{"id":2257,"date":"2019-08-01T08:54:02","date_gmt":"2019-08-01T13:54:02","guid":{"rendered":"http:\/\/scienceandsf.com\/?p=2257"},"modified":"2019-08-01T08:54:03","modified_gmt":"2019-08-01T13:54:03","slug":"paleontology-news-for-august-2019-special-trilobite-edition","status":"publish","type":"post","link":"https:\/\/scienceandsf.com\/index.php\/2019\/08\/01\/paleontology-news-for-august-2019-special-trilobite-edition\/","title":{"rendered":"Paleontology News for August 2019: Special Trilobite edition"},"content":{"rendered":"\n<p>A couple of new discoveries have recently been published about the ancient and extinct sea creatures known as trilobites so I thought that this would be a good opportunity to discuss these fascinating creatures in some detail. I’ll begin with a few general facts about trilobites.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"851\" height=\"1024\" src=\"http:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/17178725587_ce535a4f62_b.jpg\" alt=\"\" class=\"wp-image-2260\" srcset=\"https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/17178725587_ce535a4f62_b.jpg 851w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/17178725587_ce535a4f62_b-249x300.jpg 249w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/17178725587_ce535a4f62_b-768x924.jpg 768w\" sizes=\"auto, (max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px\" \/><figcaption>The Trilobite Phacops rana, the state fossil of Pennsylvania (Credit: Flickr)<\/figcaption><\/figure>\n\n\n\n<p>First of all trilobites are members of the phylum arthropoda, the jointed limbed animals that include crustaceans, insects and spiders. In fact trilobites are generally recognized as the earliest members of that group of animals with fossils going back as far as 540 Million years ago. Trilobites not only evolved a long time ago they also went extinct a long time ago. The last trilobites died in the Permian extinction event about 250 million years ago, see my posts of 16 February 2019 and 2 June 2018. That’s several million years before the first dinosaur ever evolved! <\/p>\n\n\n\n<p>Because\ntrilobites lasted so long, and their exoskeleton fossilized so easily\npaleontologists have been able to identify more than 50,000 different species.\nDuring their almost 300 million year existence trilobites evolved to occupy\nnearly all of the ecological niches occupied by modern marine arthropods\nincluding that of scavenger, predator, filter feeder and even a swimming species\nthat fed off of the plankton near the surface.<\/p>\n\n\n\n<p>Looking at the figure below, you can see that Anatomically trilobites are defined by their broadly oval shape and the three main sections of their body going <em>side to side<\/em>, right pleural lobe, axial lobe, which is often raised, and left pleural lobe. Many people incorrectly think that the three lobes of the name trilobite refer to the three sections going front to back with the cephalon (head), thorax and pygidium (tail). (I did when I was young!)<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"500\" height=\"350\" src=\"http:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/Trilobite1.jpg\" alt=\"\" class=\"wp-image-2261\" srcset=\"https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/Trilobite1.jpg 500w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/Trilobite1-300x210.jpg 300w\" sizes=\"auto, (max-width: 500px) 85vw, 500px\" \/><figcaption>The main anatomic parts of a Trilobite (Credit: Wikipedia)<\/figcaption><\/figure>\n\n\n\n<p>Early trilobites, such as Olenellus from the Cambrian period seen below, had a cephalon that was much larger than their pygidium. As trilobites evolved however their tails grew to almost the same size and shape as their head as seen below in Phacops from the Devonian period. This adaptation allowed later trilobites to roll up into a protective ball in much the same way as a modern armadillo does. Fossils of such rolled trilobites are often found in Devonian, Mississippian and Pennsylvanian rocks.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"1908\" height=\"1635\" src=\"http:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/olenellus-fremonti.jpg\" alt=\"\" class=\"wp-image-2262\" srcset=\"https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/olenellus-fremonti.jpg 1908w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/olenellus-fremonti-300x257.jpg 300w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/olenellus-fremonti-768x658.jpg 768w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/olenellus-fremonti-1200x1028.jpg 1200w\" sizes=\"auto, (max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px\" \/><figcaption>The Cambrian Trilobite Olenellus fremonti (Credit: American Museum of Natural History)<\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"869\" height=\"900\" src=\"http:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/enrolled-phacops-trilobite-phacopidae-dorling-kindersleyuig.jpg\" alt=\"\" class=\"wp-image-2263\" srcset=\"https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/enrolled-phacops-trilobite-phacopidae-dorling-kindersleyuig.jpg 