Data from: Trophic separation in planktivorous reef fishes: a new role for mucus?

Background:The feeding apparatus directly influences a species’ trophic ecology. In fishes, our understanding of feeding modes is largely derived from studies of rigid structures (i.e. bones, teeth, gill rakers). A recently described lip innovation, however, highlighted the role of soft anatomy in enabling specialized feeding modes. In this study, we explore whether similar diversification may also occur in the soft anatomy of the buccal cavity. Using four key anatomical traits to classify 19 species (14 genera) of wrasses, we evaluated the relationship between anatomical specialization of the buccal cavity and diet. Our data revealed a previously undocumented anatomical adaptation in the mouths of fairy wrasses (Cirrhilabrus): the mucosa throughout the buccal cavity (i.e. anterior to the pharynx) is packed with goblet cells, enabling it to secrete large quantities of mucus in this region; a new trait that, until now, had not been documented in wrasses. This disparity reflects diet differences, with mucus secretion found only in planktivorous Cirrhilabrus that feed predominantly on amorphous organic material (potentially gelatinous organisms). This suggests a cryptic mucus-based resource partitioning in planktivorous wrasses.
This data record contains:

R Script containing analyses for: Morphological variation, dietary variation, and correlation between morphology and diet.
.csv 'Diet Main Categories'. The data was calculated using the ‘point intercept’ method where the main item on 40 randomly allocated quadrats spread on a Petri dish containing the gut content was recorded. Then, the data was pooled into eight primary dietary categories.
.csv ‘Morphology’ containing mouth morphology measurements of 19 wrasse species.
.csv ‘Raw Data’ containing data on morphology measurements and diet/gut analysis for the 19 species included in the study.

Software/equipment used to create/collect the data: Photomicrographs were taken with an Olympus DP21 digital camera mounted on an Olympus BX40 light microscope. Resulting images were combined using the 'photomerge' tool in Adobe Photoshop CS6 (Adobe Systems, San Jose, USA) to provide a detailed view of the buccal cavity.

Prior to data collection, sampling locations were distributed evenly along the roof and base of the buccal cavity using a grid overlay in Adobe Photoshop. Then, measurements were taken from each of these images using the software FIJI (https://imagej.net/software/fiji/#downloads).

Software/equipment used to manipulate/analyse the data: All statistical analyses were conducted in the software R v.3.6.1 using the packages 'tidyverse v.1.3.1', 'ape v.5.2', 'nlme v.3.1-137', 'phytools v.0.6-60', 'vegan v.2.5-4', 'scales v.1.1.1' and 'boot v.1.3-28'.