TABLE 1. List of comparative taxa used in this study. Type-materials are indicated in bold.
| Taxa | Primary Reference | Specimens studied in first-hand by V.D.P.N. |
| Aetobarbakinoides brasiliensis | Desojo et al., 2012. | CPEZ-168. |
| Aetosauroides scagliai | Casamiquela, 1960; 1961; 1967; Desojo, 2005; Desojo and Ezcurra, 2011; Brust et al., 2018. | PVL 2052; PVL 2059; MCN-PV 2347; MCP-3450-PV; UFSM 11505. |
| cf. Aetosauroides scagliai | Desojo, 2005; Parker, 2016a. | PVSJ 326. |
| Aetosaurus ferratus | Walker, 1961; Schoch, 2007. | SMNS 5770, mainly S-16, S-18 and S-21; SMNS 18554. |
| cf. Aetosaurus ferratus | Jenkins et al., 1994. | MCZ 9479R cast of MCZ 22/92G. |
| Acaenasuchus geoffroyi | Marsh et al., 2020. | |
| Archaeopelta arborensis | Desojo et al., 2011. | CPEZ-239a |
| Caiman latirostris | - | UFRGS-PV-002-Z. |
| Calyptosuchus wellesi | Long and Murry, 1995; Parker, 2018. | UMMP 13950. Putative materials are UCMP 27409, UCMP 27414, UCMP 78695 and UCMP 195192. |
| Coahomasuchus chathamensis | Heckert et al., 2017; Hoffman et al., 2018, 2019. | NCSM 23618. |
| Coahomasuchus kahleorum | Heckert and Lucas, 1999; Desojo and Heckert, 2004. | NMMNH P-18496. |
| Desmatosuchus smalli | Small, 2002; Parker, 2005. | TTU-P 9023; TTU-P 9024; TTU-P 9025; TTU-P 9420; |
| Desmatosuchus spurensis | Case, 1922; Long and Murry, 1995; Parker, 2005; Parker, 2008; Parker, 2018. | GPIT-PV-108053; UCMP 25877; UCMP 27988; UCMP 34490*; UMMP 3396*; UMMP V7476 and MNA V 9300. |
| Diandongosuchus fuyuanensis | Stocker et al., 2017. | |
| Dyoplax arenaceus | Maisch et al., 2013. | SMNS 4760 |
| Dromicosuchus grallator | Sues et al., 2003. | NCSM 13733 (previous UCN 15574). |
| Effigia okeeffeae | Nesbitt, 2007. | AMNH 30587. |
| Erpetosuchus granti | Benton and Walker 2002. | - |
| Erpetosuchus sp. | Olsen et al., 2001. | AMNH FR 29300. |
| Hesperosuchus gracilis | Nesbitt, 2011. | AMNH FR 6758. |
| Gracilisuchus stipanicicorum | Romer, 1972; Lecuona, 2013; Butler et al., 2014. | PULR 08, MCZ 4116 and MCZ 4117. |
| Longosuchus meadei | Sawin, 1947; Witmer, 1997; Nesbitt, 2011. | TMM 31185-97; TMM 31185-98. |
| Lucasuchus hunti | Parker, 2016a. | TMM 31100-531*, TMM 31100-1 and TMM 31100-313. |
| Mandasuchus tanyauchen | Butler et al., 2017. | - |
| Neoaetosauroides engaeus | Bonaparte, 1969; Desojo, 2005; Desojo and Báez, 2007. | PVL 3525 and PULR 5698. |
| Ornithosuchus woodwardi | Walker, 1964; von Baczko and Ezcurra, 2016. | - |
| Pagosvenator candelariensis | Lacerda et al., 2018. | MMACR PV 036-T |
| Paratypothorax andressorum | Schoch and Desojo, 2016. | SMNS 19003. |
| Paratypothorax sp. | Long and Ballew, 1985; Parker, 2016a. | PEFO 3004 and TTU-P09416. |
| Parringtonia gracilis | Nesbitt and Butler, 2013; Nesbitt et al., 2018. | - |
| Polesinesuchus aurelioi | Roberto-da-Silva et al., 2013 | ULBRAPV003T. |
| Prestosuchus chiniquensis | Mastrantonio et al., 2013; Mastrantonio et al., 2019. | UFRGS-PV-0629-T. |
| Revueltosaurus callenderi | Parker et al., 2005; Nesbitt, 2011. | - |
| Riojasuchus tenuisceps | von Baczko et al. 2016. | PVL 3827 (by J.B.D.). |
| Scutarx deltatylus | Parker, 2016b. | PEFO 34616. |
| Stagonolepis robertsoni | Walker, 1961; Witmer, 1997; Gower and Walker, 2002. | ELGNM 38; MCZD 2; and several NSM casts, including R 4790 and R 4787. |
| Stagonolepis olenkae | Sulej, 2010. | ZPAL AbIII/466/17; ZPAL AbIII/1996 and ZPAL AbIII/1997; ZPAL AbIII/2000; ZPAL AbIII/2376; ZPAL AbIII/2722; and ZPAL AbIII 50124. |
| Stenomyti huangae | Small and Martz, 2013. | DMNH 34565; DMNH 60708; DMNH 61392. Putative specimens are DMNH 55070 and DMNH 45882. |
| Stegomus arcuatus | Lucas et al., 1998. | YPM [PU] 21759; YPM-PU 21750. |
| Tarjadia ruthae | Arcucci and Marscicano, 1998; Ezcurra et al. 2017. | PULR 63. |
| Typothorax coccinarum | Martz, 2002; Heckert and Lucas, 2010; Reyes et al. 2021. | TTU-P09214; YPM PV 058121. |
TABLE 2. Comparative measurements of Aetosauroides scagliai skulls, in mm.
