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Female, head disarticulated and displaced. The fish is embedded in a mass of filamentous algae. Alternative combination: Physonemus falcatus. "The genus Physonemus was originally erected for P. arcuatus by McCoy (1848) to receive elegant forwardly-curved, well omamented Paleozoic fin spines of unknown affìnities ... The Paleozoic fin spine Physonemus falcatus St. John and Worthen 1883, from the Valmeyeran St. Louis Limestone of St. Louis, Missouri, has been found on sexually mature males of a small, highly sexually dimorphic chondrichthyan from the Chesterian Bear Gulch Limestone of Montana" (Lund 1985, p.1). Diagnosis from Lund 1985, p.3: “Small sharks, maximum known size 145 mm fork length, with forwardly-curved spines, inclined at mean angle of 14.5 degrees to the horizontal. Neither spine nor first dorsal fin present on juveniles below 124 mm length, nor on females. Males with elongate rostrum, denticles covering dorsum of rostrum, cranium and dista] portion of dorsal rod, females with short rostrum and devoid of denticles. Teeth delicate, cladodont, tooth whorls of larger, non-cladodont teeth external to jaws. Pectoral fin with five prearticular basals, a metapterygium bearing six radials, and an axis of seven elements with only one radial. Pelvic girdle supports 8—10 radials; clasper of male consisting of 6—8 axials and a three-part mixopterygium. Second dorsal fin of 12—14 well spaced radials followed by a triangular basal plate, l9—21 distal radials. Axial skeleton of 44 precaudal segments, 18 preural caudals and 16—18 ural caudals. Caudal fin deeply forked, equilobate, with no radials between dorsal and ventral lobes.” Line drawing from Lund 1985, p. 13: References: St. John, O. H. and Worthen, A. H. (1875). Descriptions of fossil fishes. Geological Survey of Illinois 6:245—488. St. John, O. H. and Worthen, A. H. (1883). Descriptions of fossil fishes; a partial revision of the Cochliodonts and Psammodonts. Geological Survey of Illinois 7:55—264. Lund, Richard (1985). The morphology of Falcatus falcatus (St. John and Worthen), a Mississippian stethacanthid chondrichthyan from the Bear Gulch Limestone of Montana, Journal of Vertebrate Paleontology, 5:1-19, DOI: 10.1080/02724634.1985.10011842.
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- bear gulch
- carboniferous
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Echinochimaera snyderi belongs to the peculiar looking chimaeras (also called sea cats, ratfish or ghost sharks). Chimaeras possess two dorsal fins; the first dorsal fin is supported by a movable spine associated with a venom gland. Recent sea cats live in all oceans of the world, preferably at depths between 200 and 2000m. This juvenile specimen of Echinochimaera snyderi is most likely a female; adult males are slightly smaller and have a more curved dorsal spine. References: R. Lund. 1988. New Mississippian Holocephali (Chondrichthyes) and the evolution of the Holoceephali. In Teeth Revisited: Proceedings of the VII Int. Symp. on Dental Morph., Paris, May 1986, Russel, D.E., Santoro, J.P. and Sigogneau-Russel, D., Eds., Mem. Mus. Natn. Hist. Nat., Paris, (serie C) 53:195-205 R. Lund and E. Grogan. 2004. Five new euchondrocephalan Chondrichthyes from the Bear Gulch Limestone (Serpukhovian, Namurian E2b) of Montana, USA. In G. Arratia, M. Wilson, R. Cloutier (eds.), Recent Advances in the Origin and Early Radiation of Vertebrates 505-531
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- bear gulch
- carboniferous
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This fish belongs to the Tarrasiids, a group of extinct bony fish with elongated body and a diphycercal caudal fin that was continuous with the dorsal and anal fins. The continuous dorsal-caudal-anal fin is well webbed between the fin rays. Fish with this fin disposition today are slow weak swimmers that move either forward or backward, by body undulation, median fin undulation or pectoral paddling. Fish such as these are shelter dwellers in geometrically complex shallow water environments, such as weed or sponge beds. No valid description seems to exist. For Apholidotos ossna Lund, the reference given is "in Frickhinger, 1991". Another name - Apholidotus ossuosus Lund - is used by UMPC (University of Montana Paleontology Center) in their catalog. In his own much later publications (e.g. in 1999), Lund himself in not using any of these combinations, he is only using the nickname "Garden Eel".
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- apholidotus
- bear gulch
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Belotelson magister (Packard, 1886) from Bear Gulch
oilshale posted a gallery image in Member Collections
From the album: Invertebrates
Belotelson magister (Packard, 1886) Lower Carboniferous Serpukhovian Heath Shale Formation Bear Gulch, Fergus County Montana USA- 1 comment
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From the album: Vertebrates
Fubarichthys prolatus Lowney, 1980 Lower Carboniferous Serpukhovian Heath Shale Formation Bear Gulch, Fergus County Montana USA- 1 comment
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From the album: Invertebrates
Sairocaris centurion Schram & Horner, 1978 Carboniferous Serpukhovian Heath Shale Formation Bear Gulch, Fergus County Montana USA-
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From the album: Invertebrates
Perimecturus rapax Schram & Horner, 1978 Carboniferous Serpukhovian Heath Shale Formation Bear Gulch, Fergus County Montana USA References: Ronald A. Jenner; Cees H.J. Hof; Frederick R. Schram (1998): Palaeo- and Archaeostomatopods (Hoplocarida: Crustacea) from the Bear Gulch Limestone, Mississippian (Namurian), of central Montana. Contributions to Zoology, 67 (3) 155-186. Link (04.2013): http://dpc.uba.uva.nl/ctz/vol67/nr03/art01 FREDERICK R. SCHRAM (2007): PALEOZOIC PROTO-MANTIS SHRIMP REVISITED. Journal of Paleontology, September 2007, v. 81, p. 895-916. Haug et al. (2010): Evolution of mantis shrimps (Stomatopoda, Malacostraca) in the light of new Mesozoic fossils. BMC Evolutionary Biology 2010, 10:290 Link (04.2013): http://www.core-orsten-research.de/Publications/PDF_Paper/ulm_team/2010%20Haug_JT_etal%20BMC%20Stomatopod%20Phyl.pdf Schram (1969): Some Middle Pennsylvanian Hoplocarida (Crustacea) and their phylogenetic significance. Fieldiana, Geology, Vol.12, No.14 Link (04.2013): http://archive.org/details/somemiddlepennsy1214schr-
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