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Heavy metal pollution is an increasing threat to the marine environment and is a major health concern. Both marine limpets and algae have been employed as biomonitors elsewhere in the world, but there are few or no data for these taxa along the South African coast. We investigated heavy metal concentrations in the tissues of selected limpet and algae species sampled at four sites on the southeast coast of South Africa (Silaka, Hluleka, Mthatha and Mbhashe), and determined whether there was any relationship between heavy metal concentrations in the limpets and their algae food sources as evidenced by the trophic transfer factor (TTF). Samples were collected in July 2019 and the tissues were digested following normal protocols. Heavy metals were detected using inductively coupled plasma optical emission spectrometry (ICP-OES). Significant differences in metal concentrations were observed among the algae species. The soft tissues of limpets from Silaka had the highest heavy metal concentrations, and samples from Mthatha had the lowest, with only mercury (Hg) occurring in high concentrations. Metal concentrations in soft tissues were generally 10-times higher than in shell tissues and differed between lower- and upper-shore species. Cadmium (Cd) biomagnified (TTF > 1) in all limpet species at all sites. Cd, arsenic (As), lead (Pb) and Hg measured in our study were above the maximum limits set by the South African Department of Health. This study suggests that the use of limpet and algae species as bioindicators is feasible since they are widely distributed and can accumulate a wide range of heavy metals. [ABSTRACT FROM AUTHOR]

Here we present a new species of placoderm fish, Africanaspis edmountaini sp. nov., and redescribe Africanaspis doryssa on the basis of new material collected from the type locality of Africanaspis. The new material includes the first head shields of Africanaspis doryssa in addition to soft anatomy for both taxa. Hitherto Africanaspis was entirely described from trunk armour and no record of body and fin outlines had been recorded. In addition the first record of embryonic and juvenile specimens of Africanaspis doryssa is presented and provides a growth series from presumed hatchlings to presumed adults. The presence of a greater number of juveniles compared to adults indicates that the Waterloo Farm fossil site in South Africa represents the first nursery site of arthrodire placoderms known from a cold water environment. The preservation of an ontogenetic series demonstrates that variation within the earlier known sample, initially considered to have resulted from ontogenetic change, instead indicates the presence of a second, less common species Africanaspis edmountaini sp. nov. There is some faunal overlap between the Waterloo Farm fossil site and faunas described from Strud in Belgium and Red Hill, Pennsylvania, in north America, supporting the concept of a more cosmopolitan vertebrate fauna in the Famennian than earlier in the Devonian. [ABSTRACT FROM AUTHOR]

Rocky shores are experiencing heavy metal (HM) pollution as a result of anthropogenic activities. The information on the use of limpets Scutellastra spp. and Cellana sp. as bioindicators is limited. This study aimed to assess HM concentration in water samples, soft and shell tissues of four limpet species, Scutellastra granularis , S. longicosta; S. cochlear and Cellana capensis along the southeast coast of South Africa. Individual species were collected between 2019 and 2020 in four sites and four seasons during spring low tide. The physico-chemical parameters were simultaneously measured in situ with limpet species collection for correlation with HM. Concentration of Zn, As, Cd, Cu, Fe, Pb, Hg and Ni in limpet tissues were analysed using inductively coupled plasma optical emission spectrometry (ICP-OES). Data were explored using SPSS v26, GraphPad Prism v5, Primer v7 and MS-excel 2016. Temporal/spatial differences of physico-chemicals and HM in limpet tissues were evident. Heavy metal concentration was species specific e.g. Fe, Ni and were high in S. granularis , and Hg, As, Pb in C. capensis. The lower shore species S. longicosta and S. cochlear were notable accumulators of Zn and Cd. Limpet soft tissues concentrated 5–10 times magnitude of HM than shell tissues. This study provided a baseline information on the concentration of HM in marine limpets along the southeast coast of South Africa and suggest limpets as bioindicator species. [Display omitted] • Limpet soft tissues concentrated greater magnitude of heavy metals than shell tissues. • Scutellastra spp. and Cellana sp. are suggested as notable bioindicators species. • Concentration of heavy metals was species specific. • Cadmium, Hg, Pb and As were above regulatory limit set for fish and shellfish. [ABSTRACT FROM AUTHOR]