| Accessory cusp (ac) |
Minor pointed or rounded projection of dentine covered with enamel on the mesial/distal ridge (i.e., the labiomesial (lamc), labiodistal (ladc), linguomesial (limc) and linguodistal (lidc) accessory cusps; Figs. 2C–2G) and/or transverse crest (i.e., the central accessory cusp (cac); Fig. 2C) of a gomphodont postcanine as well as on the carina (i.e., the mesial (mac) and distal (dac) accessory cusps; Fig. 2I) of a sectorial postcanine |
| Basin (ba) |
Deep concavity located on the occlusal surface of a gomphodont postcanine, on the mesial and/or distal surfaces of the crown (i.e., the mesial (mb) and distal (db) basins, respectively; Figs. 2C–2E and 2G), and receiving the crown’s cusps and crests of postcanines of the opposite jaw during occlusion. The basin seen on gomphodont postcanines is also referred as “valley” (Crompton, 1972; Godefroit & Battail, 1997; Hopson, 2005) |
| Canine (c) |
Maxillary and dentary tooth located between the distalmost incisor and the mesialmost postcanine and specialized for cutting and/or piercing (Figs. 2A, 2B and 3F). It is usually the largest tooth of the series |
| Carina (ca) |
A sharp, narrow, and well-delimited ridge or keel-shaped structure running apicobasally on the crown and, in some case, on the root base, and typically making the cutting edge of the tooth (McGraw-Hill, 2003; Brink & Reisz, 2014; Fig. 2A). Incisors and canines of gomphodont cynodonts often have denticulated mesial and distal carinae, whereas the carinae of sectorial teeth bear accessory cusps and/or minute denticles. The carinae are also referred as “cutting edges” (Crompton, 1955; Sues & Hopson, 2010), “cutting ridges,” “enamel ridges” (Kemp, 1980), “serrated margins,” “marginal ridges” (Hopson, 1984), “keeled edges” and “sectorial edges” (Kammerer et al., 2012) |
| Central accessory cusp (cac) |
Minor pointed or rounded projection labial and/or lingual to the central cusp on the transverse crest of upper gomphodont postcanine (Fig. 2C). Central accessory cusps correspond to the “buccal accessory cusp” of Sues, Hopson & Shubin (1992) and the “accessory cusps on transverse ridge” of Hopson (2005)
|
| Central cusp (cc) |
Main centrally positioned projection of dentine covered with enamel on the transverse crest of the gomphodont postcanine (Figs. 2C and 3). The central cusp is also known as the “middle cusp” (Kemp, 1980), “main central cusp” (Crompton, 1955; Hopson, 2014; Sidor & Hopson, 2018) and “upper central cusp”/“lower central cusp” of Hopson (2005)
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| Central ridge (cri) |
Labiolingually oriented crest centrally positioned on the mesial basin of a gomphodont postcanine (Fig. 2E) |
| Central valley (cev) |
Depression delimited by the lingual margin of the labial cusp and the labial margin of the lingual cusps on the transverse crest of the lower postcanine (Fig. 2G). The central valley corresponds to the “saddle” of Crompton (1972)
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| Centrolabial ridge (clar) |
Labiolingually oriented crest-like structure running on the labial surface of the central cusp, following the edge of the transverse crest, and connected to the labiocentral ridge of the labial cusp (Fig. 2F) |
| Centrolingual ridge (clir) |
Labiolingually oriented crest-like structure running on the lingual surface of the central cusp, following the edge of the transverse crest, and connected to the linguocentral ridge of the lingual cusp (Fig. 2F) |
| Cingular cuspule (cic) |
Small accessory cusp on a cingulum of a gomphodont or sectorial postcanine (Fig. 2D). Cingular cuspules are also referred as “cingular cusps” (Crompton, 1955; Abdala & Ribeiro, 2003; Abdala, Neveling & Welman, 2006) |
