51 research outputs found
Just off the beach: intrageneric distinctiveness of the bandtail goatfish Upeneus taeniopterus (Mullidae) based on a comprehensive alpha-taxonomy and barcoding approach
Upeneus floros, a new goatfish from South Africa and Mozambique, with updated taxonomic accounts for U. guttatus and U. pori and a key to Western Indian Ocean Upeneus species (Mullidae)
The highly diverse goatfish genus Upeneus (Mullidae) requires enhanced attention regarding the possible occurrence of undescribed species in insufficiently explored regions. This study focuses on the South-Western Indian Ocean region (SWIO), and on the so-called japonicus-group, a taxonomic species group of Upeneus. Based on in-situ observations and collections in Sodwana Bay, KwaZulu-Natal, South Africa, the Floros goatfish, U. floros n. sp., is described. Detailed comparative studies of colour patterns and morphological characters of all other 13 japonicus-group species were undertaken as well as COI barcoding. The new species occurs in the coastal area between Angoche, N Mozambique and KwaZulu-Natal and partly overlaps in distribution with two similar species, U. guttatus, widely distributed in the Indo-W Pacific, and U. saiab, assumed to be endemic in a small area off Angoche. Two additional japonicus-group species occurring in the SWIO, U. seychellensis from the Seychelles Bank and U. pori from the Mediterranean Sea (as Lessepsian migrant), Northern Red Sea and Madagascar, were also compared. Because specimens as well as in-situ photographs of U. floros have been erroneously identified as either U. guttatus or U. pori during previous studies, updated taxonomic accounts and diagnoses are provided for these species taking size-related and population differences into account. For U. pori, of which a single preserved specimen from SW Madagascar was known so far, a new record from NE Madagascar is reported based on three specimens and a fresh-colour photo. Upeneus floros can be distinguished from U. guttatus and U. pori by a combination of three characters: head length, first dorsal-fin height and number of gill rakers. Upeneus guttatus can be distinguished from the other two species by disproportionally higher anterior dorsal-fin spines vs. a proportional decrease of dorsal-fin spines in height, barbels mostly yellow vs. white or creamy-white, and slightly fewer pectoral-fin rays. COI barcoding detected a clear distinction between U. guttatus and U. floros and U. pori, respectively, but no significant divergence between the two latter species. COI barcoding also failed to differentiate several other Upeneus species which are clearly distinguished morphologically. Possible interrelationships between species distribution patterns and physical oceanography are discussed. An identification key for the 22 WIO Upeneus species is provided.publishedVersio
Cryptic species and parallel genetic structuring in Lethrinid fish:Implications for conservation and management in the southwest Indian Ocean
Analysis of genetic variation can provide insights into ecological and evolutionary diversification which, for commercially harvested species, can also be relevant to the implementation of spatial management strategies and sustainability. In comparison with other marine biodiversity hot spots, there has been less genetic research on the fauna of the southwest Indian Ocean (SWIO). This is epitomized by the lack of information for lethrinid fish, which support socioeconomically important fisheries in the region. This study combines comparative phylogeographic and population genetic analyses with ecological niche modeling to investigate historical and contemporary population dynamics of two species of emperor fish (Lethrinus mahsena and Lethrinus harak) across the SWIO. Both species shared similarly shallow phylogeographic patterns and modeled historical (LGM) habitat occupancies. For both species, allele frequency and kinship analyses of microsatellite variation revealed highly significant structure with no clear geographical pattern and nonrandom genetic relatedness among individuals within samples. The genetic patterns for both species indicate recurrent processes within the region that prevent genetic mixing, at least on timescales of interest to fishery managers, and the potential roles of recruitment variability and population isolation are discussed in light of biological and environmental information. This consistency in both historical and recurrent population processes indicates that the use of model species may be valuable in