1. Herbivory in the marine realm
Robert S. Steneck, David R. Bellwood, Mark E. Hay 
Current Biology 
Volume 27, Issue 11, Pages R484-R489 (June 2017)
DOI: /j.cub
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2. Figure 1
Evolution of deep-grazing herbivore groups since the Cambrian.
The capacity to excavate calcareous coralline algae is taken as an indication of improved feeding capability. The graph represents the depth of grazing marks (horizontal axis) through time (vertical axis, with most recent era at the top). The Cenozoic era is divided into periods (top to bottom): R, Recent; P, Pleistocene; P, Pliocene; M, Miocene; O, Oligocene; E, Eocene; and P, Paleocene. The Mesozoic era is divided into (top to bottom): K, Cretaceous; J, Jurrasic; TR, Triassic. The Paleozoic era is divided into periods (top to bottom): P, Permian; P, Pennsylvanian; M, Mississippian; D, Devonian; S, Silurian; O, Ordovician. Graph adapted from Steneck (1983), reproduced with permission. Photos include parrotfish bite marks and parrotfish, limpet bites (scale 0.5 mm); and sea-urchin bites into calcareous algae. All photos by R. Steneck, including limpet images, which are republished with permission of John Wiley & Sons, from Steneck (1982).
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3. Figure 2
Global distribution of species richness among modern herbivorous fishes.
When considering fish-based herbivory, the immediate image is one of coral reefs with parrotfishes, surgeonfishes and rabbitfishes eating short algal turfs. It is true that the tropics have more herbivorous fish species, reflecting the higher species richness in these areas, and that herbivory is a major determinant of benthic community structure on coral reefs. However, herbivory by fishes is a widespread feeding mode that occurs in all ocean basins, in both tropical and temperate ecosystems.
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4. Figure 3
Feeding capabilities and diversification of selected taxa of herbivorous fishes.
Comparison of anatomically different feeding apparatuses. (A) Acanthurus surgeonfishes typically remove algae to be processed in an acidic thin-walled stomach. (B) The closely related Ctenochaetus, which selectively removes fine particles that are ground in a gizzard-like stomach. (C) Parrotfishes excavate the reef rock along with epilithic and endolithic algal turf (with all its constituents) to be triturated in a pharyngeal mill. The turf is often termed the epilithic algal matrix (EAM) and contains sediment, microbes, microalgae, detritus and invertebrates. It is this complex matrix and all its constituents that is consumed by parrotfishes. Surgeonfishes (D) evolved in the Eocene 50 million years ago, but diversified explosively in the Miocene (E) (Ctenochaetus is within the dashed lines in the Acanthurus clade), revolutionizing herbivory and benthic interactions that have led to the heavily grazed reefs we see today (F). (D) and (E) republished with permission of John Wiley & Sons, from Bellwood et al. (2016); (F) photo by M. Mihalitsis.
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5. Figure 4 Small herbivores that deter enemies using toxic hosts.
(A) The sea slug Costasiella ocellifera eats only the green alga Avrainvillea longicaulis, which sequesters the compound avrainvilleol (shown) and is therefore rejected by fish predators. (B) Similarly, the sea slug Elysia subomata consumes caulerpenyne-producing Caulerpa sp., sequestering and converting caulerpenyne to the compound shown for storage and protection of itself and its eggs (the yellow mass on the alga). (C) The amphipod Pseudamphithoides incurvaria creates a domicile from its algal host (Dictyota). Pachydictyol-A, produced by the Dictyota, cues this behavior and deters fishes from consuming the amphipod. The drawing shows the amphipod more clearly. (D) The crab Caphyra rotundifrons lives in and consumes only the green alga Chlorodesmis fastigiata, which is protected from herbivorous fishes by the cytotoxic compound chlorodesmin. Chlorodesmin deters fish feeding but stimulates feeding by the crab. (E) The crab Libinia dubia decorates itself with the chemically-defended alga Dictyota. Dictyot-E from the alga cues decoration and deters fishes from consuming the crab. All photos and figures by M. Hay.
Current Biology  , R484-R489DOI: ( /j.cub )
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