I spent today revisiting a farm ditch I last explored back in March of this year. It was there that I found some pygidia of Odontocephalus n. sp., along with occasional pygidia of the typical pre-Hamilton Gp Devonian proetid cockroaches (Pseudodechenella sp., Crassiproetus sp.), and one "Mystrocephala" (in quotations because it was discovered that this genus name is already occupied by a butterfly or some-such). Anyhow, this material is quite miserable, ugly, and by turns barren or low sedimentation rate, coral encrusted, bituminous, cherty, chalk-cherty, mottled, occasionally diagenetically reworked, etc. Most of the fossils are silicified, which is fairly typical of many horizons in the Amherstburg, Lucas, and even Dundee Fms. Finds are uncommon in this crappy material. I should also mention that the skies opened up, so that cut my time short. Despite all this series of unfortunate incidents, I still managed to find a nice bit of trilobite treasure. I was initially wrestling in identifying this Dalmanitid, whether it was a Trypaulites. However, the images in Ludvigsen and Lespérance were not exactly satisfactory to pin down the identification. I even dug into my Hall & Clarke plates, but it wasn't a good match. The age of the material ruled out Anchiopsis, as the material is younger than Bois Blanc Fm (and, it doesn't have an occipital spine, nor even an incipient one). It obviously is not an Odontocephalus as it does not have the typical "cow-catcher." So, where does this one fit, given the rather long and exaggerated anterior process? Thankfully, a trilobite expert and friend of mine (SM) provided his opinion: Neoprobolium n. sp. Although it lacks the trident of N. tridens or that of N. nasutus, it may in fact be a match as none other seem to fit. If so, a first in Ontario of this rare Dalmanitid which is reported in New York. Between two possible new species of Odontocephalus, and an Amherstburg Fm trochurine lichid, I am adding to the list of undescribed Devonian trilobites of Ontario. If only someone was out there to write these up, as lengthy and work intensive a process as that is. UPDATE: So I went back to the same site again hoping for lightning to strike twice. It kind of did. Apart from the usual suspects (fragments of the trilobites I generally find in this material), a new species for me: This one is a large specimen, too, at about 7.5 cm (about 3 inches) wide. Note the rounded tubercles. This is an exceptionally rare dalmanitid in Ontario. It belongs to the genus of Anchiopsis and the species is tuberculatus. These are simply almost never found around here, and is shown in Hall & Clarke's plates, and described in the Jeffersonville limestone by Stumm (1954). I do have the negative, but am unsure if the eyes will be in there (hopefully).
Not much to report per se, but I have been out collecting mostly at nearby locations. September has seen a slight uptick in collecting behaviour, with nothing too new and exciting to show that I haven't shown on this blog before (all local Devonian material). But I suspect there is a trip in the near future to look forward to, and then maybe a few local digs before downing tools for the winter. I can look forward to a few more lovely pieces coming my way, including some prep stuff (my own collected material plus some from other digger folks). For now, some pictures to break up the text bloc monotony: A serendipitous arrangement, got for cheap. It is nice that the asaphids and trinucleids can play well together after having been recently split up (trinucleids had previously been included under Order Asaphida). An uncommon sight. I was out with a friend of mine prospecting a relatively local mid-Devonian site. The material at this location was very ugly and not very productive, but sometimes surprises happen. This is a complete ventral of Pseudodechenella sp. which may be ridiculously common in terms of fragments, but exceptionally scarce complete. This one weighs in at under 2,5 cm. An update on this lovely slab prepared by my field comrade MT, initial and completed state. At least 15 individuals of Rielaspsis elegantula appear on this slab I collected earlier in the year. If ever there was a worthy museum piece to show off the very best of the fickle Silurian of Ontario, here it is. This would not have been possible without the phenomenal preparation skill of MT. Truly amazing work on a very special, crowded slab of lovely encrinurids. But a few more updates to this post since last I was here. I won a benefit auction and received two free trilobites, both from China: I also managed to get a day out in the field at another Dundee Fm location with a visiting fossil friend from Georgia. Not much was found beyond the usual material, but this was an odd find: Raw image above (including a pleural segment of Coronura), and closeup with greyscale below. I suspect this is possibly a younger Coronura aspectans pygidium, as it is not quite the right match for the Odontocephalus (n. sp., by the way -- any eager trilobite workers out there want to take this on? :D). Of course, there isn't always enough diagnostic detail to be drawn on a fragment alone, but do note the continuation of the pygidium where it becomes more effaced and less incised. Sadly, the fragment terminates at the natural edge of the rock, and the negative was not collected (because, well, with exceptionally dense Devonian Ontario rock of the pre-Hamilton Gp persuasion, they explode and shatter from the need for extreme blunt force using my Devonian Destroyer -- the trusty hand sledge). So, yet another oddity in the under-explored, damnable Devonian of Ontario. ------- I will leave off here with a much larger resolution image of this fantastic plate of Rielaspsis elegantula, perhaps among the very best found in Ontario. Zoom in and enjoy the view! Hash plate (Rielaspis elgantula), Thornloe Fm. Coll. K. Faucher. Prep. M. Thornley [2021] Certainly more to come. At the very least, I expect to have some new specimens coming out of the postal formation, if not also a bit of prep work, and a possible trip.
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Kane Faucher
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February 2024
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