Bryaninops,
Gobiodon,
Paragobiodon and
Pleurosicya are the most abundant genera of coral-associated gobies. These genera are adapted to live among coral, while other small
reef gobies (e.g., the genus
Eviota) show no obligate association with this living substrate. Thirteen coral-associated species and two
Eviota species were sampled from different regions of the Red Sea, along with four populations/species of
Gobiodon from the Indian and western Pacific Oceans. A molecular phylogenetic analysis was performed using partial sequences of 12S
rRNA, 16S rRNA and cytochrome
b mitochondrial genes, 1,199 base pairs in total. Several clades were consistently resolved in neighbor joining-, maximum parsimony-,
maximum likelihood and Bayesian analyses. While each of the four genera
Gobiodon,
Paragobiodon,
Bryaninops and
Pleurosicya proved to be monophyletic, their relative position in the phylogeny did not support an emergence of coral-associated gobiids
as a monophyletic assemblage. Instead, two separate monophyletic sub-groups were discovered, the first comprising
Gobiodon and
Paragobiodon, and the second
Bryaninops and
Pleurosicya. Our molecular phylogenetic examinations also revealed one unassigned species of
Gobiodon from the Maldives as a distinct species and confirmed three putative and yet unassigned species from the Red Sea. Moreover,
the uniformly black colored species of
Gobiodon are not monophyletic but have evolved independently within two distinct species groups. Genetic distances were large in particular
within
Pleurosicya and
Eviota. Estimated divergence times suggest that coral-associated gobies have diversified in parallel to their preferred host corals.
In particular, divergence times of
Gobiodon species closely match those estimated for their typical host coral genus
Acropora.
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