management initiatives with finite resources to predict population structure, at least in cases wherein biogeographic and ecological differences between taxa are minimized. Paradoxically, mtDNA sequencing and microsatellite analysis of samples from the Seychelles revealed a potential cryptic species occurring in sympatry with, and seemingly morphologically identical to, L. mahsena. BLAST results point to the likely misidentification of species and incongruence between voucher specimens, DNA barcodes, and taxonomy within the group, which highlights the utility and necessity of genetic approaches to characterize baseline biodiversity in the region before such model-based methods are employedpublishersversionPeer reviewe
Description of a new montane freshwater crab (Arthropoda, Malacostraca, Decapoda, Potamonautidae) from the Eastern Cape, South Africa
SUPPLEMENTARY INFORMATION: Authors: Gavin Gouws Data type: phylogenetic Explanation note: TABLE S1: Representatives of valid southern African Potamonautes species included in the phylogenetic analysis used to contextualise divergences and confirm the affinities of specimens included in the current study. Four species of Maritomonautes were included as outgroup taxa. GenBank accession numbers for the 16S rRNA and cytochrome c oxidase subunit I (COI) included and the data sources are provided; TABLE S2: Uncorrected sequence divergences, expressed as percentages, as calculated from a 549 nucleotide alignment of 16S rRNA mtDNA sequences (below diagonal) and a 660 nucleotide alignment of the protein-coding mtDNA cytochrome c oxidase subunit I (COI) fragment (above diagonal), between representative of Potamonautes included in the present study. Newly-sampled specimens are identified as Potamonautes danielsi and P. amathole sp. nov. This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.A new species of freshwater crab, Potamonautes amathole sp. nov., is described from the WinterbergAmathole mountain range in the Eastern Cape Province, South Africa. Morphologically, P. amathole Peer
& Gouws, sp. nov. most closely resembles P. tuerkayi but can be distinguished by key morphological characters including the variation in the shape of the subterminal segment of gonopod 2 between both species.
Genetically, P. amathole Peer & Gouws, sp. nov. is placed within the clade of small-bodied, mountaindwelling crabs including P. parvispina, P. parvicorpus, P. brincki, P. tuerkayi, P. baziya, and P. depressus. The
new species is found in slow-moving mountain streams and pools at high altitudes. The continued discovery and description of new freshwater crab species reinforces the need for ongoing research, especially
in under-sampled regions.https://zookeys.pensoft.netPlant Production and Soil Scienc
Junior synonymy of Mulloides arntatus and intraspecific comparisons of the yellowstripe goatfish Mulloidichthys flavolineatus (Mullidae ) using a comprehensive alpha-taxonomy approach
Published versio
Description of a new montane freshwater crab (Arthropoda, Malacostraca, Decapoda, Potamonautidae) from the Eastern Cape, South Africa
A new species of freshwater crab, Potamonautes amathole sp. nov., is described from the Winterberg-Amathole mountain range in the Eastern Cape Province, South Africa. Morphologically, P. amathole Peer & Gouws, sp. nov. most closely resembles P. tuerkayi but can be distinguished by key morphological characters including the variation in the shape of the subterminal segment of gonopod 2 between both species. Genetically, P. amathole Peer & Gouws, sp. nov. is placed within the clade of small-bodied, mountain-dwelling crabs including P. parvispina, P. parvicorpus, P. brincki, P. tuerkayi, P. baziya, and P. depressus. The new species is found in slow-moving mountain streams and pools at high altitudes. The continued discovery and description of new freshwater crab species reinforces the need for ongoing research, especially in under-sampled regions
The biogeography, systematics and conservation of Phreatoicidean isopods in South Africa
Dissertation (PhD)--University of Stellenbosch, 2004.ENGLISH ABSTRACT: Historically, isopods of the suborder Phreatoicidea were thought to be represented in southern
Africa by four species belonging to the endemic genus Mesamphisopus. This taxonomy was
based on poor collections and the extent of variation among and within populations were
poorly understood. In the present study, intensive sampling was undertaken to determine the
diversity, distribution and biogeography of phreatoicidean isopods within South Africa.
