title: Phylogeographic patterns and cryptic speciation across oceanographic barriers in South African intertidal fishes.
abstract: Biogeographic boundaries are the meeting zone of broadly distributed faunas, or the actual cause of a faunal break. In the latter case, closely related sister species should be found across such a boundary. To achieve such a situation, preliminary stages are expected, where phylogeographic breaks followed by genetic cryptic speciation would be observed. Biogeographic boundaries, in the Cape Point/Cape Agulhas region of southern Africa, offer an ideal system to test such predictions. Here, we studied two intertidal clinid fish species that are endemic to southern Africa, Clinus superciliosus (n = 127) and Muraenoclinus dorsalis (n = 114). Using mitochondrial control region, 16S rRNA, 12S rRNA and NADH2 genes and the nuclear rhodopsin and the first intron of the S7 ribosomal protein gene, we show both phylogeographic breaks and likely cryptic speciation in each species. Pairwise Φ(st) results suggest population genetic structuring for both species, with higher levels for M. dorsalis (Φ(st) = 0.34-0.93) than for C. superciliosus (Φ(st) = 0.1-0.74). Further, we recover two and three distinct lineages within M. dorsalis and C. superciliosus, respectively. Phylogenetic topologies, concordance between nuclear and mitochondrial markers and levels of sequence divergence, which are consistent with closely related sister species pairs, suggest the presence of cryptic species. Our results therefore meet the expectation for reduced gene flow at a biogeographic barrier, which translates into significant genetic breaks and cryptic sister species.
authors.affiliation: Evolutionary Genomics Group, Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa.
authors.forename: S
authors.initials: S
authors.lastname: von der Heyden
authors.forename: R C K
authors.initials: RC
authors.lastname: Bowie
authors.forename: K
authors.initials: K
authors.lastname: Prochazka
authors.forename: P
authors.initials: P
authors.lastname: Bloomer
authors.forename: N L
authors.initials: NL
authors.lastname: Crane
authors.forename: G
authors.initials: G
authors.lastname: Bernardi
mesh_terms: D000818:Animals; D001483:Base Sequence; D016000:Cluster Analysis; D004272:DNA, Mitochondrial / Q000235:genetics; D003710:Demography; D051456:Gene Flow / Q000235:genetics; D049810:Genetic Speciation; D014644:Genetic Variation; D005828:Genetics, Population; D016013:Likelihood Functions; D019901:Locus Control Region / Q000235:genetics; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000235:genetics; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics; D009792:Oceans and Seas; D010473:Perciformes / Q000235:genetics*; D010802:Phylogeny; D058974:Phylogeography; D012335:RNA, Ribosomal / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012243:Rhodopsin / Q000235:genetics; D017422:Sequence Analysis, DNA; D013019:South Africa; D013045:Species Specificity
chemical_list: D004272:DNA, Mitochondrial; D009097:Multienzyme Complexes; D012335:RNA, Ribosomal; D012336:RNA, Ribosomal, 16S; C075526:RNA, ribosomal, 12S; D012243:Rhodopsin; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases