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Morphology, molecules, and monogenean parasites: an example of an integrative approach to cichlid biodiversity.

Van Steenberge M, Pariselle A, Huyse T, Volckaert FA, Snoeks J, Vanhove MP - PLoS ONE (2015)

Bottom Line: Cichlidogyrus georgesmertensi sp. nov. was found on S. babaulti and S. pleurospilus, C. franswittei sp. nov. on both S. marginatus and P. curvifrons and C. frankwillemsi sp. nov. only on P. curvifrons.As relatedness between Cichlidogyrus species usually reflects relatedness between hosts, we considered Simochromis monotypic because the three Cichlidogyrus species found on S. diagramma belonged to a different morphotype than those found on the other Simochromis.Finally parasite data also supported the synonymy between S. pleurospilus and S. babaulti, a species that contains a large amount of geographical morphological variation.

View Article: PubMed Central - PubMed

Affiliation: Biology Department, Royal Museum for Central Africa, Tervuren, Belgium; Laboratory of Biodiversity and Evolutionary Genomics, Department of Biology, University of Leuven, Leuven, Belgium; Institute of Zoology, University of Graz, Graz, Austria.

ABSTRACT
The unparalleled biodiversity of Lake Tanganyika (Africa) has fascinated biologists for over a century; its unique cichlid communities are a preferred model for evolutionary research. Although species delineation is, in most cases, relatively straightforward, higher-order classifications were shown not to agree with monophyletic groups. Here, traditional morphological methods meet their limitations. A typical example are the tropheine cichlids currently belonging to Simochromis and Pseudosimochromis. The affiliations of these widespread and abundant cichlids are poorly understood. Molecular work suggested that genus and species boundaries should be revised. Moreover, previous morphological results indicated that intraspecific variation should be considered to delineate species in Lake Tanganyika cichlids. We review the genera Simochromis and Pseudosimochromis using an integrative approach. Besides a morphometric study and a barcoding approach, monogenean Cichlidogyrus (Platyhelminthes: Ancyrocephalidae) gill parasites, often highly species-specific, are used as complementary markers. Six new species are described. Cichlidogyrus raeymaekersi sp. nov., C. muterezii sp. nov. and C. banyankimbonai sp. nov. infect S. diagramma. Cichlidogyrus georgesmertensi sp. nov. was found on S. babaulti and S. pleurospilus, C. franswittei sp. nov. on both S. marginatus and P. curvifrons and C. frankwillemsi sp. nov. only on P. curvifrons. As relatedness between Cichlidogyrus species usually reflects relatedness between hosts, we considered Simochromis monotypic because the three Cichlidogyrus species found on S. diagramma belonged to a different morphotype than those found on the other Simochromis. The transfer of S. babaulti, S. marginatus, S. pleurospilus and S. margaretae to Pseudosimochromis was justified by the similarity of their Cichlidogyrus fauna and the intermediate morphology of S. margaretae. Finally parasite data also supported the synonymy between S. pleurospilus and S. babaulti, a species that contains a large amount of geographical morphological variation.

No MeSH data available.


PCA on measurements of S. babaulti and S. pleurospilus.PC4 vs. PC3 of a PCA on the 20 measurements belonging to four geographical groups of S. babaulti and to S. pleurospilus (the southern group).
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pone.0124474.g006: PCA on measurements of S. babaulti and S. pleurospilus.PC4 vs. PC3 of a PCA on the 20 measurements belonging to four geographical groups of S. babaulti and to S. pleurospilus (the southern group).

Mentions: A PCA was performed on the covariance matrix of log-transformed measurements taken on S. babaulti and S. pleurospilus specimens (Table 7). Here, the second PC did not show any pattern (not shown) and a scatter-plot of the fourth versus the third PC was presented (Fig 6). The third PC incompletely separated the northern S. babaulti (including the holotype) from all other S. babaulti groups. Values from the southern group, i.e. S. pleurospilus, overlapped with all of the other groups. The fourth PC incompletely separated S. pleurospilus from the northern and western S. babaulti. Specimens from the northern and western shores had, on average, higher values for this axis than specimens from the eastern and northeastern groups. In spite of what was observed for the meristics, none of the PC allowed for a separation between S. babaulti specimens from the central eastern and northeastern shores. For PC3, explaining 2.23% of the variance, the mouth (MW) and inter-orbital width (IOW) were the main contributors whereas for PC 4, explaining 1.79%, these were the length of the caudal peduncle (CPL) and of the premaxillary processus (PPL). The differences observed in the exploratory analysis were reflected by pair-wise Mann-Whitney U tests (Table 6). These revealed 14 measurements to differ significantly. Measurements differed significantly between all groups except between the northeastern and the eastern groups. Nevertheless, only one measurement, the length of the pectoral fin, could be used to separate any of the groups (25.39–27.75% in the northern vs. 27.45–34.13%SL in all other groups, with values for only one western specimen overlapping). As for the meristics, all measurements (as %) overlapped between S. pleurospilus and S. babaulti.


