Unrecognized and imperilled diversity in an endemic barb (Smiliogastrini,Enteromius) from the Fouta Djallon highlands

The Upper Guinean Forests of Guinea, Sierra Leone and Liberia contain high levels of freshwater biodiversity. The Guinean Range and associated Fouta Djallon highlands separate two biogeographical provinces in the region and served as a refugium during past climatic fluctuations. While many species of freshwater fishes are restricted to one biogeographical province or the other, some are reported to occur on both sides of the divide. Here, we examine the molecular and morphological diversity of an endemic small African barb, Enteromius foutensis, reported to occur in both provinces. This integrative analysis revealed unrecognized diversity and suggests recent, or ongoing, events that facilitated geodispersal and subsequent divergence in the region. The molecular analysis revealed three divergent and well‐supported populations within E. foutensis. Accounting for allometric shape variation allowed us to observe diagnostic morphological differences among the populations. Enteromius foutensis sensu stricto is restricted to the Little Scarcies drainage in Guinea and northern Sierra Leone. Our study revealed two candidate species distinct from E. foutensis. One is likely a narrow endemic restricted to a small area in the Konkouré River basin; the other candidate species inhabits the upper Senegal and Gambie River drainages. How these patterns of diversity compare with other freshwater species from the Fouta Djallon highlands and the conservation status of these candidate species are also discussed.     

Innate responses to conspecific and heterospecific alarm cues in the endangered eastern cape redfin Pseudobarbus afer

We examined innate responses to conspecific and heterospecific alarm cues in a small cyprinid minnow, the Eastern Cape redfin Pseudobarbus afer. We found that redfins respond to conspecific skin extract, which contains alarm chemicals, and showed that their preferred response is to hide in refugia. Redfins also respond to skin extract from an allopatric, distantly related minnow species, the chubbyhead barb Enteromius anoplus indicating that neither sympatry nor close phylogenetic relationships are necessary for recognition of heterospecific alarm cues. Although both conspecific and heterospecific alarm cues induced similar responses, the response to heterospecific cues was less intense. This may be explained by a trade-off between selection to maximise threat recognition and selection to avoid the costs of responding to irrelevant cues, or by differences in chemical structures of alarm cues between species. These findings have implications for the conservation of this Endangered fish species and for freshwater fishes throughout Africa.     

Enteromius thespesios (Teleostei: Cyprinidae): a new minnow species with a remarkable sexual dimorphism from the south-eastern part of the Upper Congo River

A new minnow species, Enteromius thespesios, is described from the south-eastern part of the upper Congo River; that is, the Kalule Nord, the Luvilombo and the Chambeshi Rivers. Enteromius thespesios belongs to the group of the soft-rayed species of Enteromius from the Congo Basin; that is, those with a weakly ossified, flexible last unbranched dorsal-fin ray that lacks serrations along its posterior edge. Within this group, E. thespesios is most similar to E. humeralis, from which it is distinguished by a higher number of circumpeduncular scales and shorter anterior and posterior barbels. Enteromius thespesios is a rheophilic and territorial species. It exhibits a marked sexual dimorphism, with males having: a red band towards the distal edge of dorsal, caudal and, to a lesser degree, anal fin; nuptial tubercles; a longer snout; longer pectoral fins; a shorter anal fin. This study gives extensive consideration to sexual shape differences for a species of Enteromius and also briefly reviews the current knowledge of sexual dimorphism in the species of Enteromius from the Congo Basin. Some conservation issues related to the new species are also highlighted.     

Enteromius pinnimaculatus sp. nov. (Cypriniformes: Cyprinidae) from southern Gabon

We present and describe a new species of Enteromius, adding to the 16 species of Enteromius currently recorded from Gabon, West Africa. This new species is distinguished from all other Gabonese Enteromius by the presence of several distinct spots on the dorsal fin in combination with three or four round spots on the flanks. In Africa, it is superficially similar to Enteromius walkeri and with which it shares an unusual allometry in that the proportional length of the barbels decreases as the fish grows. Nevertheless, one can distinguish these species by vertebral number, maximum standard length, the length of the anterior barbels, the length of the caudal peduncle and in most specimens, the number of lateral-line and circumpeduncular scales. These two species also inhabit widely separated drainages, with E. walkeri occurring in coastal drainages of Ghana including the Pra and Ankobra Rivers and the new species occurring in tributaries of the Louetsi and Bibaka Rivers of Gabon, which are part of the Ogowe and Nyanga drainages, respectively. Despite extensive collections in those drainages the new species is known from only two localities, suggesting the importance of conservation of its known habitat.     