869w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/enrolled-phacops-trilobite-phacopidae-dorling-kindersleyuig-290x300.jpg 290w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/enrolled-phacops-trilobite-phacopidae-dorling-kindersleyuig-768x795.jpg 768w\" sizes=\"auto, (max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px\" \/><figcaption>An enrolled specimen of Phacops rana (Credit: Fine Art America)<\/figcaption><\/figure>\n\n\n\n<p>With a history of 300 million years and at least 50,000 species trilobites varied considerably in their particulars, especially size and ornamentation, see images below. The largest known trilobites are from the genus Isotelus of the Ordovician period some 450 million years ago specimens of which are as long as a meter. There are a number of candidates for the smallest member of the group but many small trilobites were no larger than a pea.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"1500\" height=\"2000\" src=\"http:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/08\/Isotelus-maximus-trilobite-8-1500x2000.jpg\" alt=\"\" class=\"wp-image-2269\" srcset=\"https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/08\/Isotelus-maximus-trilobite-8-1500x2000.jpg 1500w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/08\/Isotelus-maximus-trilobite-8-225x300.jpg 225w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/08\/Isotelus-maximus-trilobite-8-768x1024.jpg 768w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/08\/Isotelus-maximus-trilobite-8-1200x1600.jpg 1200w\" sizes=\"auto, (max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px\" \/><figcaption>A beautiful specimen of Isotelus maximum (Credit: Geoclassics)<\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"1447\" height=\"1104\" src=\"http:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/08\/trilobite-fossil.jpg\" alt=\"\" class=\"wp-image-2270\" srcset=\"https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/08\/trilobite-fossil.jpg 1447w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/08\/trilobite-fossil-300x229.jpg 300w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/08\/trilobite-fossil-768x586.jpg 768w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/08\/trilobite-fossil-1200x916.jpg 1200w\" sizes=\"auto, (max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px\" \/><figcaption>A species of Trilobite ornamented with spines, presumably for protection (Credit: Tack Raccoons) <\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"678\" height=\"700\" src=\"http:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/08\/ae76b9a2-e18c-11e6-83a1-3fd7dc9e4c06.jpg\" alt=\"\" class=\"wp-image-2271\" srcset=\"https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/08\/ae76b9a2-e18c-11e6-83a1-3fd7dc9e4c06.jpg 678w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/08\/ae76b9a2-e18c-11e6-83a1-3fd7dc9e4c06-291x300.jpg 291w\" sizes=\"auto, (max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 984px) 61vw, (max-width: 1362px) 45vw, 600px\" \/><figcaption>Another spiny trilobite (Credit: Catawiki)<\/figcaption><\/figure>\n\n\n\n<p>For the most part however trilobites remained rather conservative in their basic body plan. This may have contributed to their eventual extinction as competitors such as crustaceans and fish evolved structures like jaws and manipulating pincers that allowed them to outperform the trilobites.<\/p>\n\n\n\n<p>As fossils a complete trilobite is fairly rare, one or two can represent a good day’s hunting. On the other hand recognizable pieces of trilobites are very common. The reason for this is that like all arthropods trilobites had to molt in order to grow. So a single live trilobite could in the course of its life produce many empty shells that would quickly break up to produce a lot of trilobite pieces.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"900\" height=\"600\" src=\"http:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/post-2629-0-23815600-1308019919.jpg\" alt=\"\" class=\"wp-image-2264\" srcset=\"https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/post-2629-0-23815600-1308019919.jpg 900w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/post-2629-0-23815600-1308019919-300x200.jpg 300w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/post-2629-0-23815600-1308019919-768x512.jpg 768w\" sizes=\"auto, (max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px\" \/><figcaption>Fragments of many fossils including a Trilobite tail right in the middle (Credit: The fissil forum)<\/figcaption><\/figure>\n\n\n\n<p>A couple of recent studies have further increased our knowledge of these ancient creatures. The first concerns the discovery of a new species of trilobite from Australia that has been named Redlichia rex. The name is a reference to the well known dinosaur Tyrannosaurus rex because of R rex’s large size, 30cm, and leg spines that could be used to crush the trilobites food. The fossils of R rex come from the Emu bay shale of Australia’s Kangaroo island and are exceptionally well preserved revealing details of even the animal’s delicate