Data and code from: Predatory behaviour on Ostracoda: Spatial analysis of drill-hole distribution in relation to shell size and ornamentation
Data files
Aug 06, 2026 version files 114.49 KB
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data.csv
54.82 KB
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morpho_functions.R
19.86 KB
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README.md
4.96 KB
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script1.R
7.18 KB
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shell_apatihowella.csv
1.40 KB
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shell_cytherella.csv
1.40 KB
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SPPAT_Analysis.R
21.48 KB
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SPPAT_create_bivalve_landmarks.R
3.39 KB
Abstract
Paleobiological evidence of predation on ostracods derives primarily from drill-hole traces. However, this record is limited to sparse reports and quantitative analyses are rare. Moreover, predation is rarely studied in deep-water settings. We analyzed 242 drilled ostracod specimens from the relatively deep-water strata of the Miocene Navidad Formation of Chile to assess how predation varies with size and ornamentation. Specimens of Cytherella (smooth) and Apatihowella (ornamented) were photographed for valve and drill-hole measurements and to map trace positions using the relatively new Spatial Point Pattern Analysis of Traces (SPPAT) method for the first time for ostracods. Using 3,425 specimens, drilling intensity was 5.38 % for Cytherella and 9.78 % for Apatihowella. All SPPAT simulations (using all traces and ichnotaxa) revealed significant concentrations of drill holes in the dorsal–median region of Cytherella and in the ventral region of Apatihowella. Moreover, drill holes located between the valves were observed only in Apatihowella for 30 % of the traces. The predators selected primarily drilling sites close the soft tissue for the smooth shelled Cytherella. In contrast, the thick dorsal shell and the strongly ornamented median regions of Apatihowella may have displaced the preferred attack site, allowing continued access to its soft tissues but toward nutritionally poorer ventral and marginal regions. Thus, ornamentation did not deter predation of the ostracod but did influence predation behaviour. Future studies from other regions and time intervals are needed to explore predator–prey interactions in the ostracod fossil record in greater depth.
Dataset DOI: 10.5061/dryad.m905qfvg6
Description of the data and file structure
ReadMe for Predatory behaviour on Ostracoda: Spatial analysis of drill-hole distribution in relation to shell size and ornamentation, by Camila S. Cruz, Cristiane F. Frozza, Jorge Villegas-Martín, Cristianini T. Bergue, João C. Coimbra, Adiël A. Klompmaker, Matias Ritter.
This ReadMe file describes the data files and supplementary files accompanying the above paper. For any further queries, please get in touch with souzacruz.camila@gmail.com
General Information
Author/Principal Investigator Information
Name: Camila Souza Cruz
ORCID: https://orcid.org/0000-0001-6437-8449
Institution: Universidade Federal do Rio Grande do Sul - UFRGS, Brasil.
Email: souzacruz.camila@gmail.com
Author/Associate or Co-investigator Information
Name: Matias Ritter
ORCID: https://orcid.org/0000-0001-8150-4443
Institution: Universidade Federal do Rio Grande do Sul - UFRGS, Brasil.
Email: matias.ritter@ufrgs.br
Files and Variables
The following files are included:
1) "data.csv"
This is the dataset used in the size and site selectivity analyses.
- Number of variables: 26
- Number of cases/rows: 242
- Code NA = Not Applicable (the variable does not apply in this case).
- Variable List:
- code, sample, formation, location and lithology: the information from the sample data was collected from Finger (2013);
- taxon: two ostracod genera analyzed: Cytherella (smooth carapace) and Apatihowella (ornamented carapace).
- length and height: data from the ostracod specimens studied. The unit of measurement is micrometer;
- ichnotaxon: identification of drill holes according to Bromley (1981, 1993);
- shape: shape of the drill holes;
- OD and ID: Outer diameter (OD) and inner diameter (ID) of the drill holes. The unit of measurement is micrometer;
- valve_hole: right valve (RV) or left valve (LV) with drill hole;
- type_hole: wall or edge drill-hole;
- site-selectivity: location of the drill hole in the carapace (anterior, posterior, dorsal, ventral, and median regions)
- L1x, L2x, L3x, L4x, L1y, L2y, L3y, L4y: landmarks correspond to the shell boundaries;
- hole_x and Hole_y: landmark corresponding to the center of the drill hole.
2) "script1.R"
This R script reproduces the analysis from the paper, including the Mann-Whitney (Figs. 7B, 8B, 9B) and Kendall (Fig. 9) statistical tests; and the creation of the figures 7-9. The comments should make it self-explanatory.
3) "SPPAT_create_bivalve_landmarks.R"
This R script was used to create the outline of the ostracods (50 landmarks) and collect the five landmarks. The codes were modified from Rojas et al. (2025) to adapt them to the study of ostracods. The landmarks generated from the ostracod outlines were stored in "shell_apatihowella.csv" and "shell_cytherella.csv". The five landmarks generated to capture the length and height of the specimens and the center of the drill holes were inserted into the "data.csv" file with the abbreviations "L1x, L2x, L3x, L4x, L1y, L2y, L3y, L4y". The comments should make it self-explanatory.
4) "SPPAT_ Analysis.R"
This R script contains the necessary code for SPPAT analysis. It was developed and made available by Rojas et al (2025). Some modifications were necessary for the present study. This R script was used for analysis and to generate figures 10-12. The comments should make it self-explanatory.
5) "morpho_functions.R"
This R script provides the functions needed to run the SPPAT analysis in SPPAT_Analysis.R. Run the script to enable the functions. This script was written by Alexis Rojas.
REFERENCES
BROMLEY, R. G. 1981. Concepts in ichnotaxonomy illustrated by small round holes in shells. Acta Geologica Hispanica, 16, 55–64.
———. 1993. Predation habits of octopus past and present and a new ichnospecies, Oichnus ovalis. Bulletin of the Geological Society of Denmark, 40, 167–173.
FINGER, K. L. 2013. Miocene foraminifera from the south-central coast of Chile. Micropaleontology, 59, 341–492.
ROJAS, A., DIETL, G. P., KOWALEWSKI, M., PORTELL, R. W., HENDY, A. and BLACKBURN, J. K. 2020. Spatial point pattern analysis of traces (SPPAT): An approach for visualizing and quantifying site-selectivity patterns of drilling predators. Paleobiology, 46, 259–271.
———, HUNTLEY, J. W., CAFFARA, M. and SCARPONI, D. 2025. Spatial patterns of trematode-induced pits on bivalve skeletons: Challenges and prospects for research on parasite-host dynamics. The Holocene, 35, 1259–1271.