rew Posted January 23, 2021 Author Share Posted January 23, 2021 3 hours ago, Kane said: Very refreshing to see this example as opposed to the usual C. gibbus. This is the last of my Moroccan Devonian Cheirurids. I've shown Crotalocephalina gibbus, Crotalocephalus africanus, and Crotalocephalus maurus. They're all of very similar design. Of course the heyday of the Cheiruridae was during the Ordovician. The Devonian has the tail end of that family, and so many other trilobite families. 1 Link to comment Share on other sites More sharing options...
piranha Posted January 23, 2021 Share Posted January 23, 2021 On 1/22/2021 at 5:41 PM, rew said: Trilobite #160 is Crotalocephalus maurus of Middle Devonian age from Hamar Laghdad, Jbel Issoumour, Alnif, Morocco. It similar to the previously shown Crotalocephaus africanus but has two stubby spines projecting from the lower front part of the head, giving it something of the appearance of having a mustache. This is Crotalocephalus sp. It has not been been formally described. Crotalocephalus maurus Alberti 1966, does not have anterior cephalic spines. text and figures from: 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, as well as the Early and Middle Devonian. Part I. Including Silurian-Devonian Stratigraphy of Regions in Morocco and Upper Franconia.] Abhandlungen der Senckenbergischen Naturforschenden Gesellschaft, 520:1-692 Alberti, G.K.B. 1966 Über einige Neue Trilobiten aus dem Silurium und Devon, besonders von Marokko. [About some New Trilobites from the Silurian and Devonian, especially from Morocco.] Senckenbergiana Lethaea, 47:111-121 4 Link to comment Share on other sites More sharing options...
rew Posted January 23, 2021 Author Share Posted January 23, 2021 Dang. Another frequently misidentified trilobite. You must have stock in a printer label company. Link to comment Share on other sites More sharing options...
Sjfriend Posted January 23, 2021 Share Posted January 23, 2021 2 hours ago, rew said: You must have stock in a printer label company. I've wondered that my self Asked that before lol Link to comment Share on other sites More sharing options...
rew Posted January 30, 2021 Author Share Posted January 30, 2021 Trilobite #161 is Pliomera fischeri of Early Ordovician age and from the Voibokalo quarry in the St. Petersburg region of Russia. You win no prizes for guessing that it is in the family Pliomeridae. 2 2 Link to comment Share on other sites More sharing options...
rew Posted February 6, 2021 Author Share Posted February 6, 2021 Trilobite #162 is Nephrolenellus geniculatus, of Early Cambrian age from the Pioche Shale of Lincoln County, Nevada. This is a complete bug although the head and first segment of the thorax are detached from the rest of the body and bent to the left further than they would be in a live trilobite. This is a close relative of the Olenellus trilobites. The patterning in the rock is impressed upon the shell giving the misleading impression that the shell is semi-transparent. 2 3 Link to comment Share on other sites More sharing options...
piranha Posted February 6, 2021 Share Posted February 6, 2021 On 2/5/2021 at 11:26 PM, rew said: Trilobite #162 is Nephrolenellus geniculatus, of Early Cambrian age from the Pioche Shale of Lincoln County, Nevada. This is a complete bug although the head and first segment of the thorax are detached from the rest of the body and bent to the left further than they would be in a live trilobite. This is a close relative of the Olenellus trilobites. The patterning in the rock is impressed upon the shell giving the misleading impression that the shell is semi-transparent. Time for another new label! Nephrolenellus geniculatus is noticeably different: the glabella extends to the anterior margin and it does not have an axial spine. This specimen is a better match with: Olenellus chiefensis. (note: the name Paedeumias has been discarded. "Instead, it makes more sense to drop Paedeumias, a name devoid of significance as a phylogenetic unit, and assign all taxa within the Olenellinae to the genus Olenellus." –Lieberman 1999) figures from: Palmer, A.R. 1998 Terminal Early Cambrian Extinction of the Olenellina: Documentation from the Pioche Formation, Nevada. Journal of Paleontology, 72(4):650-672 Lieberman, B.S. 1999 Systematic Revision of the Olenelloidea (Trilobita, Cambrian). Peabody Museum of Natural History, Yale University, Bulletin, 45:1-150 PDF LINK 6 Link to comment Share on other sites More sharing options...
rew Posted February 6, 2021 Author Share Posted February 6, 2021 Okay, I apparently have an Olenellus chiefensis I didn't know I had. This one definitely has a telson. Link to comment Share on other sites More sharing options...
