TRIRACHODONTIDAE

Abdala, F., Neveling, J. & Welman, J., 2006, A new trirachodontid cynodont from the lower levels of the Burgersdorp Formation (Lower Triassic) of the Beaufort Group, South Africa and the cladistic relationships of Gondwanan gomphodonts, Zoological Journal of the Linnean Society 147 (3), pp. 383-413 : 386

TRIRACHODONTIDAE LANGBERGIA MODISEI GEN. ET

SP. NOV.

Holotype: NMQR 3255 . A complete skull without a lower jaw ( Figs 2–6 ).

Locality: Langberg 556 (S28°13′48 ′– E27°57′57 ′), Paul Roux District , Free State Province, South Africa ( Fig. 1 ) .

Referred material: NMQR 3251 ( Figs 7 , 8B ), 3256 ( Fig. 9 ), 3268, 3280, 3281; BP /1/5362, 5363, 5400, 5401, 5404; CGP /1/33 120; SAM PK 11481 (see Table 1).

Figures

Figure 1. Map with the location of the outcrops with remains of Langbergia modisei. The dark area in the inset map is enlarged to show the localities. 1, Palmiet Fontein 94, Tarkastad. 2, Moerbeidal 648, Rouxville. 3, Kaaimansgat 146, Rouxville. 4, Hugo’s Kop 620, Rouxville. 5, Goedgedacht 15, Marquard. 6, Bosrand 12, Senekal. 7, Rexford Store 433, Bethlehem. 8, Langberg 556, Bethlehem. 9, Eerste Geluk 131, Bethlehem.

Figure 2. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in dorsal view. Ept, epipterygoid; L, lacrimal; Mx, maxilla; N, nasal; F, frontal; P, parietal; Pmx, premaxilla; Po, postorbital; Prf, prefrontal; Pro, prootic; Sq, squamosal; tf, trigeminal foramen (for maxillary and mandibular divisions of the trigeminal nerve). Note that bones in the facial region (maxillae, nasals, lacrimals, and prefrontals) are not in their original position. Shading indicates a broken portion (in the jugal) and sediment posteriorly of the postorbital bar. Scale bar = 3 cm.

Figure 3. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in right lateral view. J, jugal; L, lacrimal; Mx, maxilla; N, nasal; F, frontal; P, parietal; Pmx, premaxilla; Po, postorbital; Prf, prefrontal; pps, posterodorsal process of the septomaxilla; smf, septomaxillary foramen; Sq, squamosal; ss, squamosal sulcus. Note that bones in the facial region (maxillae, nasals, lacrimals, and prefrontals) are not in their original position. Scale bar = 3 cm.

Figure 4. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in ventral view. Bo, basioccipital; ce, cavum epiptericum; Ec, ectopterygoid; fo, fenestra ovalis; inf, incisive foramen; jf, jugular foramen; J, jugal; Mx, maxilla; Pa, palatine; pcf, paracanine fossa; Pmx, premaxilla; pop, paroccipital process; Pt, pterygoid; Q, quadrate; V, vomer. Shading indicates a broken portion (in the pterygoid flanges) and sediment covering part of the basicranium and zygoma. Scale bar = 3 cm.

Figure 5. Stereopair and interpretative drawing of the lateral wall of the braincase in NMQR 3255, holotype of Langbergia modisei. Ept, epipterygoid; otg, external orbitotemporal groove; pao, pila antotica of the prootic; P, parietal; Pro, prootic; Sq, squamosal; tf, trigeminal foramen. The dashed lines indicate broken and displaced surfaces of the epipterygoid. Shading indicates the broken surface of the prootic. Scale bar = 1 cm.

Figure 6. Stereopair and interpretative drawing of NMQR 3255, holotype of Langbergia modisei, in occipital view. Eo, exoccipital; pop, paroccipital process of the opistotic; oc, occipital condyle; Pp, postparietal; ptf, post-temporal foramen; qn, quadrate notch of the squamosal; So, supraoccipital; T, tabular; Sq, squamosal. Shading indicates the broken surface of the bone. Scale bar = 2 cm.

Figure 7. Stereopair and interpretative drawing of the palate of NMQR 3251. Ec, ectopterygoid; inf, incisive foramen; mpf, major palatine foramen; Mx, maxilla; Pa, palatine; pcf, paracanine fossa; Pmx, premaxilla; Pt, pterygoid; rc, replacement canine; V, vomer. Scale bar = 2 cm.

Figure 8. Stereopair of NMQR 3251. A, last left postcanines in lateral view (anterior, bottom). B, lower jaw in occlusal view. Note the replacement of the canine in the left ramus of the lower jaw. Scale bars = 2 cm.

Figure 9. Stereopair and interpretative drawing of NMQR 3256, in left lateral view. An, angular; D, dentary; J, jugal; L, lacrimal; Mx, maxilla; N, nasal; P, parietal; Pmx, premaxilla; Po, postorbital; Prf, prefrontal; Smx, septomaxilla; Sq, squamosal; ss, squamosal sulcus. Scale bar = 2 cm.