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Theropod specimens used for tooth, nasal, and cranial strength calculations. Symbols used in diagrams are given in parenthe− ses for each specimen, followed by its specimen number and/or literature source. in Fused and vaulted nasals of tyrannosaurid dinosaurs: Implications for cranial strength and feeding mechanics

Theropod specimens used for tooth, nasal, and cranial strength calculations. Symbols used in diagrams are given in parenthe− ses for each specimen, followed by its specimen number and/or literature source.

Fig. 7 in Fused and vaulted nasals of tyrannosaurid dinosaurs: Implications for cranial strength and feeding mechanics

Fig. 7. CT−scanned cross−sections of fused tyrannosaurid nasals, showing greater vaulting and higher cross−sectional areas of bone in larger individuals. A. Gorgosaurus libratus (juvenile: TMP 86.144.1). B. Gorgosaurus libratus (subadult: TMP 86.64.1). C. Daspletosaurus torosus (adult: TMP 98.48.1). Numbers 1–4: cross−sections at topologically similar positions, from posterior to anterior.

Fig. 13 in Fused and vaulted nasals of tyrannosaurid dinosaurs: Implications for cranial strength and feeding mechanics

Fig. 13. Strength indicators computed for theropod crania under mediolateral (A), dorsoventral (B), and torsional (C) loadings. Tyrannosaurid crania are invariably stronger than those of carnosaurs for a given skull length. See Appendix 1 for labels.

Fig. 15 in Fused and vaulted nasals of tyrannosaurid dinosaurs: Implications for cranial strength and feeding mechanics

Fig. 15. Nasal articulations with maxillae in juvenile Gorgosaurus libratus (nasals at top; TMP 86.144.1) adult Tyrannosaurus rex (nasals in middle and maxilla below; TMP 98.86.01; cast of BHI 2033). The interlocking, staircase−style articulation in the adult Tyrannosaurus rex efficiently transmitted compressional forces and increased the shear strength of the articulation. Dashed lines show the extent of the staircased articulation, and the solid line indicates a projection on the nasals and the corresponding depression in the maxilla.

FIGURE 9 in A story of nasal horns: two new subspecies of Iguana Laurenti, 1768 (Squamata, Iguanidae) in Saint Lucia, St Vincent & the Grenadines, and Grenada (southern Lesser Antilles)

FIGURE 9. Horned iguanas from the Central American clade of the "rhinolopha" phenotype. Photographed from invasive introduced populations in the Lesser Antilles: old male caught in Saint Lucia (A). young male caught on Saint Maarten (B); Annotations: 1. Huge subtympanic plate, 2 to 3 times the size of the eardrum. 2. A half crown of sublabial scales around the subtympanic plate and the first scale anterior to subtympanic plate. 3. Mosaic of sublabial scales. 4. Swelling of the jowls in breeding male. 5. Generally 2-3 small median horns and no lateral horns. 6. Flat small horns. 7. Triangular nostril. 8. Yellow to dark orange eye with not the white visible. 9. Triangular gular spikes. 10. Number of gular spikes ± 10. 11. Nuchal tubercles appear to be organised in rows. 12. High number of nuchal tubercles. 13. Very large nuchal tubercles. 14. Yellow, orange to red dorsal scales on the whole body in breeding males. 15. Variable size and colour of the dewlap but often large and not uniform black (cf. I. iguana sanctaluciae) or creamy white (cf. I. iguana insularis). 16. Body orange to red in breeding males, green in other individuals, and not heavily banded. This phenotype is recognised in this paper as a full species, I. rhinolopha, native to Central America (see text).

FIGURE 5 in A story of nasal horns: two new subspecies of Iguana Laurenti, 1768 (Squamata, Iguanidae) in Saint Lucia, St Vincent & the Grenadines, and Grenada (southern Lesser Antilles)

FIGURE 5. Nasal horns of Iguana iguana insularis ssp. nov. View of the snout of IGU75 (A) and IGU77 (B) from Palm Island (same individuals as Fig. 4). Annotations: 0. Frontal scale not developed into a horn. 1. Median horns with enlarged bases. 2. Lateral horns. 3. Oval prominent nostril. Note the differing forms and disposition of cephalic scales, and that IGU75 (a younger male) has flat scales whereas IGU77 (an older, larger male) has more prominent scales.

