Journal: Royal Society Open Science

Article Title: New monstersaur specimens from the Kaiparowits Formation of Utah reveal unexpected richness of large-bodied lizards in Late Cretaceous North America

doi: 10.1098/rsos.250435

Figure Lengend Snippet: Comparisons of left nasals of Bolg amondol to select anguimorph and monstersaur taxa in dorsal view. (A) Line drawing of UMNH VP 16266.1 (holotype, Bolg amondol ). (B) Line drawing of the left nasal of ZPAL MgR III/64 (holotype, Gobiderma pulchrum , modified from . (C) Mirrored line drawing of the right nasal of NHMG 009318 (holotype, Chiangshia nankangensis , modified from ). (D) Line drawing of the left nasal of UF 153328 ( Heloderma horridum ). (E) Line drawing of the left nasal of IGM 3/14 (holotype, Estesia mongoliensis , modified from ). Anatomical abbreviations: en, external naris; pmxp, premaxillary process; snpr, supranasal process.

Article Snippet: A prominent quadrate foramen was not described by Norell et al . [ ] on the quadrate of the holotype specimen of Estesia mongoliensis , nor is a prominent medial quadrate foramen obvious in observed specimens of Heloderma (specimen UF:Herp:153328, LACM 163852).

Techniques: Modification

Journal: Royal Society Open Science

Article Title: New monstersaur specimens from the Kaiparowits Formation of Utah reveal unexpected richness of large-bodied lizards in Late Cretaceous North America

doi: 10.1098/rsos.250435

Figure Lengend Snippet: (A) Rendered CT scan of UMNH VP 16266.2 (right jugal, Bolg amondol ) in lateral view. Black line indicates position and angle of CT slice displayed in (B). (B) Oblique transverse CT slice illustrating osteoderm attachment to the lateral surface of the postorbital process of the jugal. (C) Comparisons of dermal sculpturing on the jugal postorbital process in lateral view among select monstersaur taxa (see §5.2 for phylogenetic placement of Asprosaurus ). Line drawings: Bolg amondol UMNH VP 16266.2; Asprosaurus bibongriensis KDRC-BB4, modified from ; Estesia mongoliensis , mirrored, IGM 3/14, modified from ; Gobiderma pulchrum , IGM 3/55, modified from ; Heloderma horridum , UF 153328.

Article Snippet: A prominent quadrate foramen was not described by Norell et al . [ ] on the quadrate of the holotype specimen of Estesia mongoliensis , nor is a prominent medial quadrate foramen obvious in observed specimens of Heloderma (specimen UF:Herp:153328, LACM 163852).

Techniques: Computed Tomography, Modification

Journal: Royal Society Open Science

Article Title: New monstersaur specimens from the Kaiparowits Formation of Utah reveal unexpected richness of large-bodied lizards in Late Cretaceous North America

doi: 10.1098/rsos.250435

Figure Lengend Snippet: Comparisons of anterior right vomers of Bolg amondol (A) and selected monstersaur taxa. (B) Right vomer of IGM 3/14 (holotype, Estesia mongoliensis , modified from ). (C) Right vomer of UF 153328 ( Heloderma horridum ). (D) Right vomer of Gobiderma pulchrum , modified from . Anatomical abbreviations: ac, articular crest; evf, external vomeronasal fenestra; frm, foramen; vc, ventral crest.

Article Snippet: A prominent quadrate foramen was not described by Norell et al . [ ] on the quadrate of the holotype specimen of Estesia mongoliensis , nor is a prominent medial quadrate foramen obvious in observed specimens of Heloderma (specimen UF:Herp:153328, LACM 163852).

Techniques: Modification

Journal: Royal Society Open Science

Article Title: New monstersaur specimens from the Kaiparowits Formation of Utah reveal unexpected richness of large-bodied lizards in Late Cretaceous North America

doi: 10.1098/rsos.250435

Figure Lengend Snippet: Comparisons of the palatine in select monstersaur taxa (A–D) and close outgroups (E,F) in ventral view. (A) Line drawing of the left palatine of UMNH VP 16266 (holotype, Bolg amondol ). (B) Line drawing of the left palatine of Gobiderma pulchrum , modified from . (C) Left palatine of UF 153328 ( Heloderma horridum ). (D) Left palatine of IGM 3/196 ( Estesia mongoliensis , modified from ). (E) Left palatine of ZPAL MgR-I/43 (holotype, Parviderma inexacta , modified from ). (F) Left palatine ZPAL MgR-I/72 (holotype, Saniwides mongoliensis , modified from ). Anatomical abbreviations: pta, pterygoid articulation; sof, suborbital fenestra; tr, palatine tooth row; vp, vomerine process.

