The Gold Standard of Teaching Archaeological Fish Cleithrum Analysis | Pectoral Girdles, Species Identification and Body Size

Archaeological fish cleithrum analysis uses a pectoral-girdle bone to study historical fish remains and, in suitable cases, reconstruct body size. The bone may retain informative species-related features even after more fragile elements disappear. Yet an isolated cleithrum is not automatically one caught fish, and body length cannot be estimated responsibly without matching anatomy and a validated modern reference. This guide separates those questions and shows which measurements, contexts and cross-checks a reader needs.

The worked Harbour Reach cases below are invented teaching data. Their toy length formula and fragment counts are not results from an excavation. The featured scientific figure, by contrast, is an authentic research illustration of the pectoral girdle of Ossubtus xinguense, not the imagined archaeological specimen. Start with the chapter index for the direct answer, then work through the examples and the evidence-audit checklist.

For real comparative methods, use the Neolithic Guye sea-bass analysis, the diagnostic-bone length and digestion study and the 2024 freshwater fish osteology atlas.

1. Why the cleithrum matters in fish archaeology

The cleithrum is a substantial bone of the pectoral girdle in many bony fishes. In excavated assemblages it can survive as an isolated, curved or plate-like element after finer skull and fin structures have broken down. Its anatomy may help identify a fish group, and defined measurements may contribute to body-size estimates where an appropriate modern calibration exists. None of those advantages turns one cleithrum into a complete fish, a verified catch or a direct estimate of ancient fishing effort. A disciplined lesson begins by describing the recovered element, side, preservation and context before moving to wider interpretations.

Show students a real fish pectoral-girdle research figure alongside a fictional loose archaeological bone. Ask what each image directly establishes. The research figure helps identify the bone within its original skeletal relationships; the excavated fragment usually has much less context. They should separate claims of structural identity from species identification, inferred body size and human behaviour. These are different stages of argument, each needing its own supporting evidence.

2. Locate the pectoral girdle on a complete fish

The pectoral girdle supports the paired pectoral fins and connects several skeletal elements behind and below the head. In many teleosts the cleithrum lies alongside the scapula and coracoid, with a supracleithrum and posttemporal contributing connections toward the skull. The precise shapes and articulations vary across lineages, making whole-skeleton reference material valuable. The cleithrum is not interchangeable with a rib, jawbone or fin spine merely because fragments of all four can be narrow and curved.

In a first drawing exercise, students identify head, gill cover, pectoral fin, cleithrum, scapula, coracoid, supracleithrum and posttemporal. They then erase surrounding bones from the drawing, leaving an isolated cleithrum. Which features remain sufficient for recognition? This shows why anatomical relationships provide stronger identification than an isolated silhouette and why missing projections need to be documented instead of mentally restored.

3. Use the 2016 Ossubtus figure correctly

The featured image in this article is from Andrade and colleagues’ scientific redescription of Ossubtus xinguense, a fish of the Xingu River region. The authors labelled the cleithrum and neighbouring pectoral-girdle elements in external and internal views with a scale bar. It is an excellent teaching reference for connections among bones, but it is neither an archaeological specimen nor an illustration of a universal fish pectoral girdle. A labelled modern exemplar teaches anatomy without establishing the species identity of any loose archaeological cleithrum.

Have students identify the figure abbreviations cle, cor, scp and scl, then locate the actual shapes. Require a caption that states the species, authors, year, license and the fact that it was reproduced as reference anatomy. An incorrect caption declaring the photo to be a fossil from the fictional estuary would turn a legitimate educational resource into false documentation.

4. Distinguish cleithrum from neighbouring girdle elements

The scapula and coracoid commonly lie close to the cleithrum and have their own articular structures. A fragmented pectoral girdle may preserve several joined bones that are mistaken for one object, while a loose fragment may lose the boundary that established which part was originally present. Identification relies on the characteristic surfaces and articulations, not just on a generic curved outline. Species and developmental stage also influence morphology.

Set up a reference comparison using an intact pectoral girdle and isolated bones from the same fish. Students label boundaries and note where a scapular foramen or a contact surface can help. They must be willing to record ‘pectoral girdle fragment, exact element uncertain’ when the specimen is too incomplete. A cautious anatomical category preserves meaningful evidence without adding unwarranted certainty.

5. Record side and orientation before taking dimensions

A left cleithrum and a right cleithrum are paired anatomical elements, but a fragment can be flipped on a bench and photographed from either internal or external surface. Measurements are meaningful only when the orientation is known and the same landmarks are used. Broken processes can also create a false maximum length if the measurement ends at a fracture rather than the original bone margin.

