Submitted: October 10th, 2019 – Accepted: May 13th, 2020 – Published online: May 17th, 2020

To link and cite this article:

doi: https://doi.org/10.5710/AMGH.13.05.2020.3313

1 A REVIEW OF MORPHOLOGIES IN THE ; A 2 FRAMEWORK TO CHARACTERIZE AN ENIGMATIC BEAK FROM THE 3 , SAN JUAN, ARGENTINA 4 BRENEN M. WYND1*, RICARDO N. MARTÍNEZ2, CARINA COLOMBI2,3, and OSCAR 5 ALCOBER2 6 1Department of Geosciences, Virginia Tech, Blacksburg, Virginia 24061 USA: 7 [email protected]. 8 2Instituto Museo de Ciencias Naturales, Universidad Nacional de San Juan, Av. España 400 9 (norte), J5400DNQ San Juan, Argentina: [email protected]; [email protected]; 10 [email protected]. 11 3Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). 12 13 29 Pages, 5 figures, 2 tables. 14 15 WYND ET AL: TRIASSIC VERTEBRATE 16 17 *Corresponding author

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18 19 ABSTRACT 20 Beaks are an edentulous dietary modification present in numerous forms in turtles, ,

21 cephalopods, and some actinopterygian fishes today. Beaks have a rich record and have

22 independently evolved at least nine times over the past 300 million years in early ,

23 and their relatives, and crocodile and relatives. Here, we focus on the earliest

24 evolution of beaks in the fossil record during the Triassic Period (252 – 201.5 million

25 years ago). We analyze the phylogenetic distribution of Triassic beaks and review their

26 morphologies to create a framework to estimate beak similarity. With this, we describe a unique

27 fossil beak (PVSJ 427) from the Ischigualasto Formation, San Juan, Argentina, and

28 place it in our similarity analysis alongside other vertebrate from the Triassic Period, or

29 with Triassic origins. PVSJ 427 is a small iron-rich cast fossil that is triangular with a concave

30 midline shelf, rounded lateral walls, and an anterior point. No clear synapomorphies are present

31 in PVSJ 427, and as such, its phylogenetic position is not inferred herein. Some remnants of

32 bone are recognizable in thin sections of PVSJ 427, indicating that it likely represents a bony

33 beak replaced by minerals. The morphology of PVSJ 427 is most similar to the predentary, an

34 edentulous element restricted to ornithischian dinosaurs, although this specimen is approximately

35 three times larger than the earliest known ornithischian predentaries. Regardless of phylogenetic

36 position, PVSJ 427 reflects the earliest-known evolution of a predentary-like beak in reptiles and

37 indicates that this was ecologically convergent with the earliest ornithischian dinosaurs.

38 Keywords: Triassic. Reptilia. Beak. Ischigualasto Formation. Convergent Evolution.

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39 40 CONVERGENT evolution is the repeated evolution of morphological, behavioral, or

41 physiological similarity and suggests ecological congruence between distinct taxa (McGhee,

42 2011; Muschick et al., 2012; Mahler et al., 2013). The fossil record rarely preserves direct

43 evidence of behavior or physiology, but morphological convergence is well represented in the

44 fossil record (Nesbitt and Norell, 2006; Goswami et al., 2010; Nesbitt et al., 2010; Tseng and

45 Wang, 2011; Maidment and Barrett, 2012; Stocker et al., 2016; McCurry et al., 2017). One of

46 the most common convergences in morphology over the past 500 million years is the evolution

47 of a beak, a keratinous (=) or chitinous (=invertebrates) edentulous grasping

48 mechanism used in food manipulation and processing. In vertebrates, the bone underlying the

49 keratinous sheath is edentulous and often has a fused symphysis with extensive neurovasculature

50 foramina on the lateral surfaces (Holliday and Nesbitt, 2013).

51 Beaks have a rich fossil record, first appearing in the early in nautiloid and

52 coleoid cephalopods (Zangerl et al., 1969; Mapes, 1987; Doguzhaeva and Mapes, 2017). The

53 earliest-known beaked vertebrates are dicynodont , first appearing in the middle

54 Eodicynodon Assemblage Zone (Barry, 1974; Rubidge, 1990; Griffin and Angielczyk,

55 2019). Dicynodonts dominated the terrestrial-beaked- niche until the Middle Triassic,

56 wherein the earliest beaked diapsid reptiles are known. During the Triassic, reptiles diversified

57 and independently evolved beaks at least seven times, including in herbivorous dinosaurs

58 (Nesbitt and Norell, 2006; Spielmann et al., 2008; Nesbitt et al., 2010; Nesbitt, 2011; Desojo et

59 al., 2013; Ezcurra et al., 2016, 2017; Li et al., 2018). Although a keratinous beak has been

60 suggested in some basal sauropodomorphs (Crompton and Attridge, 1986; Sereno, 1997, 2007;

61 Martínez, 2009), it is most widely recognized amongst ornithischian dinosaurs, with their

62 characteristic predentary (Nabavizadeh and Weishampel, 2016). However, the presence of

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63 ornithischian dinosaurs in the Triassic is currently under scrutiny (Irmis et al., 2007a; Baron et

64 al., 2017; Agnolín and Rozadilla, 2018a; Baron, 2019). Regardless, there are presently no known

65 ornithischian or ornithischian-like reptile beaks from the Triassic Period.

66 Here, we describe a partial beak (PVSJ 427) from the Late Triassic Ischigualasto

67 Formation (231.4-225.9 Ma), San Juan, Argentina (Martínez et al., 2011). In conjunction, we

68 review beak morphology for vertebrate clades known from Triassic strata or with divergence

69 dates in the Triassic. We use this review to evaluate the phylogenetic, morphological and

70 ecological distribution of vertebrate beaks throughout the Triassic period. In doing so, we use

71 this framework to estimate similarity amongst Triassic beak morphotypes, including PSVJ 427,

72 to evaluate the ecological evolution of PVSJ 427 and temporally synchronous reptilian beaks.

73 MATERIALS AND METHODS

74 Geological and paleontological background

75 PVSJ 427 was found in the Ischigualasto Formation. This nonmarine unit crops out in

76 northwestern Argentina and forms part of the Ischigualasto-Villa Union Basin (Fig. 1). The

77 Ischigualasto Formation comprises a sequence of fluvial channel sandstones with well-drained

78 floodplain sandstones and mudstones. Interlayered volcanic ashes above the base and below the

79 top of the formation provide chronostratigraphic control and have yielded ages of 231.4 ± 0.3 Ma

80 and 225.9 ± 0.9 Ma (Rogers et al. 1993; Martínez et al., 2011).

81 The Ischigualasto Formation is divided into four units formalized as members (Tabor et

82 al., 2006; Currie et al. 2009): the La Peña (from the base to 40 m), the Cancha de Bochas (40 to

83 180 m), the Valle de la Luna (180 to 650 m), and the Quebrada de la Sal (650 to 700 m)

84 members (Fig. 1). The La Peña Member consists of multi-story channel sandstones and

85 conglomerates covered by poorly-drained floodplain mudstones. The Cancha de Bochas Member

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86 is composed of thick, well-drained floodplain mudstones with abundant calcisol interbedded with

87 high-sinuosity channel sandstones. The Valle de la Luna Member is mostly characterized by

88 amalgamated high-sinuosity channels with well-drained floodplain mudstones with argillisols,

89 abandoned channels and marsh deposits. Finally, the Quebrada de la Sal Member consists of

90 high-sinuosity channels, abundant volcanic ashes, and well-drained deposits with protosols.

91 The Ischigualasto Formation is divided from base to top into three abundance-based

92 biozones (Martínez et al., 2011): the Scaphonyx-Exaeretodon-, Exaeretodon, and

93 Jachaleria biozones. The Scaphonyx-Exaeretodon-Herrerasaurus biozone covers the La Peña,

94 Cancha de Bochas, and the lower part of Valle de la Luna Members. The Scaphonyx-

95 Exaeretodon-Herrerasaurus biozone is characterized by a predominance of the

96 Scaphonyx sanjuanensis, the Exaeretodon argentinus, and the Herrerasaurus

97 ischigualastensis, but also includes the majority of known from the Ischigualasto

98 Formation and has the highest recorded diversity. The Exaeretodon biozone covers the upper

99 portion of Valle de la Luna Member and is characterized by low diversity and high relative

100 abundance of the cynodont Exaeretodon argentinus. The Jachaleria biozone covers the

101 Quebrada de la Sal Member and is almost devoid of vertebrate fossils except for abundant

102 specimens of the dicynodont Jachaleria colorata.

103 PVSJ 427 was found at the “Cancha de bochas” locality, which is located in the upper

104 levels of the Cancha de Bochas Member and in the middle portion of the Scaphonyx-

105 Exaeretodon-Herrerasaurus biozone. The material was found 95 m above the base of the

106 Ischigualasto Formation. Abundant and diverse fauna were recovered from layers located at

107 similar stratigraphic levels, including the non-dinosaur dinosauriform Ignotosaurus fragilis,

108 theropod and sauropodomorph dinosaurs (e.g., Herrerasaurus ischigualastensis,

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109 lunensis), carnivorous and herbivorous (e.g., Ecteninion lunensis, Exaeretodon

110 argentinus), , and diverse pseudosuchian (e.g., scagliai,

111 galilei).

