total-evidence dating and most parsimonious
analyses, were performed. The most parsimo-
nious reconstruction was performed by the
program TNT1.1 ( 37 ), in which only morpho-
logical dataset (data S2) was used. The molec-
ular and morphological data were used in
Bayesian total-evidence dating analysis per-
formed by MrBayes 3.2.7 ( 38 ), in which a
backbone constraint for the extant taxa based
merely on the molecular data ( 36 )wasorwas
not enforced (code files S3 to S5).
Ecology investigations
Various headgear types in terms of develop-
ment and morphology were examined, includ-
ing the following groups: Bovidae, Cervidae,
Antilocapridae + Hoplitomerycidae, and
Giraffoidea/Giraffomorpha (Fig. 6A). In our
scheme, the following aspects were considered:
(i) support element (nasal, frontal, parietal,
or occipital); (ii) position on the cranial roof
(supraorbital, postorbital, or central); (iii) num-
ber of the frontal appendages (single, double,
triple, quadruple, or sextuple); (iv) covering
in the mature state (skin, keratin, or naked);
(v) morphology (spike-like, branched, palmed,
or combined multiforms); (vi) nondeciduous
or deciduous; (vii) presence or absence of burr
in antler; and (viii) fusion of horncores. The
appearance of each headgear type in geological
time was drawn in step lines showing the
cumulative number in each pecoran group
(Table 1).
We investigated the relative length and
thickness of axes and cervical vertebrae III
among various giraffoid taxa. The arithmetic
means of centrum length and cheek teeth row
length were used for generating a bivariate
diagram of cheek teeth row length versus
centrum length. The ratio of minimal width
to centrum length of axes and cervical verte-
brae III in giraffoids were also calculated and
plotted. Data were from previous publications
( 10 , 17 , 39 – 46 ).
In total, 81 enamel samples were collected
from teeth of the Halamagai herbivore com-
munity ford^13 Candd^18 O measurements (data
S7), including ruminants, proboscideans, suids,
rhinocerotids, and equids. Results are reported
in standard delta (d)notationasd^13 Candd^18 O
values in reference to the international car-
bonate standard Vienna Pee Dee belemnite.
Stable isotope data from other herbivore com-
munities from the early-middle Miocene of
northern China were obtained from literature
( 47 , 48 ). All these data (including the previ-
ously published data) were conducted at the
National High Magnetic Field Laboratory,
Florida State University, USA.
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