For organisms with complex life histories, carry-over effects (COEs) can manifest between life stages, when conditions experienced by one stage influence the next, as well as trans-generationally, when the parental environment affects offspring. Here we used multiple global change-associated stressors to examine both forms of COE simultaneously in an intertidal limpet with mixed development (i.e. planktonic larvae hatch from benthic egg masses). Adult Siphonaria australis were subjected to four treatments over four weeks: an ambient control, a treatment featuring elevated water temperature (25°C) and UVB (1.7 W m-2), a copper pollution treatment (5.0 μg L-1), and a treatment incorporating all three stressors. Egg masses laid by these adults were then redistributed among the same four treatments (producing 16 adult-to-egg treatment histories) and stressed until hatching. Finally, hatching larvae were reared under ambient conditions for 24 days. While adult survivorship was unaffected by treatment, embryonic viability in egg masses responded strongly to egg mass treatment, as well as parental stress exposure, therefore displaying trans-generational COEs. These trans-generational COEs interacted with COEs originating in egg masses to produce highly context-dependent hatching sizes and larval growth. This demonstrates that the performance of a given organism at a given time reflects not only conditions experienced during embryonic development, but also those of the parental generation, and suggests that COEs play an important but underestimated role in responses to global change scenarios.

The taxonomic status of Alcyonium aurantiacum Quoy & Gaimard, 1833, an octocoral endemic to New Zealand, was reviewed through morpho-molecular data comparisons in an integrative approach. Molecular phylogenetic analyses (nuclear 28S and mitochondrial mtMutS) resolved New Zealand taxa as more closely related to other genera and nominal Alcyonium Linnaeus, 1758 from South America than to the genus’ North Atlantic type species. Due to low genetic variation, species delimitation relied predominantly on identifying consistent differences in sclerite and colony morphology. The former A. aurantiacum is reassigned to Kotatea gen. nov. as K. aurantiaca gen. et comb. nov. and seven new species are described in this genus (K. amicispongia gen. et sp. nov., K. lobata gen. et sp. nov., K. kapotaiora gen. et sp. nov., K. kurakootingotingo gen. et sp. nov., K. niwa gen. et sp. nov., K. raekura gen. et sp. nov., and K. teorowai gen. et sp. nov.). Three new species in Ushanaia gen. nov. are also described (U. ferruginea gen. et sp. nov., U. fervens gen. et sp. nov. and U. solida gen. et sp. nov. ). These descriptions increase our understanding of New Zealand’s endemic octocoral diversity and contribute to ongoing systematic revisions of Alcyonium.

Octocorals are problematic in their systematics, and the extent of their biodiversity is poorly understood. Integrative taxonomy (the use of two or more lines of evidence for the delimitation and description of taxa) is seen as a promising way to produce more robust species hypotheses and achieve taxonomic progress in this group. However, many octocoral descriptions continue to rely on morphological evidence alone, and the prevalence of integrative methods is unclear. Here, a literature survey was conducted to gain an overview of historical description rates and to examine trends in the publication of integrative descriptions between the years 2000 and 2020. We find that recent description rates are among the highest in the history of octocoral taxonomy, and although increasing, integrative taxon descriptions remain in the minority overall. We also find that integrative taxonomy has been applied unevenly across octocoral groups and geographical regions. Description rates show no signs of slowing, and no ceiling of total species richness has yet come into view. Coupled with a continued overreliance on morphological variation, particularly at the species level, this suggests that we might be adding to the workload of taxa requiring future revision faster than such instances can be resolved.

