Stethacanthidae Lund, 1974

Ginter, Michał, 2002, Chondrichthyan fauna of the Frasnian-Famennian boundary beds in Poland, Acta Palaeontologica Polonica 47 (2), pp. 329-338 : 332

Family Stethacanthidae Lund, 1974 Genus Stethacanthus Newberry, 1889

Type species: Physonemus altonensis St. John and Worthen, 1875 .

Remarks.—Stethacanth teeth have cladodont−type crowns which means that the central cusp is the longest. The cusps are ornamented on both sides with numerous, subparallel, distinct cristae. In five−cusped specimens, which are the most common, the outer lateral pair of the cusps is higher and thicker than the intermediate ones. The lingual button (articulation boss) is elongated laterally or subcircular, its margins are perforated by several nutritive foramina. Often the lingual median foramen is larger than the others, which makes the button look like a horizontal eight. The labio−basal thickening is single, undivided, usually rectangular and straight.