Deep phylogeographic structure may indicate cryptic species within the Sparid genus Spondyliosoma:
- McKeown, Niall J, Gwilliam, Michael P, Healey, Amy J E, Skujina, Ilze, Potts, Warren M, Sauer, Warwick H H, Shaw, Paul W
- Authors: McKeown, Niall J , Gwilliam, Michael P , Healey, Amy J E , Skujina, Ilze , Potts, Warren M , Sauer, Warwick H H , Shaw, Paul W
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158085 , vital:40147 , DOI: 10.1111/jfb.14316
- Description: Two geographically nonoverlapping species are currently described within the sparid genus Spondyliosoma: Spondyliosoma cantharus (Black Seabream) occurring across Mediterranean and eastern Atlantic waters from NW Europe to Angola and S. emarginatum (Steentjie) considered endemic to southern Africa. To address prominent knowledge gaps this study investigated range‐wide phylogeographic structure across both species. Mitochondrial DNA sequences revealed deep phylogeographic structuring with four regionally partitioned reciprocally monophyletic clades, a Mediterranean clade and three more closely related Atlantic clades [NE Atlantic, Angola and South Africa (corresponding to S. emarginatum)]. Divergence and distribution of the lineages reflects survival in, and expansion from, disjunct glacial refuge areas. Cytonuclear differentiation of S. emarginatum supports its validity as a distinct species endemic to South African waters.
- Full Text:
- Date Issued: 2020
- Authors: McKeown, Niall J , Gwilliam, Michael P , Healey, Amy J E , Skujina, Ilze , Potts, Warren M , Sauer, Warwick H H , Shaw, Paul W
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158085 , vital:40147 , DOI: 10.1111/jfb.14316
- Description: Two geographically nonoverlapping species are currently described within the sparid genus Spondyliosoma: Spondyliosoma cantharus (Black Seabream) occurring across Mediterranean and eastern Atlantic waters from NW Europe to Angola and S. emarginatum (Steentjie) considered endemic to southern Africa. To address prominent knowledge gaps this study investigated range‐wide phylogeographic structure across both species. Mitochondrial DNA sequences revealed deep phylogeographic structuring with four regionally partitioned reciprocally monophyletic clades, a Mediterranean clade and three more closely related Atlantic clades [NE Atlantic, Angola and South Africa (corresponding to S. emarginatum)]. Divergence and distribution of the lineages reflects survival in, and expansion from, disjunct glacial refuge areas. Cytonuclear differentiation of S. emarginatum supports its validity as a distinct species endemic to South African waters.
- Full Text:
- Date Issued: 2020
Integrated genetic and morphological data support eco‐evolutionary divergence of Angolan and South African populations of Diplodus hottentotus
- Gwilliam, Michael P, Winkler, Alexander C, Potts, Warren M, Santos, Carmen V D, Sauer, Warwick H H, Shaw, Paul W, McKeown, Niall J
- Authors: Gwilliam, Michael P , Winkler, Alexander C , Potts, Warren M , Santos, Carmen V D , Sauer, Warwick H H , Shaw, Paul W , McKeown, Niall J
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124833 , vital:35702 , https://doi.10.1111/jfb.13582
- Description: The genus Diplodus presents multiple cases of taxonomic conjecture. Among these the D. cervinus complex was previously described as comprising three subspecies that are now regarded as separate species: Diplodus cervinus, Diplodus hottentotus and Diplodus omanensis. Diplodus hottentotus exhibits a clear break in its distribution around the Benguela Current system, prompting speculation that Angolan and South African populations flanking this area may be isolated and warrant formal taxonomic distinction. This study reports the first integrated genetic [mitochondrial (mt)DNA and nuclear microsatellite] and morphological (morphometric, meristic and colouration) study to assess patterns of divergence between populations in the two regions. High levels of cytonuclear divergence between the populations support a prolonged period of genetic isolation, with the sharing of only one mtDNA haplotype (12 haplotypes were fully sorted between regions) attributed to retention of ancestral polymorphism. Fish from the two regions were significantly differentiated at a number of morphometric (69·5%) and meristic (46%) characters. In addition, Angolan and South African fish exhibited reciprocally diagnostic colouration patterns that were more similar to Mediterranean and Indian Ocean congeners, respectively. Based on the congruent genetic and phenotypic diversity we suggest that the use of hottentotus, whether for full species or subspecies status, should be restricted to South African D. cervinus to reflect their status as a distinct species-like unit, while the relationship between Angolan and Atlantic–Mediterranean D. cervinus will require further demo-genetic analysis. This study highlights the utility of integrated genetic and morphological approaches to assess taxonomic diversity within the biogeographically dynamic Benguela Current region.
