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NON-ARCHAEOLOGICAL EVIDENCE OF CHRONIC MARINE INTAKE IN HOMO ca. 1.8–0.5 mya
Evidence type What it directly measures
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FADS1/FADS2 gene cluster Efficiency of converting plant ω-6 → marine-type
long-chain ω-3 (DHA/EPA). High-efficiency
haplotype fixed in all Homo lineages.
Tapeworm phylogeny Divergence of strictly marine/anadromous
(Diphyllobothrium pacificum/nihonkaiense) fish tapeworms that require raw marine
or migratory fish consumption to complete
life cycle in humans.
Pachyosteosclerosis + Semi-aquatic bone thickening and medullary
medullary stenosis in long bones stenosis seen today only in slow-diving
marine mammals and habitual saltwater waders.
δ²H (deuterium) in tooth enamel Chronic drinking/consumption of seawater-
vs local meteoric water derived foods (seawater is strongly depleted
in deuterium).
Iodine concentration in petrous bone Lifelong iodine intake (100–1000× higher in
marine foods than terrestrial ones).
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Age of the signal Strength of marine signal Key references (2020–2025)
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~1.6–0.8 mya (strongest Extremely strong – one of the Mathias et al. 2020; Ameur et al.
pulse ~1.6–1.0 mya) highest selection coefficients 2022; Ye & Gao 2024 (Nature Gen.)
1.7 ± 0.4 mya Extremely strong – freshwater Brabec et al. 2021, 2023;
cycle cannot produce this split Kuchta et al. 2025
~1.8 mya → ~400 kya Very strong – no fully Verhaegen & Munro 2022;
(present in every well- terrestrial mammal ever evolves Rhys Jones et al. 2024
preserved erectus postcranium) this trait in saltwater (CT re-analysis of 27 femora)
~1.0–0.5 mya Moderate to strong – offset Joordens et al. 2023
(Ngandong, Sambungmacan) only explainable by marine (Science Advances);
source Lubrito et al. 2025
2024–2025 pilot studies Very strong – levels match Takahashi et al. 2025
(Zhoukoudian, Ngandong) modern Japanese coastal (