Give learners three images of one modern cleithrum photographed in different orientations. They decide which is lateral, which is medial and whether the specimen is left or right using documented reference features. Then they choose a reproducible dimension and describe its start and end landmarks. ‘Bone length’ is not a sufficiently precise measurement instruction when several possible axes exist.

6. Know that a cleithrum is not a universal species key

Cleithrum shape can contribute to identification but varies among fish species, groups and body sizes. Some closely related taxa overlap substantially, while unrelated taxa can share superficial curvature. A modern photograph database such as the University of Nottingham’s Archaeological Fish Resource supplies useful reference views, but any one image covers only part of the variation in age, population and preservation. A physical comparative collection with documented specimens remains valuable.

Ask students to compare gilthead seabream, whiting and wrasse reference cleithra while keeping their habitats and taxonomy distinct. If a fossil resembles one broad class, they should list alternative taxa rather than choosing the most familiar fish from the modern shoreline. A species claim needs characters that actually distinguish it from credible regional alternatives.

7. Separate taxonomic certainty from statistical precision

A regression may predict fish length extremely well for a securely identified taxon, yet become inappropriate if the archaeological bone belongs to a different taxon. Likewise, a measurement could be made to a fraction of a millimetre while the anatomical identification remains uncertain. Those are distinct uncertainties: instrument precision does not compensate for misidentified source material. Both should be recorded instead of compressed into one confidence label.

Build a two-axis assessment: one field records anatomical or taxonomic confidence, and another records measurement quality and model applicability. Students should discover that the strongest numerical result occurs only when both are justified. A clean number from a doubtful bone can be more misleading than a broad but correctly qualified identification.

8. Read the 2024 freshwater fish atlas critically

Davis and colleagues’ open-access photographic atlas documents skeletal elements from common European freshwater and migratory fishes and explains identification challenges among similar taxa. Its photographs can help learners become familiar with basic element shapes and show what good osteological reference reporting looks like. The atlas is not a replacement for every relevant species or growth stage: researchers should not assume a fish from another continent belongs to the closest European reference image.

Ask students to choose one atlas entry and record what anatomical side, view and preservation the image shows. Then present an unknown fossil from outside the atlas’s geographical coverage. The appropriate response is a broader taxonomic category or an expanded reference collection, not unwarranted importation of a European species name.

9. Use the sturgeon osteological guide as a model

Thieren, Wouters and Van Neer examined 64 sea sturgeon reference specimens across 13 natural history collections to support identification of archaeological sturgeon remains from western Europe. Their guide included pectoral-girdle elements such as cleithrum and supracleithrum alongside cranial bones, fin supports and scutes. It also offered osteometric relationships for selected elements. The importance of the guide lies in its species-specific comparative coverage and recognition that some traits and size classes are more diagnostic than others.

Students should inspect why so many reference specimens and collections were needed. Taxonomic discrimination between sturgeon forms may depend on actual surfaces, size and complete morphological patterns. They should not apply a sturgeon bone-length regression to seabream, catfish or characiform fishes, and they should not assume every detached cleithrum has the same diagnostic quality.

10. Study the 1988 diagnostic fish-bone experiment

Hansel and colleagues studied cleithra, dentaries, opercles and pharyngeal arches as relatively persistent fish elements after ingestion by predators. Their sample encompassed 24 prey fish species, and they found that some close relatives were difficult to distinguish consistently. For sufficiently sampled species they developed relationships between bone length and original fish fork length. This is useful for archaeology because it demonstrates both the potential of diagnostic hard parts and the conditional nature of identification and size back-calculation.

Ask learners what the actual study measured and what its validation limits are. The paper examined prey-fish bones in a specific taphonomic pathway. A bone surviving digestion is not necessarily an unmodified specimen, and an animal-prey length regression does not become a universal archaeological fish-size rule. The method should be adapted with matching taxa and preservation.

11. Differentiate survival through digestion from survival in soil

Predator ingestion can dissolve, break or abrade selected fish skeletal elements, while burial chemistry, trampling and excavation cause different damage. A robust cleithrum may survive one pathway better than delicate fin rays or cranial bones, creating recovery bias. The ratio of cleithra to other elements in a deposit can therefore reflect taphonomy as much as fishing strategy. Predators can also concentrate fish parts in one archaeological context without human involvement.

