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 VERTEBRATE BEAK MORPHOLOGIES IN THE TRIASSIC; A 2 FRAMEWORK TO CHARACTERIZE AN ENIGMATIC BEAK FROM THE 3 ISCHIGUALASTO FORMATION, 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 BEAKS 16 17 *Corresponding author
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18 19 ABSTRACT 20 Beaks are an edentulous dietary modification present in numerous forms in turtles, birds,
21 cephalopods, and some actinopterygian fishes today. Beaks have a rich fossil record and have
22 independently evolved at least nine times over the past 300 million years in early reptiles,
23 dinosaurs and their relatives, and crocodile and mammal relatives. Here, we focus on the earliest
24 evolution of beaks in the reptile 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 Late Triassic Ischigualasto Formation, San Juan, Argentina, and
28 place it in our similarity analysis alongside other vertebrate clades 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 animal 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 (=vertebrates) 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 Carboniferous in nautiloid and
52 coleoid cephalopods (Zangerl et al., 1969; Mapes, 1987; Doguzhaeva and Mapes, 2017). The
53 earliest-known beaked vertebrates are dicynodont synapsids, first appearing in the middle
54 Permian Eodicynodon Assemblage Zone (Barry, 1974; Rubidge, 1990; Griffin and Angielczyk,
55 2019). Dicynodonts dominated the terrestrial-beaked-herbivore 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-Herrerasaurus, 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 rhynchosaur
96 Scaphonyx sanjuanensis, the cynodont Exaeretodon argentinus, and the dinosaur Herrerasaurus
97 ischigualastensis, but also includes the majority of fossils 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, Eoraptor
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109 lunensis), carnivorous and herbivorous cynodonts (e.g., Ecteninion lunensis, Exaeretodon
110 argentinus), rhynchosaurs, and diverse pseudosuchian archosaurs (e.g., Aetosauroides scagliai,
111 Saurosuchus 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). Clade durations are based
117 on published values for divergence and extinction 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 mammals, 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 Carnian (~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 amniote (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 keratin 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 animals either known from the Triassic or with proposed Triassic origins
226 (Fig. 4).
227 Description of beaked clades from the Triassic
228 Aetosauria. Aetosaurs 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 jaw 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., Desmatosuchus haplocerus; Small, 2002). The edentulous margins of
240 later diverging aetosaur 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 Neoaetosauroides 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 jaws, 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), Pisanosaurus mertii (Casamiquela, 1967), and an unnamed heterodontosaurid from
279 South America (Baez and Marsicano, 2001), which was later suggested to be Jurassic 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, Heterodontosaurus tucki
285 (Crompton and Charig, 1962) and Lesothosaurus 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
14
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 Mesosuchus 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 genus
338 Hyperodapedon (Huxley, 1859), species of which are commonly found in the Ischigualasto
15
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., Stenaulorhynchus 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 Effigia okeeffeae (Nesbitt and Norell, 2006),
352 Shuvosaurus 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
16
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 Silesauridae. 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), Sacisaurus agudoensis
373 (Ferigolo and Langer, 2007) and Silesaurus 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 Lewisuchus 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 Trilophosaurus
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 Laurasia (with the exception of early turtles and
510 Lotosaurus; Zhang, 1975; Li et al., 2018), and southwestern Gondwana. 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 Norian 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