Invertivorous fishes are key middle-order consumers that connect energy flows across different trophic levels. However, the potential for distinct functional roles to exist within this trophic guild has not been satisfactorily explored to date, meaning that current assessments of ecosystem resilience are likely to over-estimate the level of functional redundancy within a given invertivorous fish assembly. Our study examined the foraging behaviour and microhabitat preferences of invertivorous fish communities within the productive canopy macroalgal meadows of Ningaloo Marine Park, Western Australia. Our aim was to identify foraging specialisations that could yield distinct functional roles for species belonging to the guild. We found that invertivorous fishes at this location were chiefly represented by species belonging to the Labridae, Lethrinidae and Mullidae families. Individual species demonstrated strong preferences for foraging within specific microhabitat types, suggesting that the guild can be grouped into three categories of foraging specialists: 'canopy forager', 'generalist' and 'abiotic forager'. Our results highlight subtle niche partitioning of foraging microhabitats within the trophic guild of invertivorous fishes associated with tropical macroalgal meadows. Moreover, this partitioning is consistent across seasons, despite significant fluctuations in canopy structure and biomass. The resulting refinement of foraging specialisations allows us to identify the functional roles of invertivorous fishes and afford greater protection to individual species that might otherwise be considered functionally redundant. Our results will help to inform knowledge of the functional impact of particular species and their ecological specialisations and improve our understanding of trophic flows in marine food webs for appropriate management and conservation.

Secondary production connects primary producers with higher-order consumers. The response of secondary production to seasonal variation in primary producers can influence trophic flows that underpin key ecosystem functions and services. Within the canopy-forming macroalgal meadows of Ningaloo Reef, Western Australia, we quantified the secondary production generated by Sargassum-associated epifauna across seasons and seascapes. We found a strong positive correlation between overall epifaunal production and Sargassum canopy size. Variation in epifaunal production was predominantly driven by seasonal changes in Sargassum canopy size. However, these seasonal effects were not uniform across the seascape. Key predictors of spatial and temporal variation in epifaunal production were the presence of invertivorous fish families, as well as daily and monthly fluctuations in sea temperature. Areal estimates of epifaunal productivity were much higher in summer than in winter, due to higher Sargassum canopy size and percent cover in summer. Epifaunal production was estimated to be more sensitive to Sargassum percentage cover than to canopy height. Modeling a 45% reduction in canopy height and percent cover of Sargassum associated with a marine heatwave event revealed a potential 81% drop in the areal rate of secondary production by Sargassum epifauna in this tropical fringing reef ecosystem. Disturbances to Sargassum canopy structure driven by global change can therefore significantly alter the productivity of these tropical macroalgal meadows and their ability to support higher level consumers within the food web, including important fisheries species. Our results highlight the importance of including epifaunal production estimates in predictive modeling when managing macroalgal-dominated marine ecosystems.

As the rate of global change increases, the structure and functioning of marine ecosystems, including the food webs that underpin them, will radically alter.Forecasting the consequences of these changes requires a sound understanding of the fundamental components of marine food webs: their community composition, baseline biomass and productivity.Epifauna, a term restricted here to small invertebrates (both mobile and sessile) that inhabit living and non-living surfaces within marine ecosystems, are a ubiquitous and pivotal component of marine food webs, supporting the flow of energy through marine ecosystems and providing a critical trophic link between benthic primary producers and higher-order consumers.Yet, despite their importance, epifauna are rarely studied compared to the more visible and gregarious components of marine ecosystems.They are also typically neglected in management strategies for the protection of marine habitats.In addition, the plethora of alternative terms used within this research field (macrobenthos, cryptofauna, epibiont, mesograzer) can be a barrier to understanding and assimilating existing research knowledge.This review provides an assessment of epifaunal communities studied within tropical, subtropical and temperate marine ecosystems globally.We first review alternative terms used to describe marine epifaunal communities, with the aim of offering a consensus-based definition of epifauna as an aid for unifying different research areas.We then review the primary literature on epifauna, including the scarce information on tropical marine habitats.We outline how a detailed understanding of epifaunal communities within individual habitats is needed to predict how benthic food webs will alter under global change.While epifauna can persist under degraded habitat conditions, changes to taxonomic composition can fundamentally affect secondary productivity, and impact higher-order consumers through changes in prey size-spectra and foraging habitats.Finally, we issue a "call-to-arms" for increased focus on the study of epifauna, given their potential to underpin critical aspects of marine ecosystem functioning.We highlight the potential for eDNA sampling, other new technologies, and monitoring by citizen scientists to facilitate the use of epifaunal community metrics, including incorporation into marine ecosystem planning.

Tropical seascapes are comprised of a range of patch habitat types, yet we have only a partial understanding of how local patch condition and seascape position may influence patterns of marine biodiversity, particularly for invertebrate taxa. We investigated how the epifaunal abundance and biomass of tropical Sargassum varied with canopy size (volume, total length and dry weight), local patch conditions (macroalgal composition, canopy structure and invertivorous fish biomass) and seascape setting (nearshore, lagoon and back reef) within the Ningaloo fringing reef ecosystem, Australia. A total of 49431 epifauna, dominated by crustaceans and molluscs, were extracted from the thalli of 81 tropical Sargassum polycystum individuals. Epifaunal abundance and biomass were most strongly correlated with host Sargassum canopy volume and dry weight, respectively. Epifaunal abundance and biomass also varied significantly among separate Sargassum meadow patches, with a significant interaction between canopy size and seascape position. Considerable site-level variations in epifaunal biomass density (mg per g Sargassum dry weight) were best predicted by either seascape context or local invertivorous fish biomass. Sargassum within meadows furthest from the back reef tended to have the highest epifaunal biomass (dominated by molluscs), while meadows closest to the back reef were dominated by crustacea. Sargassum within meadows with a high local abundance of invertivorous labrids and serranids tended to have the lowest epifaunal biomass. Strong Sargassum canopy size-epifauna relationships indicate that even small differences in canopy extent have major flow-on effects for the trophic function of tropical marine ecosystems by affecting the epifaunal secondary productivity available to higher-order consumers, such as fishes.

A 52-year-old Taiwanese woman presented with a progressively enlarged right breast mass after 6 months of tyrosine kinase inhibitor (TKI) treatment for metastatic lung adenocarcinoma. A core needle biopsy of the breast lesion revealed invasive carcinoma with positive immunohistochemical (IHC) staining for thyroid transcription factor-1 (TTF-1), cytokeratin 7 (CK7), napsin A (Nap-A), estrogen receptor (ER), and a negative result for progesterone receptor (PR) and HER2/neu. It is difficult to distinguish the histology between metastatic lung adenocarcinoma and metachronous breast cancer. However, IHC markers can help to differentiate the site of origin. A primary breast cancer with expression of TTF-1 and Nap-A is uncommon, and metastasis to the breast is a rare clinical manifestation. We reviewed the literature for both of these rare conditions, and discussed the utility of IHC markers to distinguish lung metastasis from primary breast cancer in this case. We ultimately diagnosed that this female patient had lung adenocarcinoma with breast metastasis, and a further treatment plan was devised.