| Cingulum (ci) |
Bulge or shelf made of a succession of cingular cuspules on the rim of the occlusal surface of the gomphodont postcanine and on the basolingual or basolabial side of a sectorial tooth (Modified from Illiger, 1811; Owen, 1840; Sander, 1997c; Langer & Ferigolo, 2013; Fig. 2G). Cingula are also referred as “crenulations” by Seeley (1894)
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| Concave surface (cos) |
Apicobasally elongated concavity adjacent to the mesial and/or distal carinae on the labial and/or lingual surfaces of the crown in incisors and canines (Fig. 2B). The presence of concave surfaces on the lingual surface of the incisors and canines results in the salinon-shaped cross-sectional outlines of the crown, that is, an outline with both mesial and distal carinae facing linguomesially and linguodistally, respectively, subsymmetrical mesial and distal crown sides, a convex labial margin, and a biconcave lingual margin (Hendrickx, Mateus & Araújo, 2015, figure 5R) |
| Conical postcanine (cpc) |
Conidont tooth located in the mesialmost part of the postcanine tooth row (Figs. 2A, 2B and 3B). While Diademodon bears three or more conical postcanines (Fig. 3B), trirachodontids (Fig. 3) and some traversodontids (e.g., Boreogomphodon, possibly Andescynodon and Massetognathus) have one or two conical teeth, and the most derived traversodontids do not possess conical postcanine at all. Conical postcanine have also been known as “premolars” by 19th and 20th century authors (Broom, 1905, 1913; Brink, 1955; Grine, 1977; Gow, 1978) |
| Crown (co) |
Portion of the tooth covered with enamel, typically situated above the gum and protruding into the mouth (“couronne” of Fauchard, 1728; Cuvier, 1805; Schwenk, 2000; McGraw-Hill, 2003; Fig. 2I) |
| Cusp (cu) |
Pointed or rounded projection of dentine covered with enamel on the occlusal surface of a gomphodont postcanine or on the carina of sectorial teeth (Fig. 2G) |
| Denticle (de) |
An elaborate type of serration being formed by a projection of dentine covered with enamel along the carina of incisors, canines, and sectorial postcanines, as well as the crests of gomphodont postcanines (“dentelure” of Cuvier, 1805; Owen, 1840; McGraw-Hill, 2003; Brink & Reisz, 2014; Fig. 2J). The denticles are also referred as “denticulations” (Kammerer et al., 2012), and the large denticles in low number (<15) on the carinae are known as “mega-serrations”/“megaserrations” (Hopson, 1984), “cuspules” (Abdala & Ribeiro, 2003; Sidor & Hopson, 2018), “marginal cuspules” (Hopson, 1984; Sues, Hopson & Shubin, 1992; Abdala & Ribeiro, 2003; Abdala, Neveling & Welman, 2006; Liu & Abdala, 2014), “cusps” (Kammerer et al., 2012), “accessory cusp” and “posterior accessory cusp” (Ranivoharimanana et al., 2011; Kammerer et al., 2012) |
| Diastema (dia) |
Space separating the last upper incisor from the canine and the upper and/or lower canine from the first postcanine (Fig. 2B) |
| Distal accessory cusp (dac, D or d) |
Minor pointed or rounded projection of a sectorial postcanine, distal to the distal main cusp (Figs. 2I, 3Q and 3R). The distal accessory cusp is also referred as the “posterior cingular cusp” (Crompton, 1963; Abdala, Jasinoski & Fernandez, 2013), “posterior accessory cusp” (Abdala & Ribeiro, 2003; Abdala, Neveling & Welman, 2006; Sues & Hopson, 2010; Sidor & Hopson, 2018), “heel cusp” (Sues & Hopson, 2010), and “cuspule” (Liu & Sues, 2010). The distal accessory cusp of gomphodont is homologous to the “posterior cingular cusp” (sensu
Crompton, 1963) D and d of the upper and lower postcanines, respectively, in Crompton & Jenkins’ (1968) notation |
| Distal accessory ridge (dar) |
