rew Posted August 23, 2020 Author Share Posted August 23, 2020 Trilobite of the week #138 is Sthenarocalymene celebra, a Silurian Calymenid from the Niagra Series of Kentucky. 5 Link to comment Share on other sites More sharing options...
piranha Posted August 23, 2020 Share Posted August 23, 2020 33 minutes ago, rew said: Trilobite of the week #138 is Sthenarocalymene celebra, a Silurian Calymenid from the Niagra Series of Kentucky. Pending any possible future revision ... the current name combination is: Gravicalymene celebra "This group is now recognized as the Gravicalymene celebra Association (originally published as the Sthenarocalymene celebra Association, Mikulic, 1999)... ...Many of these taxa have been revised over the past 170 years since the first specimens were reported. Interestingly, the best-known taxon, Gravicalymene celebra, has been the subject of the most name changes, including Calymene blumenbachii, Calymene niagarensis, Calymene celebra, Flexicalymene celebra, Apocalymene celebra, Sthenarocalymene celebra, and Gravicalymene celebra." Kleffner, M.A., Cramer, B.D., Brett, C.E., Mikulic, D.G., Kluessendorf, J., Johnson, T. 2012 Lower Silurian of Western Ohio – The Case of the Disappearing Dayton, and unique Midwestern co-occurrence of Pentamerid Brachiopods with the Gravicalymene celebra Trilobite Association in the Springfield Formation. Geological Society America, Field Guides, 27:1-18 5 Link to comment Share on other sites More sharing options...
rew Posted August 23, 2020 Author Share Posted August 23, 2020 The classification of Calymenid trilobites is certainly confusing. Another relabel to do. Link to comment Share on other sites More sharing options...
rew Posted August 29, 2020 Author Share Posted August 29, 2020 Like most trilobite collectors I try to get bugs with good quality shell and minimal defects. At the opposite end of that spectrum are "naked trilobites" -- internal molds of the shell with no shell present. I generally stay away from naked trilobites but this one is an exception -- it does a good job of showing what the trilobite is about, and a good specimen with shell is not likely to pop up any time soon. Trilobite of the week #139 is Tretaspis latilimbus, a Late Ordovician Trinucleid trilobite from Vastergotland, Sweden, in the same family as Onnia and Cryptolithus. The latter two genera have an occipital spine in the middle of the back of the head. This trilobite has two spines coming from the back of the head, one on each side, and lying over the genal spines. The second picture shows a close up of the "dots" along the cephalic rim. The light comes from the left. You can see that the "dots" are not pits but bumps. When the shell was present mud got pressed up into the holes in the cephalic rim, so when the shell dissolved way what was left were the bumps showing where the holes used to be. 5 1 Link to comment Share on other sites More sharing options...
rew Posted September 5, 2020 Author Share Posted September 5, 2020 Trilobite of the week #140 is Kainops raymondi, an Early Devonian member of the Phacopidae from the Haragan Formation of Clarita, Oklahoma. 3 Link to comment Share on other sites More sharing options...
rew Posted September 12, 2020 Author Share Posted September 12, 2020 Trilobite of the week #141 is a recent acquisition, a Moroccan Leonaspis species of Devonian age. I don't know the species or whether there is any formal description of it. Unlike the earlier shown Leonaspis spinacurva, there is no occipital spine. But there are longitudinal rows of prominent nodes (not quite spines) running from the back of the head to the pygidium, making this a very bumpy trilobite. 3 Link to comment Share on other sites More sharing options...
ClearLake Posted September 12, 2020 Share Posted September 12, 2020 I don’t know the species either, but that is a really neat looking trilobite! Those spines are crazy. Link to comment Share on other sites More sharing options...
rew Posted September 12, 2020 Author Share Posted September 12, 2020 The front and side. 2 Link to comment Share on other sites More sharing options...
rew Posted September 20, 2020 Author Share Posted September 20, 2020 Trilobite of the week #142 is Hamatolenus vincenti of Middle Cambrian age from the Jbel Wawrmast Formation of Tinjdad, Morocco. The long macropleural spines distinguish it from other members of the genus. 3 Link to comment Share on other sites More sharing options...
rew Posted September 28, 2020 Author Share Posted September 28, 2020 Trilobite of the week #143 is Ceraurus "webbi" of Middle Ordovician age from the Gull River Formation of the Kingston area in Ontario, Canada. The species is given in scare quotes because it comes from an unpublished paper; there is not yet a published formal description. This is a modest sized trilobite, about one inch long -- I don't know if that size is typical of the species because I haven't seen other examples of this uncommon Cheirurid. It has a very pustulose, sandpapery shell. 3 Link to comment Share on other sites More sharing options...