Molecular and morphological evidence reveals hybridisation between two endemic cyprinid fishes

The geographic occurrence of moggel Labeo umbratus × mud fish Labeo capensis hybrids and the threat of hybridisation to the genetic integrity of L. umbratus were investigated. Genetic evidence from mtDNA cytb and nDNA s7 intron sequence data indicated probable interspecific hybridisation in two impoundments, Hardap Dam (Orange River Basin, Namibia) and Darlington Dam (Sundays River Basin, Eastern Cape, South Africa). Some putative hybrids were morphologically identifiable on account of their meristic and morphometric intermediacy to the parent species. Human activities appear to drive the observed hybridisation, either through dam construction and direct stocking of L. umbratus or via translocation of Labeo capensis and the previously isolated Orange River lineage of L. umbratus into the southern-flowing systems by inter-basin water transfers. It is recommended that further translocation of fish from these areas should be avoided.     

Variation in thermal tolerances of native freshwater fishes in South Africa's Cape Fold Ecoregion: examining the east–west gradient in species' sensitivity to climate warming

The Cape Fold Ecoregion (CFE) is a biodiversity hotspot with high levels of endemism in its freshwater fish fauna. This study examined inter and intra-specific variation in critical thermal maxima (T_Cmax) for eight native species of freshwater fish from the CFE. Cape galaxias Galaxias zebratus, Breede River redfin Pseudobarbus burchelli, Berg River redfin Pseudobarbus burgi, Clanwilliam redfin Pseudobarbus calidus and fiery redfin Pseudobarbus phlegethon were the most thermally sensitive (T_Cmax = 29.8–32.8°C). Clanwilliam rock-catfish Austroglanis gilli, Eastern Cape redfin Pseudobarbus afer and Cape kurper Sandelia capensis were moderately sensitive (T_Cmax = 33.0–36.8°C). An increase in intra-specific thermal sensitivity of S. capensis was observed from east to west. The results were related to in situ water temperature, which influenced T_Cmax for all species, suggesting that thermal history is a major driver of variation in thermal tolerance amongst populations. These thermal tolerance data for freshwater fishes in the CFE demonstrate that resilience to climate warming follows a geographical cline and that the more sensitive western species and regions are conservation priorities.     

Age and growth of a colonizing minnow,Barbus anoplus,in a man-made lake in South Africa

Synopsis Aspects of the life history of Barbus anoplus were studied in Lake le Roux, a turbid man-made lake on the Orange River, South Africa. This minnow underwent a population explosion and successfully colonized the shoreline of the newly-formed lake during the early phases of reservoir filling. Male and female B. anoplus reach sexual maturity in one year at about 40 mm fork length. They have a multiple spawning habit with the first spawning in November–January and the second in February–March. The growth of the two resulting cohorts is discussed. It is proposed that the offspring from the second spawning not only acts as a ‘back-up’ but is capable of prolonging the life of that year-class into an additional reproductive season. Most of the minnows die after their second summer, but more offspring from the second spawning, especially females, live into a third summer. Females attain a larger maximum size (73 mm FL) and age (3–4 years) than males (60 mm FL, 2–3 years). B. anoplus is small and short-lived with a high seasonal reproductive potential, which is in contrast to the larger Barbus species in the Orange River system. These life-history traits enable the species to colonize and successfully inhabit unstable environments and probably account for its widespread distribution.     

Two new species of Asteraceae (tribe Anthemideae,subtribe Pentziinae) from the Cape Floristic Region of South Africa

Two new species of Asteraceae (tribe Anthemideae, subtribe Pentziinae) from the Cape Floristic Region of South Africa are described. Marasmodes schlechteri Magee & J.C.Manning, a local endemic from the lowlands between Piketberg and the Olifants River Mountains, is distinguished by its spreading leaves with axillary fascicles and relatively large, solitary capitula with obconical involucre borne on very short lateral shoots. Pentzia trifida Schltr. ex. Magee & J.C.Manning is a well-collected limestone fynbos endemic that is readily distinguished by the regularly trifid leaves, broadly cyathiform involucres with lanceolate to oblanceolate bracts, and the well developed pappus extending the entire length of the relatively short corolla tube.     

