Sexual dimorphism in fin size and shape in bluefin killfish
Data files
Jan 14, 2026 version files 126.96 KB
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Anal_Dorsal_caudal_base.csv
31.18 KB
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Brockelsby_etal_code.R
55.56 KB
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Caudal_Area.csv
5.86 KB
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Caudal_RaysV2_noSingletons.csv
9.49 KB
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Pect_Pelv_Fin_Traits.csv
12.38 KB
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README.md
9.53 KB
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SL_correct.csv
2.97 KB
Abstract
These data accompany the analysis of sexual dimorphism in fin size in bluefin killifish. In this study, we quantified sexual dimorphism in fin size and shape across all fin types in the bluefin killifish, Lucania goodei. We found striking sexual dimorphism in the dorsal and anal fins, particularly in area, ray length, and base length. In contrast, the pelvic, pectoral, and caudal fins showed moderate, but detectable, levels of dimorphism. The package contains data on fin ray number, fin ray lengths, fin area, and fin base length for dorsal, anal, caudal, pectoral, and pelvic fins of male and female blufin killifish.
Dataset DOI: 10.5061/dryad.80gb5mm2x
Description of the data and file structure
Bluefin killifish were collected from two populations in Florida (Everglades and Rainbow River) and maintained in lab colonies. Approximately 10 males and 10 females from each population were euthanized and photographed so that morphometric data could be measured from the images using NIH Image.
Files and variables
File: Brockelsby_etal_code.R
Description: This file contains the code to analyze the data below. It estimates the repeatability of traits, correlations of traits with standard length, the effects of sex (and population) on trait values, estimates sexual dimorphism, coefficients of variation for traits, and correlations among trait values for both males and females.
File: SL_correct.csv
Description: This file contains data on the standard length for each individual fish. Fish.ID denotes the individual ID of each fish and allows for data across files to be merged. The Sex, Source Population, Individual Measurer, and trait value are also listed. There are multiple measurements for each fish.
Variables
- Fish.ID: A unique ID for each fish
- Photo.IDs: An identifier for the photo from which the measurements were taken
- Sex: Sex of the fish (M or F)
- Source: Source population (Everglades or Rainbow River)
- Measurer: Identifier for the person taking the measurements from the photo
- SL: standard length of the fish (mm)
File: Caudal_RaysV2_noSingletons.csv
Description: This file has the data on the caudal fin ray numbers and ray lengths. The caudal rays are denoted as the ‘median’ caudal ray and then rays on either the dorsal or anal (i.e., ventral) side of the median ray. We count the number of rays as the number of branched rays plus one unbranched ray each side (i.e., dorsal and ventral).
Variables
- Fish.ID: A unique ID for each fish that allows individual trait means to be merged across files
- Photo_IDs: An identifier for the photo from which the measurements were taken
- Sex: Sex of the fish (M or F)
- Source: Source population (Everglades or Rainbow River)
- Measurer: Identifier for the person taking the measurements from the photo
- median_caud: length of the median caudal fin ray (mm)
- caud_D1: length of the first caudal fin ray on the dorsal side of the median caudal ray (mm)
- caud_D2: length of the second caudal fin ray on the dorsal side of the median caudal ray (mm)
- caud_D3: length of the third caudal fin ray on the dorsal side of the median caudal ray (mm)
- caud_D4: length of the fourth caudal fin ray on the dorsal side of the median caudal ray (mm)
- caud_D5: length of the fifth caudal fin ray on the dorsal side of the median caudal ray (mm)
- caud_D6: length of the sixth caudal fin ray on the dorsal side of the median caudal ray (mm)
- caud_D7: length of the seventh caudal fin ray on the dorsal side of the median caudal ray (mm)
- caud_A1: length of the first caudal fin ray on the anal side of the median caudal ray (mm)
- caud_A2: length of the second caudal fin ray on the anal side of the median caudal ray (mm)
- caud_A3: length of the third caudal fin ray on the anal side of the median caudal ray (mm)
- caud_A4: length of the fourth caudal fin ray on the anal side of the median caudal ray (mm)
- caud_A5: length of the fifth caudal fin ray on the anal side of the median caudal ray (mm)
- caud_A6: length of the sixth caudal fin ray on the anal side of the median caudal ray (mm)
- caud_A7: length of the seventh caudal fin ray on the anal side of the median caudal ray (mm)
- caud_Rnum: number of caudal fin rays (i.e., number of branched caudal fin rays plus one unbranched ray on the dorsal and ventral side).
File: Caudal_Area.csv
Description: This file contains data on caudal fin area for each fish. Fish are identified by Fish.ID, which allows the values to be merged with the other files. Other variables are the Photo.IDs, Sex, Source Population, and the caudal fin area.
