Holotype locality (circle) for <i>Varanus</i> (<i>Varaneades</i>) <i>amnhophilis</i> nov. taxon, on Samos, Greece.

<p>Star indicates Athens, Greece.</p

FOSSIL BODY SIZE ESTIMATES.

<p>Body size estimates for fossil varanids (<i>Saniwa ensidens</i>, <i>Varanus amnhophilis</i>, and two specimens of <i>Varanus priscus</i>). Estimates derived from comparisons with the data presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone-0041767-t001" target="_blank">Table 1</a>, as described in the text. Headings/abbreviations: taxon, fossil taxon whose size is predicted; comparisons, taxon group used for making the length estimation; meas., measured element; L, observed length of the measured element in mm; PCL est., estimated precaudal length of the fossil taxon; ±, the difference between the estimated PCL length and the maximum or minimum length falling within a 95 percent confidence interval; BCL, lateral braincase length (see text); DVL, dorsal vertebra length (see text), <i>V.</i>, <i>Varanus</i>; <i>Vko</i>, <i>Varanus komodoensis</i>; <i>Vgo</i>, <i>Varanus gouldii</i>. Underlined measurements indicate those which were deemed most pertinent based on taxonomic comparisons and phylogenetic placement (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone-0041767-g005" target="_blank">Fig. 5</a>) and illustrated in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone-0041767-g006" target="_blank">Figure 6</a>.</p

Holotype (AMNH FR 30630) vertebrae for <i>Varanus</i> (<i>Varaneades</i>) <i>amnhophilis</i> nov. taxon.

<p>(A) Cervical vertebrae 3, 4, and part of 5 in left lateral view. (B) Cervical vertebrae 3 and 4 in posterodorsal view showing the absence of zygosphenes/zygantra and/or pseudozygosphenes/pseudozygantra. (C) Three posterior dorsal vertebrae in ventral view. (D) Reconstruction of AMNH FR 30630 in left lateral view with known parts illustrated on a hypothetical black silhouette for the outline of the animal as a whole. Abbreviations: con, condyle; i, intercentrum; ns, neural spine; pcc, area of precondylar constriction; ped, hypapophyseal pedicel; poz, postzygapophysis; prz, prezygapophysis; syn, synapophysis; zga, zygantrum/pseudozygantrum.</p

Holotype (AMNH FR 30630) skull elements for <i>Varanus</i> (<i>Varaneades</i>) <i>amnhophilis</i> nov. taxon.

<p>Fragmentary right postorbital (A) and squamosal (B) in lateral view. (C) Right quadrate in lateral view. (D) Fragmentary palatine in ventral view. Right pterygoid in lateral (E) and ventral (F) view. Note the absence of pterygoid teeth. Right side of the braincase (parabasisphenoid, prootic, basioccipital, and otooccipital) in lateral view (G) and medial view (H). (I) Otic region of the braincase in ventral view showing the base of the crista interfenestralis and single opening to the facial foramen. (J) Reconstruction of the braincase in right lateral view with reconstructed areas appearing as semi-opaque shadows. (K) Partial right surangular-prearticular/articular complex in lateral view. (L) Partial right coronoid in lateral view. (M) Reconstruction of the cranium and mandible in right lateral view with reconstructed areas appearing as semi-opaque shadows. All scale bars 10 mm, except in (I) wherein the scale bar is 5 mm. Abbreviations: apoc, paroccipital tuberosity; acpr, anterostapedial process of the prootic crest; bpt, basipterygoid process; bptb, basipterygoid buttress; colf, columellar fossa; cpr, prootic crest (crista prootica); cri, crista interfenestralis; fec, ectopterygoid facet; fo, fenestra ovalis; fsq, squamosal facet (on postorbital); ipr, inferior process; pbs, parabasisphenoid; pcr, posterior crest; ped, hypapophyseal pedicel; poc, otooccipital paroccipital process; prp, prootic paroccipital process; poz, postzygapophysis; pvc, posterior opening of the vidian canal; qpr, quadrate process; sot, spheno-occipital tubercle; syn, synapophysis; tcr, tympanic crest; tpr, transverse process; I–XII, cranial nerves.</p

Comparative material of modern <i>Varanus</i> for anatomical comparisons with <i>Varanus amnhophilis</i>.

