Help identify these microfossils

 by Jamie Wood, New Zealand

Editor's note: Jamie Wood and his colleagues would value any help in identifying the microfossil (object 1) and microfossil fragment (object 2) described below:

Jamie writes: I am a PhD student at Otago University, New Zealand. Part of my research involves looking at microfossils preserved in post glacial peats. Most of these are mites, beetles and seeds but I do have some strange objects I can't identify.

Object 1 (entire microfossil): It comes from a 1m thick section of mossy peat collected in Central Otago, New Zealand. The carbon-dating I have done indicated the CRA of this peat is 4000 - 10000 yrs BP. I processed the peat using the kerosene flotation method in order to concentrate the remains of beetles, mites and seeds. While picking out beetles under a microscope I noticed this strange structure. Other associated remains include beetles (mostly Hydrophilidae and Curculionidae), millipedes and millipede eggs, microlepidopteran remains, mites, seeds, moss leaves and capsules.

I have shown the object to several people. The most convincing answer I have had to date is that it is a cluster of phytoliths (NZ phytoliths are not well known). However, I then showed it to a phytolith expert who didn't think that they were phytoliths, but suggested it may be a freshwater sponge?

The entire microfossil, scale bar, top left. Click image for master.

Detail of the end of a typical spine, scale bar, top right. Click image for master.

Typical detail at base of spines. Scale bar at top, 5 µm.

Object 2 (microfossil fragment): Attached [below] are other photos of a mystery object from this same peat. Looking at some of the surface texture I think it has invertebrate origins but I can't think of what it could be. This object is quite common throughout the peat, whereas I have only found one example of the spiny object [above].

 
Typical fragment lying on support, scale bar at top, 500 µm.

Detail of membrane, scale bar at top, 100 µm.

Comments to Jamie Wood are welcomed.

Jamie Wood
Geology Dept., University of Otago, PO Box 56, Dunedin, New Zealand.

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