A sample of jaw functional morphotypes from the fossil record of Mesozoic marine
reptiles. The illustrated taxa are (A) Pliosaurus, (B)
Tylosaurus, (C) Ophthalmosaurus, (D)
Metriorhynchus, (E) Nothosaurus, (F),
Xinpusaurus, (G) Placochelys, and (H)
Mesodermochelys. Scale bars on the jaw illustrations represent
20 cm (A–D) and 5 cm (E–H).
Empirical functional morphospaces showing the distribution of all marine reptile
species and major groups. Two-dimensional plots of PCOa axes 1 and 2 and PCOa axes
2 and 3. The lower plots (B) represent the same axes but with major groups denoted
by convex hulls. The gray filled diamonds denote an unrelated assemblage of
Triassic marine reptiles. The illustrated jaws in PC1–PC2 plot are:
Placodus (sauropterygian), Tylosaurus
(mosasaur), Metriorhynchus (thalattosuchia),
Hupehsuchus (ichthyosauromorph), and
Nichollsemys (turtle). The illustrated jaws in PC2–PC3 plot are:
Placodus (sauropterygian) and Nothosaurus
Mesozoic marine reptile functional disparity. Mean disparity values based on the
sum of variances (A) and sum of ranges (B) metrics (white circles) are plotted in
16 Mesozoic time intervals. The blue envelopes represent 95% confidence intervals
based on 10,000 bootstrap replicates. The sum of ranges is rarefied to the average
sample size of the 16 bins (n=17). Partial disparity is
illustrated in plot (C). This graphic illustrates the relative contributions of
each marine reptile group to overall disparity through the Mesozoic:
sauropterygians (green), ichthyosauromorphs (dark blue), thalattosaurs (orange),
thalattosuchians (yellow), turtles (light blue), and mosasauroids (red).
Mesozoic marine reptile disparity and time-bin sample size. Disparity through
time is based on the data in Figure 3A,B,
showing the mean sum of variances (solid black line) and sum of ranges (dashed
black line) results. Bin sample size is plotted in the same 16 Mesozoic time
intervals (solid red line).
Patterns of functional morphospace occupation for marine reptiles through the
Mesozoic. Two-dimensional plots of PCOa axes 1 and 2 are illustrated for nine
sampled intervals: Anisian, Carnian, Norian, Hettangian–Sinemurian,
Aalenian–Bathonian, Kimmeridgian–Tithonian, Berriasian–Barremian,
Cenomanian–Turonian, and Campanian. Symbols are used to represent the major
groups. The temporal position of each sampled interval is illustrated in a
disparity through time plot based on the sum of variances and sum of ranges
(dotted line) metrics. All 16 intervals are figured in Supplementary Figure 7.
Marine reptile functional disparity plotted through time. Based on (A) within-bin
mean pairwise dissimilarity calculated from the Gower intertaxon distance matrix
using all characters, (B–E) using PC scores from analyses using only continuous
characters. Mean disparity values based on pairwise dissimilarity (A), and the sum
of variances (B, C) and sum of ranges (D, E) metrics (white circles) are plotted
in 16 Mesozoic time intervals. The blue envelopes represent 95% confidence
intervals based on 10,000 bootstrap replicates. The sum of ranges is rarefied to
the average sample size of the 16 bins (n=17). In (C) and (E) the
character total mandibular length was excluded from the data set.
Temporal trends of marine reptile skull-size evolution. In the upper plot,
log10 skull length for 354 marine reptile species is plotted at the
midpoint of their stratigraphic range. Symbols are used to differentiate the major
groups. Lower plot represents the same data expressed as box-and-whisker diagrams
plotted at the midpoint of each time bin. Group symbols correspond to Figures 2 and 5.
Temporal diversity and disparity trends in five marine reptile groups.
Phylogenetic diversity estimates are plotted in the first column. Mean disparity
values (white circles) are plotted in time bins through each group’s duration,
with associated 95% confidence intervals based on 10,000 bootstrap replicates. Two
disparity metrics are shown: the sum of variances and the sum of ranges. The
groups plotted are sauropterygians, eosauropterygians, ichthyosauromorphs,
mosasauroids, and thalattosuchians. In the sum of ranges metric, the sample size
is rarefied to n=7, representing the median sample size for
sauropterygians, eosauropterygians, ichthyosauromorphs, and thalattosuchians and
the minimum sample size for mosasauroids. In column four, temporal trends of
skull-size diversity based on log10 skull length are plotted at the
midpoint of each taxon’s stratigraphic range. Note the contrasting temporal
duration of each clade given on the x-axes.
Evolutionary model fittings for morphospace axes and skull size in five marine
reptile groups. Akaike weights of three models are expressed as circle charts for
each group and trait. The groups plotted are: sauropterygians, eosauropterygians,
ichthyosauromorphs, mosasauroids, and thalattosuchians. In all instances where
delta is the favored model, it is associated with early high rates, with the
exception of mosasauroid PC axis 2. EB, early burst; BM, Brownian motion.
Functional characters measured and scored for 206 Mesozoic marine reptile taxa.
Detailed descriptions of all characters are provided in the Supplementary
Eigenvalues and percentages of variance associated with each PCO axis from the
multivariate analysis. The primary analysis is based on all 18 characters.
Statistical tests for significant differences/shifts in functional disparity and
functional morphospace occupation between successive Mesozoic time bins. For
comparative purposes, statistical tests for a disparity shift between the Carnian
and Hettangian–Sinemurian are also provided. Disparity tests are based on
paired-sample t-tests and likelihood ratios (LR). Functional
morphospace occupation tests are based on nonparametric multivariate analysis of
variance (NPMANOVA), performed on PC scores from the first 11 PC axes. Uncorrected
and Bonferroni-corrected p-values are reported. Bold values
represent statistically significant results where p-values are
<0.05 and LRs are >8. See text in the “Stratigraphic Binning”
section for full time-bin names and age ranges.
Summary of maximum-likelihood model-fitting analyses. Sample size–corrected
Akaike’s information criterion (AICc), model parameter values, and AICc weights
are documented for each analytical permutation. For the AICc values, we report the
mean and standard error based on multiple dating and topology replicates, as
described in the text. The results from this table are visualized in Figure 9. The best-fitting evolutionary models
are highlighted in bold for each analysis: lowest AICc value, highest AICc weight.
MSL, maximum skull length; BM, Brownian motion; and EB, early burst.