112 Phylogenetic distribution of beaked taxa

113 To reconstruct the evolution of reptile beaks, we use recent phylogenetic hypotheses for

114 archosauromorphs, crown archosaurs, and dicynodonts in conjunction with estimated divergence

115 dates for internal nodes (Benton and Donoghue, 2006; Nesbitt, 2011; Ezcurra et al., 2017;

116 Sengupta et al., 2017; Li et al., 2018; Griffin and Angielczyk, 2019). durations are based

117 on published values for divergence and dates (Tab. 1). For Pantestudines, we used the

118 lowest stratigraphic occurrence of Eunotosaurus africanus to estimate the divergence date of the

119 clade, because of its position in Pantestudines (Li et al., 2018), and the unresolved phylogenetic

120 position of Testudines. A branch length of 1 million years was added to all internal branches

121 with zero length.

122 Non-metric multidimensional scaling

123 We use a non-metric multidimensional scaling (nMDS) ordination to plot similarity of beak

124 morphology (see Stocker et al., 2016). We use an nMDS because it is able to accept discrete

125 characteristics (i.e., ordination method is non-Euclidean), which is often readily available in the

126 literature, and missing data, which is often characteristic for vertebrate fossils. We use an nMDS

127 over other methods (e.g., principal coordinates) because nMDS with a Gower ordination is non-

128 Euclidean, which is representative of the categorical input data. Furthermore, nMDS is iterative,

129 and will maximize similarity based on the number of axes the model is permitted to explore. We

130 sample 11 similarity characters (Tab. 2) for 12 taxa spanning stem , herbivorous

131 dinosaurs and their relatives, stem crocodiles and stem archosaurs. For each taxon, we score the

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132 anterior dentary and anterior premaxilla separately, to test how PVSJ 427 plots out between

133 cranial or mandibular morphotypes. Following Stocker et al. (2016) we use a Gower ordination,

134 under three, rather than four dimensions. Analyses were done in the R statistical environment

135 (Team, 2013), using the claddis and vegan packages (Oksanen et al., 2007; Lloyd, 2015) in code

136 modified from Stocker et al. (2016). Convex hulls are drawn around the taxa most similar to

137 PSVJ 427. Similarity is estimated based on clustered dendrograms (see supplement). Clustered

138 dendrograms are generated by performing a hierarchical cluster analysis (hclust: base R) on the

139 distance matrix used for the nMDS analysis (R Core Team, 2019). The hierarchical cluster

140 analysis iteratively clusters similar objects (taxa) until only a single cluster exists. We use a

141 Ward D2 clustering algorithm, which represents similarity amongst objects based by clustering

142 groups such that Euclidean distance between groups is minimized at each iteration (Murtagh and

143 Legendre, 2014). The resultant cluster nests taxa in a phylogenetic-like structure, but instead of

144 following relationship, taxa more similar to one another (based on the distance matrix) are

145 clustered together in what resembles clades.

146 Thin section and Scanning Electron Microscope

147 Petrographic thin sections of PVSJ 427 were created and analyzed at the Museo de Ciencias

148 Naturales in San Juan, Argentina. A thin section (30 µ) of PVSJ 427, taken from the

149 posteriormost margin of the specimen, was analyzed to determine its diagenetic history. The thin

150 section was examined under a transmission and reflection polarized petrographic microscope

151 XP607. To complete the analyzes, the sample was analyzed under a Scanning Electron

152 Microscope (SEM-EDS; Carl Zeiss EVO MA10W), with an X-ray energy dispersion micro

153 analysis system (Bruker Quantax 200) with an analytical detector (SDD XFlash 6|30). For figure

154 images, one sample was metallized with gold-palladium (spray coating technique), and for the

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155 EDS (Energy Dispersive X-Ray Spectroscopy) elemental analysis, the sample was graphitized

156 (carbon evaporation technique).

157 Institutional abbreviations

158 MCZ, The Louis Agassiz Museum of Comparative Zoology, Cambridge, Massachusetts, USA;

159 NMT, National Museum of Tanzania, Dar es Salaam, Tanzania; PVSJ, Museo de Ciencias

160 Naturales, Universidad Nacional de San Juan, Argentina.

161 SYSTEMATIC PALEONTOLOGY

162 GNATHOSTOMATA Cope, 1889

163 Incertae sedis

164 Fig. 2

165 Referred materials. PVSJ 427; partial beak replaced by iron-rich minerals.

166 Geographic and stratigraphic occurrence. “Cancha de bochas” locality in Ischigualasto

167 Provincial Park, San Juan Province, Argentina (Fig. 1). PVSJ 427 was found isolated in a meter

168 thick tabular paleochannel deposit, characterized by trough-cross stratified medium-grained

169 sandstone, surrounded by thick floodplain deposits with Calcisols of the Cancha de Bochas

170 Member (sensu Currie et al., 2009) and the middle portion of the Scaphonyx-Exaeretodon-

171 Herrerasaurus biozone (sensu Martínez et al., 2011), at around 95 m from the base of the

172 Ischigualasto Formation.

173 Age. Late (~230 Ma) on the basis of a radioisotopic date near the base of the

174 Ischigualasto Formation (Rogers et al., 1993; Martínez et al., 2011).

175 Comments. We refrain from assigning a formal diagnosis to this specimen as it does not retain

176 any clearly synapomorphic characters and is thus taxonomically ambiguous; however, it is

177 clearly unique to the Ischigualasto Formation (Rogers et al., 1993; Martínez et al., 2011).

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178 Although PVSJ 427 likely represents an (based on the representative Ischigualasto

179 Fauna; Martínez et al., 2011), we refrain from assigning it to any taxonomic group above

180 Gnathostoma. We offer a brief description of the specimen followed by a brief review of Triassic

181 beak morphologies.

182 Description. PVSJ 427 is a fragmentary beak, broken posteriorly, and as preserved is slightly

183 wider than it is long, though there appears to be some lateral compression (Fig. 2). PVSJ 427 is a

184 natural cast featuring a thick layer of an iron-rich mineral, but the overall morphology of the

185 specimen appears to be retained.

186 A cross section of the beak cast shows that, despite its excellent external morphology, its

187 internal structure cannot be differentiated into original or bone (hydroxyapatite) tissues

188 (Fig. 3). However, two well differentiated areas can be recognized in the cast. Externally, an area

189 that almost completely surrounds the outer edge of the beak cast and most likely represents the

190 beak material (=bone). This external region most likely received a major influence of decay from

191 the beak during fossil-diagenesis. Surrounded by the external area, there is an internal region that

192 is characterized by detrital fill. Both areas are separated by a net limit, although the limits are

193 very irregular (Fig. 3.1-2).

194 The outer zone is characterized by an opaque iron-oxide cement (likely hematite) coating

195 angular detrital grains of monocrystalline quartz with scarce muscovite and other siliciclastic

196 grains (Fig. 3.1 and 3.3). This outer zone also hosts microcrystalline carbonate cement,

197 intergrowing in paragenesis with the iron-rich mineral cement. However, something outstanding

198 of this zone is that the calcite also seems to have replaced remains of bone chip in some areas.

199 This is attested by the curved and net morphologies of calcite chips that resemble the walls of

200 vascular canals or trabecular bone (Fig. 3.3). If this is the case, calcite would have completely

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201 replaced the hydroxyapatite of the original bone tissue that would have formed the beak. Unlike

202 the outer zone, the internal zone is characterized by detrital grains of polycrystalline and

203 monocrystalline quartz, micas. and feldespars, surrounded dominantly by poikilitic sparry-calcite

204 as preponderant cement (Fig. 3.4-5). In some areas, detrital grains are scarce and big dogtooth

205 calcite crystals are present, showing that they grew in empty spaces among detrital grains (Fig.

206 3.5). Taken together, this indicates that PVSJ 427 represents a natural cast of a bony beak, based

207 on the presence of an iron-rich mineral layer near the outermost regions of the beak, as well as

208 some original bone material in this iron-rich layer that has been diagenetically altered.

209 Anatomically, the anteriormost margin of the beak curves dorsally to form a shallow

210 point. No morphological features are present to suggest whether PVSJ 427 represents the upper

211 or lower beak. PVSJ 427 is broken opposite its occlusal margin, such that it does not preserve its

212 dorsal or ventral extent. In occlusal view, PVSJ 427 is “V”-shaped, and is taphonomically not

213 symmetrical along the sagittal plane, as the right side extends more laterally than does the left.

214 Medially, there is a thin shelf that is broken posteriorly. The lateral sides of the beak are

215 expanded occlusally and have a generally blunt and rounded morphology (Fig. 2.1 and 2.3).

216 There is a concavity that connects the medial shelf to the medial walls of the beak opposite the

217 occlusal surface (Fig. 2.2). However, petrographic thin sections were not able to sample this

218 midline shelf to confirm whether or not it preserves the iron-mineral rich arrangement similar to

219 the lateral walls.

220 Remarks. PVSJ 427 is unique in that it bears a distinct medial shelf with rounded lateral walls.

221 Based on the thin-section, the rounded lateral walls show signs of replaced bone material with

222 potential signs of vasculature, suggesting that they reflect the morphology of the original beak.

223 However, this feature is not synapomorphic to any known clades, and thus is not enough to

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224 assign this specimen to a clade beyond Amniota. As such, we compare the morphology of PSVJ

225 427 to other beaked either known from the Triassic or with proposed Triassic origins

226 (Fig. 4).

