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1682 C. Gubili et al. Historical dispersal of white sharks

Lamna nasus
SA
95/100
SA
SA
SA
AU
100/100 NWA
NWA
100/100
SA
97 SA
SA
95 SA
AU
AU
AU
AU
NZ
AU
AU
66
AU
AU
NZ
MED
NEP
NEP
NEP
NEP
NEP
NEP
NEP
NEP
NEP
NEP
NEP
NEP
NEP
NEP
NEP
NEP
NEP
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AU
NZ
NZ
AU
60/95
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0.1
Figure 2. Maximum-likelihood phylogeny, depicting genetic relationships among C. carcharias, inferred from mtDNA control
region sequences (an alignment length of 1087 bp including indels). The two main haplotype lineages correspond to the Indo-
Pacific and South African/north-west Atlantic clades. Mediterranean samples cluster with Indo-Pacific haplotypes, from which
they are only weakly differentiated. The tree is rooted with Lamna nasus and values above branches indicate support for each
node based on Bayesian/ML inference. Bootstrap values under 60% are not shown.

and eight substitutions (GW12 to the group of GW18/7/ Nevertheless, occurrence of white sharks in the Red Sea
4/3/1), respectively. This suggests that divergence is disputed [38], and a recent record from the Arabian
between Indo-Pacific and MED haplotypes corresponds Sea is considered a misidentification [39]. Zuffa et al.
to levels of genetic differentiation observed within each [40] reported the presence of C. carcharias off southern
group. However, the large geographical distance separ- and western Madagascar, with northernmost records off
ating Mediterranean and Oceania waters, and the Kenya and Zanzibar, findings consistent with descriptions
absence of the Mediterranean haplotype along routes of a 6.4 m pregnant female off Kenya [41]. Additionally,
from the Indo-Pacific, including comprehensively the thermal barrier of tropical waters, and hypersalinity of
sampled South African locations, suggest that demo- the Red Sea, Bitter Lakes and Suez Canal, were thought
graphically contiguous contemporary or historical to prevent white shark dispersal. However, satellite
populations are unlikely. tagging reveals that this species tolerates a wide tempera-
The shortest route connecting Indo-Pacific and MED ture range [3], consistent with it traversing the Red Sea.
populations is through the Red Sea and Suez Canal. Nevertheless, Fergusson [11] suggests some seasonality
Proc. R. Soc. B (2011)