rew Posted May 26, 2022 Author Share Posted May 26, 2022 5 hours ago, piranha said: From this angle it looks like this one does not have a median preoccipital lobe. If that feature is absent then Kaskia sp. is a better match. Yikes.. Phillipsia, Ditomopyge, Kaskia... I sure wish you experts could get everything sorted out. 2 Link to comment Share on other sites More sharing options...
piranha Posted May 26, 2022 Share Posted May 26, 2022 18 hours ago, rew said: Yikes.. Phillipsia, Ditomopyge, Kaskia... I sure wish you experts could get everything sorted out. The commercial sellers and the dodgy info that accompanies their specimens is what needs to be sorted out. Actually, the experts have this issue very well sorted out. Ironically, on the previous trilobite you posted a few days earlier, I attached a diagram that illustrated the median preoccipital lobe, a key identifying feature on Ditomopyge. I would submit that in this instance you had the opportunity to catch this simple oversight if you had taken an extra moment to examine your specimen more carefully. 2 Link to comment Share on other sites More sharing options...
rew Posted May 28, 2022 Author Share Posted May 28, 2022 My apologies for an overly churlish remark. I was just a bit frustrated that the AMNH got this one wrong too. Anyhow, it is now relabeled "Kaskia sp." with the understanding that it's bound to change again. Link to comment Share on other sites More sharing options...
rew Posted May 28, 2022 Author Share Posted May 28, 2022 Trilobite of the week #230 is Delocare bensaidi (= Saharaops bensaidi) of Early Devonian (Emsian Stage) age and from Bou Lachrhal, Morocco. This Acastid trilobite has three rows of short vertical spines in addition to showy genal, pleural, and pygidal spines. 1 5 Link to comment Share on other sites More sharing options...
rew Posted June 5, 2022 Author Share Posted June 5, 2022 Trilobite of the week #231 is Pterocephalia norfordi, of Late Cambrian age, from the McKay Group - Elvinia Biozone, at Tanglewood Creek, north of Cranbrook, British Columbia. This is in the Pterocephaliidae, so is an eponymous bug for its family, the same family that includes Cernuolimbus. 1 3 Link to comment Share on other sites More sharing options...
rew Posted June 12, 2022 Author Share Posted June 12, 2022 (edited) Trilobite of the week #232 is Agnostotes weugi of Late Cambrian age from the McKay Group near Cranbrook, British Columbia, Canada. A shade over 8 mm long, it's typical size for an agnostid trilobite. As is often the case with trilobites in the Agnostida, I have to make my best guess when trying to make this photo be "heads up". Edited June 12, 2022 by rew 1 4 Link to comment Share on other sites More sharing options...
rew Posted June 19, 2022 Author Share Posted June 19, 2022 (edited) Trilobite of the week #233 is Cyphaspis eximia of Middle Devonian (Eifelian stage) age from the Diademaproetus couche at Ofaten, Morocco. This bug has long genal spines that extend past the pygidium and an even longer axial spine. But what defines the species are the four tiny spines arranged at the corners of a rectangle on the glabella. You may have noticed that I like Cyphaspis trilobites. Well, this is the last one in my collection. Edited June 19, 2022 by rew 1 5 Link to comment Share on other sites More sharing options...
Sjfriend Posted June 26, 2022 Share Posted June 26, 2022 That one has a cool chephalon! Link to comment Share on other sites More sharing options...
rew Posted June 27, 2022 Author Share Posted June 27, 2022 Trilobite of the week #234 is Altiocculus harrisi of Middle Cambrian age from the Wheeler Shale Formation at Millard County, Utah. This is one of the less common members of the Alokistocaridae. This bug has lots of thoracic segments ending in a tiny pygidium. There are small pustules scattered over the head and thorax. 1 5 Link to comment Share on other sites More sharing options...
rew Posted July 3, 2022 Author Share Posted July 3, 2022 Trilobite of the week #235 is Harpes hamrlaghdadensis, of Middle Devonian (Eifelian) age from Jorf Morocco. I have two specimens. A small one that is complete and undistorted although with some obvious repair cracks, and a larger one with some deformation. The larger specimen seems to have a short abdomen because the anterior segments go straight down vertically from the back of the head. Furthermore, the vertical section has a melted appearance, with no distinct segments or trilobation visible, The rock at Jorf is semi-metamorphised and some of the fossils are metamorphised along with it. The raw rock from Jorf has a somewhat glassy appearance -- we're fortunate that any trilobites have been preserved there at all. Here the first two photographs are of the small specimen and the next four are of the large specimen. 1 4 Link to comment Share on other sites More sharing options...
piranha Posted July 3, 2022 Share Posted July 3, 2022 10 minutes ago, rew said: Trilobite of the week #235 is Harpes hamrlaghdadensis, of Middle Devonian (Eifelian) age from Jorf Morocco. This one is Harpes perradiatus Richter & Richter 1943. Harpes hamarlaghdadensis Crônier et al. 2018 is differentiated by a subrectangular glabella versus the conical glabella illustrated well in your specimen. Richter, R., Richter, E. 1943 Trilobiten aus dem Devon von Marokko mit einem Anhang über Arten des Rheinlandes. [Trilobites from the Devonian of Morocco with an Appendix about the Rhineland Species.] Senckenbergiana Lethaea, 26:116-198 Crônier, C., Oudot, M., Klug, C., De Baets, K. 2018 Trilobites from the Red Fauna (Latest Emsian, Devonian) of Hamar Laghdad, Morocco and their Biodiversity. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 290(1-3):241-276 PDF LINK 3 Link to comment Share on other sites More sharing options...