Morphology, molecules, and monogenean parasites: an example of an integrative approach to cichlid biodiversity.

Van Steenberge M, Pariselle A, Huyse T, Volckaert FA, Snoeks J, Vanhove MP - PLoS ONE (2015)

PCA on measurements of S. babaulti and S. pleurospilus.PC4 vs. PC3 of a PCA on the 20 measurements belonging to four geographical groups of S. babaulti and to S. pleurospilus (the southern group).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4414595&req=5

pone.0124474.g006: PCA on measurements of S. babaulti and S. pleurospilus.PC4 vs. PC3 of a PCA on the 20 measurements belonging to four geographical groups of S. babaulti and to S. pleurospilus (the southern group).
Mentions: A PCA was performed on the covariance matrix of log-transformed measurements taken on S. babaulti and S. pleurospilus specimens (Table 7). Here, the second PC did not show any pattern (not shown) and a scatter-plot of the fourth versus the third PC was presented (Fig 6). The third PC incompletely separated the northern S. babaulti (including the holotype) from all other S. babaulti groups. Values from the southern group, i.e. S. pleurospilus, overlapped with all of the other groups. The fourth PC incompletely separated S. pleurospilus from the northern and western S. babaulti. Specimens from the northern and western shores had, on average, higher values for this axis than specimens from the eastern and northeastern groups. In spite of what was observed for the meristics, none of the PC allowed for a separation between S. babaulti specimens from the central eastern and northeastern shores. For PC3, explaining 2.23% of the variance, the mouth (MW) and inter-orbital width (IOW) were the main contributors whereas for PC 4, explaining 1.79%, these were the length of the caudal peduncle (CPL) and of the premaxillary processus (PPL). The differences observed in the exploratory analysis were reflected by pair-wise Mann-Whitney U tests (Table 6). These revealed 14 measurements to differ significantly. Measurements differed significantly between all groups except between the northeastern and the eastern groups. Nevertheless, only one measurement, the length of the pectoral fin, could be used to separate any of the groups (25.39–27.75% in the northern vs. 27.45–34.13%SL in all other groups, with values for only one western specimen overlapping). As for the meristics, all measurements (as %) overlapped between S. pleurospilus and S. babaulti.

Bottom Line: Cichlidogyrus georgesmertensi sp. nov. was found on S. babaulti and S. pleurospilus, C. franswittei sp. nov. on both S. marginatus and P. curvifrons and C. frankwillemsi sp. nov. only on P. curvifrons.As relatedness between Cichlidogyrus species usually reflects relatedness between hosts, we considered Simochromis monotypic because the three Cichlidogyrus species found on S. diagramma belonged to a different morphotype than those found on the other Simochromis.Finally parasite data also supported the synonymy between S. pleurospilus and S. babaulti, a species that contains a large amount of geographical morphological variation.

View Article: PubMed Central - PubMed

Affiliation: Biology Department, Royal Museum for Central Africa, Tervuren, Belgium; Laboratory of Biodiversity and Evolutionary Genomics, Department of Biology, University of Leuven, Leuven, Belgium; Institute of Zoology, University of Graz, Graz, Austria.

ABSTRACT
The unparalleled biodiversity of Lake Tanganyika (Africa) has fascinated biologists for over a century; its unique cichlid communities are a preferred model for evolutionary research. Although species delineation is, in most cases, relatively straightforward, higher-order classifications were shown not to agree with monophyletic groups. Here, traditional morphological methods meet their limitations. A typical example are the tropheine cichlids currently belonging to Simochromis and Pseudosimochromis. The affiliations of these widespread and abundant cichlids are poorly understood. Molecular work suggested that genus and species boundaries should be revised. Moreover, previous morphological results indicated that intraspecific variation should be considered to delineate species in Lake Tanganyika cichlids. We review the genera Simochromis and Pseudosimochromis using an integrative approach. Besides a morphometric study and a barcoding approach, monogenean Cichlidogyrus (Platyhelminthes: Ancyrocephalidae) gill parasites, often highly species-specific, are used as complementary markers. Six new species are described. Cichlidogyrus raeymaekersi sp. nov., C. muterezii sp. nov. and C. banyankimbonai sp. nov. infect S. diagramma. Cichlidogyrus georgesmertensi sp. nov. was found on S. babaulti and S. pleurospilus, C. franswittei sp. nov. on both S. marginatus and P. curvifrons and C. frankwillemsi sp. nov. only on P. curvifrons. As relatedness between Cichlidogyrus species usually reflects relatedness between hosts, we considered Simochromis monotypic because the three Cichlidogyrus species found on S. diagramma belonged to a different morphotype than those found on the other Simochromis. The transfer of S. babaulti, S. marginatus, S. pleurospilus and S. margaretae to Pseudosimochromis was justified by the similarity of their Cichlidogyrus fauna and the intermediate morphology of S. margaretae. Finally parasite data also supported the synonymy between S. pleurospilus and S. babaulti, a species that contains a large amount of geographical morphological variation.

No MeSH data available.