Have students map a catchment containing fish predators, human food processing and a quiet sediment basin. Which routes can deliver cleithra to a layer, and how might their surface damage differ? The correct response is to request contextual evidence, not to assume that every fish girdle bone in a settlement is table refuse.

12. The Late Neolithic Guye study and its lesson

Yu and Cui’s 2022 Guye site study in the Pearl River Delta developed modern skeletal measurement relationships for Chinese sea bass, Lateolabrax maculatus, using 20 reference fishes. The archaeological assemblage included cleithra but their exact measurement requirements and fragmentation differed from other elements. The authors chose a robust dentary measurement for a body-length reconstruction partly because it was more frequently preserved and could be measured consistently. Their decision illustrates an essential principle: a mathematically good cleithrum relation may not be the best archaeological estimator when too few intact specimens survive.

Students should identify which variables were originally measured on modern fish, which cleithrum dimensions were defined and why the archaeological workflow selected another skeletal element. A good interpretation reports bone survival, sample size and measurement feasibility alongside statistical fit. A regression never rescues an absent or fractured landmark.

13. Know the distinction between standard, fork and total length

Fish body length can be measured from snout to the base of the tail fin, to the tail fork, or to the far end of the tail, depending on the species and research convention. These are standard length, fork length and total length, respectively. The distinction matters when cleithrum dimensions are fitted against a specified target. A model predicting standard length in millimetres cannot be labelled total length in centimetres without an appropriate biological conversion.

Give learners one diagram with all three landmarks and ask them to identify which definition their reference paper used. Students should write the unit and length type beside every equation and graph. This prevents a deceptively simple error when comparing modern fisheries data with archaeology.

14. Measure the right cleithrum dimension

Possible measurements include maximum cleithrum length, selected process distances, depth or height at a defined landmark, depending on the specific reference. The Guye study defined two cleithrum variables rather than an informal overall bone size. A fracture can remove precisely the process required for one model while leaving another dimension intact. Measuring a convenient remaining edge and substituting it for the defined reference variable changes the model’s biological meaning.

Give learners a real modern reference figure with two labelled measurement lines and a hypothetical fossil missing one endpoint. Their task is to choose which, if either, measurement is genuinely available. They should not invent the absent landmark or place the caliper where the bone ‘would have ended’. A correct model application depends on the exact operational definition.

15. Fit a modern reference model and retain uncertainty

Species-specific allometry can relate a bone dimension to known fish length through linear or power equations. The choice depends on actual biological data and appropriate model assessment. Useful reporting includes the number of reference fish, their length span, coefficient estimates, fit diagnostics and predictive uncertainty. A high coefficient of determination describes fit within the training data; it does not guarantee a narrow prediction interval for every archaeological specimen.

Ask students to evaluate a hypothetical regression trained on twenty fish spanning a defined size range. If the ancient bone lies near the edge of that span, or beyond it, they should flag extrapolation. Before converting a number to a historical fish size, a report must identify what was observed and how much uncertainty the prediction adds.

16. Read the Maya catfish study without exporting its formula

An archaeological study of hardhead catfish, Ariopsis felis, used measurements from 36 modern individuals to build size-estimation models for bones recovered in two Maya sites, Xcambó and Mayapán. Its selected predictors included cleithrum height alongside other diagnostic bones. The paper illustrates an application to settlement-level questions about fish acquisition, but the coefficients belong to that catfish and its reference definitions. Reusing them for another fish would be scientifically indefensible.

Students should locate the target length definition and the specific measured cleithrum feature in the cited research before discussing its results. They should also ask whether the archaeological cleithra were complete enough for that dimension and whether the model range covered the fossils. A species-specific validation cannot be replaced with a generic statement that bigger bones always mean bigger fish.

17. Build a strictly fictional Harbour Reach measurement

For arithmetic practice, imagine one imaginary fish taxon with a made-up calibration: predicted standard length in centimetres equals 9 plus 5 times a particular cleithrum measurement in millimetres. This formula is invented for teaching and not valid for any real species. A fictional complete cleithrum measuring 6.0 mm produces 9 + 5(6.0) = 39 cm; one at 7.5 mm produces 46.5 cm. These are model outputs, not historical fish measurements.

Students must label both results explicitly as toy predictions. They should explain which assumption is missing if the archaeological element is only a fragment, if its species is unknown or if the measurement axis differs from the one defined in the imaginary model. The purpose is to practise dimensions and model validity rather than fabricate a useful fish-size equation.