piranha Posted February 7, 2021 Share Posted February 7, 2021 1 hour ago, rew said: Okay, I apparently have an Olenellus chiefensis I didn't know I had. This one definitely has a telson. The Olenellinae have a thoracic axial spine---not a telson: Kaesler, R.L. (ed.) 1997 Treatise on Invertebrate Paleontology, [Part O] Trilobita, (Revised). Geological Society of America, University of Kansas Press, 530 pp. 5 Link to comment Share on other sites More sharing options...
rew Posted February 7, 2021 Author Share Posted February 7, 2021 I have a bug not yet posted, from Kinzer's Formation in Pennsylvanian. that was labeled Paedumias transitans. Is it now Olenellus transitans, or what? 7 hours ago, piranha said: Time for another new label! Nephrolenellus geniculatus is noticeably different: the glabella extends to the anterior margin and it does not have an axial spine. This specimen is a better match with: Olenellus chiefensis. (note: the name Paedeumias has been discarded. "Instead, it makes more sense to drop Paedeumias, a name devoid of significance as a phylogenetic unit, and assign all taxa within the Olenellinae to the genus Olenellus." –Lieberman 1999) figures from: Palmer, A.R. 1998 Terminal Early Cambrian Extinction of the Olenellina: Documentation from the Pioche Formation, Nevada. Journal of Paleontology, 72(4):650-672 Lieberman, B.S. 1999 Systematic Revision of the Olenelloidea (Trilobita, Cambrian). Peabody Museum of Natural History, Yale University, Bulletin, 45:1-150 PDF LINK Link to comment Share on other sites More sharing options...
piranha Posted February 7, 2021 Share Posted February 7, 2021 On 2/6/2021 at 5:48 PM, rew said: I have a bug not yet posted, from Kinzer's Formation in Pennsylvanian. that was labeled Paedumias transitans. Is it now Olenellus transitans, or what? Same answer as above. The name Paedeumias has been discarded. "Paedeumias" is a synonym of Olenellus. "Instead, it makes more sense to drop Paedeumias, a name devoid of significance as a phylogenetic unit, and assign all taxa within the Olenellinae to the genus Olenellus." Lieberman, B.S. 1999. Systematic Revision of the Olenelloidea (Trilobita, Cambrian). Peabody Museum of Natural History, Yale University, Bulletin, 45:1-150 PDF LINK Here is the most recent paper to address and reaffirm the synonymy: Cuen-Romero, F.J. et al. 2018 Trilobite-Based Biostratigraphy (Arthropoda-Trilobita) and Related Faunas of the Cambrian from Sonora, Mexico. Journal of South American Earth Sciences, 83:227-236 2 Link to comment Share on other sites More sharing options...
rew Posted February 13, 2021 Author Share Posted February 13, 2021 Trilobite #162 is Illaenus atavus, of Middle Ordovician age from the Vilpovitsy quarry, Asery stage, in the St. Petersburg region of Russia. If you see a trilobite with a face like the third picture, it's probably in the Illaenidae. 1 Link to comment Share on other sites More sharing options...
rew Posted February 20, 2021 Author Share Posted February 20, 2021 Trilobite #163 is Dionide mareki, of Ordovican age and from the Llandeilan Series of Valongo, Portugal. 1 3 Link to comment Share on other sites More sharing options...
Sjfriend Posted February 20, 2021 Share Posted February 20, 2021 Wow! Look at those spines. Nice trilobite Link to comment Share on other sites More sharing options...
rew Posted February 28, 2021 Author Share Posted February 28, 2021 Trilobite of the week #164 is Kettneraspis williamsi, of Early Devonian age and from the Haragan Formation at Black Cat Mountain, Clarita, Oklahoma. This is a close relative of the Leonaspis trilobites. 2 1 Link to comment Share on other sites More sharing options...
rew Posted March 3, 2021 Author Share Posted March 3, 2021 Here's a side view of the Kettneraspis williamsi, which clearly shows the raised eyes and the short, thin occipital spine. 1 Link to comment Share on other sites More sharing options...
rew Posted March 5, 2021 Author Share Posted March 5, 2021 Trilobite of the week #165 is Olenellus transitans (= Paedumias transitans). When one hears "Olenellus" one naturally thinks of desert states like Utah, Nevada, and California, where most of those bugs are found. But this is from the Early Cambrian Kinzers Formation, in York County, Pennsylvania. The preservation is very flat, and almost ghost like. But it is essentially complete, including the axial spine at the end. 2 Link to comment Share on other sites More sharing options...
