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Just today I was reminded of an idea by a friend about trying to do an SVP meeting for Amateur Palaeontologist. Amateur Palaeontologist could join and share their research while getting suggestions by others as well as getting to know other people in the Paleo community. I’m wondering what everyone would think of something like this and if they would join if it is to happen.

Hi All, I spent some time this afternoon to do some research on the brachiopod Mucrospirifer mucronatus as I was writing a blog post. I'd heard from friends a while back that someone was combining a number of species of Mucrospirifer into M. mucronatus due to similarities. I decided to see if I could find anything to verify this and would up locating a paper from 1964 where John Tillman did just that. ("Variation in Species of Mucrospirifer from Middle Devonian Rocks of Michigan, Ontario, and Ohio", John R. Tillman, Journal of Paleontology, Vol. 38, No. 5 (Sep., 1964), pp. 952-964) The TLDR of the paper is that, M. arkonensis, M. alpenensis, M. attenuatus, M. multiplicatus, and M. prolificus are combined into M. mucronatus. As well as M. profundus, M. grabaui, M. intermedia, M. latus are combined into M. thedfordensis. Furthermore I found a doctoral thesis by Delpfine Ellen Welsh from Virginia Tech that further summarized these changes as part of her study of the evolution of Mucrospirifer across West Virginia, Maryland, Pennsylvania, New York, Michigan, and Ontario. Welch, Delpfine Ellen. Geographical variation and evolution in the middle Devonian brachiopod, MUCROSPIRIFER. Diss. Virginia Tech, 1991 "The most recent systematic work is that of Tillman (1964) who studied the variation of Mucrospirifer from the Middle Devonian rocks of Michigan. Ontario. and Ohio by measuring previously described species and constructing histograms for each set of measurements. Tillman studied characters emphasized in previous descriptions: number of costae, width of costae, length of interarea, presence or absence of medial ridge in the sulcus and medial groove on the fold, presence or absence of mucronate points at the cardinal extremities, size of shell, width/length ratios, and the shape of the fold and sulcus. Tillman (1964) concluded that number of costae depends on the age and/or size of the individual, as does length of interarea. Width of costae was not constant even within a given population. Development of the medial ridge and groove in the sulcus and fold, respectively, was quite variable except in specimens from the Arkona Shale and Genshaw Formation where they are usually well formed. In observing growth lines on individual specimens. Tillman found that all previously described specimens of Mucrospirifer are mucronate at some stage in their development. This includes specimens from the Arkona Shale which as adults do not appear mucronate because of the addition of lamellae that decrease the degree of deflection at the anterior border at the cardinal extremities and increase the shell thickness wi'thout significantly changing the length or width of the specimen. Because the cardinal extremities are rarely preserved and the growth lines are very difficult to trace, Tillman determined width/length ratios to be of doubtful value. He found that as the angle made by the plane of commissure at the fold increases, the height of the fold decreases, and he also found that angle to be highly variable in all populations. The shape of the fold and sulcus and the shape and general proportions of the shell were the characters determined by Tillman (1964) to be most useful in distinguishing species. Because he observed such an overlap among the species in the range of variation for the characters studied, Tillman felt that no more than two species could be identified. Tillman retained the species M. mucronatus and M. thedfordensis and considered all the rest to be variations of these two. He placed arkonensis, attenuatus, multiplicatus, alpenensis, and prolificus into synonymy with M. mucronatus; and thedfordensis, profundus, intermedia, latus, and grabaui into synonymy with M. thedfordensis. Tillman (1964) states that "M. mucronatus (Conrad) differs from M. thedfordensis (Shimer and Grabau) in having a broadly U-shaped sulcus with flattened floor and subangular edges and a gently convex to flattened fold"; "M. thedfordensis (Shimer and Grabau) differs from M. mucronatus (Conrad) in having a U-shaped to V-shaped sulcus, never with a flattened floor; a low moderately convex fold, never with a flattened surface." This was all news to me but is helpful when identifying what I have found. This is very much a "lumper" situation where Tillman found that the variation used by others to differentiate species was not valid as it all represented different growth stages or were influenced by local environments. I don't like having to change labels every time a species or genus gets it's name changes (I'm talking about you Eldredgeops and Vinlandostrophia!) but this makes sense to me due to the similarities visually of specimens from distant locations. Besides, at least we get to keep the Mucrospirifer genus name. Thus this specimen from the Mahantango of Mucrospirifer mucronatus from the Mahantango formation in Pennsylvania is now the same species .... As this this formerly Mucrospirifer arkonensis example from the Arkona formation of Ontario is.