rew Posted October 7, 2020 Author Share Posted October 7, 2020 Well, I'm late this week. I've been kind of busy. Trilobite of the week #144 is Protolenus (Protolenus) densigranulatus. This is from the Jbel Wawrmast Formation at Tinjdad, Morocco and is of Middle Cambrian age, later than the Early Cambrian Protolenus termierelloides shown earlier. 2 Link to comment Share on other sites More sharing options...
rew Posted October 11, 2020 Author Share Posted October 11, 2020 Trilobite of the week #145 is another Moroccan scutellid, Kolihapeltis rabatensis of Middle Devonian age from Aatchana, Morocco. This bug has a long occipital spine, and both a long and a short spine over each eye. But it's weird appearance is primarily due to the segments of the left and right pleural lobes thinning out to become spines, so that the only contiguous part of the segments of the thorax is at the central lobe. There are preserved lenses in the eyes, particularly in the right eye. As is usual with holochroal eyes the lenses are too small to be seen with the naked eye. 2 Link to comment Share on other sites More sharing options...
rew Posted October 11, 2020 Author Share Posted October 11, 2020 Here's the right eye. 2 Link to comment Share on other sites More sharing options...
rew Posted October 20, 2020 Author Share Posted October 20, 2020 Trilobite of the week #147 is Lochovella deckeri of Early Devonian age from the Haragan Formation at Black Cat Mountain, Clarita, Oklahoma. This is my third member of the Phacopidae from that location. 3 Link to comment Share on other sites More sharing options...
rew Posted October 24, 2020 Author Share Posted October 24, 2020 This week's trilobite of the week, #146, is Modocia brevispina, of Middle Cambrian age and from the Upper Wheeler Formation in Millard County, Utah. I believe this is the plainest Jane bug within its genus. 3 Link to comment Share on other sites More sharing options...
rew Posted November 3, 2020 Author Share Posted November 3, 2020 Trilobite of the week #148 is Cordania falcata, an Early Devonian proetid from the Haragan Formation at Black Cat Mountain, Clarita, Oklahoma. This is the second member of the family Brachymetopidae I've posted so far, the Radnoria bretti being the first. 3 Link to comment Share on other sites More sharing options...
Top Trilo Posted November 7, 2020 Share Posted November 7, 2020 I just went through the whole thing “If fossils are not "boggling" your mind then you are simply not doing it right” -Ken (digit) "No fossil is garbage, it´s just not completely preserved” -Franz (FranzBernhard) "With hammer in hand, the open horizon of time, and dear friends by my side, what can we not accomplish together?" -Kane (Kane) "We are in a way conquering time, reuniting members of a long lost family" -Quincy (Opabinia Blues) "I loved reading the trip reports, I loved the sharing, I loved the educational aspect, I loved the humor. It felt like home. It still does" -Mike (Pagurus) “The best deal I ever got was getting accepted as a member on The Fossil Forum. Not only got an invaluable pool of knowledge, but gained a loving family as well.” -Doren (caldigger) "it really is nice, to visit the oasis that is TFF" -Tim (fossildude19) "Life's Good! -Adam (Tidgy's Dad) Link to comment Share on other sites More sharing options...
rew Posted November 8, 2020 Author Share Posted November 8, 2020 I have the magnifying macro lens on my camera now so you'll be seeing some of the smaller bugs for a while. Trilobite of the week #149 is another one of those little post-Devonian proetids -- Ditomopyge olsoni, of Pennsylvanian age, from the Staunton Formation at Coal Run, Indiana. This is not as big or as pretty as its Russian cousin, D. producta, but it is an example of what was crawling around in the ocean destined to become the Eastern USA when amphibians ruled the swamps. For the last 100 million years of trilobite existence they were all small humble proetids like this one. Trilobites were rare in the last two periods of the Paleozoic, and became rarer as time went on, with more Mississippian trilobites than Pennsylvanian trilobites, and more Pennsylvanian trilobites than Permian trilobites. In the 3rd stage of the Cambrian trilobites came in with a bang, they left at the end of the Permian with a whimper. 3 Link to comment Share on other sites More sharing options...
