Plate with Ambonychia - Fossil Mobile Search

Scientific identification

Family: Ambonychiidae
Common name: Ambonychia bivalve
Author: Denis Arcand

Specimen interpreted as a bivalve assigned to Ambonychia, preserved on a shale plate. Supported by: Filename taxonomic keyword 'Ambonichia/Ambonychia' and bivalve code BIV indicate a bivalve specimen rather than an echinoderm concentration. Species-level confirmation requires: Better preserved hinge, shell outline, ornamentation, and diagnostic morphological details. Certainty: Identification considered reliable at genus level from filename and specimen context; species not assigned.

Geology and provenance

Formation: Nicolet River Formation
Group: Lorraine Group
Locality: Écluse de Chambly
Region: Richelieu Valley
Province: Quebec
Country: Canada

Lithostratigraphy

Locality: CEDC- Chambly Écluse de Chambly Region: Richelieu Valley Formation: Nicolet River Formation Group: Lorraine Group Depositional environment: Soft muddy seafloor Note: Exact site and stratigraphic unit unknown; only Ordovician age and bivalve context retained.

Observed lithology

Description: Dark shale slab preserving a bivalve fossil. Interpretation: Fine-grained marine siliciclastic sediment. Certainty: High confidence

Physical description

Assemblage description: Shale plate preserving a visible Ambonychia specimen or shell impression. Associated fossils: No associated fossils confidently identified from the current record.

Matrix description

Fossil assemblage: Sparse shelly assemblage Fossil density: Low Species composition: Mixed / uncertain Plate surface: Weathered Relief: High relief Ornamentation: Fine growth lines Rock type: Calcareous Shale Color: Brown / Dark gray - Mottled - Medium-dark Shape: Sub-rounded block Dimensions: W 10.2 × L 15.2 × T 1.5 cm (centimeters) Approximate volume: 0.2 cm (centimeters)³ Weight: 0.3 Gramme Note: Plate centered on a single Ambonychia bivalve specimen. Additional note: Plate dimensions derived from filename code 4x6 inches, converted to centimeters.

Taphonomy

Summary: Bivalve shell preserved on a shale plate; exact degree of transport and reworking uncertain. Evaluator: Paleontologist Transport origin: Indeterminate Occurrence position: Reworked Articulation: Moderate Fragmentation: High Abrasion: Low Compression: Low Observed processes: Single shelly fossil preserved on a shale plate, with limited contextual taphonomic information available. Interpretation: The specimen likely represents a shelly bivalve preserved in low-energy muddy marine sediment. Taphonomic quality: C — Moderately informative preservation of a shelly fossil on matrix Justification: The specimen is useful for identification and collection purposes, but locality and detailed taphonomic context remain uncertain. Evaluation date: 2026-03-09T00:00:00

Palaeoecological interpretation

Interpretation: Marine benthic bivalve from an Ordovician muddy shelf environment. Hypothesis: Ambonychia likely lived on or near the substrate in a marine setting. Certainty: Moderate. Note: Interpretation remains general because provenance is unknown.

Conservation state

General state: Fair Stability: Monitor closely Scientific readability: Poor Note: Specimen remains interpretable and displayable, but matrix friability requires cautious handling.

Museum exhibition value

Provenance: Type or figured specimen provenance documented Aesthetic appeal: High aesthetic and educational value Systematic collections: Systematic value not assessed Note: Good display value as a recognizable Ordovician bivalve on shale matrix.

Scientific value

Completeness / preservation: Poor preservation with limited diagnostic features Taxonomic novelty: Not evaluated for taxonomic novelty Note: Useful collection specimen of an Ordovician bivalve, but provenance is unknown.

Public exhibit text

This plate preserves a bivalve attributed to the genus Ambonychia, a marine mollusk that lived in Ordovician seas.