Crest-like structure on the distal surface of the transverse crest, perpendicular, diagonally oriented or even parallel from the latter (Figs. 2H, 3A and 3N) |
| Distal basin (db) |
Main concavity distal to the transverse crest on the occlusal surface of a postcanine (Figs. 2C, 2D, 2G and 2H). The distal basin, which is typically delimited by the distal ridge/cingulum distally, is also known as the “posterior basin” (Crompton, 1972; Hopson, 1984, 2005, 2014; Godefroit & Battail, 1997; Sues, Olsen & Carter, 1999; Hopson & Sues, 2006; Liu & Sues, 2010; Sues & Hopson, 2010; Sidor & Hopson, 2018) and the “posterior valley” (Crompton, 1972; Godefroit & Battail, 1997; Hopson, 2005) |
| Distal cingular cuspule (dcc) |
Minor pointed or rounded projection on the distal cingulum (dci) of a gomphodont postcanine (Figs. 2G and 3G). Distal cingular cusps are also known as “posterior cingular cusps” (Hopson, 2005; Abdala, Hancox & Neveling, 2005; Abdala, Jasinoski & Fernandez, 2013) and “heel cusp” (Crompton, 1955) |
| Distal cingulum (dci) |
Labiolingually oriented row of distal cingular cuspules (dcc) distal to the transverse crest and typically delimiting the distal rim of the occlusal surface of a gomphodont postcanine (Figs. 2C, 2D and 2F). The distal cingulum is also known as the “posterior cingulum” (Crompton, 1972; Kemp, 1980; Hopson, 2005; Abdala, Hancox & Neveling, 2005; Liu & Sues, 2010; Sues & Hopson, 2010; Martinelli, 2010; Hendrickx, Abdala & Choiniere, 2016), “posterior marginal cingulum” (Hopson, 2005; Sidor & Hopson, 2018), “posterior cingular crest” (Abdala & Ribeiro, 2003; Kammerer et al., 2012), and “crenulated posterior ridge” (Crompton, 1955) |
| Distal main cusp (dmc, C or c) |
Largest pointed or rounded projection of a sectorial postcanine distal to the main cusp (Figs. 2I, 3P and 3S). The distal main cusp is also known as the “posterior cusp” (Hopson, 2005; Liu & Sues, 2010; Sidor & Hopson, 2018), and the “posterior accessory cusp” (Crompton, 1963; Abdala & Ribeiro, 2003; Abdala, Neveling & Welman, 2006; Sues & Hopson, 2010; Sidor & Hopson, 2018). The distal main cusp is homologous to the “posterior accessory cusp” (sensu
Crompton, 1963) C and c of the upper and lower postcanines, respectively, in the notation proposed by Crompton & Jenkins (1968)
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| Distal ridge (dri) |
Labiolingually oriented crest-like structure distal to the transverse crest and delimiting the distal rim of the occlusal surface of a gomphodont postcanine (Fig. 2H). Also known as the “posterior wall” (Godefroit & Battail, 1997; Hopson & Sues, 2006; Hopson, 2014) and “posterior ridge” (Crompton, 1955; Godefroit & Battail, 1997) |
| Distal valley (dv) |
Depression delimited by the distal margin of the main cusp and the mesial margin of the distal main cusp on a sectorial postcanine (Fig. 2I) |
| Enamel texture (ent) |
Pattern of sculpturing on the crown surface at a sub-millimeter scale (Hendrickx, Mateus & Araújo, 2015; Fig. 2K). The enamel surface texture of incisors, canines, and postcanines of gomphodont cynodonts shows different patterns (Hendrickx, Mateus & Araújo, 2015, figure 6). A smooth enamel texture is here defined as the absence of enamel texture so that the crown surface does not show any irregularity. A non-oriented enamel texture with no pattern is referred as irregular. Finally, the enamel surface texture is called braided if the texture is oriented and made of alternating and interweaving grooves and short, moderately elongated or long sinuous ridges that are typically apicobasally oriented on the crown (Hendrickx, Mateus & Araújo, 2015; Fig. 2K). The term “crenulation” was used by Sidor & Hopson (2018) to describe the braided enamel texture seen on the canines of Cricodon