227 Description of beaked clades from the Triassic

228 Aetosauria. are a clade of herbivorous early diverging pseudosuchians known from

229 the Late Triassic globally (Desojo et al., 2013), including the Ischigualasto Formation (Martínez

230 et al., 2012a). Aetosaurs retain teeth except for the anterior margins of the dentary and

231 premaxilla, which are edentulous, except in the earliest diverging members of the clade (Desojo

232 et al., 2013; Brust et al., 2018). Anteriorly, the premaxillae curve dorsally, such that there is no

233 overbite that would obscure the lower in occlusion. From the anteriormost dentary tooth, the

234 dentaries curve anterodorsally (=occlusally) and are mediolaterally compressed to form an

235 elongate tip (see Desojo and Báez, 2007, Fig. 5), additionally, the mandibular symphysis is also

236 anteroposteriorly elongate (Holliday and Nesbitt, 2013), forming an extended midline shelf of

237 the dentary. Dentaries of early diverging members of the clade (e.g., Aetosauroides scagliai;

238 Brust et al., 2018) are edentulous anteriorly, but do not curve dorsally to the same degree as later

239 diverging members (e.g., haplocerus; Small, 2002). The edentulous margins of

240 later diverging mandibles are characterized by numerous neurovasculature foramina,

241 suggesting a keratinous beak was present, although this has been refuted for early diverging

242 members, such as engaeus (Desojo and Báez, 2007; Holliday and Nesbitt,

243 2013).

244 Dicynodontia. Dicynodonts are a highly diverse clade of synapsids known globally from the

245 Permian and Triassic periods (Kammerer et al., 2011a). Although not synapomorphic of the

246 group, many dicynodonts are recognized by having edentulous , often with the exception of

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247 a large maxillary canine. In all presently known Triassic forms, Kannemeyeriiformes and

248 lystrosaurids, the premaxillae and anterior dentaries are entirely edentulous and bear extensive

249 pitted foramina, indicative of a keratinous beak (Kammerer et al., 2013). Relatively complete

250 kannemeyeriiform crania are known from the stahleckeriids Ischigualastia jenseni and

251 Jachaleria colorata, which are well known from the Ischigualasto and Los Colorados

252 formations, respectively (Martínez et al., 2012a). Although stahleckeriids are not the only clade

253 of kannemeyeriiform dicynodont, premaxillary and anterior dentary morphology does not differ

254 significantly between the stahleckeriids and the shansiodontids or kannemeyeriids (Renaut and

255 AJ, 2001; Domnanovich and Marsicano, 2012; Kammerer et al., 2013). As such, we refrain from

256 reviewing the beak morphology for each individual kannemeyeriiform clade and we focus on

257 characteristics representative of Kannemeyeriiformes in general. Specifically, we use

258 Ischigualastia jenseni as our model, because it is known from the same beds as PVSJ 427 from

259 multiple crania, and its beak morphology is consistent with its stratigraphic successor, Jachaleria

260 colorata (Cox, 1965; Keyser and Cruickshank, 1979; Araújo and Gonzaga, 1980; Martínez et al.,

261 2012a).

262 Kannemeyeriiform beaks are characteristic amongst Triassic beaks by being anteriorly

263 flattened, having a squared-off morphology (Cox, 1965). Occlusally, both the premaxillae and

264 dentaries have straight edges, but in some cases, the premaxillae can be weakly occlusally

265 directed (e.g., MCZ VPRA 3120; Cox, 1965). The lateral walls of the premaxillae are thin and

266 sharp, forming a relatively tall wall (e.g., MCZ VPRA 3118), though the same condition is not

267 present in the dentaries (Cox, 1965; Hancox et al., 2013). Medially and ventrally, the palate often

268 bears paired ridges that originate anteriorly at the wall of the premaxilla and taper posteriorly

269 onto the vomer (Cox, 1965). The left and right dentaries and premaxillae are fused and

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270 posteriorly expanded, forming medial shelves, although the premaxillary shelf is deeper

271 occlusally than that of the dentary. Laterally, both the premaxilla and dentary are covered in

272 small foramina at their anterior margins, suggesting kannemeyeriiforms possessed a horny

273 rhamphotheca in life (Crompton and Hotton, 1967).

274 Ornithischia. Ornithischian dinosaurs represent one of the two major groups of herbivorous

275 dinosaurs which dominate the Mesozoic period; however, their occurrence during the Triassic

276 has undergone scrutiny (Irmis et al., 2007a; Baron et al., 2017; Baron, 2019). Three distinct taxa

277 are known from the Triassic and have been recovered as ornithischians, Eocursor parvus (Butler

278 et al., 2007), mertii (Casamiquela, 1967), and an unnamed heterodontosaurid from

279 South America (Baez and Marsicano, 2001), which was later suggested to be in age

280 (Olsen et al., 2010). Basal members of Ornithischia are united by a series of characters, of which

281 include the predentary, a separate ossification anterior to and in articulation with the dentaries

282 (Nabavizadeh and Weishampel, 2016). Because neither the South American ‘heterodontosaurid’,

283 Eocursor parvus, nor Pisanosaurus mertii have a preserved predentary or premaxilla, we use the

284 predentaries and premaxillae of the early-diverging ornithischians, tucki

285 (Crompton and Charig, 1962) and diagnosticus (Porro et al., 2015; Galton, 1978)

286 to describe the plesiomorphic ornithischian beak condition.

287 The premaxillae of Heterodontosaurus tucki and Lesothosaurus diagnosticus are united

288 by the presence of posterior premaxillary teeth and a short, edentulous anterior margin of the

289 predentary with clear foramina present, indicating the presence of a rhamphotheca (Norman et

290 al., 2011; Porro et al., 2015). However, the two differ from one another in that the premaxillae of

291 L. diagnosticus are unfused and the anteriormost tip is not ventrally directed, as in H. tucki

292 (Norman et al., 2011; Porro et al., 2015). The skull material of H. tucki is laterally compressed,

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293 but it appears that the anterior tip of the premaxillae of both H. tucki and L. diagnosticus are

294 rounded in morphology and do not come to a distinct point (Norman et al., 2011; Porro et al.,

295 2015). The anterior morphology of the predentary for early-diverging ornithischians is roughly

296 triangle-shaped with a rounded anterior margin (Norman et al., 2011; Porro et al., 2015), and this

297 morphology is consistent throughout ontogeny in heterodontosaurids (Butler et al., 2008).

298 Posteriorly, most ornithischians have lateral and ventral processes which articulate with the

299 anterior margin of the dentaries (Porro et al., 2015; Nabavizadeh and Weishampel, 2016), though

300 this morphology is not present in H. tucki (Norman et al., 2011). In dorsal view, the medial

301 margin of the predentary is concave, forming a scoop-shape morphology that is more shallow in

302 L. diagnosticus than in H. tucki (Norman et al., 2011; Porro et al., 2015; Nabavizadeh and

303 Weishampel, 2016). In lateral view, the morphology of the predentary tip can vary between

304 species from pointed dorsally (H. tucki) to straight (L. diagnosticus); furthermore, in dorsal view,

305 the lateral walls of the predentary can vary between species from dorsally beveled and rounded

306 (H. tucki) to mediolaterally thin and forming a sharp ridge (L. diagnosticus; Norman et al., 2011;

307 Porro et al., 2015; Nabavizadeh and Weishampel, 2016).

308 Pantestudines. Turtles and many proto-turtles are a beaked clade that have their origin in the

309 Permian, and their first beaked members appearing in the Late Triassic, with the early-diverging

310 proto-turtle taxa Odontochelys semitestacea (IVPP 15639; Li et al., 2008) and Eorhynchochelys

311 sinensis (Li et al., 2018), and the testudinatans Palaeochersis talampayensis (Rougier et al.,

312 1995; Sterli et al., 2007) and Proganochelys quenstedti (Baur, 1888) displaying a progressive

313 loss of teeth. Odontochelys semistestacea, as the one of the earliest proto-turtles, is unique in

314 having the plesiomorphic condition of both dentaries and maxillae with teeth (Li et al., 2008).

315 Eorhynchochelys sinensis has endentulous premaxillae, maxillae, and dentaries, however the

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316 occlusal surfaces are not well represented and thus are not suitable for comparison (Li et al.,

317 2018). Palaeochersis talampayensis has edentulous premaxillae, maxillae, and dentaries, though

318 the beak is taphonomically distorted in both recovered crania (Sterli et al., 2007). Therefore, we

319 compare PVSJ 427 to the morphology present in P. quenstedti, as it represents one of the earliest

320 known beaked testudinatans, has mandibular and rostral elements that are morphologically

321 consistent with other early turtles such as Australochelys africanus (Gaffney and Kitching,

322 1994), and character scores (Tab. 2) were readily available in the literature. The premaxillae of

323 P. quenstedti are very thin and make up only a small portion of the beak, which is primarily

324 composed of the maxillae (Gaffney, 1990). In ventral view, the maxillae are thin, and they come

325 to a sharp cutting surface (i.e., triturating surface), where the rhamphotheca would cover the

326 bone (Gaffney, 1990). Ventrally, there is a shallow ridge that spans the premaxilla and maxilla

327 and contacts the vomers posteriorly. Importantly, at the anterior margin of the skull, the

328 pre/maxillae are dorsoventrally short where they border the external nares (Gaffney, 1990). The

329 dentaries also have a sharp triturating surface, with no morphological change at the symphysis

330 (i.e., no dorsally projecting tip), and there exists no medial shelf (Gaffney, 1990).

331 Rhynchosauria. Though rhynchosaurs are not beaked based on our above definition, they have

332 been classically referred to as beaked vertebrates or those with beak-like premaxillae (e.g.,

333 Benton, 1990) and therefore we include them in this analysis. Rhynchosaurs are herbivorous

334 archosauromorphs that are common representatives of the Middle to early Late Triassic. With the

335 exception of browni (Dilkes, 1998), rhynchosaurs are characterized by ventral

336 expansion of the paired premaxillae (not premaxillary teeth), which forms a large bilobed beak in

337 anterior view (Dilkes, 1995; Gentil and Ezcurra, 2017). In many taxa, including the

338 (Huxley, 1859), species of which are commonly found in the Ischigualasto

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339 Formation (e.g., Hyperodapedon [=Scaphonyx] sanjuanensis; Sill, 1970; Martínez et al., 2012;

340 Gentil and Ezcurra, 2017), the premaxillae are separated by a clear symphysis and are ventrally

341 rounded and extend well below the ventral margin of the maxillae in lateral view, as is similarly

342 seen in later-diverging southern African rhynchosaurs (e.g., stockleyi; Huene,

343 1938; Dilkes, 1995). Anteriorly, the dentaries are edentulous and have a dorsal expansion of the

344 bone which occludes with the posterior margin of the ventrally expanded premaxillae (Dilkes,

345 1995; Langer and Schultz, 2000). Similar to the premaxillae, the dentaries are unfused and

346 commonly terminate anterodorsally in a bilobed beak (Sill, 1970; Dilkes, 1998; Langer and

347 Schultz, 2000). Importantly the premaxillae and anterior dentaries do not have increased

348 vasculature that would be characteristic of a rhamphotheca (Sill, 1970; Langer and Schultz,

349 2000).