Analyses of allozyme data and mitochondrial DNA sequences (from the 12S rRNA and
protein-coding COI genes) were used to examine differentiation among populations, extricate
species boundaries (in combination with morphometric and morphological data) and to
elucidate the evolutionary relationships among taxa. Additionally, conservation units were
identified among the sampled populations and conservation threats highlighted.
First, genetic and morphometric differentiation was examined among populations identified
morphologically as M. capensis. Collection localities spanned two mountainous regions in
the Western Cape and these were separated by a coastal plain remnant. Five
morphometrically and genetically distinct species were identified. These taxa are also
geographically partitioned in two regions, which were regarded as Evolutionarily Significant
Units. Differentiation among populations of the two regions, and similar patterns in other
taxa, was attributed to Cenozoic sea-level fluctuations.
Second, populations, variably assigned to M. abbreviatus or M. depressus, were examined to
determine whether they were conspecific. A large geographic area was sampled to account
for intraspecific differentiation. Limited morphometric discrepancies were observed, with
individual populations being either similar to the M. abbreviatus or the M. depressus
syntypes. Genetic support for the recognition of a cryptic species complex among the
sampled populations was equivocal. Substantial genetic differentiation and a lack of gene
flow were observed among all populations. Clear patterns of isolation by distance were not
detected, and genetic structure appeared to be unrelated to geography or drainage systems.
The mosaic pattern of relatedness among populations was best explained by stochastic
demographic processes, such as extinction-recolonization events or population bottlenecks.Thirdly, detailed taxonomic descriptions and illustrations of six new species, identified
genetically and morphometrically among the populations included in the above analyses, were
provided. These species were largely distinguished from each other, and the four original
species, using a combination of setation, mouthpart, pleopod and uropod features.
Lastly, phylogenetic relationships among all ten recognized Mesamphisopus species, and an
additional unresolved group of populations, were examined. MtDNA data partitions and a
recoded allele frequency matrix were analysed independently and in combination. Topologies
indicated unrecognized species-diversity within an unresolved group of populations.
Evolutionary relationships, the identification of six biogeographic centres, and the dating of
divergences using a relaxed Bayesian clock suggested that differentiation and speciation
within Mesamphisopus was largely allopatric or vicariant and driven by Mesozoic sea-level
and climate change. Chance long distance dispersal events would, in turn, explain spurious
phylogenetic relationships and distributions.
This study contributes significantly to the understanding of the diversity and the conservation
of the little-studied southern African freshwater invertebrates. Moreover, this study is the first
to investigate genetic and morphometric differentiation, and phylogenetic relationships, below
the generic level within the Phreatoicidea; thus establishing a methodological and theoretical
framework for species delineation and the accurate determination of biodiversity within
individual phreatoicidean genera.AFRIKAANSE OPSOMMING: Isopoda van die suborder Phreatoicidea was histories in suidelike Afrika verteenwoordig deur
vier spesies wat almal aan die endemiese genus Mesamphisopus behoort. Hierdie taksonomie
is op ’n beperkte hoeveelheid versamelings gebaseer en die omvang van variasie tussen (en
binne) bevolkings was swak verstaan. In die huidige studie is ekstensiewe versameling
onderneem om die verspreiding, diversiteit asook biogeografie van dié Isopoda in Suid Afrika
te bepaal. Analises van allosiem data en mitokondriale DNS volgorderbepalings (van die 12S
rRNS en die proteïenkoderende COI geen) was gebruik om differensiasie tussen bevolkings te
ondersoek, om (in kombinasie met morfometriese en morfologiese data) spesiesgrense te
bepaal asook om die evolusionêre-verwantskappe tussen taksa te definieer. Benewens word
bewaringseenhede binne die studie-bevolkings geïndentifiseer en moontlike bedreigings
uitgelig.