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| Gomphodont postcanine (gpc) |
Oval, quadrangular, subrectangular or subtriangular tooth in apical view allowing tooth-to-tooth occlusion (Figs. 2A, 2B and 3B). Upper gomphodont postcanines are typically labiolingually expanded whereas lower gomphodont postcanines can be labiolingually expanded, quadrangular or mesiodistally expanded |
| Incisor (i) |
Premaxillary or dentary tooth mesial to the canine and specialized for cutting (Figs. 2B and 3F) |
| Labial cingular cuspule (lacc) |
Minor pointed or rounded projection on the labial cingulum of a gomphodont and/or sectorial postcanine (Fig. 2C) |
| Labial cingulum (laci) |
Mesiodistally oriented row of accessory cuspules on the basolabial surface of a sectorial postcanine and/or delimiting the labial rim of the occlusal surface of a gomphodont postcanine (Fig. 2C). The labial cingulum is also known as the “external cingulum” (Crompton, 1972; Flynn et al., 2000; Abdala & Ribeiro, 2003; Abdala & Sa-Teixeira, 2004; Hopson, 2005, 2014; Abdala, Neveling & Welman, 2006; Melo, Martinelli & Soares, 2017), “buccal cingulum” (Sues, Olsen & Carter, 1999; Sues & Hopson, 2010; Melo, Martinelli & Soares, 2017), “crenulated ridge” (Crompton, 1955) and “cingular labial crest” (Martinelli, 2010) |
| Labial cusp (lac) |
Main labially positioned projection on the transverse crest of a gomphodont postcanine (Figs. 2C–2H and 3). The labial cusp is also know as the “external cusp” (Seeley, 1894; Crompton, 1972; Kemp, 1980; Flynn et al., 2000; Hopson, 2005, 2014; Hendrickx, Abdala & Choiniere, 2016; Sidor & Hopson, 2018), “upper external cusp”/“lower external cusp” (Hopson, 2005), “main external cusp” (Hopson, 2005, 2014; Sidor & Hopson, 2018), “main upper external cusp”/“main lower external cusp” (Hopson, 2014), “buccal cusp” (Grine, 1977; Sues, Hopson & Shubin, 1992; Sues, Olsen & Carter, 1999; Hopson & Sues, 2006), “buccal main cusp” (Melo, Abdala & Soares, 2015; Melo, Martinelli & Soares, 2017), “posterior buccal main cusp” (Melo, Abdala & Soares, 2015), “labial main cusp” (Godefroit & Battail, 1997; Abdala, Barberena & Dornelles, 2002) and “main labial cusp” (Chatterjee, 1982; Hopson, 1984, 2005, 2014; Godefroit & Battail, 1997; Abdala, Barberena & Dornelles, 2002; Abdala & Ribeiro, 2003; Abdala, Hancox & Neveling, 2005; Abdala & Smith, 2009; Martinelli, 2010; Ranivoharimanana et al., 2011; Kammerer et al., 2012; Liu & Abdala, 2014) |
| Labial ridge (lar) |
Mesiodistally oriented and labially positioned crest-like structure delimiting the labial rim of the occlusal surface of a lower gomphodont postcanine in Traversodontidae (Fig. 2D). The labial ridge is also referred as the “external ridge” (Seeley, 1895; Kemp, 1980; Hopson, 1984), “shearing ridge” (Hopson, 1984), “buccal ridge” (Sues, Olsen & Carter, 1999; Hopson & Sues, 2006; Liu & Sues, 2010), “posterior ridge” (Crompton, 1972), and “buccal longitudinal crest” (Hopson & Sues, 2006) |
| Labial valley (lav) |
Depression delimited by the lingual margin of the labial cusp and the labial margin of the central cusp on the transverse crest (Fig. 2F). The labial valley corresponds to the “embayment” of Crompton (1972) and the “V-shaped notch” of many authors (Crompton, 1955; Sues, Olsen & Carter, 1999; Sues & Hopson, 2010; Martinelli, 2010; Hopson, 2014) |
| Labiocentral ridge (lacr) |
Labiolingually oriented crest-like structure running on the lingual surface of the labial cusp, following the edge of the transverse crest, and connected to the centrolabial ridge of the central cusp (Figs. 2F and 2G) |
| Labiodistal accessory cusp (ladc) |