<p>Global change is increasingly impacting coastal marine systems. Organisms inhabiting the intertidal zone may be especially vulnerable to additional anthropogenic influences, which augment the naturally stressful, highly variable conditions to which they are already subjected and may lead to the manifestation of artificially severe carry-over effects (COEs). In marine invertebrates with complex life histories, COEs can occur between life stages, when the conditions experienced by one stage influence the characteristics or performance of the next, as well as trans-generationally, in which case the environment experienced by a parental generation affects offspring. Most of the existing literature surrounding COEs focuses only on those between life stages or generations, seldom both simultaneously, and do so with the implementation of only a single stressor. In nature however, organisms may be affected by both forms of COE, since the presence of one does not preclude the other, and are invariably subjected to multiple co-occurring stressors that can interact in complex ways. Consequently, how trans-generational COEs might impact the propagation of stress through offspring life stages remains unclear, and how these processes operate in a global change context is little understood. It was here aimed to elucidate the role of COEs under ongoing global change by addressing these common literature imitations and taking the novel approach of examining how the effects of multiple, global change-associated stressors carry-over from a parental generation through their offspring’s life stages in order to provide a more realistic representation of the conditions under which COEs manifest in the field.  This was done using Siphonaria australis, an intertidal pulmonate limpet that deposits benthic egg masses, from which hatch planktonic veliger larvae. Adult S. australis were subjected to one of four treatments for 4h/day over four weeks to induce trans-generational COEs: a no-stress control, a pollution treatment with added copper (5.0μg/L), a “climate change” treatment with elevated temperature (25°C) and UVR (1.7W/m2), and a full global change treatment incorporating all three stressors. At the end of this period, the egg masses laid under each of these adult treatments were subjected to further experimentation for two weeks by being redistributed among the same four treatments again, so as to produce 16 unique treatment histories of adult-to-egg mass stress. Of these, 11 provided successfully hatching larvae, which were reared and observed for COEs between life stages (from egg to larva) under ambient conditions (ie. no added stressors) for 27 days.  In adult S. australis survivor size, the size of egg masses laid and the size of individual eggs varied in complex ways over time and across treatments, while the number of survivors was unaffected by stress. Egg masses were unaffected in terms of hatching time but displayed strong responses to parental and developmental stress exposure through hatching success, and the percentage of viable eggs per egg mass, with the latter clearly declining according to adult treatment severity and both showing trans-generational COEs. Larval characteristics were extremely varied across treatment histories and highly context-dependent as hatching size, size reached by 27 days, growth rate, and size at death all showed evidence of COEs between generations and life stages, as well as interaction between both types of COE, with the number of survivors again being the only unaffected response variable. Overall, trans-generational COEs were slightly more common than those between life stages.  These results show that both forms of COE, each triggered by exposure to multiple stressors in progenitors and developmental stages, interact to form highly context-dependent legacies of mostly impaired performance in S. australis larvae. This implies that COEs may become more prominent with worsening stressors in the future and suggests that the role of COEs in the persistence of marine invertebrates under ongoing global change may so far have been underestimated by the existing literature.</p>

<p><b>Octocorals are a diverse group of sessile, colonial, filter-feeding anthozoan cnidarians, which form significant components of benthic marine communities worldwide. Globally, the most critical hurdle to the effective management of octocorals in the face of increasing anthropogenic pressure is the poor state of their species-level taxonomy, which hinders understanding of their biodiversity. New Zealand’s octocoral assemblage is among the most diverse of any country and is characterised by high levels of endemism, yet over half of its octocoral species remain undescribed. While progress is being made, this has focussed almost exclusively on protected deep-sea gorgonian octocorals.</b></p> <p>Unprotected coastal soft corals are less studied in New Zealand. This includes the endemic Alcyonium aurantiacum Quoy and Gaimard, 1833. Multiple, morphologically diverse forms have been attributed to this species. Here, the taxonomic status of A. aurantiacum is reviewed, and its phylogenetic relationships are examined using molecular data (nuclear 28S and mitochondrial MutS genes), which is compared to morphology in an integrative approach. As a result, evidence for two new, endemic genera and ten new species is presented. Alcyonium aurantiacum is referred to Kotatea gen. n. (as K. aurantiaca comb. n.), which contains seven additional new species. A second genus, Ushanaia gen. n., contains three new species.</p> <p>Of the new taxa described herein, K. aurantiaca and K. lobata sp. n. are the most commonly encountered and widespread, yet little is known regarding their biology. Both species co-occur in their natural habitat, could not be differentiated genetically with the tools used here, and can be difficult to distinguish without microscopic sclerite examinations. To facilitate the identification of these two similar species by non-taxonomists, a statistical model was developed that can discriminate them with up to 90% accuracy using easily obtainable measurements of gross colony morphology. Relationships between colony morphology and depth are also examined.</p> <p>Considering the difficulties associated with species discrimination among octocorals, a literature survey was conducted to review the use of integrative taxonomy in this group since the start of the 21st century, focusing particularly on morpho-molecular data comparisons. This revealed that, while description rates at family, genus, and species levels over the last twenty-one years rank among the highest ever, integrative techniques have been applied unevenly across taxonomic groups and geographic regions and overall remain a minority compared to taxonomic research based solely on morphology. Implementation of the integrative approach is increasing, however, as are the per-annum number of taxonomic publications and the total pool of authors associated with these publications.</p> <p>It is hoped that the research presented herein can contribute to ongoing global efforts of revising octocoral systematics and that the examination of integrative practices in octocoral taxonomy will serve as a baseline against which future taxonomic progress can be compared and promoted. For New Zealand specifically, elucidating the taxonomy and variability of these endemic taxa will enable aspects such as their contribution to ecosystem functioning and management needs to be examined accurately for the first time, which in turn may lead to their recognition as organisms worthy of legal protection.</p>