Article Snippet: A prominent quadrate foramen was not described by Norell et al . [ ] on the quadrate of the holotype specimen of Estesia mongoliensis , nor is a prominent medial quadrate foramen obvious in observed specimens of Heloderma (specimen UF:Herp:153328, LACM 163852).

Techniques: Modification

Journal: Royal Society Open Science

Article Title: New monstersaur specimens from the Kaiparowits Formation of Utah reveal unexpected richness of large-bodied lizards in Late Cretaceous North America

doi: 10.1098/rsos.250435

Figure Lengend Snippet: Comparisons of quadrates of select monstersaur taxa, in lateral view (top row) and posterior view (bottom row). (A) UMNH VP 16266.7 (holotype, Bolg amondol ). (B) LACM 163582 ( Heloderma horridum ). (C) IGM 3/905 (referred specimen, Gobiderma pulchrum , modified from ). (D) IGM 3/14 (holotype, Estesia mongoliensis , modified from [ , ]). Anatomical abbreviations: alc, anterolateral crest; pc, posterior crest.

Article Snippet: A prominent quadrate foramen was not described by Norell et al . [ ] on the quadrate of the holotype specimen of Estesia mongoliensis , nor is a prominent medial quadrate foramen obvious in observed specimens of Heloderma (specimen UF:Herp:153328, LACM 163852).

Techniques: Modification

Journal: Royal Society Open Science

Article Title: New monstersaur specimens from the Kaiparowits Formation of Utah reveal unexpected richness of large-bodied lizards in Late Cretaceous North America

doi: 10.1098/rsos.250435

Figure Lengend Snippet: Comparisons of the medial subdental margin (depicted in white) on the dentaries of monstersaurian taxa. (A) Reconstructed left dentary of Bolg amondol , upper Campanian Kaiparowits Formation (Fm), Utah, USA, using a mirrored image of the right dentary fragment UMNH VP 16266.6. (B) Left dentary ANSP 18664 (holotype, Labrodioctes montanaensis , upper Campanian Oldman Fm, Alberta,Canada, modified from . (C) Left dentary span >MNHAH D1049652 (holotype, Morohasaurus kamitakiensis , lower Albian Ohyamashimo Formation, Japan, modified from . (D) Left dentary OMNH 27750 (referred specimen, Primaderma nessov i, Cenomanian Mussentuchit Member, Cedar Mountain Fm, Utah, USA, modified from . (E) Right dentary (reflected for comparison) TMP 1989.121.0001 (referred specimen, Palaeosaniwa canadensis , upper Campanian Oldman Fm, Alberta, Canada, modified from . (F) Left dentary UALVP 29845 (referred specimen, Paraderma bogerti , Maastrichtian Scollard Fm, Alberta, Canada, modified from . (G) Left dentary IGM 3/14 (holotype, Estesia mongoliensis , Campanian Djadokhta Fm, Mongolia, modified from . (H) Left dentary TMM-M 9001 (referred specimen, Heloderma suspectum , modern, modified from . (I) Left dentary SDSNH 59469 (referred specimen, Heloderma horridum , modern, modified from . (J) Right dentary (reflected for comparison) BMNHR 3487 (referred specimen, Eurheloderma gallicum , Eocene Phosphorites du Quercy, France, modified from . (K) Left dentary IGM 3/55 (referred specimen, Gobiderma pulchrum , Campanian Djadokhta Fm, Mongolia, modified from .

Article Snippet: A prominent quadrate foramen was not described by Norell et al . [ ] on the quadrate of the holotype specimen of Estesia mongoliensis , nor is a prominent medial quadrate foramen obvious in observed specimens of Heloderma (specimen UF:Herp:153328, LACM 163852).