Minor pointed or rounded projection distal to the labial cusp and located on the labiodistal margin of the occlusal surface of a gomphodont postcanine (Figs. 2C, 2D and 2F–2H). The labiodistal accessory cusp is also known as the “posterior labial cusp” (Crompton, 1955; Liu, 2007; Martinelli, 2010; Liu & Abdala, 2014; Melo, Abdala & Soares, 2015), “posterolabial cusp” (Abdala & Ribeiro, 2003; Hopson, 2014), “posterior labial accessory cusp” (Kammerer et al., 2012), “posterior external accessory cusp” (Hopson, 2014), “posterior accessory labial cusp” (Abdala, Barberena & Dornelles, 2002; Abdala & Ribeiro, 2003; Abdala & Sa-Teixeira, 2004; Battail, 2005; Abdala, Hancox & Neveling, 2005; Kammerer et al., 2012), “posterior buccal cusp” (Liu & Sues, 2010; Melo, Abdala & Soares, 2015), “posterobuccal cusp” (Sues, Olsen & Carter, 1999; Hopson & Sues, 2006; Liu & Sues, 2010; Sues & Hopson, 2010), “posterior buccal accessory cusp” (Melo, Abdala & Soares, 2015), “posterolateral accessory cusp” (Hopson, 1985) and “posterior accessory cusp” (Crompton, 1972; Hopson, 1985) |
| Labiodistal ridge (ladr) |
Mesiodistally oriented crest-like structure running on the distal surface of the labial cusp and typically connected to the distal ridge/cingulum (Figs. 2C and 2F). The labiodistal ridge corresponds to the “posteroexternal ridge” of Hopson (2005) and Hendrickx, Abdala & Choiniere (2016)
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| Labiomesial accessory cusp (lamc) |
Main pointed or rounded projection mesial to the labial cusp and located on the labiomesial margin of the occlusal surface of a gomphodont postcanine (Fig. 2C). The labiomesial accessory cusp is also known as the “anterior accessory cusp of upper postcanine”/“anterior accessory cusp of lower postcanine” (Crompton, 1972), “anterior labial cusp” (Crompton, 1955; Liu, 2007; Martinelli, 2010), “anterolabial cusp” (Flynn et al., 2000; Liu, 2007; Hopson, 2014; Liu & Abdala, 2014), “anterolabial accessory cusp” (Hopson, 2014; Liu & Abdala, 2014; Melo, Martinelli & Soares, 2017), “anteroexternal accessory cusp” (Hopson, 2014), “anterior buccal cusp” (Melo, Abdala & Soares, 2015), “anterobuccal cusp” (Sues, Olsen & Carter, 1999; Hopson & Sues, 2006; Liu & Sues, 2010; Sues & Hopson, 2010), “anterior buccal accessory cusp” (Melo, 2014; Melo, Abdala & Soares, 2015), “mesiobuccal accessory cusp” (Melo, Martinelli & Soares, 2017), and “anterior accessory labial cusp” (Abdala, Barberena & Dornelles, 2002; Abdala & Ribeiro, 2003; Abdala & Sa-Teixeira, 2004; Battail, 2005; Abdala, Hancox & Neveling, 2005; Abdala & Smith, 2009; Ranivoharimanana et al., 2011; Kammerer et al., 2012) |
| Labiomesial ridge (lamr) |
Mesiodistally oriented crest-like structure running on the mesial surface of the labial cusp and typically connected to the mesial ridge/cingulum (Fig. 2C). The labiomesial ridge corresponds to the “anterior ridge” (Crompton, 1972; Hopson, 1985) and “anteroexternal ridge” (Hopson, 2005; Hendrickx, Abdala & Choiniere, 2016) |
| Lingual cingular cuspule (licc) |
Minor pointed or rounded projection on the lingual cingulum of a conical or sectorial postcanine (Figs. 2I and 3O). The lingual cingular cuspules are also known as the “lingual cingular cusps” (Sidor & Hopson, 2018) |
| Lingual cingulum (lici) |
Mesiodistally oriented row of cuspules on the basolingual surface of a sectorial postcanine and/or delimiting the lingual rim of the occlusal surface of a gomphodont postcanine (Figs. 2I and 3O) |
| Lingual cusp (lic) |
Main lingually positioned projection on the transverse crest of the postcanine (Figs. 2C–2H and 3). The lingual cusp is also known as the “internal cusp” (Romer, 1967; Kemp, 1980; Hopson, 1985), “main internal cusp” (Hopson, 2005, 2014; Sidor & Hopson, 2018), “upper internal cusp”/“lower internal cusp” (Hopson, 2005), “lingual main cusp” (Melo, Martinelli & Soares, 2017) and “main lingual cusp” (Crompton, 1955; Godefroit & Battail, 1997; Godefroit, 1999; Sues & Hopson, 2010; Melo, Martinelli & Soares, 2017) |