rew Posted July 3, 2022 Author Share Posted July 3, 2022 So both species are found at Jorf. You learn something new every day. Link to comment Share on other sites More sharing options...
rew Posted July 11, 2022 Author Share Posted July 11, 2022 Trilobite of the week #236 is Flexicalymene senaria of Late Ordovician age from the Neuville Formation near Quebec City, Quebec. I wouldn't call this a rare trilobite but it seems less common than F. retrorsa or F. meeki. It has a modest but clear rostrum. 1 4 Link to comment Share on other sites More sharing options...
rew Posted July 17, 2022 Author Share Posted July 17, 2022 Trilobite of the week #237 is Cummingella belisama of Early Mississippian age from the Tournai Formation at Tournai, Belgium. 1 3 Link to comment Share on other sites More sharing options...
rew Posted July 25, 2022 Author Share Posted July 25, 2022 (edited) Trilobite of the week #238 is Aphelaspis westropi (= Labiostria westropi) of Late Cambrian age from the McKay Formation at Tanglefoot Creek, north of Cranbrook, British Columbia. This member of the Aphelaspididae is usually sold as Labiostria westropi but Sam Gon's site lists Labiostra as a junior synonym of Aphelaspis. Edited July 25, 2022 by rew 1 3 Link to comment Share on other sites More sharing options...
piranha Posted July 25, 2022 Share Posted July 25, 2022 30 minutes ago, rew said: Trilobite of the week #238 is Aphelaspis westropi (= Labiostria westropi) of Late Cambrian age from the McKay Formation at Tanglefoot Creek, north of Cranbrook, British Columbia. This member of the Aphelaspididae is usually sold as Labiostria westropi but Sam Gon's site lists Labiostra as a junior synonym of Aphelaspis. The synonymy of Palmer 1962 is old info and has been removed: Labiostria westropi remains the current classification. figures from: Chatterton, B.D.E., Gibb, S. 2016 Furongian (Upper Cambrian) Trilobites from the McKay Group, Bull River Valley, Southeastern British Columbia, Canada. Palaeontographica Canadiana, 35:1-275 Chatterton, B.D.E., Ludvigsen, R. 1998 Upper Steptoean (Upper Cambrian) Trilobites from the McKay Group of Southeastern British Columbia, Canada. Journal of Paleontology, 72(Memoir 49):1-43 Palmer, A.R. 1962 Glyptagnostus and Associated Trilobites in the United States. United States Geological Survey, Professional Paper, 374F:1-49 Link to comment Share on other sites More sharing options...
rew Posted July 25, 2022 Author Share Posted July 25, 2022 (edited) Rats. Even when I try to be right, I'm wrong. Edited July 25, 2022 by rew Link to comment Share on other sites More sharing options...
Mark Kmiecik Posted July 25, 2022 Share Posted July 25, 2022 14 hours ago, rew said: Rats. Even when I try to be right, I'm wrong. I know the feeling. Mark. Fossil hunting is easy -- they don't run away when you shoot at them! Link to comment Share on other sites More sharing options...
Scylla Posted July 26, 2022 Share Posted July 26, 2022 12 hours ago, Mark Kmiecik said: I know the feeling. Married too I see. Link to comment Share on other sites More sharing options...
rew Posted July 30, 2022 Author Share Posted July 30, 2022 Trilobite of the week #239 is Eremiproetus sp. of Middle Devonian age from Jorf, Morocco. This little proetid (about 1.6 cm long) is in the family Tropidocoryphidae. 1 4 Link to comment Share on other sites More sharing options...
piranha Posted July 30, 2022 Share Posted July 30, 2022 14 hours ago, rew said: Trilobite of the week #239 is Eremiproetus sp. of Middle Devonian age from Jorf, Morocco. This little proetid (about 1.6 cm long) is in the family Tropidocoryphidae. Eremiproetus is quite different with larger eyes, genal spines and a short pygidial axis. Your trilobite is an undescribed species, most similar to Gerastos with very small eyes. 4 1 Link to comment Share on other sites More sharing options...
rew Posted July 31, 2022 Author Share Posted July 31, 2022 Well, my bug certainly has no genal spines. I think I'll just have to label this one as another undescribed proetid from Jorf. Link to comment Share on other sites More sharing options...
rew Posted August 5, 2022 Author Share Posted August 5, 2022 (edited) Trilobite of the week #240 is Ananaspis guttulus of Late Silurian age from the Henryhouse Formation south of Ada, Pontotoc County, Oklahoma. This is a fairly typical looking member of the Phacopidae, but is one of only two members of that family in my collection of Silurian age, the other being Acernaspis orestes. This is an uncommon trilobite. Edited August 5, 2022 by rew 1 4 Link to comment Share on other sites More sharing options...
rew Posted August 14, 2022 Author Share Posted August 14, 2022 Trilobite of the week #241 is Paralejurus spatuliformis of Early Devonian age (Pragian Stage), from the Lhander Formation at Atchana, Morocco. This is a good example of a fairly common scutellid trilobite. Despite dimples and wrinkles in the optical surfaces, the lenses of the holochroal eyes are well preserved. 1 4 Link to comment Share on other sites More sharing options...
rew Posted August 22, 2022 Author Share Posted August 22, 2022 Trilobite of the week #242 is Wallacia sp. of Middle Silurian age from the Rytterrakker Formation at Lier, Norway. This is an uncommon Encrinurid trilobite, I'm the only one on my block with this one. 1 3 Link to comment Share on other sites More sharing options...
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