350 Shuvosauridae. Shuvosauridae is a clade of possibly herbivorous pseudosuchians convergent

351 with ornithomimid dinosaurs, including okeeffeae (Nesbitt and Norell, 2006),

352 inexpectatus (Chaterjee, 1993) and Sillosuchus longicervix (Alcober and Parrish,

353 1997). Additionally, Lotosaurus adentus (Zhang, 1975), the sister taxon to Shuvosauridae, also

354 lacks teeth on the premaxilla, maxilla and dentary suggesting that the presence of a beak is

355 ancestral to Shuvosauridae (Nesbitt, 2011). The shuvosaurids are united in being entirely

356 edentulous and a series of synapomorphic characters relating to the pelves (Nesbitt and Norell,

357 2006); however, cranial material is only known for S. inexpectatus and E. okeeffeae (Alcober and

358 Parrish, 1997; Lehane, 2005; Nesbitt, 2007). The shuvosaurid premaxillae are unfused, rounded

359 and parabola-shaped in ventral view, form a short secondary palate ventrally, and are covered in

360 foramina laterally (Lehane, 2005; Nesbitt, 2007). The ventral and lateral edges of the premaxillae

361 and dentaries are mesiodistally thin and sharp, forming a cutting surface in S. inexpectatus

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362 (Lehane, 2005), whereas the cutting surface is restricted to the dentaries in E. okeeffeae (Nesbitt,

363 2007). In lateral view, the symphyseal region of the shuvosaurid premaxillae do not come to

364 ventrally extended tip, nor is a pointed dorsal tip present in the symphyseal region of the dentary

365 (Lehane, 2005; Nesbitt, 2007). The dentaries are also covered in foramina at their anterior extent

366 and have an anteroposteriorly elongate symphysis, which forms a medial shelf just ventral to the

367 cutting surfaces (Lehane, 2005; Nesbitt, 2007).

368 . Silesaurid dinosauriforms synapomorphically possess a dentary that at its anterior

369 end is thin, edentulous, tapers to a point and covered in vasculature. This is interpreted as beak

370 that would have been covered by a horny rhamphotheca in life (Dzik, 2003; Ferigolo and Langer,

371 2007; Nesbitt et al., 2010). Importantly, anterior dentary morphology is only confidently known

372 for Asilisaurus kongwe (Nesbitt et al., 2010; Nesbitt et al., 2019), agudoensis

373 (Ferigolo and Langer, 2007) and opolensis (Dzik, 2003), while the anteriormost

374 margin of the dentary is not presently known for Diodorus scytobrachion (Kammerer et al.,

375 2011), the “Hayden Quarry silesaur,” (Irmis et al., 2007) or admixtus (Romer, 1972;

376 Arcucci, 1987; Ezcurra et al., 2019). Importantly, recently recovered dental elements of

377 Lewisuchus admixtus indicate that the full anteroposterior extent of the lower and upper jaws

378 possessed teeth (Ezcurra et al., 2019). The orientation of the beak may vary across taxa, but

379 silesaurid beaks can be identified on the basis that the dentary tapers to a point anteriorly, the

380 meckelian groove extends through the dentary symphysis (except D. scytobrachion), and that the

381 meckelian groove is restricted to the ventral margin of the dentary (Nesbitt et al., 2010;

382 Kammerer et al., 2011b). Additionally, specimens of A. kongwe, S. agudoensis and S. opolensis

383 have distinct striations on the lateral surface of the anterior margin of the dentary (Dzik, 2003;

384 Ferigolo and Langer, 2007; Nesbitt et al., 2010). Furthermore, the dentaries are unfused and are

17

385 mediolaterally thin in A. kongwe (NMT RB159; Nesbitt et al., 2019). The premaxillae of A.

386 kongwe are anteriorly edentulous, unfused and are adorned laterally with foramina, indicating a

387 horny rhamphotheca was present here as well (NMT RB159; Nesbitt et al., 2019). Ventrally, the

388 premaxillae are weakly concave and taper to a rounded point anteriorly, having a half-parabola-

389 like morphology (pers. obs.).

390 Trilophosauridae. Trilophosaurids are a clade of herbivorous archosauromorphs from the Late

391 Triassic of North America. Currently, there are two trilophosaurid genera with edentulous jaws

392 that are extensively covered in neurovasculature (=keratinous rhamphotheca); Teraterpeton

393 hrynewichorum from the Late Triassic of Nova Scotia (Sues, 2003), and

394 (buettneri and jacobsi) from the Late Triassic of the southwestern US (Spielmann et al., 2008).

395 Trilophosaurus buettneri is known from multiple nearly complete crania (Spielmann et al., 2008)

396 and possesses triangle-shaped premaxillae and dentaries that are anteriorly rounded. Both the

397 premaxillae and endentulous margins of the dentaries have a broad medial shelf, formed by an

398 anteroposteriorly expanded symphysis (Spielmann et al., 2008). The lateral walls of both

399 premaxillae and dentaries form sharp and thin blade-like surfaces (Spielmann et al., 2008).

400 Anteriorly, the premaxillae and dentaries of Trilophosaurus have straight occlusal margins, and

401 do not have occlusally directed tips (Spielmann et al., 2008). The beak of T. hrynewichorum is

402 anteroposteriorly elongate, compared to T. buettneri, but are otherwise morphologically similar

403 (Sues, 2003).

404 RESULTS

405 Morphological similarity of Triassic beaks

406 Our non-metric multidimensional scaling (nMDS) ordination show the morphospace distribution

407 of Triassic beak types and how PVSJ 427 compares to other taxa. Both the lower jaw and

18

408 premaxillary ordinations returned low stress values of 0.0647 and 0.0367, respectively. Based on

409 clustered dendrograms (Supplemental Fig. 1), PSVJ 427 is recovered as most similar to the early

410 ornithischians, Heterodontosaurus tucki and Lesothosaurus diagnosticus, and the lower jaw of

411 the Permian dicynodont Odontocyclops whaitsi (Fig. 5).

412 DISCUSSION

413 Fossil-diagenesis of PVSJ 427

414 Based on the petrographic analyses, we propose a four-stage pathway for the necrolysis,

415 biostratinomy, and fossil-diagenesis of PVSJ 427. The first stage occurred after disarticulation

416 and burial of PVSJ 427 in a fluvial channel deposit, implied by the almost complete physical and

417 chemical destruction of the organic tissues. A countermold would have formed around the

418 isolated remains of the original organic material (e.g., the bony beak and possibly some keratin).

419 Thus, as the bone was destroyed, detrital grains from the surrounding sediments could partially

420 fill this space.

421 The second stage is related to precipitation of an iron-rich mineral that would have filled

422 the empty spaces left by decay and destruction of the original soft material. This precipitate then

423 formed the internal mold of the beak, discussed above as the external layer. The mineral phase

424 rich in iron is interpreted as a biogenic mineral, because iron oxides can form in close association

425 with bacteria during decomposition of organic material (Downing and Park, 1998; Fortin and

426 Langley, 2005). Consequently, it cannot be ruled out that acid products of bacterial decay had

427 also caused the simultaneous dissolution of the bone of PVSJ 427. Thus, iron-rich mineral

428 precipitation would have occurred simultaneously with the destruction of original bone material

429 in stages 1 and 2. A biogenic origin of iron-rich minerals could also explain the limited extent of

430 iron-rich minerals, which only precipitate in the most superficial regions (=external layer) of

19

431 PVSJ 427. That is, the original beak was probably the source of iron mineralization during its

432 bacterial breakdown. Other fossil vertebrates found near PSVJ 427 in the Upper Triassic Cancha

433 de Bochas Member, Ischigualasto Formation, are also characterized by iron-rich minerals,

434 focused closest to regions near original soft tissue and, consequently, regions with increased

435 bacterial activity during decay (Colombi and Rogers, 2014).

436 The third stage corresponds with precipitation of micritic calcite, filling empty spaces left

437 by iron-rich mineral cement, and mostly in the internal areas where cements the detrital grains.

438 Importantly, remains of bone are present, but are completely replaced by mineralized calcite.

439 Other fossil vertebrates from the Cancha de Bochas Member also have calcite as one of the

440 predominate authigenic minerals, in addition to iron-rich minerals (Colombi and Rogers, 2014).

441 The precipitation of calcite is linked with geochemical conditions that form oxidized calcic

442 paleosols (Colombi and Rogers, 2014).

443 The final stage could be related to a later diagenesis, also represented in other fossil vertebrates

444 from the Cancha de Bochas Member (Colombi and Rogers, 2014). This would have partially

445 dissolved the calcite formed in the third stage, and would create secondary porosity, which was

446 filled by reprecipitation of iron-rich minerals intergrowing with sparry-calcite. In addition to

447 sparry-calcite, large crystals of dogtooth calcite were present in the internal region of PVSJ 427.