| Lingual ridge (lir) |
Mesiodistally oriented and lingually positioned crest-like structure delimiting the lingual rim of the occlusal surface of a gomphodont postcanine (Fig. 2E) |
| Lingual valley (liv) |
Depression delimited by the labial margin of the lingual cusp and the lingual margin of the central cusp on the transverse crest (Fig. 2F). The labial valley corresponds to the “embayment” of Godefroit & Battail (1997) and the “V-shaped notch” of Hopson & Sues (2006)
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| Linguocentral ridge (licr) |
Labiolingually oriented crest-like structure running on the labial surface of the lingual cusp, following the edge of the transverse crest, and connected to the centrolingual ridge of the central cusp (Fig. 2F) |
| Linguodistal accessory cusp (lidc) |
Minor pointed or rounded projection distal to the lingual cusp and located on the linguodistal margin of the occlusal surface of a gomphodont postcanine (Figs. 2C and 2F). The linguodistal accessory cusp is also known as the “posterior lingual cusp” (Crompton, 1955; Abdala, Barberena & Dornelles, 2002; Kammerer et al., 2012; Melo, Abdala & Soares, 2015), “posterolingual cusp” (Hopson & Sues, 2006; Liu, 2007), “posteromesial accessory cusp” (Hopson, 1985) and “posterior accessory lingual cusp” (Abdala & Ribeiro, 2003; Kammerer et al., 2012) |
| Linguodistal ridge (lidr) |
Mesiodistally oriented crest-like structure running on the distal surface of the lingual cusp and typically connected to the distal ridge/cingulum (Figs. 2C and 2F). The linguodistal ridge is equivalent to the “posterointernal ridge” of Hopson (2005)
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| Linguomesial accessory cusp (limc) |
Main pointed or rounded projection mesial to the lingual cusp and located on the linguomesial margin of the occlusal surface of a gomphodont postcanine (Figs. 2C and 2H). The linguomesial accessory cusp is also known as the “anterior accessory cusp of upper postcanine”/“anterior accessory cusp of lower postcanine” (Crompton, 1972), “anterior lingual cusp” (Crompton, 1955; Abdala & Smith, 2009; Martinelli, 2010; Melo, Abdala & Soares, 2015), “anterior lingual accessory cusp” (Melo, 2014), “anterolingual cusp” (Hopson, 1984; Sues, Hopson & Shubin, 1992; Abdala & Ribeiro, 2003; Abdala, Neveling & Welman, 2006; Gao et al., 2010; Sues & Hopson, 2010; Ranivoharimanana et al., 2011; Liu & Abdala, 2014), “anterolingual accessory cusp” (Sues & Hopson, 2010; Hopson, 2014; Liu & Abdala, 2014; Melo, Abdala & Soares, 2015; Sidor & Hopson, 2018) and “anterointernal accessory cusp” (Hopson, 2014) |
| Linguomesial ridge (limr) |
Mesiodistally oriented crest-like structure running on the mesial surface of the lingual cusp and typically connected to the mesial ridge/cingulum (Fig. 2C). The linguomesial ridge is equivalent to the “anterointernal ridge” of Hopson (2005)
|
| Longitudinal ridge (lri) |
Apicobasally high and mesiodistally short convexity on the labial and/or lingual surface of incisors and/or canines (modified from Hendrickx, Mateus & Araújo, 2015; Fig. 2B). Longitudinal ridges are also known as “flutes”/“fluting” (Seeley, 1894; Crompton, 1955), “longitudinal striations” (Hopson, 1984), “vertical striations” (Liu & Sues, 2010), and “vertical ridges” (Sues & Hopson, 2010) |
| Main cusp (mc, A or a) |