Seasonal occurrence and ecological aspects of Afrodiplozoon polycotyleus (Monogenea: Diplozoidae) from the gills of three cyprinids from the Nwanedi-Luphephe dams,South Africa

The effect of seasonal changes and ecological aspects of Afrodiplozoon polycotyleus (Paperna, 1973) collected on Labeobarbus marequensis (Smith, 1841), Enteromius trimaculatus (Peters, 1852) and Enteromius radiatus (Peters, 1853) was investigated from January to October 2008. Fish were collected at the Nwanedi-Luphephe dams, Limpopo River System, South Africa using gill, cast and seine nets and electrofishing gear. Enteromius radiatus and E. trimaculatus were the most infested compared with L. marequensis. Seasonal changes had an influence on the intensity of A. polycotyleus, with infestation rates higher in spring, summer and autumn. The adults predominantly infected the medial region of the second gill arch, whereas diporpae were mainly found on the first gill. Neither sex nor water quality changes had an influence on the intensity of the parasite. The health condition of the hosts was not affected by the parasite. The different infestation rates of the parasite between the species could be attributed to host characteristics, behaviour and habitat preferences. The selection of a particular gill/region could be attributed to space for attachment organs and food supply, as well as flow and velocity of the water over the gills. The occurrence of A. polycotyleus on E. radiatus constitutes a new host record.     

The Orange River avifauna: abundance,richness and comparisons

Like many other southern African rivers, the avifaunal richness and abundance of the Orange River, southern Africa's longest, remains virtually unknown. Given that the Orange River runs through hyper-arid regions in its lower reaches, its linear oasis effect and its role as a reservoir for Red Data bird species is likely but has not been quantified. Two surveys either side of the border town of Noordoewer, in the rainy and dry seasons of 1996 and 1997 deter-mined that species richness was higher in riverine habitat (71 species) than in the surrounding Nama Karoo (46 species) confirming the linear oasis effect. Surveys revealed five Namibian Red Data species. Peregrine Falcons, Falco peregrinus, and African Fish Eagles, Haliaeetus vocifer, were relatively common while the endangered Cape Eagle Owl, Bubo capensis, occurred sporadically. Among wetland Red Data bird species, Black Storks, Ciconia nigra, occurred in less disturbed areas, and White-backed Night Herons, Gorsachius leuconotus, were an unexpected species at this locality. The overall species richness of 103 birds and a density of riparian birds of 31 -3 4 birds/10 km, makes the lower Orange River avifauna similar to the Cunene River but tenfold less abundant than Namibia's other perennial rivers. Despite the low diversity, the arid habitats of the lower Orange River support greater diversity than more easterly regions when all current surveys of richness and abundance from Lesotho to the mouth on the Namib coast are combined. This east-west trend may be explained by the slower flow and warmer water of the lower Orange River but natural turbidity and regulation may explain the generally low diversity and abundance indices. Major rivers in southern Africa appear to have been over-looked as wetland habitats, and further avifaunal surveys of all of them are recommended.     

Recognition of a species-poor, geographically restricted but morphologically diverse Cape lineage of diving beetles (Coleoptera: Dytiscidae: Hyphydrini)

