthropod parasites

Project finished early 2011. In the latest paper on this animal group several different larval stages of pentastomids could be distinguished adding significantly to our understanding of the ontogeny, morphogenesis and evolution of this parasitic arthropod taxon. Indeed few parameters change during growth except size. Particularly the segment number does not increase at all, implying that already the hatchlings have the definite number of body segments. This is very unusual among arthropods and, again, besides the head composition, refutes any affinities to Crustacea of any kind. The last paper was mainly the work of Christopher Castellani.

We know that this contradicts molecular data and the sperm morphology, but also have to stress that sperm is just a weak character, and the molecular data apparently cheat the view on true relationships _Different Orsten pentastomids
because they cannot distinguish from symplesiomorphies and long-branch effects cannot be filtered
out. Relationship interpretations, according to Phylogenetic Systematics, can only based on characters, individuals in populations of species only react on mrophologies, only characters are subject to a biological interpretation of functions, ontogenetic development, and evolutionary changes. Only characters can be assembled in ground patterns of species and discussed properly, while trees derived from molecular data are just to be taken, so cannot be discussed in a scientific way.

This project included the collaboration with John Repetski (joint paper in 2006, as the third paper on a Cambrian pentastomid dealing mainly with a new Cambrian species, named Aengapentastomum andresi, from Västergötland), and nice help from Wolfgang Böckeler, pentastomid specialist, and from John Ahlgren discovering a piece of rock that contained about 70 new specimens aiding in the description of the larval cycle in 2011.

2010 – 2006

Wujicaris klausmuellerae, the oldest known eucrustacean metanauplius, and Yicaris dianensis , the first eucrustacean from the Lower Cambrian – Project in collaboration with Prof. Zhang from Kunming

The name Wujicaris has been given in June 2010 to a tiny larva from the same locality in China as Yicaris, but
from a slightly younger horizon. The species name in honor of the late Klaus J. Müller.

The larval status of Wujicaris – an early metanauplius – can be derived from its fairly immature maxillula and the initial maxilla, which is represented by only a spine. The larva is of a clearly entomostracan eucrustacean species and has a more modern-fashioned look than Yicaris. Exceptional are its posterior head shied spine and another spine extending perpendicularly from the hypostome in front of the labrum, features shared, strangely, by different eucrustacean taxa, shield spine by barnacle larvae (Cirripedia), and hypostomal spine by fish lice (Branchiura).

The descriptive paper on this new form has been published in Current Biology and even made it to the cover page of this journal – click on Publications above to get the PDF.

Yicaris dianensis is, according to our analysis, a member of the crowngroup of Crustacea, the eucrustaceans, and, even, more, fits nicely into the Entomostraca, so strengthening the monophyly of this taxon. This can be drawn from several features, which are shared only with cephalcoarids, maxillopods and branchiopods, members of this clade. See more on the page "Evolutionary implications".

Furthermore, Yicaris has two remarkable features to be added to the discussion of eucrustacean/ entomostracan features: epipodites (see also this paper on the evolution of epipodites in crustaceans) and six-segmented endopods on the trunk limbs.

Lastly, the endopods of the anterior limbs have more endites than known from any of the extant entomostracans and any of the hitherto described 'Orsten' forms representing members of this clade: Dala, Bredocaris, Skaracarida, Walossekia and Rehbachiella.

2009 – 2004

Nemathelminthes from the Cambrian: 1) Loricate larvae from the Middle Cambrian of
Australia – published 12/2009

2) New species of Markuelia from Australia – published 12/2009

The Australian material also contained two specimens of a new species of Markuelia. The description also appeared in the second volume in honour of the late Dr. John Shergold in 2009.

3) Shergoldana australiensis, a larval nemathelminth – published 2008

A single specimen of a 145 µm long cycloneuralian has been published by the Ulm team in the first AAAP volume in memoriam of the late Dr. John Shergold, formally Canberra, Australia. Actually John had guided our expedition in the outback in 1986 (Dieter Waloszek and Raimond Below). The fossil received, thus, the
name Shergoldana australiensis.

2008 – 2004

Oelandocaris oelandica Müller, 1983 – see references

Our investigations led to the discovery of various new features. One is the huge antennula comprising of three long spike-bearing extensions. Another is that there is only a single proximal endite, one of the crustacean features sensu Walossek & Müller (1990), present on the third head limb (mandibula). The proximal endite is embedded within the arthrodial membrane at the inner proximal edge of the basipod. Again, fine pores on the thoracic tergites and the large flap-shaped exopods of the serial post-„mandibular“ limbs (plesiomorphy) may have been the holes for sensilla. This supports a mainly swimming life of this form considered as a derivative of the stem lineage of the Crustacea toward the Labrophora.

