Edited by oilshale
- 1
Report Fossil
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By oilshale (edited)
Palaeoniscoid
Kingdom: Animalia
Eon: Phanerozoic
Era: Paleozoic
Period: Carboniferous
Sub Period: Mississippian
Epoch: Late
International Age: Serpukhovian
Big Snowy Group
Heath Formation
Bear Gulch Bed
Acquired by: Purchase/Trade
Length: 11 cm
Bear Gulch
Fergus County
Montana
United States
Taxonomy from Fossilworks.org
Diagnosis from Lund & Poplin 2000, p. 429: "Aesopichthyidae up to 9 cm long, with a subterminal mouth; single median rostropostrostral remote from the rim of the mouth; premaxillae small and loose, not meeting in the midline, resulting in a median rostral notch; vertically oriented pillar-shaped antorbital; three infraorbitals, the first is below and posterior to the orbit, the third is T-shaped and contacts the nasal anterodorsally; suborbitals thin, one large and occasionally up to three; dermosphenotic small, triangular; two paired extrascapulars; tear-drop shaped maxilla; mandible with short, anterior, toothed portion, a coronoid process and greatly overlapped by maxilla; a single row of marginal teeth on the premaxilla, maxilla and dentary; preoperculum, high, nearly vertical with a long quadratojugal line; operculum shorter anteroposteriorly than suboperculum, vertical to long axis of the fish; seven to eight branchiostegal rays; characteristic ornamentation of the dermal skull with heavy transverse ganoine ridges on the rostropostrostral, prominent, thick and posteriorly pointed tubercles on the skull roof, but significant ganoine absent from suborbitals, preoperculum and dermohyal; first infraorbital and extrascapulars fringed with sharp posterior spikes; pectoral fin with well spaced, unbranched, entirely articulated rays; dorsal fin with contiguous and entirely articulated rays except the seven posterior ones which are separated, unarticulated and borne by a short scaled lobe; caudal fin equilobate and deeply cleft with webbed rays; 12 to 14 median scutes continuous from skull to dorsal fin, and small scutes between dorsal and caudal fins. For meristics and morphometrics see Table 1."
Line drawing from Lund & Poplin 2000, p. 439:
Identified by oilshale using Lund & Poplin 2000.
Edited by oilshale
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