Aim To establish the phylogeny and geographical origin of the genera of the diving beetle tribe Hyphydrini in order to investigate the origin of differences in geographical range size, intrageneric species‐richness and morphological disparity. In particular, we tested the hypothesis that the geographically restricted, species‐poor and morphologically deviating genera found in the Cape Region of South Africa are a paraphyletic pool of ‘primitive’ Hyphydrini, from which the morphologically more uniform, species‐rich and geographically widespread genera have originated. Location Worldwide, with special reference to the Cape Region of South Africa. Methods We constructed a genus‐level molecular phylogeny of 10 of the 14 known genera of Hyphydrini, including the five endemic to the Cape Region, using sequences from four gene fragments (two mitochondrial, rrnL and cox1; and two nuclear, 18S rRNA and histone 3, c. 2200 bp). Phylogenies were built with Bayesian methods, and linearized using penalized likelihood. Morphological disparity was characterized by correspondence analysis of a data matrix of 21 binary characters. We compare morphological disparity among groups using distance to the global and local centroids and the total range of morphospace occupied. Geographical range was estimated using the number of 6° longitude × 8° latitude Universal Transverse Mercator squares known to contain any species of each genus. Results Hyphydrini is made up of four well supported clades of similar relative genetic divergence: (1) Hyphydrus (Old World plus Australasia, 133 species), (2) the five endemic genera of the Cape Region, sister to Hovahydrus (Madagascar) (10 species), (3) Desmopachria (America, 92 species), and (4) two Oriental genera (Microdytes and Allopachria, 68 species). The morphological disparity within the Cape Region lineage has apparently increased with time, with the two genera closest to the global centroid paraphyletic and basal with respect to the three more recent, morphologically deviating genera. Differences in the number of species between each of the four lineages were not significant. The correlation between the number of species in each lineage and geographical range extent was highly significant, with the low species number of the Cape Region (six) well within the 95% confidence interval of the regression. Main conclusions Contrary to expectations, the species‐poor, morphologically deviating endemic genera of the Cape Region are not a ‘primitive’ relictual pool from which the widespread, species‐rich and morphologically uniform genera have originated. The morphological disparity within the Cape lineage has increased with time, and the apparent lack of species‐level diversification disappears when species–area relationships are considered. A major unanswered question is why one of the four main lineages of Hyphydrini has remained restricted to a very reduced area (the Cape Region), but despite this evolved the highest degree of morphological diversity seen in the tribe.     

Bloodmeal analysis in Culicoides midges collected near horses,donkeys and zebras in the Eastern Cape,South Africa

An upsurge in African horse sickness (AHS) in the Eastern Cape, South Africa, from 2006 led to an epidemiological reassessment of the disease there. Light trapping surveys carried out near horses, donkeys and zebras in 2014–2016 collected 39 species of Culicoides midge (Diptera: Ceratopogonidae) that are potential vectors of AHS. To establish if these midges fed on equids, DNA sequences were obtained from the gut contents of 52 female midges (35 freshly blood‐fed, 13 gravid and four parous), representing 11 species collected across 11 sites. Culicoides leucostictus fed on all three equids. Culicoides bolitinos, Culicoides imicola and Culicoides magnus fed on both horses and donkeys. Culicoides onderstepoortensis fed on donkeys, and Culicoides similis and Culicoides pycnostictus fed on zebras. Bloodmeals from cows, pigs, warthogs, impalas and a domestic dog were also identified in various species, but none of the midges tested had fed on birds. These results contribute to knowledge of the vectorial capacity of several species of Culicoides with regard to AHS in the Eastern Cape and point to potential reservoir hosts, of which donkeys, zebras and domestic dogs have previously been found to harbour AHS. Blood‐fed midges were also obtained throughout winter, indicating the potential for endemic AHS in the province.     

Hooded Vulture Necrosyrtes monachus and African White-backed Vulture Gyps africanus nesting at the Olifants River Private Nature Reserve,Limpopo province,South Africa

Basic ecological information is still lacking for many species of African vultures. The Hooded Vulture Necrosyrtes monachus is known as a rare breeding resident in north-eastern South Africa. This study set out to monitor the nests of Hooded Vultures and, secondarily, White-backed Vultures Gyps africanus in the Olifants River Private Nature Reserve over two breeding seasons in 2013 and 2014. A total of 12 Hooded Vulture nests, placed mostly in the tree Diospyros mespiliformis, were found along the Olifants River, with an average inter- nest distance of 0.76 km. Nest success was estimated to be between 0.44–0.89 offspring pair?1 y?1 in 2013 and 0.50–0.67 offspring pair?1 y?1 in 2014, which are the first estimates for Hooded Vultures in South Africa. It is thought that nests of this species have been under-reported due to the fact that they are placed within or below the canopy of densely leafed trees and hence difficult to view from aerial surveys. African White-backed Vultures also bred along the Olifants River, with nests placed in clusters of up to six. Nesting density of this species ranged from about 1.0 to 1.2 nests km?1 and nests were predominantly placed in Ficus sycomorus trees.     

