Articulation Index Skeleton
Compute observed articulation fraction over assessable expected joints and extreme bounds for unassessable opportunities; denominator is joint opportunities, not surviving bones.
Description
Articulation is assessed over joint opportunities rather than surviving bone counts.
Articulation is assessed over joint opportunities rather than surviving bone counts. Unassessable joints permit lower and upper bounds.
Compute observed articulation fraction over assessable expected joints and extreme bounds for unassessable opportunities; denominator is joint opportunities, not surviving bones.
When to use Articulation Index Skeleton
Use this tool to compute observed articulation fraction over assessable expected joints and extreme bounds for unassessable opportunities; denominator is joint opportunities, not surviving bones.
Prepare the fossil measurements or occurrence records and the chosen calibration parameters. Retain the stated coordinate, age and measurement conventions.
How to use Articulation Index Skeleton and understand its results
- Prepare the fossil measurements or occurrence records and the chosen calibration parameters. Retain the stated coordinate, age and measurement conventions.
- Enter observableExpectedJointCount, observedArticulatedJointCount, unassessableExpectedJointCount using the field table and calculation rules, then run the tool.
- Read observableArticulationIndex, fullExpectedJointArticulationBounds. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| observableExpectedJointCount | Observable expected joint count | integer | Required |
| observedArticulatedJointCount | Observed articulated joint count | integer | Required |
| unassessableExpectedJointCount | Unassessable expected joint count | integer | Required |
Use positive integer assessable joints, nonnegative articulated no greater than assessable, and nonnegative unassessable joints. Return observed fraction and extreme full-inventory bounds.1
observed index = articulated/assessable; full bounds = [articulated,articulated+unassessable]/full opportunities Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| observableArticulationIndex | Observable articulation index | number |
| fullExpectedJointArticulationBounds | Full expected joint articulation bounds | list of number |
{
"input": {
"observableExpectedJointCount": 10,
"observedArticulatedJointCount": 4,
"unassessableExpectedJointCount": 5
},
"output": {
"observableArticulationIndex": 0.4,
"fullExpectedJointArticulationBounds": [
0.26666666666666666,
0.6
]
}
}Limitations and assumptions
Bounds assume all unassessable joints are either unarticulated or articulated, not probabilities.
Numbers and computed results must be finite; overflow produces an error. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Specimen Completeness Percentage: Distinguish observed anatomical inventory coverage from preservation-weighted element equivalents on caller expectations; neither index certifies taxonomic identification or skeleton completeness. For a complementary task, use Minimum Animal Units MAU: Normalize independently established MNE by skeletal element copies and maximum MAU; fractional animal units are representational indexes, unlike ceiling-based MNI individual bounds.
References
-
Articulation Index Skeleton — tool.io
Similar or alternative tools
- Specimen Completeness Percentage
Distinguish observed anatomical inventory coverage from preservation-weighted element equivalents on caller expectations; neither index certifies taxonomic identification or skeleton completeness.
- Minimum Animal Units MAU
Normalize independently established MNE by skeletal element copies and maximum MAU; fractional animal units are representational indexes, unlike ceiling-based MNI individual bounds.