FIGURE 6 in A story of nasal horns: two new subspecies of Iguana Laurenti, 1768 (Squamata, Iguanidae) in Saint Lucia, St Vincent & the Grenadines, and Grenada (southern Lesser Antilles)

FIGURE 6. Distribution of iguanas in the Grenadine islands. Locations are mapped to the nearest 2 × 2 km square representing groups of islands in the Grenadines. We have deliberately avoided being specific to protect the animals (see Auliya et al. 2016). Note that there are alien iguanas on some islands and not all of the island clusters shown here have purebred populations of Iguana iguana insularis. We have no confirmed specific localities for the main island of Grenada, although a museum specimen (MCZ R-79747) confirms this subspecies occurred here. Henderson & Breuil (2012), Henderson & Powell (2018), Baldwin (2012) and Baldwin & Mahon (2011), G. Gaymes and J. Daltry (pers. obs.; the Grenadines). While iguanas are present on St. Vincent, these have not been identified to subspecies level and cannot be assumed to be identical to those on the Grenada Bank. The grey line just south of St Vincent marks the brake between the St. Vincent Bank to the north and the Grenada Bank to the south. The black line between Petit Saint Vincent and Petit(e) Martinique shows the political boundary between St. Vincent and the Grenadines to the north and Grenada to the south. The Grenadine islands form an archipelago from the south of St. Vincent to the north of Grenada.

FIGURE 3 in A story of nasal horns: two new subspecies of Iguana Laurenti, 1768 (Squamata, Iguanidae) in Saint Lucia, St Vincent & the Grenadines, and Grenada (southern Lesser Antilles)

FIGURE 3. Holotype of Iguana iguana insularis ssp. nov. MCZ X-17620/R-79057 © Museum of Comparative Zoology, Harvard University. © President and Fellows of Harvard College. Specimen in alcohol with discolouration. Annotations: 1. Small size of subtympanic plate ± 10-20% of the eardrum. 2. Two or three scales of decreasing size anterior to subtympanic plate. 3. Juxtaposed elongated sublabial scales 5. Median and lateral horns on the snout. 6. Horns with enlarged bases. 7. Oval and prominent nostrils. 9. Flat and triangular gular spikes. 10. Six gular spikes. 11. Scattered nuchal tubercles. 12. Low number of nuchal tubercles. 13. Small size of nuchal tubercles. 15. Dewlap of medium size.

FIGURE 8 in A story of nasal horns: two new subspecies of Iguana Laurenti, 1768 (Squamata, Iguanidae) in Saint Lucia, St Vincent & the Grenadines, and Grenada (southern Lesser Antilles)

FIGURE 8. Ontogenetic change in colour of Iguana iguana sanctaluciae. Young male (A), old male (B). Annotations: 1. Small subtympanic plate ± 10% of the eardrum. 2. Two or three scales of decreasing size anterior to subtympanic plate. 3. Low number of sublabial scales with black margins. 4. No swelling of the jowls in breeding males. 5. Lateral and median horns. 6. Median horns with enlarged bases. 7. Oval to rounded nostril. 8. Brown eye with the white of the eye visible. 9. Triangular gular spikes. 10. 7 gular spikes. 11. Dispersed nuchal tubercles. 12. Low number of nuchal tubercles. 13. Small size of nuchal tubercles. 14. Orange in first dorsal spikes in breeding animals. 15. Entirely black dewlap in old adults. 16. Body and tail black and bright green in young individuals and very light green to almost pale greenish grey in old adults. Old individuals may look nearly "black and white". The brilliant colouration of the young male results from the flash of the camera.

FIGURE 13 in A story of nasal horns: two new subspecies of Iguana Laurenti, 1768 (Squamata, Iguanidae) in Saint Lucia, St Vincent & the Grenadines, and Grenada (southern Lesser Antilles)

FIGURE 13. Median-Joining haplotype network. Based on 23 mtDNA sequences of Iguana (21 from this study, 2 from Gen- Bank). Black circles are median vectors that represent extinct or unsampled haplotypes. Numbers of mutational steps are indicated by hatch marks.

FIGURE 16 in A story of nasal horns: two new subspecies of Iguana Laurenti, 1768 (Squamata, Iguanidae) in Saint Lucia, St Vincent & the Grenadines, and Grenada (southern Lesser Antilles)

FIGURE 16. STRUCTURE bar plot showing admixture coefficient of each individual to the three inferred genetic clusters. This bar plot was produced using the DISTRUCT program (Rosenberg 2004).