Major projection of dentine covered with enamel on the sectorial postcanine (Figs. 2I, 3Q and 3S). The main cusp can be denticulated on both its mesial and distal carinae. The main cusp is also known as the “central cusp” (Liu & Sues, 2010; Sues & Hopson, 2010; Sidor & Hopson, 2018), and the “central main cusp” (Sidor & Hopson, 2018). The main cusp is homologous to the cusps A and a of the upper and lower postcanines, respectively, in Crompton & Jenkins’ (1968) notation |
| Mesial accessory cusp (mac, E or e) |
Minor pointed or rounded projection on the mesial carina of a sectorial postcanine, mesial, or linguomesial to the mesial main cusp. The mesial accessory cusp is homologous to the “anterior cingular cusp” (sensu
Crompton, 1963) E and e of the upper and lower postcanines, respectively, in Crompton & Jenkins’ (1968) notation. Visible in some sectorial postcanines of Thrinaxodon and possibly Cynognathus, one or several mesial accessory cusps are assumed to be present in the multicuspid/crenulated lower sectorial teeth of juveniles Andescynodon (PVL 4390) and Massetognathus (MCZ 4267) |
| Mesial accessory ridge (mar) |
Crest-like structure on the mesial surface of the transverse crest, perpendicular, diagonally-oriented or parallel to the latter (Figs. 2H, 3A, 3C and 3N) |
| Mesial basin (mb) |
Main concavity mesial to the transverse crest on the occlusal surface of a gomphodont postcanine (Figs. 2C, 2E and 2H). The mesial basin is also known as the “anterior excavation in the crown” (Crompton, 1955), “anterior valley” (Crompton, 1972), “occlusal basin” (Melo, Martinelli & Soares, 2017) and “anterior basin” (Sues, Hopson & Shubin, 1992; Godefroit & Battail, 1997; Sues, Olsen & Carter, 1999; Hopson & Sues, 2006; Liu & Sues, 2010; Hopson, 2014) |
| Mesial cingular cuspule (mcc) |
Minor pointed or rounded projection on the mesial cingulum of a gomphodont postcanine (Figs. 2C, 2H and 3E) |
| Mesial cingulum (mci) |
Labiolingually oriented row of accessory cuspules mesial to the transverse crest and typically delimiting the mesial rim of the occlusal surface of a gomphodont postcanine (Fig. 2C). The mesial cingulum is also known as the “anterior cingulum” (Sues, Hopson & Shubin, 1992; Abdala & Sa-Teixeira, 2004; Battail, 2005; Hopson, 2005; Hopson & Sues, 2006; Abdala, Neveling & Welman, 2006; Kammerer et al., 2008; Gao et al., 2010; Sues & Hopson, 2010; Liu & Abdala, 2014; Hendrickx, Abdala & Choiniere, 2016), “crenulated ridge” (Kemp, 1980; Abdala, Neveling & Welman, 2006), “anterior crenulated ridge” (Crompton, 1955), “anterior marginal cingulum” (Hopson, 2005; Sidor & Hopson, 2018), “anterior external cingulum” (Hopson, 2005) and “anterior cingular crest” (Abdala & Ribeiro, 2003; Kammerer et al., 2012) |
| Mesial main cusp (mmc, B or b) |
Largest pointed or rounded projection on the mesial carina of a sectorial postcanine directly mesial to the main cusp (Figs. 2I, 3Q and 3S). The mesial main cusp, as used by Sidor & Hopson (2018), is also known as the “anterior cusp” (Liu & Sues, 2010; Sues & Hopson, 2010; Sidor & Hopson, 2018), the “anterior main cusp” (Abdala, Jasinoski & Fernandez, 2013), the “anterior accessory cusp” (Crompton, 1963; Abdala, Neveling & Welman, 2006; Sues & Hopson, 2010; Sidor & Hopson, 2018) and the “mesial accessory cusp” (Martinelli, Soares & Schwanke, 2016). The mesial main cusp is homologous to the “anterior accessory cusp” (sensu
Crompton, 1963) B and b of the upper and lower postcanines, respectively, in Crompton & Jenkins’ (1968) notation |
| Mesial ridge (mri) |
Labiolingually oriented crest-like structure mesial to the transverse crest and typically delimiting the mesial rim of the occlusal surface of a gomphodont postcanine (Figs. 2C and 2E). Also known as “transverse ridge” (Seeley, 1894), “anterior wall” (Hopson, 1985; Sues, Olsen & Carter, 1999; Flynn et al., 2000; Battail, 2005; Martinelli, 2010; Melo, Abdala & Soares, 2015; Melo, Martinelli & Soares, 2017) and “anterior crest” (Melo, Abdala & Soares, 2015) |