448 This late-stage diagenesis is restricted to the most internal areas, distinctly separated from the

449 permineralized bone.

450 PVSJ 427 is unique amongst Ischigualasto beaks

451 The Ischigualasto Formation was home to at least five different clades with beaked taxa

452 (Martínez et al., 2012a). Cranial material is reported in Ischigualastia, Hyperodapedon, and

453 Aetosauroides (Cox, 1965; Gentil and Ezcurra, 2017; Brust et al., 2018), however

20

454 neurovasculature is not reported in the premaxillae or dentaries of Aetosauroides. Crania,

455 specifically beaks, are not presently known in the shuvosaurid Sillosuchus (Alcober and Parrish,

456 1997) or the silesaurid dinosauriform Ignotosaurus (Martínez et al., 2012a). However, based on

457 their phylogenetic position, we would expect Sillosuchus and Ignotosaurus to have beaks

458 morphologically similar to Effigia and Silesaurus or Asilisaurus, respectively. Neither

459 shuvosaurids nor silesaurids have beaks that morphologically resemble PSVJ 427 (Fig. 5). The

460 other potentially beaked taxon from the Ischigualasto, Pisanosaurus mertii, does not preserve a

461 premaxilla or the anterior margin of the lower jaw (Casamiquela, 1967). Additionally, the

462 phylogenetic position of P. mertii is currently under scrutiny (Casamiquela, 1967; Irmis et al.,

463 2007a; Agnolín and Rozadilla, 2018a; Baron, 2019), and without additional material, we cannot

464 assess whether or not PVSJ 427 could be attributed to P. mertii. However, PVSJ 427 is ~50% the

465 length of preserved dentary of P. mertii, which we would expect to be large for early-diverging

466 ornithischians (Heterodontosaurus predentary, ~25% dentary length; Norman et al., 2011;

467 Agnolín and Rozadilla, 2018). If P. mertii is the earliest ornithischian PVSJ 427 could represent

468 the beak of a large individual, but it is currently more parsimonious that PVSJ 427 represents a

469 distinct taxon. Regardless, PVSJ 427 is morphologically distinct from all other beaked taxa

470 currently known from the Ischigualasto Formation.

471 PVSJ 427 is morphologically similar to a heterodontosaurid predentary

472 PVSJ 427 represents a partial beak, unique to the Ischigualasto Formation, and lacks any

473 clear synapomorphies that could be used to phylogenetically place it (Fig. 2). However, our

474 review of Triassic beak morphology represents a framework to systematically exclude clades

475 whose beaks are not morphologically consistent with PVSJ 427. Beaks of most Triassic reptiles

476 either lack a lateral wall (e.g., rhynchosaurs), or they are thin and blade-like (e.g., turtles);

21

477 suggesting that the rounded lateral walls in PVSJ 427 are unique. Rounded lateral walls are

478 known in Jurassic heterodontosaurid ornithischians (Norman et al., 2011), but definitive

479 ornithischians are not presently known from the Triassic (Irmis et al., 2007a; Baron et al., 2017;

480 Agnolín and Rozadilla, 2018a; Baron, 2019). The anterior tip of PVSJ 427 terminates anteriorly

481 in a single point, which is consistent with the heterodontosaurid premaxilla and predentary,

482 though it lacks their generally rounded morphology. Importantly, heterodontosaurids possess

483 enlarged caniniform teeth, ventrally, near the anteroposterior midpoint of their premaxilla that

484 are absent in PVSJ 427. Therefore, PVSJ 427 is more similar to the heterodontosaurid predentary

485 than to its premaxilla.

486 Our nMDS analysis supports PVSJ 427 being recovered closest to early-diverging

487 ornithischians in both ordination plots (Fig. 5) and in clustered dendrograms (supplemental Fig.

488 1). However, a lack of definitive Triassic ornithischians (Irmis et al., 2007a; Baron et al., 2017;

489 Agnolín and Rozadilla, 2018b; Baron, 2019), and the fragmentary nature of PVSJ 427 preclude

490 us from assigning this specimen to anything beyond Amniota indet. Regardless, PVSJ 427 is

491 recovered as relatively similar to the lower jaw of Odontocyclops whaitsi, a Permian dicynodont

492 from South Africa (Angielczyk, 2002). However, kannemeyeriiform lower jaws are not

493 recovered as similar to their Permian forms (Fig. 5). Because of its returned close similarity with

494 Heterodontosaurus tucki, we argue that PVSJ 427 is morphologically most like the

495 heterodontosaurid predentary, and thus likely exploited similar ecological resources as early

496 ornithischians.

497 Repeated independent evolution of beaks

498 The earliest evolution of beaked tetrapods dates back to the Permian with dicynodont synapsids

499 (Fig. 4). The earliest known reptile beaks are Middle Triassic silesaurid dinosauriforms (Nesbitt

22

500 et al., 2010). During the Triassic there was a diversification burst, wherein a true beak

501 (=keratinous rhamphotheca) evolved at least four separate times in reptiles known from Late

502 Triassic strata (e.g, aetosaurs, shuvosaurids, trilophosaurids and turtles). Rhynchosaurs diversify

503 in the Middle Triassic, but morphological evidence (=lack of extensive foramina) suggests that

504 they lack a rhamphotheca (Sill, 1970; Langer and Schultz, 2000); however, the edentulous

505 premaxilla and dentary of the rhynchosaur are beak-like and were likely used in food

506 manipulation or digging, similar to other beaked taxa (Benton, 1990). Beaked reptiles further

507 diversify into the Late Triassic and are then known across Pangea (Sues, 2003; Nesbitt and

508 Norell, 2006; Spielmann et al., 2008; Desojo et al., 2013; Ezcurra et al., 2016; Li et al., 2018);

509 though they are less represented in northeastern (with the exception of early turtles and

510 Lotosaurus; Zhang, 1975; Li et al., 2018), and southwestern . Beaked dicynodonts,

511 however, are known from northeastern Laurasia and southwestern Gondwana, though the

512 occurrence of dicynodonts and beaked taxa in the Ischigualasto suggests dicynodonts were not

513 competitively excluding beaked reptiles (Sun, 1980; Hammer et al., 1990; Fröbisch et al., 2010;

514 Martínez et al., 2012b). Although beaked vertebrates were globally distributed, only turtles and

515 ornithischians survive into the Jurassic (Fig. 4).

516 Triassic reptile beak diversity represents ecological diversification

517 Beaked vertebrates today are some of the most taxonomically and ecologically diverse

518 tetrapods on the planet. Although largely distinct diet categories can be differentiated amongst

519 some birds (e.g., granivore vs carnivore) smaller differences in diet (e.g., small vs medium

520 vertebrate carnivore) are more difficult to detect based on morphology alone (Bright et al., 2016;

521 Navalón et al., 2019). Differentiation becomes more difficult in taxa that have sharp and blade-

522 like edges (=triturating surface), such that they could be used for shearing plants or meat.

23

523 However, many Triassic vertebrates are distinct from extant beaked taxa, in that most possess

524 maxillary teeth to process food posterior to their beaks, with the exception of shuvosaurids

525 kannemeyeriiform dicynodonts, and later diverging testudines; with this, Triassic beaked

526 vertebrates have been largely reconstructed as omnivorous or herbivorous (Crompton and

527 Attridge, 1986; Nesbitt et al., 2010; Desojo et al., 2013). Moreover, Triassic beaked taxa are

528 nested within plesiomorphically carnivorous clades (Nesbitt, 2011). This suggests that the

529 repeated convergent evolution of a beak allows for ecological diversification into both

530 specialized (e.g., ornithischian) and more varied (e.g., testudines) dietary niches, allowing for

531 distinct taxa to exist in the same geographic space.

532 ACKNOWLEDGEMENTS

533 We thank K. Angielzcyk, A. Farke, C. Holliday, A. Nabavizadeh, S. Nesbitt, K. Poole, M.

534 Schwid, and K. To for helpful discussion regarding the morphology, identification, and burial

535 history of PVSJ 427. We thank our reviewers, J. Sterli and R. Butler for their comments which

536 improved the manuscript. We are indebted to the field crew of 1990 when PVSJ 427 was

537 discovered. We thank D. Abelin for the preparation of PSVJ 427.

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793

794 FIGURE CAPTIONS

795 Table 1. Temporal distribution of beaked clades. Dates are based on published records of

796 temporally calibrated phylogenies. Where exact dates or estimated dates were not included, we

797 report ages as the base (divergence) or end (extinction) of the stages in which these taxa have

35

798 been discovered. We report a tentative Olenekian divergence date for Trilophosauridae based on

799 the probably trilophosaurid, Coelodontognathus donensis (Arkhangelskii and Sennikov, 2008).

800

801 Table 2. Characters representing non-phylogenetic similarity amongst Triassic beaks.

802

803 Figure 1. Geologic map of the Ischigualasto Formation showing the locality of PVSJ 427.

804

805 Figure 2. The morphology of PVSJ 427 in 1, occlusal view; 2, dorsal or ventral view; 3, lateral

806 view. Abbreviations: ms, medial shelf; odt, occlusally directed tip; pc, posterior cavity; rlw,

807 rounded lateral wall; spt, single pointed tip. Scale bar = 2 cm.

808

809 Figure 3. Petrological analysis of PVSJ 427. 1, Hand sample of the beak in cross section where

810 internal and external areas are differentiated. 2, Irregular boundary between internal and external

811 areas. 3, Outer area characterized by massive iron-rich mineral cement and calcite replacing

812 remains of bone chips. Arrows indicate regions resembling walls of vasculature canals. 4,

813 Internal area characterized by poikilitic sparry calcite (dogtooth calcite crystals), identified by

814 the letter C. 5, Scanning Electron Microscope image of iron-rich mineral (H) surrounded by a

815 phyllosilicate (S). 6, Scanning Electron Microscope image of sparry calcite (C) surrounded a

816 phyllosilicate (S). 7, EDS elemental analysis of the external area cement. 8, EDS elemental

817 analysis of the internal area cement. In 2, 3, and 4, scale bars = 0.4 mm.

