Review Papers Claim by Claim

Critical analysis (visual-first then evidence-weighted commentary)

1. Are the main claims supported? Yes, within constraints. The CT images and VHI evaluation support well-preserved primary microstructures (plexiform-like + primary osteons) consistent with late fetal stages in Homo sapiens; authors correctly avoid overclaiming (they state 'broadly equivalent' rather than identical) and provide comparative images and references Main results and caveats
2. IGD interpretation: Reasonable but not definitive. Visible clustered circumpulpal hypodensities are consistent with pathological IGD patterns used to infer vitamin D / Ca disturbance, but authors prudently note multiple possible aetiologies (nutritional vitamin D deficiency, calcium-poor diet, malabsorption, renal problems) and the impossibility of a conclusive diagnosis from CT alone; D'Ortenzio et al. (2018) provides histological diagnostic context and cautions IGD diagnostic criteria
3. Major methodological limitations: (a) micro-CT resolution (~15–23 μm) is excellent for non-destructive work but cannot resolve osteocyte lacunae or cement lines needed to distinguish primary vs secondary osteons quantitatively; (b) no ground histology or synchrotron imaging was allowed, limiting cellular-level validation; (c) small, site-limited sample (one perinate skeletal assemblage + two teeth) risks over-generalization; (d) taphonomic signs (possible carnivore gastric alteration) create potential bias despite VHI screening — the authors acknowledge these limitations and avoid overstating generality Methods and limits
4. Alternative explanations / blindspots: (a) Localized advanced compactness could reflect intra-individual biological variation (regional growth rates), maternal effects, or perimortem taphonomic compaction rather than true developmental acceleration — authors discuss maternal/dietary/genetic possibilities but lack direct evidence; (b) IGD could be developmental micro-IGD magnified by preservation bias or represent postmortem mineral alteration in rare cases; authors compare to micro-CT groundtruth studies to reduce this risk CT reliability for IGD

High-value next steps (tests that would change conclusions)

• Obtain higher-resolution imaging (SR-μCT) or targeted thin-section histology of non-diagnostic spare fragments (if permitted) to quantify osteocyte lacunae, primary vs secondary osteon cement lines, and confirm woven vs lamellar collagen arrangement.
• Perform incremental-line dental histology (or higher-res CT aimed at neonatal line) on Sesselfelsgrotte teeth or other contemporaneous Neanderthal deciduous teeth to time IGD episodes (prenatal vs postnatal) and detect systemic vs local events.
• Expand sample across multiple Neanderthal perinates/infants (La Ferrassie, Le Moustier, Mezmaiskaya, Krapina) with controlled diagenesis scoring to test whether the local long-bone advancement is general to Neanderthals or an individual/ maternal effect.
• Combine stable isotope or enamel peptide analyses of these teeth to check dietary vitamin D / calcium proxies or maternal physiology markers (if preservation allows).