FIGURE 11 in A story of nasal horns: two new subspecies of Iguana Laurenti, 1768 (Squamata, Iguanidae) in Saint Lucia, St Vincent & the Grenadines, and Grenada (southern Lesser Antilles)

FIGURE 11. Distribution of iguanas on Saint Lucia. Locations are mapped to the nearest 1×1 km square. Data come from Morton et al. (2007). Grey squares, Saint Lucia endemic iguana, Black squares, alien iguana from Central America clade. "False absences" were minimized by interviewing persons about iguana presence in grid squares confirmed independently, through sightings and captures by us, to have iguanas present. We rejected some reported sightings of native iguanas, shown here as open grid squares, as being iguanas captured for food or pets or reports based on misidentification (for example on the islet of Maria Major off the far south of Saint Lucia; J. Lazell, in litt. 2010). Some of the reports that were accepted from the interior of the northern half of Saint Lucia may also be suspect, though they are all below 300 m ASL. These patterns of distribution suggest that the mountainous interior of Saint Lucia may create at least a partial barrier to direct east-west movements of iguanas.

FIGURE 1 in A story of nasal horns: two new subspecies of Iguana Laurenti, 1768 (Squamata, Iguanidae) in Saint Lucia, St Vincent & the Grenadines, and Grenada (southern Lesser Antilles)

FIGURE 1. Drawing by Provancher (1890) of a stuffed iguana on Saint Lucia. Provancher identified it as Iguana delicatissima (see text), but the body and tail seem to have vertical black stripes, and there are small and scattered tubercular nape scales, and no subtympanic plate. There is no tympanum and no nasal horns on this drawing, which also shows a forked tongue.

FIGURE 17 in A story of nasal horns: two new subspecies of Iguana Laurenti, 1768 (Squamata, Iguanidae) in Saint Lucia, St Vincent & the Grenadines, and Grenada (southern Lesser Antilles)

FIGURE 17. Nesting periods of various iguana populations. Monthly mean precipitation is indicated in mm. Precipitation varies according to altitude and aspect, but the important point is that after a 3 months incubation period, the eclosions occur at the beginning or during the rainy season. The brackets indicate the main laying period for the different species at different insular and continental locations. Note that the nesting period of Iguana iguana sanctaluciae overlaps the laying periods of both Iguana delicatissima and Iguana iguana iguana, which suggests that mating periods could also overlap, potentially enabling all three species to interbreed.

FIGURE 10. Adult breeding males I. iguana sanctaluciae and I in A story of nasal horns: two new subspecies of Iguana Laurenti, 1768 (Squamata, Iguanidae) in Saint Lucia, St Vincent & the Grenadines, and Grenada (southern Lesser Antilles)

FIGURE 10. Adult breeding males I. iguana sanctaluciae and I. rhinolopha. The endemic Saint Lucia horned iguana (I. iguana sanctaluciae, photo from Grand Anse, A) is clearly different from the Central America horned iguana (I. rhinolopha: this specimen was photographed from an introduced population on Sint Maarten by M. Yokoyama, B) by size, body proportion, body colour, size and form of the horns, eye colouration, scalation of the jowls, and dewlap size, colour and form.

FIGURE 12 in A story of nasal horns: two new subspecies of Iguana Laurenti, 1768 (Squamata, Iguanidae) in Saint Lucia, St Vincent & the Grenadines, and Grenada (southern Lesser Antilles)

FIGURE 12. Phylogenetic tree. Based on mtDNA of 23 iguanas (21 from this study, 2 from GenBank). Four clades are identified. Iguana delicatissima (AF217783) serves as the outgroup. The monophyly of Lazell's southern Lesser Antilles group, characterised by horns, is described here as two new subspecies Iguana iguana insularis and Iguana iguana sanctaluciae. The horned iguanas from Central America are also considered here as a full species I. rhinolopha. The sister group of I. iguana insularis and Iguana iguana sanctaluciae is I. iguana iguana (based on specimens shown here from French Guiana). This phylogenetic tree shows that I. iguana iguana is present as an invasive alien species in the Grenadines (IGU74) and that there is I. delicatissima mitochondrial DNA in some specimens of I. iguana sanctaluciae. The ML tree with the highest log likelihood is shown. Node supports were indicated by bootstrap values from ML (>70) and posterior probability from BI (>0.95).

FIGURE 15 in A story of nasal horns: two new subspecies of Iguana Laurenti, 1768 (Squamata, Iguanidae) in Saint Lucia, St Vincent & the Grenadines, and Grenada (southern Lesser Antilles)

FIGURE 15. Results from the Evanno's Method using the STRUCTURE HARVESTER software. This analysis reveals a maximum likelihood for K=3.