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hajar | profile | all galleries >> Palaeogalleries >> The Whole Trilobite: Limbs, Antennae and Guts tree view | thumbnails | slideshow

The Whole Trilobite: Limbs, Antennae and Guts

Only very occasionally are the limbs (legs), antennae and digestive systems of trilobites preserved. This gallery shows some exceptional examples ranging in age from Early Cambrian to Early Devonian. The specimens come from China, Australia, USA and Germany. Orders Redlichiida, Ptychopariida, Odontopleurida and Phacopida are represented. They provide extraordinary glimpses of what these extinct arthropods would have looked like in life and also rare views of the animals' internal anatomy. In addition to the photographs, X-radiographs and CT scans are used here to illustrate limb morphology.

The finely preserved limbs and antennae shown here, even exhibiting minute claws and setal hairs, were recorded by early precipitation of pyrite. The pyrite has subsequently oxidized in the case of the Chinese fossils, leaving red and orange stains (and external molds of tiny pyrite framboids). The mineralized alimentary canals and gastric caeca shown have recently been discussed by Robison & Babcock (2011), who suggested that phosphate precipitation in trilobite guts began within about a week of death. They inferred from the lack of sediment fill in the guts of Meniscopsia and Coosella that these animals were not sediment-deposit-feeders, but rather predaceous. Note that the Cedaria gut illustrated below is sediment-filled.