Variables
- Fish.ID: A unique ID for each fish that allows individual trait means to be merged across files
- Photo.IDs: An identifier for the photo from which the measurements were taken
- Sex: Sex of the fish (M or F)
- Source: Source population (Everglades or Rainbow River)
- Measurer: Identifier for the person taking the measurements from the photo
- Caud_Area: caudal fin area (mm^2)
File: Pect_Pelv_Fin_Traits.csv
Description: This file contains data on pectoral and pelvic fin traits. There are 2 repeated measurements for each trait for each individual. This file has the following columns:
Variables
- Fish.ID: A unique ID for each fish that allows individual trait means to be merged across files
- Photo.IDs: An identifier for the photo from which the measurements were taken
- Measurer: Identifier for the person taking the measurements from the photo
- Sex: Sex of the fish (M or F)
- Source: Source population (Everglades or Rainbow River)
- Pelvic_RNum: number of pelvic rays
- Pelvic_Base: length of the pelvic fin base (mm)
- Pelvic_Area: pelvic fin area (mm^2)
- Pelvic_R1: length of the first pelvic ray (mm)
- Pelvic_R2: length of the second pelvic ray (mm)
- Pelvic_R3: length of the third pelvic ray (mm)
- Pelvic_R4: length of the fourth pelvic ray (mm)
- Pelvic_R5: length of the fifth pelvic ray (mm)
- Pelvic_R6: length of the sixth pelvic ray (mm)
- Pect_RNum: number of pectoral fin rays
- Pect_Base: length of the pectoral fin base (mm)
- Pect_Area: pectoral fin area (mm^2)
- Pect_R1: length of pectoral ray 1 (mm)
- Pect_R2: length of pectoral ray 2 (mm)
- Pect_R3: length of pectoral ray 3 (mm)
- Pect_R4: length of pectoral ray 4 (mm)
- Pect_R5: length of pectoral ray 5 (mm)
- Pect_R6: length of pectoral ray 6 (mm)
- Pect_R7: length of pectoral ray 7 (mm)
- Pect_R8: length of pectoral ray 8 (mm)
- Pect_R9: length of pectoral ray 9 (mm)
- Pect_R10: length of pectoral ray 10 (mm)
- Pect_R11: length of pectoral ray 11 (mm)
- Pect_R12: length of pectoral ray 12 (mm)
File: Anal_Dorsal_caudal_base.csv
Description: This file has data on fin area, fin base length, and fin ray lengths for dorsal and anal fins and data on caudal fin base length. Fish.ID allows for data to be merged across files with other trait data.
Variables
- Fish.ID: A unique ID for each fish that allows individual trait means to be merged across files
- Photo.IDs: An identifier for the photo from which the measurements were taken
- Measurer: An identifier for the person who measured the trait
- Sex: Sex of the fish (M or F)
- Source: Source population (Everglades or Rainbow River)
- BD – body depth (mm)
- Dor_RNum – number of dorsal rays
- Dor_Base – dorsal fin base length (mm)
- Dor_Area – dorsal fin area (mm^2)
- Dor_R1 – dorsal fin ray 1 length (mm)
- Dor_R2 – dorsal fin ray 2 length (mm)
- Dor_R3 – dorsal fin ray 3 length (mm)
- Dor_R4 – dorsal fin ray 4 length (mm)
- Dor_R5 – dorsal fin ray 5 length (mm)
- Dor_R6 – dorsal fin ray 6 length (mm)
- Dor_R7 – dorsal fin ray 7 length (mm)
- Dor_R8 – dorsal fin ray 8 length (mm)
- Dor_R9 – dorsal fin ray 9 length (mm)
- Dor_R10 – dorsal fin ray 10 length (mm)
- Dor_R11 – dorsal fin ray 11 length (mm)
- Dor_R12 – dorsal fin ray 12 length (mm)
- Anal_RNum – number of anal fin rays
- Anal_Base – anal fin base length (mm)
- Anal_Area – anal fin area (mm^2)
- Anal_R1 – anal fin ray 1 length (mm)
- Anal_R2 – anal fin ray 2 length (mm)
- Anal_R3 – anal fin ray 3 length (mm)
- Anal_R4 – anal fin ray 4 length (mm)
- Anal_R5 – anal fin ray 5 length (mm)
- Anal_R6 – anal fin ray 6 length (mm)
- Anal_R7 – anal fin ray 7 length (mm)
- Anal_R8 – anal fin ray 8 length (mm)
- Anal_R9 – anal fin ray 9 length (mm)
- Anal_R10 – anal fin ray 10 length (mm)
- Anal_R11 – anal fin ray 11 length (mm)
- Caud_Base – caudal fin base length (mm)
Code/software
We used R (ver. 4.5.0) and Rstudio (Version 2025.05.0+496) to analyze these data.
The code does the following:
Reads in data for various traits, estimates the repeatability and compiles those estimates into a table.
Calculates the mean for each trait for each individual and combines them into one dataframe that is used for the main analyses.
Calculates the average fin ray length for dorsal, anal, caudal, pelvic, and pectoral fins.
Calculates the correlations between the various traits and standard length, which is an overall estimate of size.
For each trait, it performs an analysis of variance to estimate the effects of source population and sex on the traits. For each trait, it takes the residuals from a regression of trait value on standard length. It then analyzes these values in an ANOVA framework and estimates the effect size due to sex.
It creates graphs shows the effect size due to sex for the major traits.
It creates graphs showing the patterns due to sex and population for standard length and anal and dorsal fin traits.
It creates tables showing the results from the ANOVAs for the various traits.
It creates graphs of the size-adjusted fin ray lengths for males and females and displays them as a function of fin base length.
It calculates the coefficients of variation for both absolute and size-adjusted trait values.
It calculates the correlations between size-adjusted trait values for males and females separately.