Ken K Posted November 13, 2020 Share Posted November 13, 2020 Just catching up here rew...terrific collection. Really enjoyed perusing your postings. Look forward to more and following closely...Ken Link to comment Share on other sites More sharing options...
rew Posted November 14, 2020 Author Share Posted November 14, 2020 On 9/24/2019 at 4:47 PM, piranha said: Ditomopyge zhirnovskiensis is not a valid name as it has not been formally published yet. It has been described in an unpublished thesis and only mentioned in a peer reviewed paper. Mychko, E.V. 2016. Trilobites of the Middle-Upper Carboniferous and Permian of Northern Eurasia. Thesis, Moscow State University, 393 pp. Mychko, E.V. & Alekseev, A.S. 2017 Locations of middle Carboniferous-Permian trilobites in Russia and neighboring countries. Byulleten' Moskovskogo Obshchestva Ispytateley Prirody, Otdel Geologicheskiy, 92(3):40-83 I note that the AMNH trilobite gallery now lists that trilobite as Ditomopyge (Ditomopyge) "zhirnovskiensis". Link to comment Share on other sites More sharing options...
piranha Posted November 14, 2020 Share Posted November 14, 2020 2 hours ago, rew said: I note that the AMNH trilobite gallery now lists that trilobite as Ditomopyge (Ditomopyge) "zhirnovskiensis". The caveat listed above still applies. The name is 'nomen nudum' until it is formally described and published. Evidently, AMNH is well aware of this stipulation by placing the specific epithet in quotation marks. Link to comment Share on other sites More sharing options...
piranha Posted November 14, 2020 Share Posted November 14, 2020 Update: This trilobite has a preliminary description in Geyer et al. 2020: Cambrosaurura robusta Cambrosaurura robusta Geyer in Cederström et al., under review from the Bréche à Micmacca Member of the Jbel Ougnate area has a thick, moderately long and obliquely rearwardly directed occipital spine, but lacks distinct spines on the thoracic axial rings. Nevertheless, the axial rings of some of the thoracic segments show bulbous protuberances resembling short spines. Geyer, G., Pais, M.C., Wotte, T. 2020. Unexpectedly curved spines in a Cambrian trilobite: considerations on the spinosity in Kingaspidoides spinirecurvatus sp. nov. from the Anti‑Atlas, Morocco, and related Cambrian ellipsocephaloids. Paläontologische Zeitschrift, 94:645-660 PDF LINK Cederström, P., Geyer, G., Ahlberg, P., Nilsson, C.A., Ahlgren, J. 2020. Ellipsocephalid trilobites from Cambrian Series 2 and Stage 4 in Scania, Sweden: taxonomy, morphological plasticity and biostratigraphic significance. Fossils & Strata (under review) 2 Link to comment Share on other sites More sharing options...
rew Posted November 14, 2020 Author Share Posted November 14, 2020 It's "under review" so I assume this is not official yet. But I'll keep in mind that I'll have to probably relabel the bug again pretty soon. Link to comment Share on other sites More sharing options...
rew Posted November 14, 2020 Author Share Posted November 14, 2020 Trilobite of the week #150 is a small proetid -- which I have labeled as Koneprusites aff. bconi. This trilobite has macropleural spines, which would be commonplace for a Redlichid but is pretty fancy for a Proetid. This bug is about 14 mm long, including the spines. This is of Middle Devonian age and comes from Jbel Issoumour, Morocco. 4 Link to comment Share on other sites More sharing options...
piranha Posted November 14, 2020 Share Posted November 14, 2020 6 hours ago, rew said: Trilobite of the week #150 is a small proetid -- which I have labeled as Koneprusites aff. bconi. This trilobite has macropleural spines, which would be commonplace for a Redlichid but is pretty fancy for a Proetid. This bug is about 14 mm long, including the spines. This is of Middle Devonian age and comes from Jbel Issoumour, Morocco. Alberti, G.K.B. 1969 Trilobiten des Jüngeren Siluriums sowie des Unter- und Mitteldevons. Part I. Mit Beiträgen zur Silur-Devon-Stratigraphie einiger Gebiete Marokkos und Oberfrankens. [Trilobites of the late Silurian, and the early and Middle Devonian. Part I. With contributions to the Silurian-Devonian stratigraphy of some areas of Morocco and upper Franconia.] Abhandlungen Senckenbergischen Naturforschenden Gesellschaft, 520:1-692 1 Link to comment Share on other sites More sharing options...
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