Phylogeographic patterning in a freshwater crab species (Decapoda: Potamonautidae: Potamonautes) reveals the signature of historical climatic oscillations

Aim The phylogeographic relationships among populations of the common Cape River crab, Potamonautes perlatus, are examined to investigate whether the contemporary population genetic structure is congruent with the hypothesized hydrographic evolution of drainage systems established during the Pliocene, or whether it reflects an older Miocene climatic amelioration. Location 139 samples of P. perlatus were collected from 31 populations distributed among the five major perennial drainage systems and a number of smaller catchments in the Western and Eastern Cape, South Africa. Methods Phylogeographic analysis using parsimony, maximum likelihood, minimum evolution and Bayesian inferences was employed for the 16S rRNA mtDNA gene region, while bootstrapping and posterior probabilities were used to assess the robustness of clades. In addition, nested clade analysis was performed in an attempt to disentangle the contemporary and historical factors that have sculpted genealogical relationships among conspecific populations of P. perlatus. Results Phylogenetic topologies were congruent irrespective of the evolutionary method employed. Two highly distinct reciprocally monophyletic clades characterized by marked levels of corrected sequence divergence were present, with no shared haplotypes between the two major phylogroups. Phylogroup one comprises the populations of the westward‐flowing drainages (mainly the Berg and Olifants drainages), and phylogroup two comprises all of the southward‐flowing drainages and can further be divided into two subclades – one containing the Breede River populations, and the other containing the Gamtoos and Gourits drainage systems. The nested clade analysis demonstrated restricted gene flow and long‐distance dispersal for a number of higher clade levels. The higher‐level groups and results for the total cladogram suggest either fragmentation or isolation by distance. Main conclusions Freshwater crabs are generally highly philopatric, and dispersal, although not common, has occurred historically. The westward‐flowing drainages (Berg, Olifants, Eerste, Liesbeeck and Tokai) are isolated from the southward‐flowing drainages by the Cape Fold Mountains, while the southward‐flowing drainages have a number of tributaries that extend into the low‐lying regions, allowing for gene flow between these three major drainages systems (Breede, Gamtoos and Gourits). Among the westward‐flowing drainages, a more intensive sampling regime is required to understand evolutionary relationships. Our molecular results suggest that the observed patterns pre‐date the formation of contemporary hydrographic patterns in the Cape. This suggests that an older Late Miocene event has severely impacted the contemporary population structure in this species, as recent Pliocene hydrographic boundaries do not correspond to the phylogeographic pattern observed. Conservation efforts for aquatic taxa should clearly be directed at the catchments, in an attempt to conserve biological diversity.     

Moult,breeding season,mass, wing length,and dispersal in Cape Robins (Cossypha caffra) and Olive Thrushes (Turdus olivaceus): results from mist-netting garden birds

We compared a data set from the Western Cape, South Africa (GDU, n = 170 Olive Thrushes (Turdus olivaceus), n = 475 Cape Robins (Cossypha caffra)) with our captures in the Eastern Cape, South Africa (n = 197 Olive Thrushes, n = 203 Cape Robins). In both regions Olive Thrushes began moult in December-January, while wing-moult lasted for 89 days in the Western Cape compared to 53 days in the Eastern Cape. Cape Robins began moult in early November in the Western Cape, early January in the Eastern Cape and again the duration of wing-moult was longer in the Western Cape (64 days) than in the Eastern Cape (50 days). For both species the start of moult coincided with the end of the breeding season. Cape Robins were heavier and longer-winged in the Western Cape than in the Eastern Cape. There was no significant difference in mean mass or mean wing length of the Olive Thrush between the two provinces. Both ringing and atlas data suggest that Cape Robins are relatively more common than Olive Thrushes in the Western Cape, but not in the Eastern Cape. In the Eastern Cape we observed colour-ringed robins (n = 2) and thrushes (n = 2) on their breeding territory in all months of the year, suggesting that some individuals of both species are strongly resident.     

THE DISTRIBUTION AND ECOLOGY OF TWO MULLET SPECIES IN SOME FRESH WATER RIVERS IN THE EASTERN CAPE,SOUTH AFRICA

SUMMARY

Data on the relative abundance, penetration and breeding biology of the freshwater mullet Mugil cephalus and the flathead mullet Mugil cephalus in the freshwater reaches of some Eastern Cape coastal rivers are described. The differences found between the two species indicate that Myxus capensis is more specialized for a catadromous life history in an unstable riverine environment. Evidence showing the importance of the freshwater phase for the latter species is given and the disastrous effects of the erection of barriers to fish movement are stressed.     