- Full Text:
- Date Issued: 2018
- Authors: Gwilliam, Michael P , Winkler, Alexander C , Potts, Warren M , Santos, Carmen V D , Sauer, Warwick H H , Shaw, Paul W , McKeown, Niall J
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124833 , vital:35702 , https://doi.10.1111/jfb.13582
- Description: The genus Diplodus presents multiple cases of taxonomic conjecture. Among these the D. cervinus complex was previously described as comprising three subspecies that are now regarded as separate species: Diplodus cervinus, Diplodus hottentotus and Diplodus omanensis. Diplodus hottentotus exhibits a clear break in its distribution around the Benguela Current system, prompting speculation that Angolan and South African populations flanking this area may be isolated and warrant formal taxonomic distinction. This study reports the first integrated genetic [mitochondrial (mt)DNA and nuclear microsatellite] and morphological (morphometric, meristic and colouration) study to assess patterns of divergence between populations in the two regions. High levels of cytonuclear divergence between the populations support a prolonged period of genetic isolation, with the sharing of only one mtDNA haplotype (12 haplotypes were fully sorted between regions) attributed to retention of ancestral polymorphism. Fish from the two regions were significantly differentiated at a number of morphometric (69·5%) and meristic (46%) characters. In addition, Angolan and South African fish exhibited reciprocally diagnostic colouration patterns that were more similar to Mediterranean and Indian Ocean congeners, respectively. Based on the congruent genetic and phenotypic diversity we suggest that the use of hottentotus, whether for full species or subspecies status, should be restricted to South African D. cervinus to reflect their status as a distinct species-like unit, while the relationship between Angolan and Atlantic–Mediterranean D. cervinus will require further demo-genetic analysis. This study highlights the utility of integrated genetic and morphological approaches to assess taxonomic diversity within the biogeographically dynamic Benguela Current region.
- Full Text:
- Date Issued: 2018
Phylogeny of the Sepia officinalis species complex in the eastern Atlantic extends the known distribution of Sepia vermiculata across the Benguela upwelling region
- Healey, Amy J E, McKeown, Niall J, Potts, Warren M, de Beer, Chénelle L, Sauer, Warwick H H, Shaw, Paul W
- Authors: Healey, Amy J E , McKeown, Niall J , Potts, Warren M , de Beer, Chénelle L , Sauer, Warwick H H , Shaw, Paul W
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125631 , vital:35802 , https://doi.10.2989/1814232X.2017.1371076
- Description: Accurate species identification and biogeographic characterisation are fundamental for appropriate management of expanding cephalopod fisheries. This study addresses this topic within the common cuttlefish Sepia officinalis species complex (S. officinalis, S. hierredda and S. vermiculata), with an emphasis on occurrence in African waters. Tissue samples from the currently presumed distributions of S. vermiculata and S. hierredda (from South Africa and Ghana/Angola, respectively) were sequenced for the cytochrome c oxidase subunit I (COI) and the cytochrome b (cytb) genes of the mitochondrial genome and then compared to existing S. officinalis sequences. Three highly divergent and reciprocally monophyletic clades, corresponding to S. officinalis, S. hierredda and S. vermiculata, were resolved, representing the first molecular confirmation of the distinct species status of S. hierredda and S. vermiculata. The sequences also revealed that, contrary to expectations based on presently published information, all samples from southern Angola were S. vermiculata. These results indicate that the range of S. vermiculata extends beyond the currently described northern limit and that S. hierredda and S. vermiculata may be indiscriminately harvested in Angolan waters. Finer-scale patterns within S. vermiculata phylogeography also indicate that the Benguela Current System and/or other environmental factors serve to isolate northern and southern stocks.
- Full Text:
- Date Issued: 2017
- Authors: Healey, Amy J E , McKeown, Niall J , Potts, Warren M , de Beer, Chénelle L , Sauer, Warwick H H , Shaw, Paul W
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125631 , vital:35802 , https://doi.10.2989/1814232X.2017.1371076
- Description: Accurate species identification and biogeographic characterisation are fundamental for appropriate management of expanding cephalopod fisheries. This study addresses this topic within the common cuttlefish Sepia officinalis species complex (S. officinalis, S. hierredda and S. vermiculata), with an emphasis on occurrence in African waters. Tissue samples from the currently presumed distributions of S. vermiculata and S. hierredda (from South Africa and Ghana/Angola, respectively) were sequenced for the cytochrome c oxidase subunit I (COI) and the cytochrome b (cytb) genes of the mitochondrial genome and then compared to existing S. officinalis sequences. Three highly divergent and reciprocally monophyletic clades, corresponding to S. officinalis, S. hierredda and S. vermiculata, were resolved, representing the first molecular confirmation of the distinct species status of S. hierredda and S. vermiculata. The sequences also revealed that, contrary to expectations based on presently published information, all samples from southern Angola were S. vermiculata. These results indicate that the range of S. vermiculata extends beyond the currently described northern limit and that S. hierredda and S. vermiculata may be indiscriminately harvested in Angolan waters. Finer-scale patterns within S. vermiculata phylogeography also indicate that the Benguela Current System and/or other environmental factors serve to isolate northern and southern stocks.
- Full Text:
- Date Issued: 2017
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