| MCN-PV 2347 | UFSM 11505 | PVL 2059 | |
| Skull total height (from jugal to parietal) | 46.5 | - | - |
| External nares height | 10.4 | 11 | 11 |
| External nares length | - | 39.8 | ~50 |
| Antorbital fenestra length | 29.6 | 32.9 | - |
| Antorbital fenestra height | ~07.2 | 12 | - |
| Antorbital fossa length | 36.6 | 45.8 | - |
| Antorbital fossa height | 24.5 | 25.5 | - |
| Orbit height | 24.8 | 33 | - |
| Orbit length | 27.7 | 28.8 | - |
| Infratemporal fenestra length | 5.3 | - | - |
| Infratemporal fenestra height | 10.7 | - | - |
| Supratemporal fenestra length | ~20 | - | - |
| Supratemporal fenestra height | 22.3 | - | - |
TABLE 3. Measurements of the skull of Aetosauroides scagliai specimen MCN-PV 2347, in mm.
| Premaxilla height | ~4.5 |
| Maxilla length | ~70.8* |
| Maxilla height | ~25.7* |
| Nasal maximum width | 12.7 |
| Nasal length (preserved) | 63.1 |
| Prefrontal length | 19.5 |
| Prefrontal height | - |
| Lacrimal length | ~30.0 |
| Lacrimal height | 18.5 |
| Frontal length | ~30 |
| Frontal width | 14.2 |
| Postfrontal length | ~8.7 |
| Parietal length | 18.7 |
| Parietal width | 2.22 |
| Jugal length | 42.1 |
| Jugal height | 10.0 |
| Quadratojugal ventral length | 16.6 |
| Quadratojugal height | 16.1 |
| Squamosal dorsal length | 16.0 |
| Squamosal maximum height | ~31.1 |
TABLE 4. Comparative measurements of the quadrate of Aetosauroides scagliai specimens MCN-PV 2347 (left element) and MCP-3450-PV.
| MCN-PV 2347 | MCP-3450-PV left | |
| Height | 37.5 | - |
| Condyle width | ~13.2 | 13.0 |
| Condyle length | 7.0 | 6.2 |
TABLE 5. Measurements of the mandible of Aetosauroides scagliai specimen MCN-PV 2347, in mm.
| Dentary height at mid length | 31.4 |
| Mandibular fenestra height | 12.4 |
| Mandibular fenestra length | 37.1 |
| Retroarticular process from posterior border of mandibular fenestra |
31.1 |
| Surangular maximum height | 12.7 |
| Surangular maximum length | ~64.6 |
TABLE 6. Measurements of the teeth of Aetosauroides scagliai (MCN-PV 2347 and UFSM 11505).
| Specimen | Position | Crown height (CH) | Crown length (CL) | CH/CL (%) |
Crown width | Crown base length |
| UFSM 11505 | MX3L | 4.9 | 3.1 | 63.3% | - | 2.7 |
| UFSM 11505 | MX6L | 4.4 | 2.9 | 65.9% | - | 3.3 |
| UFSM 11505 | MX8L | 4.6 | 3.2 | 69.6% | - | 3.0 |
| UFSM 11505 | PMX4R | 2.3 | 1.6 | 69.6% | - | 1.7 |
| UFSM 11505 | D?L | 4.9 | 2.1 | 42.9% | - | 2.4 |
| MCN-PV 2347 | PMX1L | 2.8 | 1.5 | 53.6% | 1.4 | 1.6 |
| MCN-PV 2347 | PMX3L | 3.5 | 2.1 | 60.0% | 1.1 | 2.1 |
| MCN-PV 2347 | D10R | 3.9 | 2.3 | 59.0% | - | - |