rew Posted March 13, 2021 Author Share Posted March 13, 2021 Trilobite of the week #166 Symphysurus ebbestadi, of Early Ordovician age and from the Fezouata Formation located in Draa Valley, north of Zagora, Morocco. This is the only trilobite I have in the family Nileidae, and, despite its very ordinary eyes, is the closest relative I have to Cyclopyge. 1 Link to comment Share on other sites More sharing options...
rew Posted March 20, 2021 Author Share Posted March 20, 2021 (edited) Trilobite of the week #167 is Damesella paronai, in the family Damesellidae, which, if you regard the Odontopleurida as a distinct order from the Lichida, is in the order Odontopleurida. It is of Middle Cambrian age from the Zhangxia Formation near Laiwu City, Shandong, China. It is the earliest member of the order Odontopleurida in my collection. I remember seeing the first few specimens of this bug from China and I wanted to cry -- they were prepped with a wire brush -- you ruined it! Somebody realized they could get a much better price if they were prepped properly, and now I've seen quite a few nice specimens of this species. This is a contender for "Most Beautiful Chinese Trilobite". The right genal spine is a little short but shows no signs of a break. The tip probably broke off while it was alive and healed over. Edited March 20, 2021 by rew 1 2 Link to comment Share on other sites More sharing options...
rew Posted March 27, 2021 Author Share Posted March 27, 2021 (edited) Trilobite of the week #168 is the Late Cambrian Pseudagnostus securiger from the McKay Formation near Cranbrook, British Columbia, Canada. At 14 mm this is a relative large agnostid, and is the only member I have of the family Diplagnostidae. It has a pair of short spines on the pygidium. You can see quite a lot of rock where there ought to be shell. Is the shell just missing, or is there more rock that the preparator ought to have removed? It's hard for me to tell, when I zoom in at the transition I don't see a clear edge of the shell, suggesting that maybe there's rock to be removed. OTOH, this would hardly be the first trilobite to be missing one third of its shell. I'd like to hear the opinion of some preparators on this one. Edited March 27, 2021 by rew 1 Link to comment Share on other sites More sharing options...
rew Posted April 3, 2021 Author Share Posted April 3, 2021 Trilobite of the week #169 is Dresbachia amata of Late Middle Cambrian age, from the Weeks Formation in Millard County, Utah. This is in the Menomoniidae and like other trilobites in that family the eyes are small and close together and there are many thoracic segments. This is an uncommon trilobite. This is a small bug, about 17 mm long. The magnifying macro lens is back on my camera while I get through some of the smaller trilobites. 1 2 Link to comment Share on other sites More sharing options...
rew Posted April 9, 2021 Author Share Posted April 9, 2021 Trilobite of the week #170 is Destombesina tafilaltensis, of Early Devonian (Emsian) age from Jebel Issoumour, Morocco. This is a small member of the Acastidae, at 2.1 cm this is not much smaller than any other specimen of the species I have seen. This bug makes Greenops look big. 1 3 Link to comment Share on other sites More sharing options...
piranha Posted April 9, 2021 Share Posted April 9, 2021 1 hour ago, rew said: Trilobite of the week #170 is Destombesina tafilaltensis, of Early Devonian (Emsian) age from Jebel Issoumour, Morocco. This is a small member of the Acastidae, at 2.1 cm this is not much smaller than any other specimen of the species I have seen. This bug makes Greenops look big. Destombesina tafilaltensis has 4 eye lenses per lens file and 4 pairs of short pygidial spines. Instead, this one is a better match with a different member of the Acastidae: Acastella sp. Morzadec, P. 2001 Les Trilobites Asteropyginae du Dévonien de l'Anti-Atlas (Maroc). [Asteropyginae Trilobites from the Devonian of the Anti-Atlas (Morocco).] Palaeontographica Abt. A 262:53-85 3 Link to comment Share on other sites More sharing options...
rew Posted April 9, 2021 Author Share Posted April 9, 2021 Dang, I misidentified yet another trilobite. You are right, this one's a poor match for Destombesina. Link to comment Share on other sites More sharing options...
piranha Posted April 9, 2021 Share Posted April 9, 2021 9 minutes ago, rew said: Dang, I misidentified yet another trilobite. You are right, this one's a poor match for Destombesina. Many of the commercial trilobite dealers are at fault for propagating erroneous information. 1 Link to comment Share on other sites More sharing options...
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