| Mesial valley (mv) |
Depression delimited by the mesial margin of the main cusp and the distal margin of the mesial main cusp on a sectorial postcanine (Fig. 2I) |
| Postcanine (pc) |
Maxillary or dentary tooth positioned distal to the canine. Postcanines include conical, gomphodont and sectorial teeth, which can change (e.g., Diademodon) from one morphology to the other (Fig. 2B) |
| Root (ro) |
Portion of the tooth beneath the gum and embedded in an alveolus (“racine” of Fauchard, 1728; Cuvier, 1805; “radix dentis” of Illiger, 1811; Owen, 1840; Hillson, 2005; Fig. 2I) |
| Sectorial postcanine (spc) |
Labiolingually compressed tooth typically located in the distalmost part of the postcanine tooth row, distal to the gomphodont teeth, and more rarely in the anteriormost part of the postcanine tooth row, and adapted for cutting in a shearing manner. Sectorial postcanines typically include a main cusp and often one or several accessory cusps mesial and/or distal to the main cusp (Figs. 2A, 2B, 3F and 3H) |
| Serration (se) |
A projection along a ridge or keel-like structure of a tooth, whether composed of enamel or by both enamel and dentine (modified from Brink & Reisz, 2014; Fig. 2J). Unlike the carinae of incisors, canines, and sectorial teeth which bear large and elaborate serrations (i.e., denticles), the serrated transverse crest and mesial and distal ridges of gomphodont postcanines only have simple and minute serrations visible with a microscope. Besides the well-delimited denticles of non-gomphodont postcanines, these serrations should not be confused with the triangular, hemi-spherical or sub-pyramidal cusps and cuspules present on the transverse crest and/or cingula of gomphodont and sectorial postcanines of some taxa |
| Shouldering (sho) |
Extension of the labiomesial margin of the upper postcanine forward, producing a “shoulder-like” process over the preceding postcanine (modified from Romer, 1967; Abdala & Ribeiro, 2003: figure 10C, D) |
| Transitional postcanine (tpc) |
Labiolingually expanded sectorial postcanine sharing an intermediate morphology between a gomphodont tooth and a sectorial postcanine (Figs. 2A, 3B, 3D and 3O). Transitional postcanines are typically formed by a recurved blade shape labial portion and a relatively flat lingual projection (Goñi & Goin, 1988). They are also referred as “intermediate gomphodont” (Fourie, 1963; Osborn, 1974; Grine, 1977; Goñi & Goin, 1988), “intermediate sectorial” (Osborn, 1974; Goñi & Goin, 1988), “semi-gomphodont” (Hopson, 1971; Crompton, 1972; Brink, 1977), “sub-gomphodont” (Hopson, 1964) and “sub-sectorial” (Martinelli, 2010) postcanines |
| Transverse crest (tc) |
Main labiolingually oriented ridge on the occlusal surface of the gomphodont postcanine and bearing the labial, lingual and often the central cusps (Figs. 2C–2E and 2H). The transverse crest is also known as the “transverse ridge” (Crompton, 1972; Hopson, 1984, 2005, 2014; Godefroit, 1999; Abdala, Neveling & Welman, 2006; Sues & Hopson, 2010; Sidor & Hopson, 2018), “anterior ridge” (Martinelli, 2010), “transverse anterior ridge” (Hopson & Sues, 2006), “anterior crest” (Liu & Abdala, 2014), “central crest” (Hendrickx, Abdala & Choiniere, 2016; Sidor & Hopson, 2018) and “posterior transverse crest” (Abdala, Barberena & Dornelles, 2002; Abdala & Ribeiro, 2003; Melo, Abdala & Soares, 2015) |
| Transverse undulation (tun) |
Band like enamel wrinkle extending along most of the incisor or canine length, typically from the mesial to distal carinae, perpendicular from the long axis of the crown (modified from Hendrickx, Mateus & Araújo, 2015; Fig. 2B) |
