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Taken from Lund, Richard, and Grogan, E.D., 2005, Bear Gulch web site, www.sju.edu/research/bear_gulch, 14/11/2016, page last updated 2/1/2006: "Heteropetalus elegantulus is an elegantly slim little euchondrocephalan with many different tooth shapes along its jaws. It ranges to only about 4 inches in length. Skull, jaws, and dentition place it close to Debeerius. It is common in the weedier shallow water areas. http://people.sju.edu/~egrogan/BearGulch/images_fish_art/Hetelegantulus_duo.jpg Male (top) and female (bottom). There are no scales, except for a small patch at the rear of the dorsal fin of males. Lateral line canals of the head are supported by rather large highly modified scales. Heteropetalus has an almost eel-like body, a protocercal tail, rounded and very flexible pectoral fins midway up the sides of the body, and a single long flexible undulatory dorsal fin (preceded by a small fin spine). All these features indicate a maneuverer in weedy or reef-like environments as well as along the bottom. Mature males have a distinctly strengthened, hooked and denticulated posterior end of the dorsal fin; the dorsal fin of males was significantly higher than that of females. This dorsal fin dimorphism is similar to that seen in the Gouramies, modern bony tropical fish available in any pet store. http://people.sju.edu/~egrogan/BearGulch/fossils_fish/Helegantulus_head_640.jpg Dorsal view of Heteropetalus elegantulus head They have a very small mouth, with the teeth crowded to the front of the jaws, and a variety of plucking, nipping, and crunching teeth. The jaw suspension itself is rather flexible to give it a certain amount of both lateral and fore-and-aft motion. The bright yellow spots in the dorsal view of a head are the inner ears, and the yellow is from iron oxide particles that were bio-concentrated during the life of this fish. H. elegantulus was originally described as a petalodont, but subsequent discoveries proved it to be otherwise; it is closely related to Debeerius ellefseni." Lit.: Lund, R. 1977 - A new petalodont (Chondrichthyes, Bradyodonti) from the Upper Mississippian of Montana. Annals of Carnegie Museum, 46 (19): 129-155. Grogan E.D. & Lund, R. (2000): Debeerius ellefseni (Fam. Nov., Gen. Nov., Spec. Nov.), an autodiastylic chondrichthyan from the Mississippian Bear Gulch Limestone of Montana (USA), the relationships of the Chondrichthyes, and comments on gnathostome evolution. Journal of Morphology, 243 (3): 219-245.

References: UM Paleotology center: http://hs.umt.edu/paleo/collections/browse.php?id=25460

The dark spot in the living chamber is either thought to be an ink sac or a beak and radula. References: Doguzhaeva, L., Mapes, R. and Mutvei, H. (2007):Beaks and radula of Early Carboniferous goniatites. Lethaia 30(4):305 - 313

Taxonomy from Factor & Feldman 1985. Diagnosis from Factor & Feldman 1985, p. 328: "Bivalved phyllocarid. Elongate telson with medial longitudinal carina, longer than pretelson segment, dorsally flexed at posterior end. Uropods reduced, blade-like, pretelson segment elongate. Fifth abdominal segment with circular notch in antero-ventral corner of pleuron. Line drawing from Factor & Feldman 1985, p. 328; Line bar represents 1 cm. Identified by oilshale using Factor & Feldman 1985. References: Frederick R. Schram & John Horner (1978). "Crustacea of the Mississippian Bear Gulch Limestone of Central Montana". Journal of Paleontology 52 (2): 394–406. Factor, D. F., and Feldmann, R. M. (1985) Systematics and paleoecology of malacostracan arthropods in the Bear Gulch Limestone (Namurian) of Central Montana. Annals of Carnegie Museum 54, p. 319-356.

Kalops monophrys is known by over 125 specimens from the Bear Gulch Limestone. K. monophrys is distinguished from its smaller sister species, Kalops diophrys, by having more caudal fin rays, a different number of supraorbital bone rows, and the development of its ganoine ridging at a larger size. The cranial osteology of Kalops most closely resembles that of the poorly known Palaeoniscus and "Elonichthys" serratus. The snout structure is closest to that of the Tarrasiiformes. Diagnosis from Poplin & Lund 2002, p. 1014: "Total length ranging from 44 to 116 mm; postrostral meeting the frontal in the midline anteriorly to mid-orbit level; ovoid antorbital; one row of supraorbitals; about five infraorbitals and five suborbitals; anterior extremity of the preopercle as high as the posterior plate of the maxillary; about 15 branchiostegal rays; one pair of extrascapulars; supracleithrum higher than opercle; from eight up to 17 predorsal median scutes, continuous between skull and dorsal fin; dorsal fin spanning 14 scale rows; anal fin with fulcra; scaled lobe of the caudal fin at 25 degrees to the body axis." Line drawing from Poplin & Lund 2002, p. 1017: Identified by oilshale using Poplin & Lung 2002. References: Poplin, C., & R. Lund (2002) "Two Carboniferous fine-eyed paleoniscoids (Pisces, Actinopterygii) from Bear Gulch (USA)." Journal of Paleontology 76: 1014-1028.

Lit.: MOORE, R., McKENZIE, S. and LIEBERMAN, B. (2007): A CARBONIFEROUS SYNZIPHOSURINE (XIPHOSURA) FROM THE BEAR GULCH LIMESTONE, MONTANA, USA. Palaeontology, Vol. 50, Part 4, 2007, pp. 1013–1019. Schram, F. (1979): Limulines of the Mississippian Bear Gulch limestone of central Montana, USA. Transactions of the San Diego Society of Natural History 19:67-74 (1979)

References: Lund, R. 1982 - Harpagofututor volsellorhinus new genus and species (Chondrichthyes, Chondrenchelyiformes) from the Namurian Bear Gulch Limestone, Chondrenchelys problematica Traquair (Visean), and their sexual dimorphism. Journal of Paleontology, 56 (4): 938-958. Lund, R. & Grogan, E.D. 1997 - Soft tissue pigments of the Upper Mississippian chondrenchelyid, Harpagofututor volsellorhinus (Chondrichthyes, Holocephali) from the Bear Gulch Limestone, Montana, USA. Journal of Paleontology, 71 (2): 337-342.

Paraconularia subulata (Hall 1858) together with Aviculopecten sp., a bivalve mollusc. References: Babcock, L. E., and R. M. Feldmann (1986): Devonian and Mississippian conulariids of North America. part B. Paraconularia, Reticulaconularia, New Genus, and organisms rejected from Conulariida. Annals of Carnegie Museum 55: 411-479.

Taxonomy from Fossilworks.org. Diagnosis from Factor & Feldman 1985 p.344: “Eumalacostracan, shrimp-like in overall appearance, with large, smooth carapace; rostrum long; 8 pairs of long, subequal, achelate thoracopods.” Line drawing from Factor & Feldman 1985, p 345. Bar represents 1 cm. Identified by oilshale. References: Schram, F. R. and Horner J. (1978): Crustacea of the Mississippian Bear Gulch Limestone of Central Montana. Journal of Paleontology 52(2):394-406. Factor D. F. and Feldmann R. M. (1985): Systematics and Paleoecology of Malacostracan Arthropods in the Bear Gulch Limestone (Namurian) of central Montana. Carnegie Museum of Natural History. 54, 319-356. Jenner, R. A., Hof, C. and Schram, F. R. (1998): Palaeo- and archaeostomatopods (Hoplocarida, Crustacea) from the Bear Gulch Limestone, Mississippian (Namurian), of central Montana. Contributions to Zoology 67 (3) 155-185.

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".