818

819 Figure 4. Phylogenetic distribution of independently evolved beaks in Triassic taxa. Clade

820 distributions are based on Table 1. Divergence of Archosauria and Amniota are based on tip

36

821 dated and molecular clock analyses, respectively (Benton and Donoghue, 2006; Ezcurra et al.,

822 2017).The temporal span of the Ischigualasto is represented in light grey to represent that all

823 Triassic beaked clades had diversified by the time of deposition of the Ischigualasto Formation

824 (Martínez et al., 2011). Ornithischia is represented in dark grey because there are no definitive

825 Triassic ornithischians, but the divergence between ornithischians and saurischians is estimated

826 to be Carnian. Dotted lines represent clades that extend beyond the Triassic Period. Taxa present

827 in the Ischigualasto Formation are denoted with asterisks and include; kannemeyeriiforms,

828 rhynchosaurs, aetosaurs, shuvosaurids, and silesaurids (Martínez et al., 2012b), as well as the

829 putative ornithischian, Pisanosaurus mertii (Casamiquela, 1967).

830

831 Figure 5. Similarity between Triassic vertebrate beaks. 1-2, lower jaw; 3-4, upper jaw. Axes 1, 2

832 and 3 of our non-metric multidimensional scaling (nMDS) are represented to reconstruct the 3-

833 dimensional morphospace of beak morphology in the Triassic. Convex hulls are drawn based on

834 clustered dendrograms (see supplement) to reflect which beaked vertebrates were recovered as

835 most similar to PVSJ 427.

37

TABLE 1 – Divergence dates for clades with beaked members

Divergence Extinction Clade Stage Stage Source date (Ma) date (Ma)

Desojo et al., Aetosauria 235 Carnian 208.5 Rhaetian 2013

Griffin and Kannemeyeriiformes 260 Lopingian 227 Angielzcyk, 2019

Nesbitt et al., Silesauridae 247 Anisian 212 middle Norian 2010; Irmis et al., 2011

Nesbitt et al., end 2010; Ornithischia 231.5 Carnian 66 Maastrichtian Martínez et al., 2011

Ezcurra et al., Rhynchosauria 251.9 Induan 227 Norian 2016

Nesbitt and Shuvosauridae 235 Carnian 208.5 Rhaetian Norell, 2006

Day et al., middle Pantestudines 263 - - 2013; Li et al., Capitanian 2018

Sengupta et. al, 2017; Trilophosauridae 251.2? Olenekian? 201.5 end Rhaetian Arkhangelskii and Sennikov, 2008

TABLE 2 – Beak character similarity matrix Character State 0 State 1 State 2 Beak shape Triangle Square Chisel

Lateral walls Thin and sharp Rounded Absent

Midline shelf Absent Present -

Midline symphysis Present Absent -

Posteroventral cavity Absent Present -

Pitted vasculature Present Absent -

Anterior tip Straight or downturned Occlusally directed -

Teeth Present Absent -

Anterior tip Single point Two points -

Anterior margin Pointed Rounded -

Anterior length vs mediolateral width Equal or near equal Longer than wide -

SUPPLEMENTAL MATERIALS

A REVIEW OF VERTEBRATE BEAK MORPHOLOGIES IN THE TRIASSIC; A FRAMEWORK TO MORPHOLOGICALLY PLACE AN ENIGMATIC BEAK FROM THE ISCHIGUALASTO FORMATION, SAN JUAN, ARGENTINA

BRENEN M. WYND1* and RICARDO N. MARTÍNEZ2, CARINA COLOMBI2,3, and OSCAR

ALCOBER2

non-Metric Multidimensional Scaling outputs

We include a table of coordinate values (Table S1 and S2) for taxa estimated in the R statistical environment (Team, 2013). Our code is included as a supplemental file to encourage reproducibility of our methods. We also generated stressplots, (see Stocker et al., 2016 supplement) by plotting Observed Dissimilarity against Ordination Distance (Fig. S1). A regression analysis on this plot was able to explain 99.6% and 99.7% of the variation in our data for lower jaws and premaxillae, respectively. and by examining the results of our nMDS (via the function ‘metaMDS’), we report stress values of 0.01950748 for lower jaws and 0.01915624 for premaxillae. Finally, we generated a clustered dendogram to visualize which taxa are estimated to be the most similar to one another (Fig S2). We use this structure to identify clusters.

Taxon NMDS1 NMDS2 NMDS3 PVSJ 427 -0.53823 0.005291 0.052956 Ischigulastia 0.378873 0.255745 -0.38838 Odontocyclops -0.27453 0.120908 -0.25174 Odontochelys 0.275485 -0.46139 0.303643 Proganochelys 0.434492 0.03473 0.211536 Heterodontosaurus -0.47912 0.309468 0.155451 Lesothosaurus -0.40241 -0.13427 0.122407 Hyperodapedon 0.378936 0.573496 0.132484 Asilisaurus 0.24854 -0.29349 -0.07571 Silesaurus 0.033461 -0.3179 -0.07242 Effigia 0.039388 0.048569 0.129044 Trilophosaurus -0.0372 0.078713 0.110119 Desmatosuchus -0.05768 -0.21986 -0.42939 Supplementary Table 1: Returned nMDS ordination coordinates for lower jaw similarity along the first four axes.

Taxon NMDS1 NMDS2 NMDS3 PVSJ 427 -0.48042 0.005495 -0.25873 Ischigulastia 0.436997 0.288716 0.249782 Odontocyclops 0.089514 0.237691 -0.08624 Odontochelys -0.17206 -0.50978 0.135175 Proganochelys 0.318114 -0.19534 0.114271 Heterodontosaurus -0.3052 0.38182 -0.14146 Lesothosaurus -0.512 0.155837 0.080985 Hyperodapedon 0.358721 -0.26042 -0.51199 Asilisaurus -0.17148 -0.15563 0.273948 Silesaurus -0.27836 -0.05779 0.123406 Effigia 0.085468 -0.03468 0.094166 Trilophosaurus 0.013696 0.015503 -0.10219 Desmatosuchus 0.617014 0.128581 0.028864 Supplementary Table 2: Returned nMDS ordination coordinates for lower jaw similarity along the first four axes.

A

B

Supplemental figure 3. Stressplot for the nMDS plots reported in text for A, lower jaws and B, premaxilla. A

B

Supplemental figure 4. Convergence dendrogram illustrating the taxa that are most similar to one another based on results from the nMDS for A, lower jaw and B, premaxilla. Supplemental references Stocker, M.R., Nesbitt, S.J., Criswell, K.E., Parker, W.G., Witmer, L.M., Rowe, T.B., Ridgely, R. and Brown, M.A. 2016. A Dome-Headed Stem Archosaur Exemplifies Convergence among Dinosaurs and Their Distant Relatives. Current Biology 26: 2674–2680. Team, R.C. 2013. R: A language and environment for statistical computing.

library(Claddis) library(labdsv) library(ecodist) library(vegan)

#Lower jaw #Choose a file and read it in clad.matrix.lower<-ReadMorphNexus("Wynd et al_lower jaw character matrix") clad.matrix.lower #Generate a distance matrix from the above matrix morph.dist.matrix<-MorphDistMatrix(clad.matrix.lower)

#Isolate only the points from the distance matrix generated above dist.matrix <- morph.dist.matrix$DistanceMatrix

#Creates a starting point for the nMDS to run. Minimizes the chance for the analysis to find local optima dist.matrix<-dist(cmdscale(as.dist(dist.matrix),k=nrow(dist.matrix)-1))

### NMDS using the vegan package under a gower ordination method vegannmds<-metaMDS(dist.matrix,distance="gower",k=3,trymax=2000)

#Check the above object to make sure each taxon has a distance, and to check stress value vegannmds

#save the nMDS datapoints to a .csv file write.csv(vegannmds$points, "nMDS_values_LowerJaw.csv")

#Generate a stressplot based on the ordination stressplot(vegannmds,main="Stress Plot for lower jaw beaks", cex=1.2, pch=19,mar=c (5,5,5,5))

#Read in a seperate .csv file of the generic names for the taxa in the analysis taxa<-read.csv("Beaked_taxa.csv",header=T) tax.names <- as.data.frame.array(taxa)

#bind the taxon names to the nmds axes for all three axes dsv.nmds1<-cbind(vegannmds$points[,1]) rownames(dsv.nmds1)<-taxa[,1] dsv.nmds2<-cbind(vegannmds$points[,2]) rownames(dsv.nmds2)<-taxa[,1] dsv.axes1n2<-cbind(vegannmds$points[,1],vegannmds$points[,2]) rownames(dsv.axes1n2)<-taxa[,1] dsv.nmds3<-cbind(vegannmds$points[,3]) rownames(dsv.nmds3)<-taxa[,1]

#plot the first and second axes plot(dsv.axes1n2,pch=16,col="black",main="Archosauromorph cranial disparity",sub="Axes 1 & 2", ) text(dsv.axes1n2,row.names(dsv.axes1n2),cex=0.4,pos=4,col="black")

#plot the first and third axes plot(dsv.nmds1,dsv.nmds3,pch=16,col="black",main="Archosauromorph cranial disparity",sub="Axes 1 & 3") text(dsv.nmds1,dsv.nmds3,row.names(dsv.nmds1),cex=0.4,pos=4,col="black")

