 | Texas Pennsylvanian FossilsDedicated to the Study of Pennsylvanian Fossils, Sponsored by Members of the Dallas Paleontological Society |
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Cephalopods - Nautiloids | The Phylum Mollusca is a large and varied invertebrate group within the Animal Kingdom. They are characterized by a soft body with a strong muscular foot and usually (but not always) covered by a shell. The Cephalopods are a highly diversified, exclusively marine, Class of mollusks some of which possess an external shell (nautiloids, goniatites and ammonites) and others which no longer have an external shell (squid, octopus) but all of which have tentacles which are a modification of the molluscan foot. The cephalopod shell is a series of chambers connected by a tube (siphuncle) that are added as the animal grows. The last chamber is the living chamber. Clearly recognizable cephalopods were first seen in the Ordovician and the shelled forms became a dominant group in the Paleozoic. Today, shelled forms are very limited in variety and distribution, but the non-shelled forms are more widely dispersed. During the Pennsylvanian one group of cephalopods was the Subclass Nautiloidea. This group is characterized by a shell that is either coiled or straight and the chambers are separated by relatively simple septa. Where the septa intersect the outer shell it forms a suture and the shape of this suture is often diagnostic in species identification. The nautiloid sutures are usually straight or only slightly wavy. This subclass contains the only extant group of shelled cephalopods. The Finis contains nearly four dozen forms of cephalopods and nautiloids comprise almost half of them. Nautiloid fossils are fairly common, but nowhere near the volume of brachiopods or the larger mollusk groups. Among the nautiloids, Cryptocycloceras, Euloxoceras, and Pseudorthoceras are genera that can commonly be found. ---------------------------------------------------------------------------------------------------------------------------------------- Scroll through images or click to enlarge. Fossils are in alphabetical order by Genus except the bactrids and the straight nautiloids are grouped together. Collections are from Mike DeBrock (MD), Josh Hanley (JH), Dr. Peter Holterhoff (PH), Mark McKinzie (MM), John McLeod (JM), Dr. Ben Neuman (BN), Bob Williams (BW), Sveta Earnest (SE), and Rodney Wise (RW). All scales are shown in millimeters unless otherwise noted. |
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Images | Taxonomy/Stratigraphy/ | Images | Taxonomy/Stratigraphy/ |
Bactrids |
Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Bactritida Family: Bactritidae Genus: Bactrites Species: B. finisensis Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: BW | Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Parabactritida Family: Uncertain Genus: Rugobactrites Species: R. jacksboroensis Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: RW |
Straight Nautiloids |
Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Orthoceratoidea Order: Uncertain Family: Uncertain Genus: Cryptocycloceras Species: C. spectrum Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: MM Note: Formerly Brachycycloceras normale | Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Orthoceratoidea Order: Uncertain Family: Spyroceratidae Genus: Euloxoceras Species: E. greeni Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: MM |
Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Pseudorthoceratida Family: Pseudorthoceratidae Genus: Pseudorthoceras Species: P. knoxense Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: MM, RW | Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Nautilida Family: Neptunoceratidae Genus: Texanoceras Species: T. jacksboroensis Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: SE, MM |
Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Oncocerida Family: Poterioceratidae Genus: Poterioceras Species: P. sp. Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: MM |
Coiled Nautiloids |
Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Nautilida Family: Metacoceratidae Genus: Cooperoceras Species: C. sp Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: JM | Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Nautilida Family: Domatoceridae Genus: Domatoceras Species: D. sculptile Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: RW, MM |
Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Nautilida Family: Domatoceridae Genus: Domatoceras Species: D. tuckeri Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: RW, MM
| Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Nautilida Family: Temnocheilidae Genus: Endolobus Species: E. sturgeoni Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: MM |
Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Nautilida Family: Ephippioceratidae Genus: Ephippioceras Species: E. ferratum Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: MM | Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Nautilida Family: Liroceratidae Genus: Liroceras Species: L. liratum Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: MM Note: Formerly Coloceras liratum |
Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Nautilida Family: Metacoceratidae Genus: Metacoceras Species: M. cornutum (quadratum) Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: RW, MM | Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Nautilida Family: Liroceratidae Genus: Peripetoceras Species: P. bridgeportense Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: MM |
Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Nautilida Family: Solenochilidae Genus: Solenochilus Species: S. jackense Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: | Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Nautilida Family: Stenopoceratidae Genus: Stenopoceras Species: S. sp. Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: BW |
Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Nautilida Family: Tainoceratidae Genus: Tainoceras Species: T. monilifer Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: RW, MM | Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Nautilida Family: Tainoceratidae Genus: Tainoceras Species: T. sp. (New) Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: JM |
Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Subclass: Nautiloidea Order: Nautilida Family: Domatoceratidae Genus: Titanoceras Species: T. sp. Finis Shale, Graham Formation Lost Creek Dam, Jacksboro, TX Collection: MM |
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