Thrinacodus ferox ( Turner, 1982 )
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publication ID |
https://doi.org/ 10.26879/583 |
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persistent identifier |
https://treatment.plazi.org/id/ED189025-606B-FF8A-FECD-FDE96D559675 |
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treatment provided by |
Felipe |
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scientific name |
Thrinacodus ferox ( Turner, 1982 ) |
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Thrinacodus ferox ( Turner, 1982)
Figure 3.8 View FIGURE 3 -11
v. 1982 Harpago ferox sp. nov.; Turner, pp. 119, 121–122, figs. 2–4.
v. 1985 Harpagodens ferox Turner ; Wang and Turner, pp. 226–227, pl. 2, figs. 11–12.
v. 1989 Harpagodens ferox Turner ; Wang, pp. 105–106, pl. 28, figs. 6–7, pl. 29, fig. 2a, b, pl. 30, figs. 1–4.
v. 1991 Thrinacodus (Harpagodens) ferox Turner ; Turner, fig. 6, pl. 2, fig. G.
v. 1992 cf. Thrinacodus ferox Turner ; Kietzke and Lucas, p. 18, fig. 2D–H.
v. 1993 Thrinacodus ferox Turner ; Turner, fig. 8.7F.
v. 1996 Thrinacodus ferox Turner ; Ginter and Ivanov, p. 267, figs. 1, 2C–D.
v. 1999 Thrinacodus ferox Turner ; Ginter, p. 34, pl. 3, figs. 1–3, 5–7.
v. 1999 Thrinacodus sp. ; Ivanov, p. 273, pl. 4, figs. 2–4.
v. 2001 Thrinacodus ferox Turner ; Ginter, p. 719, figs. 3C–E, 4A–C.
v. 2003 Thrinacodus incurvus ; Duncan, pp. 119– 120, figs. 5–6.
v. 2010 Thrinacodus ferox Turner ; Ginter and Turner, p. 1669, fig. 3A–H.
v. 2010 Thrinacodus ferox Turner ; Ginter, Hampe and Duffin, p. 41, fig. 33B–F.
v. 2011 Thrinacodus ferox Turner ; Habibi and Ginter, pl.1, fig. A–B.
v. 2011 Thrinacodus ferox Turner ; Ivanov and Lucas, p. 55, fig. 3A–L.
v. 2012 Thrinacodus ferox Turner ; Behan, Walken and Cuny, p. 1249, fig. 3A–M.
Material. Eight teeth from sample 198404, 12 from
TS-1, and nine teeth from sample LG-1, Laurel
Formation, Laurel Downs, Tournaisian.
Description. Tricuspidate teeth with symmetrical
( Figure 3.11 View FIGURE 3 ) to highly asymmetrical forms (Figure
3.10). All cusps are strongly inclined lingually, circular in cross section and typically bear faint striations on both lingual and labial faces. The symmetrical tooth form (WAM 15.6.9, Figure 3.10 View FIGURE 3 - 11) is incomplete but comprises a crown and three cusps with equally sized basal circumferences. Asymmetrical teeth comprise one enlarged lateral cusp, a second medial cusp approximately one-third to two-thirds its size and the third smaller lateral cusp varying from a quarter of the size of the central cusp to equal in proportion. The tooth base is elongate lingually and when preserved, shows a greater than 45 degrees of torsion towards the distal end of the base. A large canal is present on the occlusal face of the base ( Figure 3.8 View FIGURE 3 -11) with a few smaller foramina on both the lingual and labial faces of the base ( Figure 3.10 View FIGURE 3 ).
Remarks. We consider both the symmetric and asymmetric teeth to be from the one species due to the gradation from symmetric to asymmetric forms recovered from the sample. The presence of just one symmetrical tooth ( Figure 3.11 View FIGURE 3 ) supports Turner’s (1982, figure 5) reconstruction of the Thinacodus ferox Turner, 1982 jaw placing the symmetrical forms in a symphyseal position of the jaw and the asymmetric teeth in more lateral positions. The teeth with lower degrees of symmetry ( Figure 3.9 View FIGURE 3 ) were not figured in the original description ( Turner, 1982) but appear similar in form to end member teeth figured in a reconstruction of Thrinacodus incurvus Newberry and Worthen, 1866 by Duncan (2003).