With the help of two young volunteers – pupils from the Humboldt Gymnasium in Ulm –, we had buildt a plasticine model (magnification 500 times), which we used for our reconstruction of the morphology and for the improvement of our understanding of functional-morphological aspects (food intake etc.).

Subsequently Martin Stein, now in Copenhagen, Denmark, started to build models in Blender – actually he started this –, which even became animated, allowing a first glimpse onto the metachronic beating and swimming mode of such earlxy crustaceans in a surprisingly plausible way and very similar to small living crustaceans.

2008

Cambrian Series 3 lobopodian – see references

This was an investigation in co-operation with Reinhardt M. Kristensen, Copenhagen, Denmark and Georg Mayer, currently Australia: The new form is indeed the smallest, the youngest and the best preserved lobopodian ever found.

The most important aspect of the animal from the Swedish Orsten is: It has a single gonopore, see on right, just as in Recent onychophorans, below the image. This is the definite proof that arthropods, having paired gonads with gonoducts, but started out having a single gonopore and not paired ones as, e.g. in eucrustaceans (known only from living forms).

Another new aspect is its insertion of the appendages ventro-laterally at a kind of bridg, which preformed the orientation to a strict lateral one. The most likely pretty long legs were as tubular as the body and liekwise annulated.
Anteroventrally and posteroventrally they bore spine-like outgrowths of two diferent types, a multicelluar outgrowth and a telescoping spine nesting in a socket. We could identify this so well because the specimens are hollow and we could look into the leg! IMAGES SOON! These spines must have been used to anchor and push the legs so that they could operate in a crawling llike lizzards, but with more legs involved.

A longer version including also a detailed account on the cuticular features and the legs is currently under way.

2006

Short overview on the 'Orsten', taphonomic aspects and occurrences on a world-wide scale
(Maas et al. 2006)

This is our first joint venture (Maas et al. 2005, short communication presented on a conference in Nanjing, China) bringing together data from several of us about Orsten-type preservation and the current record of such preservation, including latest information on material from China. The second, larger paper has been published before Christmas 2006.

2003

Phosphatocopina (see Maas et al. 2003, also Maas & Waloszek 2005)

A big monograph published 2003 and a short version published in 2005, pdf on request. Phosphatocopina are the sister taxon of Eucrustacea sharing a large number of significant features, such as the labrum, the coxa on antenna and mandible, the sternum, the paragnath humps on the mandibular part of the sternum and fine setulae on sternum, labral flanks and setae of the limbs. These features are all missing in the stem taxa. The taxon embracing Phosphatocopina and Eucrustacea has been named LABROPHORA, formally by Siveter et al. (2003, p¡df on request).

Phosphatocopina hatch with a head larva, a plesiomorphic feature, but this larva has "already" the characteristic bivalve shield embracing the whole body (autapomorphy of this taxon). Furthermore, the phosphatocopine antennulae are tiny and the trunk region is highly reduced. Plesiomorphic are the serial arrangement of the postmandibular limbs (no limb pair specialized to maxillae), a large proximal endite on all post-mandibular limbs, and no movable endites along the basipod.

This morphology stands opposite to that of the Eucrustacea, which possess, in their ground pattern, a nauplius – a larva with all features developed in the stem species of Labrophora (labrum, coxa on antenna and mandible, sternum, paragnath humps on the mandibular part of the sternum and fine setulae on sternum, labral flanks and setae of the limbs), and a specialized fourth head limb, the so-called maxillula.

2003 – 2001

Klausmuelleria salopensis Siveter, Waloszek & Williams, 2003 (Siveter et al. 2003)

The single specimen discovered in Comley, UK, turned out to represent the hitherto oldest 3d-preserved arthropod, the oldest phosphatocopine and oldest arthropod larva. A short pre-version was published in Science by Siveter et al. (2001, pdf on request).

2002

Cambropycnogon klausmuelleri Waloszek & Dunlop, 2002 (in Waloszek & Dunlop 2002)

In this paper Jason and Dieter described in detail the hitherto only 3d chelicerate of the 'Orsten' (pdf on request), prepresenting a pycnogonid and sister taxon to all other fossil and Recent pycnogonids (Pantopoda is the crown group). Retaining a classical view, they remained interpreting the cheliphore as the second appendage and a pair of tiny outgrowths flanking the mouth as possibly the antennulae. This view could be corrected by Vilpoux & Waloszek (2003, pdf on request) on the basis of own studies of the larval development of the Recent pantopod Pycnogonum litorale (Ström, 1763) and evidence from different disciplines.