Nipponites: No measured body size data available to draw at scale.
- · Grid units represent actual meters (m); human and animals are drawn to the exact same scale with original silhouette aspect ratios preserved.
- · When a size range is recorded (e.g. 1–1.6m), the lower bound is used for scale comparison.
- · Human silhouette: PhyloPic — NASA · Public Domain Mark 1.0
Nipponites
Nipponites mirabilis (Nipponites · Nipponites)
Known only from fossils. The IUCN Red List assesses only species extant since 1500 CE, so fossil taxa are not assigned a category.
💡 Everyday Comparisons for Size, Mass & Speed
- 💡 The University Museum, the University of Tokyo describes it in its open-shelf display guide as 'the rarest species among heteromorph ammonites.'
- 💡 A 2020 PLOS ONE study that calculated center of mass and buoyancy using computer 3D models to reconstruct the swimming posture of an extinct animal is an example of how CT and 3D scanning are used in fossil research.
Reference standards: coach bus ~12 m, mid-size car ~4.9 m, compact car ~1 t, basketball hoop 3.05 m, credit card 8.56 cm.
📖 1. Overview
Nipponites mirabilis (genus Nipponites) was a heteromorph ammonite that lived in the seas of Japan during the Late Cretaceous; instead of coiling in a single flat plane like typical ammonites, its shell twisted in a bizarre tangle. Hisakatsu Yabe described it in 1904 based on a specimen from Obira, Hokkaido.
🦴 2. Anatomy & Morphology
Unlike a planispiral shell coiled in one plane, its shell formed an irregular three-dimensional tangle of loose coils and bends. Complete specimens are extremely rare, and it is introduced as one of the rarest heteromorph ammonites.
🔍 3. Fossil Record & Paleoecology
A 2020 study used 3D models to calculate buoyancy across 14 growth stages and concluded that it could maintain neutral buoyancy at every stage rather than being confined to the seafloor. A nearly complete specimen is housed at the Mikasa City Museum in Hokkaido, Japan.
🇰🇷 4. Connection to Korea
No direct record connecting this species to Korea has been found.
📚 Sources & References
- • Fossil taxon — the IUCN Red List assesses only species living or extinct since 1500
- • paleobiodb.org — basicTaxonInfo
- • um.u-tokyo.ac.jp — b 12.html
- • pmc.ncbi.nlm.nih.gov — PMC7410299
Recorded dimensions are widely cited representative estimates from public literature and may vary by study or specimen.