I have added some images from Raymond's 1920 work on the complete anatomy of trilobites, together with some notes on the history of discoveries ( http://lifeartearth.blogspot.com/2013/11/trilobite-limbs-antennae-and-guts.html ).
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Eoredlichia intermedia, 5 cm long, Lower Cambrian, Chengjiang, China, partially dissected to show limbs and antennae.
Eoredlichia intermedia, 5 cm long, Lower Cambrian, Chengjiang, China, partially dissected to show limbs and antennae.
Eoredlichia intermedia (3 cm long), Lower Cambrian, Chengjiang, China, showing antennae and diverticulae.
Eoredlichia intermedia (3 cm long), Lower Cambrian, Chengjiang, China, showing antennae and diverticulae.
Detail of Eoredlichia showing paired gastric diverticulae. Glabella length is 8 mm.
Detail of Eoredlichia showing paired gastric diverticulae. Glabella length is 8 mm.
Eoredlichia intermedia, 26 mm, showing antennae and thoracic spine. Lower Cambrian, Chengjiang, China.
Eoredlichia intermedia, 26 mm, showing antennae and thoracic spine. Lower Cambrian, Chengjiang, China.
Balcoracania dailyi (12 mm long), Emu Bay Shale Fm, Lower Cambrian, S Australia, showing mineralized gut.
Balcoracania dailyi (12 mm long), Emu Bay Shale Fm, Lower Cambrian, S Australia, showing mineralized gut.
Balcoracania dailyi (12 mm long), Emu Bay Shale Fm, Lower Cambrian, S Australia, showing mineralized gut.
Balcoracania dailyi (12 mm long), Emu Bay Shale Fm, Lower Cambrian, S Australia, showing mineralized gut.
Meniscopsia beebei with mineralized gut and gastric caeca, 36 mm. Weeks Formation, M Cambrian, Utah, USA.
Meniscopsia beebei with mineralized gut and gastric caeca, 36 mm. Weeks Formation, M Cambrian, Utah, USA.
Detail of the Meniscopsia mineralized alimentary canal and caeca. The outline of the hypostome is shown.
Detail of the Meniscopsia mineralized alimentary canal and caeca. The outline of the hypostome is shown.
Cedaria minor with preserved gut, 12 mm, Weeks Formation, M Cambrian, Utah, USA.
Cedaria minor with preserved gut, 12 mm, Weeks Formation, M Cambrian, Utah, USA.
Cedaria minor with preserved gut, 12 mm, Weeks Formation, M Cambrian, Utah, USA.
Cedaria minor with preserved gut, 12 mm, Weeks Formation, M Cambrian, Utah, USA.
Triarthrus eatoni, 22mm showing limbs and antennae. Whetstone Gulf Formation, U Ordovician, Lewis Co, New York, USA.
Triarthrus eatoni, 22mm showing limbs and antennae. Whetstone Gulf Formation, U Ordovician, Lewis Co, New York, USA.
Detail showing eye and proximal antennae of a New York Triarthrus. Note dusting of pyrite micro crystals across the glabella.
Detail showing eye and proximal antennae of a New York Triarthrus. Note dusting of pyrite micro crystals across the glabella.
Detail of Triarthrus antennae showing some fine setal hairs on proximal segments
Detail of Triarthrus antennae showing some fine setal hairs on proximal segments
Triarthrus eatoni, 49 mm showing limbs and antennae. Whetstone Gulf Formation, U Ordovician, Lewis Co, New York, USA.
Triarthrus eatoni, 49 mm showing limbs and antennae. Whetstone Gulf Formation, U Ordovician, Lewis Co, New York, USA.
Triarthrus eatoni, 45 mm showing limbs and antennae. Whetstone Gulf Formation, U Ordovician, Lewis Co, New York, USA.
Triarthrus eatoni, 45 mm showing limbs and antennae. Whetstone Gulf Formation, U Ordovician, Lewis Co, New York, USA.
Detail of Triarthrus limbs. Notice the spines and the terminal claws.
Detail of Triarthrus limbs. Notice the spines and the terminal claws.
Detail of Triarthrus claws
Detail of Triarthrus claws
Detail of Triarthrus claw
Detail of Triarthrus claw
Detail of Triarthrus exopods showing terminal paddles and filamentous lamellae.
Detail of Triarthrus exopods showing terminal paddles and filamentous lamellae.
Detail of an exopod terminal oar
Detail of an exopod terminal "oar"
3D extraction from CT scan of pyritized trilobite with limbs, 10 mm. Now in the collection of Paul Hille.
3D extraction from CT scan of pyritized trilobite with limbs, 10 mm. Now in the collection of Paul Hille.
Meadowtownella cf trentonensis, 9 mm, showing limbs and antennae. Lorraine Group, U Ordovician, Lewis County, New York.
Meadowtownella cf trentonensis, 9 mm, showing limbs and antennae. Lorraine Group, U Ordovician, Lewis County, New York.
Meadowtownella cf trentonensis, 9 mm, showing limbs and antennae. Lorraine Group, U Ordovician, Lewis County, New York.
Meadowtownella cf trentonensis, 9 mm, showing limbs and antennae. Lorraine Group, U Ordovician, Lewis County, New York.
Meadowtownella cf trentonensis, 9 mm, showing limbs and antennae. Lorraine Group, U Ordovician, Lewis County, New York.
Meadowtownella cf trentonensis, 9 mm, showing limbs and antennae. Lorraine Group, U Ordovician, Lewis County, New York.
Meadowtownella with limbs and antennae. CT image.
Meadowtownella with limbs and antennae. CT image.
Meadowtownella with limbs and antennae.
Meadowtownella with limbs and antennae.
Meadowtownella in CT image. A series of vertical spines on the pleurae is visible in this view.
Meadowtownella in CT image. A series of vertical spines on the pleurae is visible in this view.
X-radiograph showing Rhenops sp, 45 mm long. Limbs are visible.
X-radiograph showing Rhenops sp, 45 mm long. Limbs are visible.
Rhenops sp, 45 mm ventral view, complete with limbs and antennae. Hunsrueckschiefer, L Devonian, Bundenbach, Germany.
Rhenops sp, 45 mm ventral view, complete with limbs and antennae. Hunsrueckschiefer, L Devonian, Bundenbach, Germany.
Rhenops sp, 45 mm complete with limbs and antennae. Hunsrueckschiefer, L Devonian, Bundenbach, Germany.
Rhenops sp, 45 mm complete with limbs and antennae. Hunsrueckschiefer, L Devonian, Bundenbach, Germany.
Rhenops detail of antenna, like the Triarthrus showing setal hairs
Rhenops detail of antenna, like the Triarthrus showing setal hairs
Rhenops detail showing limbs with claws
Rhenops detail showing limbs with claws
Chotecops ferdinandi, 55 mm complete with limbs and antennae. Hunsrueckschiefer, L Devonian, Bundenbach, Germany.
Chotecops ferdinandi, 55 mm complete with limbs and antennae. Hunsrueckschiefer, L Devonian, Bundenbach, Germany.
Chotecops ferdinandi, 55 mm complete with limbs and antennae. Hunsrueckschiefer, L Devonian, Bundenbach, Germany.
Chotecops ferdinandi, 55 mm complete with limbs and antennae. Hunsrueckschiefer, L Devonian, Bundenbach, Germany.
Chotecops ferdinandi, 55 mm complete with limbs and antennae. Hunsrueckschiefer, L Devonian, Bundenbach, Germany.
Chotecops ferdinandi, 55 mm complete with limbs and antennae. Hunsrueckschiefer, L Devonian, Bundenbach, Germany.
Chotecops ferdinandi, 55 mm complete with limbs and antennae. Hunsrueckschiefer, L Devonian, Bundenbach, Germany.
Chotecops ferdinandi, 55 mm complete with limbs and antennae. Hunsrueckschiefer, L Devonian, Bundenbach, Germany.
Naraoia spinosa, 15 mm long, showing antennae and limb preservation. Heilinpu Formation, Lower Cambrian, Chengjiang, China.
Naraoia spinosa, 15 mm long, showing antennae and limb preservation. Heilinpu Formation, Lower Cambrian, Chengjiang, China.
Naroia compacta, 23 mm, Marjum Formation, Middle Cambrian, Millard County, Utah.
Naroia compacta, 23 mm, Marjum Formation, Middle Cambrian, Millard County, Utah.
C.E. Beecher, frontispiece to Raymond (1920)
C.E. Beecher, frontispiece to Raymond (1920)
Restoration of Triarthrus, Fig. 10 in Raymond (1920)
Restoration of Triarthrus, Fig. 10 in Raymond (1920)
Restoration of Isotelus gigas, Fig. 9 in Raymond (1920), based on Walcott's thin sections and a specimen from Ohio.
Restoration of Isotelus gigas, Fig. 9 in Raymond (1920), based on Walcott's thin sections and a specimen from Ohio.
Isotelus gigas, approximately 7 cm long. Trenton Group, Rust Formation, Spillway Member, Walcott-Rust Quarry, Russia, New York.
Isotelus gigas, approximately 7 cm long. Trenton Group, Rust Formation, Spillway Member, Walcott-Rust Quarry, Russia, New York.
Restoration of Calymene (now Flexicalymene) senaria, Fig. 16 in Raymond (1920).
Restoration of Calymene (now Flexicalymene) senaria, Fig. 16 in Raymond (1920).
Flexicalymene senaria, 22 mm long. Trenton Group, Rust Formation, Spillway Member, Walcott-Rust Quarry, Russia, New York.
Flexicalymene senaria, 22 mm long. Trenton Group, Rust Formation, Spillway Member, Walcott-Rust Quarry, Russia, New York.
Ceraurus pleurexanthemus reconstruction, Plate 10 (Raymond 1920).
Ceraurus pleurexanthemus reconstruction, Plate 10 (Raymond 1920).
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