First report of metazoan parasites from the cichlid Pseudocrenilabrus philander and the cyprinid Enteromius paludinosus in a South African Ramsar wetland

Parasites of two small fish species from a Ramsar wetland in South Africa were studied in 2014–2015. The cichlid Pseudocrenilabrus philander (Weber, 1897) was parasitised by the copepod Lernaea cyprinacea Linnaeus, 1758, the monogenean Gyrodactylus thlapi Christison, Shinn & van As, 2005 and four gryporhynchid metacestode (Cyclophyllidea) species: Paradilepis scolecina (Rudolph, 1819), Paradilepis maleki Khalil, 1961, Neogryporhynchus lasiopeius Baer & Bona, 1960 and Valipora campylancristrota (Wedl, 1855). The cyprinid Enteromius paludinosus (syn. Barbus paludinosus) (Peters, 1852) was infected with the monogenean parasites Dogielius intorquens Crafford, Luus-Powell & Avenant-Oldewage, 2012, Dactylogyrus teresae Mashego, 1983, and three Dactylogyrus spp. These results represent several new locality as well as host records and further contribute information on the parasitic diversity in the Barberspan Ramsar wetland.     

Role of Life History Strategy in the Colonisation of Western Australian Aquatic Systems by the Introduced Crayfish <Emphasis Type="Italic">Cherax destructor</Emphasis> Clark, 1936

The presence of the yabbie Cherax destructor in a number of wild aquatic systems in the Pilbara and Southwest Coast Drainage Divisions of Western Australia is documented. This is of great concern as all native freshwater crayfishes in Western Australia are endemic and restricted to the southwest, while the Pilbara Division has no native species. An introduced population of C. destructor was sampled monthly from the Hutt River (Pilbara Drainage Division) for determination of life-history and reproductive biology in a wild aquatic system in Western Australia for the first time. Proliferation in that system was attributed to specific traits including: attaining first maturity at the end of its first year of life; a protracted spawning period (July–January); relatively high mean ovarian fecundity of 210.2 (±9.24 S.E.); and a rapid growth rate (curvature parameter K = 0.78 and asymptotic orbital carapace length OCL_∞ = 51.25 mm ascertained from a seasonal von Bertalanffy growth curve) that was comparable to the larger sympatric marron Cherax cainii in this system. The life-history characteristics of C. destructor in the Hutt River were typical of many other invasive crayfish species and it has the potential to impact the unique aquatic ecosystems and the endemic freshwater crayfish species of the region.     

Ochthebius (s.str.) capicola (Coleoptera) re-discovered in the Cape Peninsula,South Africa

New distributional records and ecological observations are presented for the Cape endemic hydraenid Ochthebius capicola. Considered extinct on the Cape Peninsula, the species has been re-discovered at two adjacent locations as well as at a new site in Tsitsikamma National Park, Eastern Cape. New species associations are recorded, in conjunction with observations confirming this species' preference for algae-covered rock surfaces in the hypersaline pools of the supralittoral zone. Provisional internationally-endangered status for this species was examined but considered dependent on future data. It was considered likely that the beetle may be insufficiently recorded, due to its atypical habitat requirement. A synopsis of the taxonomic status of this species and Ochthebius rubripes is given. Notes on both species are provided, as well as a record of sympatric occurrence.     

Microfossils in surface sediments of brackish waters on the west coast of South Africa and their palaeoecological implications

A faunistic survey covering 25 sites in estuaries, coastal lakes and ponds along the west coast of South Africa between the Cape of Good Hope in the south and the Olifants River in the north was carried out in May 2014. The study aimed to establish a dataset with ecological and distribution data of ostracods and foraminifers for later palaeoenvironmental reconstructions. Canonical correspondence analysis showed that the distribution of the 19 foraminifer and 32 ostracod taxa was controlled mainly by habitat structure, but that specific conductivity (salinity) was best and solely described by the second axis, highlighting the usefulness of the two microfossil groups for salinity reconstructions. Habitat structure was demonstrated by the foraminifer species Trochamminita irregularis’ preference for stillwater areas of lakes. Sarscypridopsis aculeata and Sarscypridopsis glabrata were the dominant ostracod species in coastal ponds and lakes. However, their living distributions excluded each other, with S. aculeata preferring areas of lower salinity and S. glabrata dominating areas of higher salinity up to hyperhaline conditions in small, closed water bodies.