Eerstens is genetiese en morfometriese differensiasie tussen bevolkings, wat as M. capensis
geïdentifiseer is, ondersoek. Versamelingslokaliteite was versprei oor twee bergagtige streke
in die Weskaap wat geskei word deur ’n voormalige kusvlakte. Vyf morfometries- en
geneties-afsonderlike spesies is geïdentifiseer. Dié taksa was geografies geskei tot die twee
streke, wat elk as ’n Evolusionêre Beduidende Eenheid (ESU) gesien kan word.
Differensiasie tussen populasies van die twee streke en vergelykbare patrone binne ander
taksa word aan Cenosoïese seevlak veranderings toegeskryf.
Tweedens is bevolkings wat as M. abbreviatus óf as M. depressus geïdentifiseer kan word
ondersoek om te bepaal of hulle konspesifiek is. Bevolkings is oor ’n groot geografiese
gebied versamel om intraspesifieke variasie in aanmerking te neem. Beperkte morfometriese
verskille is waargeneem – enkel bevolkings was morfometries identies aan of die M.
abbreviatus of die M. depressus sintipes. Genetiese getuienis vir die herkenning van ’n
kriptiese spesieskompleks was dubbelsinnig. Bevolkings is gekenmerk deur merkbare
genetiese differensiasie en die afwesigheid van geenvloei. Duidelike bewys van isolasie-metafstand
was nie waargeneem nie en genetiese struktuur was nie verwant aan geografiese
ligging of riviersisteme nie. Die mosaïese patroon van verwantskappe is moontlik teweeg
gebring deur stogastiese demografiese prosesse soos uitsterwing en hervestiging of deur
afnames in bevolkingsgrootte.Derdens is omvattende taksnomiese beskrywings en illustrasies van ses nuwe spesies wat deur
bogenoemde analises geneties en morfometries uitgelig was, verskaf. Dié spesies is van
mekaar, asook die ander vier spesies onderskeibaar deur ’n kombinasie van setasie-,
monddeel-, pleiopoot- en uropooteienskappe.
Laastens is die filogenetiese verwantskappe tussen al tien herkende Mesamphisopus-spesies
en ’n groep bevolkings waarvan verhoudings onseker was, ondersoek. MtDNS datastelle en
’n hergekodeerde alleelfrekwensie matriks is afsonderlike en in kombinasie geanaliseer.
Topologië het onherkende spesies-vlak diversiteit binne die bogenoemde groep bevolkings
aangedui. Evolusionêre verwantskappe, die herkenning van ses biogeografiese gebiede, en
die bepaling van tye van divergensie (d.m.v. ’n ontspanne Bayesiaanse molekulêre klok) het
aangetoon dat spesiasie binne Mesamphisopus grootliks allopatries was en deur Mesosoïese
seevlak- en klimaatsveranderings teweeg gebring is. Toevallige lang-aftstand verspreiding
kon dan eienaardige filogenetiese verhoudings en verspreidings verklaar.
Dié studie lewer ’n wesenlike bydrae tot die kennis van die diversiteit en tot die bewaring van
die onbestudeerde Suid Afrikaanse varswater ongewerweldes. Daarenbowe, is hierdie studie
die eerste om genetiese en morfometriese differensiasie benede die genusvlak binne die
Phreatoicidea te ondersoek; sodoende word die metodologiese en teoretiese raamwerk vir die
herkenning van spesies en die akkurate beskrywing van diversiteit binne afsonderlike genera
van die Phreatoicidea geskep
Resurrection of Lethrinus scoparius Gilchrist & Thompson, 1908 (Perciformes: Lethrinidae), from South African waters
Holleman, Wouter, Gouws, Gavin (2022): Resurrection of Lethrinus scoparius Gilchrist & Thompson, 1908 (Perciformes: Lethrinidae), from South African waters. Zootaxa 5174 (5): 551-567, DOI: 10.11646/zootaxa.5174.5.
Genotypes Clinus cottoides Parentage
Contains microsatellite genotypes of all adults and embryos used for parentage analyse
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