antenna, see image below. <\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"362\" height=\"400\" src=\"http:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/Redlichia.jpg\" alt=\"\" class=\"wp-image-2265\" srcset=\"https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/Redlichia.jpg 362w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/Redlichia-272x300.jpg 272w\" sizes=\"auto, (max-width: 362px) 85vw, 362px\" \/><figcaption>Artists impression of Redlichia rex along with a fossil specimen (Credit: Species new to Science)<\/figcaption><\/figure>\n\n\n\n<p>Because\nof R rex’s large size and crushing legs it is believed that the trilobite was a\npredator, and perhaps even a cannibal. Specimens of R rex have been found with\nhealed injuries so the question is, what could have preyed on these large, for\nthe Cambrian period, animals. While there are several possibilities it has also\nbeen suggested that R rex may have preyed on its own kind!<\/p>\n\n\n\n<p>The\nsecond discovery also comes from a fossil site that is well known for\nexceptionally well-preserved specimens, the Guanshan location in eastern Yunnan\nprovince China. In this study it’s not a new species of trilobite that’s been\nannounced, it\u2019s the discovery of the earliest known evidence for a stomach and\ndigestive system!<\/p>\n\n\n\n<p>Using some of the best specimens of the trilobite Palaeolenus lanteroisi, see image below, researchers from the American Museum of Natural History in New York and the Early Life Institute at Northwest University in Xi’an China actually succeeded in ‘dissecting’ the fossils. That is, they have managed to carefully remove a portion of the upper layers of the fossil in order to examine the petrified remains of the animal’s internal organs. <\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"618\" height=\"827\" src=\"http:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/TrilobiteStomach.jpg\" alt=\"\" class=\"wp-image-2266\" srcset=\"https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/TrilobiteStomach.jpg 618w, https:\/\/scienceandsf.com\/wp-content\/uploads\/2019\/07\/TrilobiteStomach-224x300.jpg 224w\" sizes=\"auto, (max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 984px) 61vw, (max-width: 1362px) 45vw, 600px\" \/><figcaption>Examples of dissections performed on fossils of long dead Trilobites (Credit: Hopkins, Chen, Hu and Zhang)<\/figcaption><\/figure>\n\n\n\n<p>What\nthey found was a well-developed digestive system with a large stomach or ‘crop’\nin its cephalon. That’s right trilobites appear to have had their stomach’s in\ntheir heads not far from their mouths! \nA long alimentary canal then went through the length of the rest of the\ntrilobite’s body to an anus at the animal’s posterior.\n\nTrilobites have a special place in the history\nof life, as one of the first complex, multi-cellular forms of animal they\ndominated the ancient Cambrian and Ordovician seas. Thereafter they gradually\ndeclined, finally becoming extinct during the Permian catastrophe. Nowadays for\nany fossil hunter a good trilobite specimen will always be a small prize to be\ntreasured. \n\n\n\n<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A couple of new discoveries have recently been published about the ancient and extinct sea creatures known as trilobites so I thought that this would be a good opportunity to discuss these fascinating creatures in some detail. I’ll begin with a few general facts about trilobites. First of all trilobites are members of the phylum … <a href=\"https:\/\/scienceandsf.com\/index.php\/2019\/08\/01\/paleontology-news-for-august-2019-special-trilobite-edition\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> “Paleontology News for August 2019: Special Trilobite edition”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[12],"tags":[754,796,306,797,795],"class_list":["post-2257","post","type-post","status-publish","format-standard","hentry","category-science","tag-paleontology-news","tag-redlichia-rex","tag-trilobite-anatomy","tag-trilobite-stomach","tag-trilobites"],"_links":{"self":[{"href":"https:\/\/scienceandsf.com\/index.php\/wp-json\/wp\/v2\/posts\/2257","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/scienceandsf.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/scienceandsf.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/scienceandsf.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/scienceandsf.com\/index.php\/wp-json\/wp\/v2\/comments?post=2257"}],"version-history":[{"count":3,"href":"https:\/\/scienceandsf.com\/index.php\/wp-json\/wp\/v2\/posts\/2257\/revisions"}],"predecessor-version":[{"id":2272,"href":"https:\/\/scienceandsf.com\/index.php\/wp-json\/wp\/v2\/posts\/2257\/revisions\/2272"}],"wp:attachment":[{"href":"https:\/\/scienceandsf.com\/index.php\/wp-json\/wp\/v2\/media?parent=2257"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/scienceandsf.com\/index.php\/wp-json\/wp\/v2\/categories?post=2257"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/scienceandsf.com\/index.php\/wp-json\/wp\/v2\/tags?post=2257"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}