Techniques: Modification, Comparison

Journal: Royal Society Open Science

Article Title: New monstersaur specimens from the Kaiparowits Formation of Utah reveal unexpected richness of large-bodied lizards in Late Cretaceous North America

doi: 10.1098/rsos.250435

Figure Lengend Snippet: Comparisons of ventral centrum morphotypes on vertebrae referred to monstersaur taxa. (A) Deep pit on the ventral surface of the centrum, as observed on DMNH EPV.134394.2 (top, middle), monstersaur vertebra from the upper Campanian Kaiparowits Formation (Fm) and USNM 10864 (Holotype, Palaeosaniwa canadensis , upper Campanian Oldman Fm, modified from , pl. XI, fig. 5a). (B) Shallow pit on the ventral surface of the centrum, as observed on UMNH VP 36373 (upper Campanian Kaiparowits Fm, left), and MOR 792 ( Palaeosaniwa canadensis , Campanian Two Medicine Fm, modified from , fig. 5D). (C) Flat ventral surface, as observed on UMNH VP 16266 (left, upper Campanian Kaiparowits Fm), Heloderma horridum (middle, modern, UF:Herp:153328), Gobiderma pulchrum (IGM 3/905, Campanian Djadokhta Fm, modified from , fig. 46B), and Paraderma bogerti (modified from ). (D) Large depression on the ventral surface of the centrum, as observed on Estesia mongoliensis (IGM 3/15, Campanian Djadokhta Fm, modified from ). Anatomical abbreviations: vd, ventral depression; vp, ventral pit.

Article Snippet: A prominent quadrate foramen was not described by Norell et al . [ ] on the quadrate of the holotype specimen of Estesia mongoliensis , nor is a prominent medial quadrate foramen obvious in observed specimens of Heloderma (specimen UF:Herp:153328, LACM 163852).

Techniques: Modification

Journal: Royal Society Open Science

Article Title: New monstersaur specimens from the Kaiparowits Formation of Utah reveal unexpected richness of large-bodied lizards in Late Cretaceous North America

doi: 10.1098/rsos.250435

Figure Lengend Snippet: Line drawings comparing parietal morphology among Late Cretaceous and Modern monstersaurs. (A–D) Campanian monstersaur specimens, denoted by black border. (A) Monstersaur parietals from the upper Campanian Kaiparowits Formation (Fm) in dorsal (top) and ventral (bottom) views. (B) Dorsal view of the parietal from specimen MOR 792 (referred to Palaeosaniwa canadensis ) from the Campanian Two Medicine Fm, modified from Balsai and Hamilton et al . . (C) Dorsal (top) and ventral (bottom) views of specimen TMP 1985.058.058 (Helodermatidae indet.) from the upper Campanian Oldman Fm, modified from Gao & Fox . (D) Described monstersaur parietals from the Campanian Djadokhta/Baruungoyot formations. Left: Parietal from the holotype specimen IGM 3/14 of Estesia mongoliensis in dorsal (top) and ventral (bottom) views, modified from Norell et al . . Right: dorsal views of parietals referred to Gobiderma pulchrum . Top: ZPAL MgR III/64 (holotype), modified from Conrad et al . ; middle: ZPAL MgR III/66, modified from Conrad et al . ; bottom: IGM 3/59, modified from Conrad et al . . (E) Parietal UALVP 33385 from the Maastrichtian Scollard Fm, referred to Paraderma bogerti , in dorsal (top) and ventral (bottom) views. Modified from Gao & Fox . (F) Parietal OMNH 27022 referred to Primaderma nessovi from the Cenomanian Mussentuchit Member, Cedar Mountain Fm, in dorsal (top) and ventral (bottom) views. Modified from Nydam . (G) Parietal of UF 153328 ( Heloderma horridum ) in dorsal (top) and ventral (bottom) views. Anatomical abbreviations: am, adductor musculature attachment; fps, frontoparietal suture; pfos, parietal fossa; pfrm, parietal foramen.

Article Snippet: A prominent quadrate foramen was not described by Norell et al . [ ] on the quadrate of the holotype specimen of Estesia mongoliensis , nor is a prominent medial quadrate foramen obvious in observed specimens of Heloderma (specimen UF:Herp:153328, LACM 163852).

Techniques: Modification