#Generate a cluster dendrogram of the distance matrix used in the nMDS analysis #We use ward.D2 to square the matrix following recommendation from Murtagh and Legendre (2014) convergence.clust<-hclust(dist.matrix,method="ward.D2")

#Plot the cluster dendrogram plot(convergence.clust)

#premaxilla clad.matrix.pmax<-ReadMorphNexus("Wynd et al_Premaxilla character matrix") clad.matrix.pmax morph.dist.matrix.p<-MorphDistMatrix(clad.matrix.pmax) dist.matrix.p <- morph.dist.matrix.p$DistanceMatrix dist.matrix.p<-dist(cmdscale(as.dist(dist.matrix.p),k=nrow(dist.matrix.p)-1)) vegannmds.p<-metaMDS(dist.matrix.p,distance="gower",k=3,trymax=2000) vegannmds.p write.csv(vegannmds.p$points, "nMDS_values_Premaxilla.csv") stressplot(vegannmds.p,main="Stress Plot for premaxillary beaks", cex=1.2, pch=19,mar=c (5,5,5,5)) taxa<-read.csv("Beaked_taxa.csv",header=T) dsv.nmds1.p<-cbind(vegannmds.p$points[,1]) rownames(dsv.nmds1.p)<-taxa[,1] dsv.nmds2.p<-cbind(vegannmds.p$points[,2]) rownames(dsv.nmds2.p)<-taxa[,1] dsv.axes1n2.p<-cbind(vegannmds.p$points[,1],vegannmds.p$points[,2]) rownames(dsv.axes1n2.p)<-taxa[,1] dsv.nmds3.p<-cbind(vegannmds.p$points[,3]) rownames(dsv.nmds3.p)<-taxa[,1]

#plot the first and second axes plot(dsv.axes1n2.p,pch=16,col="black",main="Archosauromorph cranial disparity",sub="Axes 1 & 2", ) text(dsv.axes1n2.p,row.names(dsv.axes1n2.p),cex=0.4,pos=4,col="black")

#plot the first and third axes plot(dsv.nmds1.p,dsv.nmds3.p,pch=16,col="black",main="Archosauromorph cranial disparity",sub="Axes 1 & 3") text(dsv.nmds1.p,dsv.nmds3.p,row.names(dsv.nmds1.p),cex=0.4,pos=4,col="black")

#Clustered dendrogram using Ward.D metric. Distance matrix is squared following Murtagh and Legendre, 2014 convergence.clust.p<-hclust(dist.matrix.p,method="ward.D2") plot(convergence.clust.p) 3313 Supplementary 3 nexus file 1 #NEXUS [written Sun Feb 16 11:50:42 EST 2020 by Mesquite version 3.6 (build 917) at LAPTOP-H1NPGV2G/10.0.0.71]

BEGIN TAXA; TITLE Taxa; DIMENSIONS NTAX=13; TAXLABELS PVSJ_427 Ischigulastia Odontocyclops Odontochelys Proganochelys Heterodontosaurus Lesothosaurus Hyperodapedon Asilisaurus Silesaurus Effigia Trilophosaurus Desmatosuchus ;

END;

BEGIN CHARACTERS; TITLE 'Matrix in file "Wynd and Martinez_lower jaw character matrix_05-21-2019"'; DIMENSIONS NCHAR=11; FORMAT DATATYPE = STANDARD RESPECTCASE GAP = - MISSING = ? SYMBOLS = " 0 1 2"; CHARSTATELABELS 1 Beak_Shape / Triangle Square Chisel, 2 Lateral_walls / Thin_and_sharp Rounded absent, 3 Midline_shelf / Absent Present, 4 Midline_symphysis / Present Absent, 5 Posteroventral_cavity / Absent Present, 6 Pitted_vasculature / Present Absent, 7 Anterior_tip / Straight_or_downturned Occlusally_directed, 8 Teeth / Present Absent, 9 Anterior_tip / Single_point Two_points, 10 Anterior_margin / Pointed Rounded, 11 Anteroposterior_length_vs_mediolateral_width / equal_or_near_equal longer_than_wide ; MATRIX PVSJ_427 011?1?11000 Ischigulastia 12100001111 Odontocyclops 01110011011 Odontochelys 00000100000 Proganochelys 10000001010 Heterodontosaurus 01111011010 Lesothosaurus 00111011000 Hyperodapedon 22000111110 Asilisaurus 00000001001 Silesaurus 00000011001 Effigia 00100001010 Trilophosaurus 00100011010 Desmatosuchus 02100010001

;

END; BEGIN ASSUMPTIONS; TYPESET * UNTITLED = unord: 1- 11;

END;

BEGIN MESQUITECHARMODELS; ProbModelSet * UNTITLED = 'Mk1 (est.)': 1- 11; END;

Begin MESQUITE; MESQUITESCRIPTVERSION 2; Página 1 3313 Supplementary 3 nexus file 1 TITLE AUTO; tell ProjectCoordinator; timeSaved 1581871842202; getEmployee #mesquite.minimal.ManageTaxa.ManageTaxa; tell It; setID 0 4814411397018782418; tell It; setDefaultOrder 0 1 2 3 4 5 11 6 7 9 8 17 13; attachments ; endTell; endTell; getEmployee #mesquite.charMatrices.ManageCharacters.ManageCharacters; tell It; setID 0 6825179307120588734; mqVersion 360; checksumv 0 3 3441966782 null getNumChars 11 numChars 11 getNumTaxa 13 numTaxa 13 short true bits 7 states 7 sumSquaresStatesOnly 363.0 sumSquares 363.0 longCompressibleToShort false usingShortMatrix true NumFiles 1 NumMatrices 1; mqVersion; endTell; getWindow; tell It; suppress; setResourcesState false false 100; setPopoutState 300; setExplanationSize 0; setAnnotationSize 0; setFontIncAnnot 0; setFontIncExp 0; setSize 1920 961; setLocation -8 0; setFont SanSerif; setFontSize 10; getToolPalette; tell It; endTell; desuppress; endTell; getEmployee #mesquite.charMatrices.BasicDataWindowCoord.BasicDataWindowCoord; tell It; showDataWindow #6825179307120588734 #mesquite.charMatrices.BasicDataWindowMaker.BasicDataWindowMaker; tell It; getWindow; tell It; getTable; tell It; rowNamesWidth 141; endTell; setExplanationSize 30; setAnnotationSize 20; setFontIncAnnot 0; setFontIncExp 0; setSize 1820 889; setLocation -8 0; setFont SanSerif; setFontSize 10; getToolPalette; tell It; setTool mesquite.charMatrices.BasicDataWindowMaker.BasicDataWindow.ibeam; Página 2 3313 Supplementary 3 nexus file 1 endTell; setActive; setTool mesquite.charMatrices.BasicDataWindowMaker.BasicDataWindow.ibeam; colorCells #mesquite.charMatrices.NoColor.NoColor; colorRowNames #mesquite.charMatrices.TaxonGroupColor.TaxonGroupColor; colorColumnNames #mesquite.charMatrices.CharGroupColor.CharGroupColor; colorText #mesquite.charMatrices.NoColor.NoColor; setBackground White; toggleShowNames on; toggleShowTaxonNames on; toggleTight off; toggleThinRows off; toggleShowChanges on; toggleSeparateLines off; toggleShowStates on; toggleAutoWCharNames on; toggleAutoTaxonNames off; toggleShowDefaultCharNames off; toggleConstrainCW on; toggleBirdsEye off; toggleShowPaleGrid off; toggleShowPaleCellColors off; toggleShowPaleExcluded off; togglePaleInapplicable on; togglePaleMissing off; toggleShowBoldCellText off; toggleAllowAutosize on; toggleColorsPanel off; toggleDiagonal on; setDiagonalHeight 80; toggleLinkedScrolling on; toggleScrollLinkedTables off; endTell; showWindow; getWindow; tell It; forceAutosize; endTell; getEmployee #mesquite.charMatrices.AlterData.AlterData; tell It; toggleBySubmenus off; endTell; getEmployee #mesquite.charMatrices.ColorByState.ColorByState; tell It; setStateLimit 9; toggleUniformMaximum on; endTell; getEmployee #mesquite.charMatrices.ColorCells.ColorCells; tell It; setColor Red; removeColor off; endTell; getEmployee #mesquite.categ.StateNamesEditor.StateNamesEditor; tell It; makeWindow; Página 3 3313 Supplementary 3 nexus file 1 tell It; getTable; tell It; rowNamesWidth 304; endTell; setExplanationSize 30; setAnnotationSize 20; setFontIncAnnot 0; setFontIncExp 0; setSize 1820 889; setLocation -8 0; setFont SanSerif; setFontSize 10; getToolPalette; tell It; setTool mesquite.categ.StateNamesEditor.StateNamesWindow.ibeam; endTell; rowsAreCharacters on; toggleConstrainChar on; toggleConstrainCharNum 3; togglePanel off; toggleSummaryPanel off; endTell; showWindow; endTell; getEmployee #mesquite.categ.StateNamesStrip.StateNamesStrip; tell It; showStrip off; endTell; getEmployee #mesquite.charMatrices.AnnotPanel.AnnotPanel; tell It; togglePanel off; endTell; getEmployee #mesquite.charMatrices.CharReferenceStrip.CharReferenceStrip; tell It; showStrip off; endTell; getEmployee #mesquite.charMatrices.QuickKeySelector.QuickKeySelector; tell It; autotabOff; endTell; getEmployee #mesquite.charMatrices.SelSummaryStrip.SelSummaryStrip; tell It; showStrip off; endTell; getEmployee #mesquite.categ.SmallStateNamesEditor.SmallStateNamesEditor; tell It; panelOpen true; endTell; endTell; endTell; getEmployee #mesquite.charMatrices.ManageCharacters.ManageCharacters; tell It; showCharacters #6825179307120588734 #mesquite.lists.CharacterList.CharacterList; tell It; Página 4 3313 Supplementary 3 nexus file 1 setData 0; getWindow; tell It; useTargetValue off; setTargetValue ; newAssistant #mesquite.lists.DefaultCharOrder.DefaultCharOrder; newAssistant #mesquite.lists.CharListInclusion.CharListInclusion; newAssistant #mesquite.lists.CharListPartition.CharListPartition; newAssistant #mesquite.parsimony.CharListParsModels.CharListParsModels; getTable; tell It; columnWidth 1 33; endTell; setExplanationSize 30; setAnnotationSize 20; setFontIncAnnot 0; setFontIncExp 0; setSize 1820 889; setLocation -8 0; setFont SanSerif; setFontSize 10; getToolPalette; tell It; setTool mesquite.lists.CharacterList.CharacterListWindow.ibeam; endTell; endTell; showWindow; getEmployee #mesquite.lists.CharListAnnotPanel.CharListAnnotPanel; tell It; togglePanel off; endTell; endTell; endTell; endTell; end;