Among the teeth attributed to Th. ferox , are six significantly smaller teeth. These teeth typically have a well-formed base; however, the cusps are shorter than in larger specimens and bear well-rounded apices ( Figure 3.8 View FIGURE 3 ). It is possible the teeth belong to juvenile specimens and the susceptibility to wear contributed to the well-rounded cusps.
Distribution and stratigraphic range. In Australia Th. ferox is recorded from the latest Famennian in Queensland ( Turner, 1982) and Tournaisian in both the Canning and Carnarvon basins of Western Australia ( Trinajstic et al., 2014) and New South Wales ( Turner, 1982). Globally, Th. ferox is known from the Famennian in southern China ( Wang, 1993), Germany (Ginter, 1999), Morocco ( Derycke, 1992; Derycke et al., 2008) and Utah, USA ( Ginter, 2001). Teeth have also been recorded around the Devonian-Carboniferous boundary in New Mexico, USA ( Kietzke and Lucas, 1992). Thrinacodus ferox is known from the Mississippian in the South Urals and Moscow syncline Russia ( Ivanov, 1996), Belgium ( Delsate et al., 2003), Ireland ( Duncan, 2003).
Superorder CLADODONTOMORPHI Ginter, Hampe and Duffin, 2010
Order SYMMORIFORMES Zangerl, 1981
Family STETHACANTHIDAE Lund, 1974
Genus STETHACANTHUS Newberry, 1889
Stethacanthus ? sp.
Figure 3.12 View FIGURE 3 -16
Material. Two teeth from sample TS-1, Laurel Formation, Laurel Downs, Tournaisian.
Description. The description is primarily based on the most intact specimen (WAM 15.6.7, Figure 3.12 View FIGURE 3 -16) in which the tooth crown includes three ( Figure 3.14 View FIGURE 3 -16) to four cusps ( Figure 3.12 View FIGURE 3 ). The tooth possesses a distinct and highly elongate medial cusp with a basal width occupying approximately one-third of the mesio-distal length crown ( Figure 3.14 View FIGURE 3 -16). Two small, rounded lateral cusps are directed approximately 45 degrees from the centre of the tooth. The larger specimen (WAM 15.6.6, Figure 3.12 View FIGURE 3 ) bears a single smaller, laterally-divergent cusplet between the medial and lateral cusp. The cusps are relatively smooth apart from very faint vertical ridges on specimen WAM 15.6.7 ( Figure 3.16 View FIGURE 3 ). In the smaller specimen (WAM 15.6.7) the base extends lingually beyond the crown and is roughly rectangular in outline ( Figure 3.15 View FIGURE 3 ). The lingual margin is rounded with a small central indentation. The lateral margins of the base extend furthest at the corner of the lingual margin. In the larger specimen the base is asymmetrical, having a roughly ovoid outline ( Figure 3.12 View FIGURE 3 ). A distinct crown-base interface is lacking on the labial face of the tooth ( Figure 3.16 View FIGURE 3 ) with only a slight thickening along the baso-labial margin. An ovoid button, approximately the same width as the base of the central cusp ( Figure 3.14 View FIGURE 3 ), is located close to the lingual margin of the tooth base. A large canal opening is positioned in the centre of the button ( Figure 3.14 View FIGURE 3 ) with the opposing end on the underside of a very shallow concave base ( Figure 3.13 View FIGURE 3 ).
Remarks. Stethacanthid affinities are suggested by the elongate and thin, biconvex central cusp, the lack of a baso-labial depression (with slight labial projection under the main cusp) and a large foraminal opening on the lingual face of the orolingual button ( Duffin and Ginter, 2006). Furthermore, the larger tooth, which bears a single intermediate cusplet, suggests some of the teeth belonging to this species may be pentacuspid.
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