Dirt-sifting devilfish: winnowing in the geophagine cichlid Satanoperca daemon and evolutionary implications

Quantifying production rates and size fractions of parrotfish‐derived sediment: A key functional role on Maldivian coral reefs

“…Secondly, future work on parrotfish functional roles would benefit from quantifying the amount of eroded material or loose sediment that is disturbed, but not ingested. This is different to the winnowing behavior observed in other sediment ingesting fish (e.g., Weller et al, 2016), which is not observed in parrotfish. On occasion, excavator parrotfish were anecdotally observed to break off tips of branching corals and drop the fragments onto the seabed.…”

“…Sediment production was assumed to match direct estimates of bioerosion rate (as assumed in other studies, such as Bellwood, 1996 ) because there is currently no clear evidence for dissolution of carbonates within the gut and there have also been no attempts to quantify the amount of material that parrotfish remove from the substrate, but do not ingest. Parrotfish also have tightly spaced gill rakers, which minimizes loss of sediment through the gills (Clements et al, 2017 ), so it is unlikely that any significant quantities of sediment were lost via “winnowing” (sensu Weller et al, 2016 ) as, for example, observed in some sediment feeding surgeonfish. Data on annual bioerosion rates for range of representative parrotfish species (and body sizes) at Vavvaru, and total annual habitat bioerosion rates were extracted from Yarlett et al ( 2018 ), Yarlett et al ( 2020 ).…”

Relaxed Feeding Constraints Facilitate the Evolution of Mouthbrooding in Neotropical Cichlids

“…Here, we hypothesize that mouthbrooding may be more likely to evolve in lineages with feeding modes that were already well-suited for mouthbrooding. Precisely what makes a feeding mode well-suited for mouthbrooding probably varies, and feeding traits that may be co-opted in parental care range from behavioral neural circuitry (Fischer and O'Connell, 2017) and motor control patterns (Barkan and Zornik, 2019) to cranial and branchial morphology (Hoey et al, 2012;O'Connor et al, 2012;Weller et al, 2017). We can make some generalizations based on the physiological requirements of incubating eggs: at a minimum, the upper limit on brood size is set by the upper limit on mouth volume, as opposed to batch fecundity or defensible nest size (Fig.…”

“…Unlike most mouthbrooding taxa (including African cichlids), most mouthbrooding Neotropical cichlids exhibit biparental care and little sexual dimorphism , minimizing the effects of what could be major confounding variables. Lastly, many Neotropical cichlids-including most of the mouthbrooding species-are winnowers that feed by sifting mouthfuls of substrate for invertebrates or edible detritus (Weller et al, 2017). Winnowing and mouthbrooding, at least superficially, are strikingly similar behaviors in Neotropical cichlids, involving intraoral manipulation of small objects (eggs or substrate) via repeated cycles of premaxillary protrusion, hyoid depression, and opercular flaring (in contrast with most African lake mouthbrooders, which pack the expanded buccal cavity with eggs and maintain a noticeable bulge at the hyoid (Van Wassenbergh et al, 2016;Weller et al, 2017)).…”

“…Lastly, many Neotropical cichlids-including most of the mouthbrooding species-are winnowers that feed by sifting mouthfuls of substrate for invertebrates or edible detritus (Weller et al, 2017). Winnowing and mouthbrooding, at least superficially, are strikingly similar behaviors in Neotropical cichlids, involving intraoral manipulation of small objects (eggs or substrate) via repeated cycles of premaxillary protrusion, hyoid depression, and opercular flaring (in contrast with most African lake mouthbrooders, which pack the expanded buccal cavity with eggs and maintain a noticeable bulge at the hyoid (Van Wassenbergh et al, 2016;Weller et al, 2017)). This makes Neotropical cichlids an excellent candidate clade to test the hypothesis that mouthbrooding co-opts sustrate sifting morphology.…”