Keep ichthyosaurs, plesiosaurs and pterosaurs as three independent radiations, and compare an older uncertain Bobosaurus candidate with diagnostic Rhaeticosaurus without turning either into a direct ancestor.
Each step names its evidence claims, with references below. Interactive Explorer states are available in the full application; the narrative remains an editorial synthesis.
AGM I-1 preserves a small short-snouted body with large flippers and dense limb and rib bone. Amphibious habits and suction feeding are functional interpretations, not recorded behaviour or proof of direct ancestry.
The corrigendum is part of the evidence record; it changed character descriptions and tree statistics while retaining the reported topology.
claim:event:cartorhynchus-holotype-body-planMaternal Chaohusaurus specimen AGM I-1 contains two embryos and an adjacent neonate. Their association supports pregnancy, whereas head-first delivery and a terrestrial origin of viviparity remain comparative inferences.
A specimen-level reproductive record does not define the ancestral state of all marine reptiles.
claim:event:chaohusaurus-maternal-specimenMH 432 preserves skin layers, a blubber-like subcutaneous layer and eumelanin-bearing structures. Countershading and thermoregulation are interpretations from distribution and living comparisons, not directly measured physiology.
One exceptional specimen does not establish a universal tissue condition for Ichthyosauria.
claim:event:stenopterygius-soft-tissuesEarly Carnian Bobosaurus combines nothosaurian and plesiosaurian features, but alternative placements remain viable. It is an older near-lineage candidate, not evidence that diagnostic Plesiosauria already extended into the Carnian.
Compare this uncertain candidate with the separately documented Rhaetian Rhaeticosaurus skeleton.
claim:event:bobosaurus-plesiosaurian-affinityLWL-MFN P 64047 supplies articulated anatomy and vascularized long-bone tissue from the Rhaetian. Basal pliosaurid placement and physiological implications remain dependent on phylogenetic and histological interpretation.
A named Triassic skeleton is not automatically the global first occurrence or a direct ancestor of later plesiosaurs.
claim:event:rhaeticosaurus-holotype-histologyAdult Polycotylus LACM 129639 contains one large articulated fetus identified as the same taxon. Pregnancy and viviparity are specimen evidence; parental care, sociality and K-selection are broader analogical hypotheses.
Preserved reproductive anatomy and inferred life-history strategy have different evidentiary strength.
claim:event:polycotylus-gravid-specimenA physical model measured thrust and efficiency at prescribed fore- and hind-flipper phase offsets. Vortex interaction supports mechanical plausibility, not a filmed extinct gait or one stroke shared by every plesiosaur.
Model inputs, measured outputs and palaeobiological extrapolation remain separate.
claim:event:plesiosaur-four-flipper-modelMCT.R.1884 preserves monofilaments, branched feather-like structures and melanosomes around a Tupandactylus skull and crest. The evidence does not directly recover exact colours or a universal pterosaur covering.
Preserved structures, colour-function hypotheses and reconstructed ancestral states are different claim types.
claim:event:tupandactylus-feather-melanosomesA Hamipterus block exposes 215 eggs and may contain about 300; sixteen eggs in the wider assemblage preserve embryonic remains across multiple levels. Nesting, transport and hatchling behaviour remain interpretations.
Egg and embryo counts do not by themselves demonstrate parental care or post-hatching flight capacity.
claim:event:hamipterus-egg-assemblageScaling, bone mechanics and aerodynamic calculations make powered flight and forelimb-assisted launch feasible for sampled giant-pterosaur reconstructions. The model is not direct observation of an extinct takeoff.
COL26.8 contributes zero accepted species through these fossil-root routes; naming coverage and dossier maturity are independent, and the three radiations remain separate.
claim:event:giant-pterosaur-launch-model