Página 5 3313 Supplementary 4 nexus file 2 #NEXUS [written Sun Feb 16 11:51:01 EST 2020 by Mesquite version 3.6 (build 917) at LAPTOP-H1NPGV2G/10.0.0.71]

BEGIN TAXA; TITLE Taxa; DIMENSIONS NTAX=13; TAXLABELS PVSJ_427 Ischigulastia Odontocyclops Odontochelys Proganochelys Heterodontosaurus Lesothosaurus Hyperodapedon Asilisaurus Silesaurus Effigia Trilophosaurus Desmatosuchus ;

END;

BEGIN CHARACTERS; TITLE 'Matrix in file "Beak similarity matrix"'; DIMENSIONS NCHAR=11; FORMAT DATATYPE = STANDARD RESPECTCASE GAP = - MISSING = ? SYMBOLS = " 0 1 2"; CHARSTATELABELS 1 Beak_Shape / Triangle Square Chisel, 2 Lateral_walls / Thin_and_sharp Rounded absent, 3 Midline_shelf / Absent Present, 4 Midline_symphysis / Present Absent, 5 Posteroventral_cavity / Absent Present, 6 Pitted_vasculature / Present Absent, 7 Anterior_tip / Straight_or_downturned Occlusally_directed, 8 Teeth / Present Absent, 9 Anterior_tip / Single_point Two_points, 10 Anterior_margin / Pointed Rounded, 11 Anteroposterior_length_vs_mediolateral_width / equal_or_near_equal longer_than_wide ; MATRIX PVSJ_427 011?1?11000 Ischigulastia 10110001111 Odontocyclops 10110011010 Odontochelys 00000100000 Proganochelys 10000001010 Heterodontosaurus 02111010010 Lesothosaurus 00111010000 Hyperodapedon 22000111110 Asilisaurus 00100000000 Silesaurus 00100010000 Effigia 00100001010 Trilophosaurus 00100011010 Desmatosuchus 12100001111

;

END; BEGIN ASSUMPTIONS; TYPESET * UNTITLED = unord: 1- 11;

END;

BEGIN MESQUITECHARMODELS; ProbModelSet * UNTITLED = 'Mk1 (est.)': 1- 11; END;

Begin MESQUITE; MESQUITESCRIPTVERSION 2; TITLE AUTO; Página 1 3313 Supplementary 4 nexus file 2 tell ProjectCoordinator; timeSaved 1581871862020; getEmployee #mesquite.minimal.ManageTaxa.ManageTaxa; tell It; setID 0 4814411397018782418; tell It; setDefaultOrder 0 1 2 3 4 5 11 6 7 9 8 17 13; attachments ; endTell; endTell; getEmployee #mesquite.charMatrices.ManageCharacters.ManageCharacters; tell It; setID 0 6825179307120588734; mqVersion 360; checksumv 0 3 678070234 null getNumChars 11 numChars 11 getNumTaxa 13 numTaxa 13 short true bits 7 states 7 sumSquaresStatesOnly 357.0 sumSquares 357.0 longCompressibleToShort false usingShortMatrix true NumFiles 1 NumMatrices 1; mqVersion; endTell; getWindow; tell It; suppress; setResourcesState false false 100; setPopoutState 300; setExplanationSize 0; setAnnotationSize 0; setFontIncAnnot 0; setFontIncExp 0; setSize 958 952; setLocation -7 0; setFont SanSerif; setFontSize 10; getToolPalette; tell It; endTell; desuppress; endTell; getEmployee #mesquite.charMatrices.BasicDataWindowCoord.BasicDataWindowCoord; tell It; showDataWindow #6825179307120588734 #mesquite.charMatrices.BasicDataWindowMaker.BasicDataWindowMaker; tell It; getWindow; tell It; getTable; tell It; rowNamesWidth 141; endTell; setExplanationSize 30; setAnnotationSize 20; setFontIncAnnot 0; setFontIncExp 0; setSize 858 880; setLocation -7 0; setFont SanSerif; setFontSize 10; getToolPalette; tell It; setTool mesquite.charMatrices.BasicDataWindowMaker.BasicDataWindow.ibeam; endTell; Página 2 3313 Supplementary 4 nexus file 2 setActive; setTool mesquite.charMatrices.BasicDataWindowMaker.BasicDataWindow.ibeam; colorCells #mesquite.charMatrices.NoColor.NoColor; colorRowNames #mesquite.charMatrices.TaxonGroupColor.TaxonGroupColor; colorColumnNames #mesquite.charMatrices.CharGroupColor.CharGroupColor; colorText #mesquite.charMatrices.NoColor.NoColor; setBackground White; toggleShowNames on; toggleShowTaxonNames on; toggleTight off; toggleThinRows off; toggleShowChanges on; toggleSeparateLines off; toggleShowStates on; toggleAutoWCharNames on; toggleAutoTaxonNames off; toggleShowDefaultCharNames off; toggleConstrainCW on; toggleBirdsEye off; toggleShowPaleGrid off; toggleShowPaleCellColors off; toggleShowPaleExcluded off; togglePaleInapplicable on; togglePaleMissing off; toggleShowBoldCellText off; toggleAllowAutosize on; toggleColorsPanel off; toggleDiagonal on; setDiagonalHeight 80; toggleLinkedScrolling on; toggleScrollLinkedTables off; endTell; showWindow; getWindow; tell It; forceAutosize; endTell; getEmployee #mesquite.charMatrices.AlterData.AlterData; tell It; toggleBySubmenus off; endTell; getEmployee #mesquite.charMatrices.ColorByState.ColorByState; tell It; setStateLimit 9; toggleUniformMaximum on; endTell; getEmployee #mesquite.charMatrices.ColorCells.ColorCells; tell It; setColor Red; removeColor off; endTell; getEmployee #mesquite.categ.StateNamesEditor.StateNamesEditor; tell It; makeWindow; tell It; Página 3 3313 Supplementary 4 nexus file 2 getTable; tell It; rowNamesWidth 136; endTell; setExplanationSize 30; setAnnotationSize 20; setFontIncAnnot 0; setFontIncExp 0; setSize 858 880; setLocation -7 0; setFont SanSerif; setFontSize 10; getToolPalette; tell It; setTool mesquite.categ.StateNamesEditor.StateNamesWindow.ibeam; endTell; rowsAreCharacters on; toggleConstrainChar on; toggleConstrainCharNum 3; togglePanel off; toggleSummaryPanel off; endTell; showWindow; endTell; getEmployee #mesquite.categ.StateNamesStrip.StateNamesStrip; tell It; showStrip off; endTell; getEmployee #mesquite.charMatrices.AnnotPanel.AnnotPanel; tell It; togglePanel off; endTell; getEmployee #mesquite.charMatrices.CharReferenceStrip.CharReferenceStrip; tell It; showStrip off; endTell; getEmployee #mesquite.charMatrices.QuickKeySelector.QuickKeySelector; tell It; autotabOff; endTell; getEmployee #mesquite.charMatrices.SelSummaryStrip.SelSummaryStrip; tell It; showStrip off; endTell; getEmployee #mesquite.categ.SmallStateNamesEditor.SmallStateNamesEditor; tell It; panelOpen true; endTell; endTell; endTell; getEmployee #mesquite.charMatrices.ManageCharacters.ManageCharacters; tell It; showCharacters #6825179307120588734 #mesquite.lists.CharacterList.CharacterList; tell It; setData 0; Página 4 3313 Supplementary 4 nexus file 2 getWindow; tell It; useTargetValue off; setTargetValue ; newAssistant #mesquite.lists.DefaultCharOrder.DefaultCharOrder; newAssistant #mesquite.lists.CharListInclusion.CharListInclusion; newAssistant #mesquite.lists.CharListPartition.CharListPartition; newAssistant #mesquite.parsimony.CharListParsModels.CharListParsModels; getTable; tell It; columnWidth 1 33; endTell; setExplanationSize 30; setAnnotationSize 20; setFontIncAnnot 0; setFontIncExp 0; setSize 858 880; setLocation -7 0; setFont SanSerif; setFontSize 10; getToolPalette; tell It; setTool mesquite.lists.CharacterList.CharacterListWindow.ibeam; endTell; endTell; showWindow; getEmployee #mesquite.lists.CharListAnnotPanel.CharListAnnotPanel; tell It; togglePanel off; endTell; endTell; endTell; endTell; end;

Página 5 TAXON PVSJ Ischigualastia Odontocyclops Odontochelys Proganochelys Heterodontosaurus Lesothosaurus Hyperodapedon Asilisaurus Silesaurus Effigia Trilophosaurus Desmatosuchus