Search

Societal Impact Statement The watermelon (Citrullus lanatus subsp. vulgaris) is among the world's most important fruit crops. We here use C‐14 dating and morphometric analysis to test whether ancient seeds can be identified to species level, which would help document food expansion, innovation, and diversity in Northeastern Africa. We dated a Libyan seed to 6182–6001 calibrated years BP, making it the oldest Citrullus seed known. Morphometric analysis could not reliably assign ancient seeds to particular species, but several seeds showed breakage patterns characteristic of modern watermelon seeds cracked by human teeth. Our study contributes to the understanding of the early history of watermelon use by humans, who may have mostly snacked on the seeds, and cautions against the use of morphology alone to identify Citrullus archaeological samples.

Cross-entropy estimates of genomic sNMF analysis of the Pallenopsis patagonica species complex. Figure showing cross-entropy estimates of genomic sNMF analysis of the Pallenopsis patagonica species complex for 1 to 20 ancestral populations (K value). (PDF 263 kb)

Morphological distances against genomic distances. Figure showing morphological distances plotted against genomic distances (based on target hybrid enrichment data) between individuals of the Pallenopsis patagonica species complex. Red: intraspecific distances (the rightmost red squares represent intraclade distances of SUB_2); grey: interspecific distances. Linear regression line is given (r = 0.51, p

PCA from morphological data of the Pallenopsis patagonica species complex. PCA plots based on morphological measurements. All mitochondrial clades are indicated by different symbols. Symbols of samples from Patagonian (SUB) have no filling, in contrast to the filled symbols of Antarctica (ANT). Male specimens have a blue, females a red outline. (PDF 569 kb)

Detailed protocols of methods used. Detailed written protocols for bait enrichment, de novo reference assembly and SNP calling as performed for analyses within the study. (PDF 177 kb)

Phylogenetic EOG tree of the Pallenopsis patagonica species complex. Maximum-Likelihood tree based on concatenated EOG sequences of all samples using P. pilosa and transcriptomic data of Anoplodactylus insignis as outgroup. Bootstrap values are given next to the respective branches. (PDF 296 kb)

Phylogenetic SNP tree of the Pallenopsis patagonica species complex. Maximum-Likelihood tree based on aligned SNP data of all Pallenopsis samples. Bootstrap values are given next to the respective branches. (PDF 330 kb)

Matrices of PCA plots based on reduced morphometric data sets of the Pallenopsis patagonica species complex. All combinations of all five axes (PCs) are represented for data sets including A) absolute and B) relative values. Each color represents a different clade (see legend). (PDF 677 kb)