Bumastoides milleri Price: SOLD

Bumastoides cf. milleri Trilobite: length – 18.30 mm (0.72”)          Width – 12.89 mm (0.50”) Matrix: length - 30.60 mm (1.20”)       Width – 30.10 mm (1.18”) Mifflin Member, Platteville Formation Grant County, Wisconsin
There are 3 factors that qualify a particular Bumastoides trilobite to be considered an exceptional specimen. This one has it all! First, an exceptional Bumastoides needs to be inflated and this one, as visible in the side photos, illustrates its full inflation. This Bumastoides shows absolutely no compression. Second, an exceptional Bumastoides needs to have both free cheeks tightly affixed. This is important in order to fully appreciate the specimens eyes. This specimen has beautiful eyes. Finally, an exceptional Bumastoides needs to a prone specimen. Rolled trilobites are beautiful in the own right but nothing approaches the beauty of a nicely articulated prone specimen. This is it!

Bumastoides Bumastoides were first recognized by Harry Whittington while working on the Baffin Island fauna (published in 1954). The fauna included a single, partial cephalon with some exoskeleton preserved. This specimen was not sufficient to identify to the species level. Whittington, as well as earlier workers (Raymond and Toedeson), recognized that the Ordovician species currently referred to Bumastus represented a unique group. He assigned these species (bellevillensis, beckeri, billingsi, milleri, porrectus and tenurugosus) to the new subgenus Bumastoides and made B. milleri the type species. Ludvigsen and Chatterton, 1980, raised the subgenus status of the group to full generic status. The differentiation of the specific species is difficult and though complete specimens of most of the species have been collected many of the distiquishing characteristics are not observable on a complete dorsal exoskeleton. Larry DeMott, 1963 (published in 1987) compared Bumastoides milleri with Bumastoides from the Mifflin Member of the Platteville Formation in the UMV and though material was limited in the collection reviewed concluded that the Mifflin material was essentially the same as B. milleri from the Le Ray Rockland beds of Ontario. Whether the Pre-Chatfieldian Mifflin Bumastoides and the Post- Chatfieldian B. milleri will actually be the same trilobite remains a question requiring additional investigation. Whether the number of thoracic segments will remain a determining factor or whether this is found not to be a constant has not been definitely determined. Whittington, 1954, makes the statement that B. milleri exhibits 8-10 thoracic segments. Later workers (De Mott, Westrop & Ludvigsen) state that all the Canadian/New York material appears to exhibit 9 thoracic segments for B. milleri; 10 thoracic segments for B. porrectus, B. billingsi and B. beckeri. B. bellevillensis has been described as possessing 8 thoracic segments. There is also a Decorah Formation Bumastoides that we have observed in well over 20 complete specimens that consistently exhibit only 7 segments.