<p>Braincases of <i>Varanus komodoensis</i> (Australasian clade) (A), <i>Varanus bengalensis</i> (<i>Varanus</i> [<i>Indovaranus</i>] group) (B), and <i>Varanus albigularis</i> (<i>Varanus</i> [<i>Polydaedalus</i>]) group) (C). Ventral views of vertebrae of <i>Varanus nebulosus</i> (<i>Varanus</i> [<i>Indovaranus</i>] group) (D), and <i>Varanus flavescens</i> (E). (F) <i>Varanus albigularis</i> cervical vertebra in left dorsolateral view showing the pseudozygosphene. <i>Varanus komodoensis</i> (A) lacks an accessory prootic crest, <i>Varanus bengalensis</i> (B) possesses a hook-like accessory prootic crest, and <i>Varanus albigularis</i> (C) has a tabular accessory prootic crest. Insets with (D) and (E) show the strong and intermediate precondylar constrictions, respectively. Dotted gray lines show the intersection of hypothetical extensions of the ventrolateral surfaces. With a strong precondylar constriction, the lines intersect anterior to the vertebral condyle, but the intersection occurs beyond the level of the condyle in taxa with weak precondylar constriction. Abbreviations: acpr, anterostapedial process of the prootic crest; con, condyle; cpr, prootic crest (crista prootica); pcc, area of precondylar constriction; prz, prezygapophysis; pzgs, pseudozygosphene; syn, synapophysis.</p

Temporally calibrated phylogeny of varanids and their outgroups.

<p>Size data are indicated by color included on the known temporal ranges are derived from published accounts <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone.0041767-Pianka2" target="_blank">[21]</a>, ranges in black indicate taxa without reliable size data. Extant <i>Shinisaurus</i> was used as an outgroup for tree reconstruction, but the shinisaur clade is homogenous in size and extends into the Cretaceous <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone.0041767-Conrad2" target="_blank">[3]</a>. Some nodes collapsed for space considerations, but the number of included species is in parentheses next to the taxon name (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone.0041767.s001" target="_blank">Dataset S1</a>). Maps present the known distributions of the indicated taxa in red. Mosasaur distribution is based on the five basal taxa included in the analysis. <i>Varanus amnhophilis</i> is a nested member of the Indo-Asian A clade and the discordant distribution of that taxon with respect to other Indo-Asian A taxa is illustrated by the map on the lower left.</p

Size estimates for <i>Varanus</i> (<i>Varaneades</i>) <i>amnhophilis</i> (AMNH FR 30630) and Megalania (<i>Varanus priscus</i>, BMNH 39965 and AMNH FR 6304) based on comparisons of lateral braincase length (BCL) and dorsal vertebral length (DVL).

<p>The open diamonds indicate <i>Varanus</i> (<i>Varaneades</i>) <i>amnhophilis</i> and the open triangles indicate <i>Varanus priscus</i>. The dotted trend lines was calculated using <i>Varanus komodoensis</i> (PCL/BCL, y intercept [yi] = 17.67, x intercept [xi] = −59.67; PCL/DVL, yi = 44.71, xi = 131.4). The solid gray trend line was calculated using extant species from the Indo-Asian A clade of <i>Varanus</i> (PCL/BCL, yi = 22.08, xi = −85.53, R² = 0.918; PCL/DVL, yi = 42.21, xi = −64–96, R² = 0.994). Solid black trendline was calculated using all the data (PCL/BCL, yi = 17.16, xi = 14.11, R² = 0.956; PCL/DVL, yi = 39.93, xi = −24.20, R² = 0.975). Open line drawing represents <i>Varanus prasinus</i> (Vpr), the medium represents <i>Varanus</i> (<i>Polydaedalus</i>) <i>exanthematicus</i> (Vex), and the large represents <i>Varanus komodoensis</i> (Vko)—all to scale. Gray bars indicate predictive size range within 95 percent confidence interval. See text and (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone.0041767.s002" target="_blank">Text S1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone.0041767.s004" target="_blank">Text S3</a>).</p

Principal data from the measurement of 28 specimens of <i>Varanus</i> for comparison of fossils forms and size predictions.

<p>Abbreviations: BCL, linear length of the braincase from the anterior tip of the basipterygoid process of the parabasisphenoid to the tip of the paroccipital process of the otooccipital; DVL, length of a posterior dorsal vertebra; PCL, pre-caudal length of the animal (an osteological skeletal length similar to the snout-vent length often used for extant taxa. All measurements in millimeters [mm]).</p

SIZES OF EXTANT VARANIDAE.

<p>Lengths of 52 species of Varanidae (51 species of <i>Varanus</i> and <i>Lanthanotus borneensis</i>) based on published data <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone.0041767-Pianka2" target="_blank">[21]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone.0041767-Auffenberg1" target="_blank">[79]</a>. These data were used to reconstruct the lineage sizes in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone-0041767-g005" target="_blank">Figure 5</a>. Note that not all measurements and/or data are available for all included species. Abbreviations: SVL, snout-to-vent length of the animal; TL, total length of the animal (snout to tail tip); approx, approximate length based on published data <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone.0041767-Pianka2" target="_blank">[21]</a>; Auffenberg approx, approximate dimensions based on data presented for wild-caught specimens in Auffenberg's study on Komodo Dragons <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone.0041767-Auffenberg1" target="_blank">[79]</a>; F, female; holotype/type/voucher, measurements based on the type specimen—these data are usually reported in the case of species wherein there are few available specimens; M, male; max, reported maximum measurement; max field, reported maximum measurement of wild-caught specimens—these data are usually included when the species in question is popular in the pet trade.</p