18. Test measurement error at a broken endpoint

Suppose a fictional cleithrum’s true defined landmark was lost and two readers select surrogate endpoints, obtaining 6.0 and 6.5 mm. Under the invented arithmetic rule, the predicted lengths differ by 2.5 cm. This visible sensitivity does not quantify real biological uncertainty, but it demonstrates why landmark consistency matters even when the measuring device reads to high precision. A fractured specimen may introduce more uncertainty than the instrument’s stated error.

Ask students to retain both proposed measurements as observations of an incomplete bone and withhold a normal regression result if the model requires the lost endpoint. Reporting the sensitivity is more honest than arbitrarily averaging incompatible landmarks.

Harbour Reach: a made-up length-equation exercise

19. Distinguish cleithrum fragments from fish individuals

A fish has paired pectoral-girdle bones and one cleithrum can break into several pieces. A raw tally of identified cleithrum fragments is therefore not a count of fish. Left-right duplication can sometimes constrain minimum numbers of individuals within a closed context when the pieces are secure and cannot be refitted, but damaged archaeological finds often lack that certainty. Recording fragment condition and possible refits is part of abundance analysis.

Students should compare a bag of ten fragments with one containing three confidently identified left cleithra of the same position and taxon. The first set does not necessarily imply ten fish. The second may support a minimum of three in the defined context under appropriate identification rules. The counting unit and depositional grouping need to be written beside the number.

20. Introduce a fictional sediment-mass comparison

In a second Harbour Reach exercise, Unit East yields 54 confidently classified cleithrum fragments from 1.8 kg of processed dry sediment. Unit West yields 72 from 4.8 kg. The observed rates are 54 / 1.8 = 30 fragments per kilogram and 72 / 4.8 = 15 fragments per kilogram. West has more raw fragments yet a lower concentration under the invented comparable recovery protocol. These are fictitious numbers, not evidence from any historical fishery.

Have learners plot raw fragment totals and per-kilogram rates on separate labelled axes. They should identify which conclusion each plot can support and why neither measures individual fish or annual catches. This is the most useful mathematical habit in zooarchaeology: the denominator belongs to the claim.

21. Consider screening, preservation and body-part bias

The size and robustness of cleithra affect whether they survive and are recovered. A coarse sieve can miss small fish elements, and sorting intensity can differ between excavation projects. Cleithra may be overrepresented relative to some fragile bones in acidic, disturbed or predator-processed deposits. Different rates per sediment mass may therefore reflect methodology and taphonomy before they reflect ancient population or technology.

Present a modern training assemblage screened twice at different mesh sizes. Students should predict which skeletal pieces become newly visible and which identifications may improve. Then ask whether an apparent shift toward larger fish in a coarse-screened historical sample would remain credible. A strong answer asks for compatible field recovery rather than relying solely on raw bone totals.

22. Trace natural death, predator feeding and human food waste

Cleithra can enter deposits from fish dying naturally, from predators consuming them, from butchery and cooking, from traded fish products or from later flood transport. The same gross element may appear in several of those settings. Surface damage, refits, anatomical representation, associated hearth materials and site stratigraphy help discriminate pathways. No single cleithrum is definitive proof of a meal.

Ask students to construct three formation histories for a charred cleithrum found near a ditch. It could have been food refuse burned in a hearth, discarded material burned later, or bone deposited through water transport from another source. They propose one independent observation to help distinguish each account. Archaeological interpretation gains strength by testing alternatives rather than naming a preferred story.

Harbour Reach: a made-up sediment denominator

23. Recognise imported fish and market movement

A cleithrum from a marine taxon at an inland settlement could reflect transport of whole or processed fish rather than a lost marine shoreline. A fish may have lived and died in one place, been traded elsewhere and finally discarded at the excavation site. Cleithrum anatomy may support identification but cannot alone reconstruct the route. The history of a bone contains more possible stages than the simple label ‘local fishing’.

Students draw a map linking coastal catches, a drying area, inland markets and household refuse. They should locate where the taxonomic ecology applies and where the archaeological deposition actually occurred. A correct scientific account separates biological habitat from human distribution networks.

24. Avoid mistaking the size distribution for fishing gear

Reconstructed fish lengths may help compare capture selectivity or changing resource use under suitable archaeological context. Yet changes can also result from prey availability, imported products, body-size-dependent bone survival and recovery techniques. A collection dominated by larger cleithra is not automatic proof of larger hooks or more sophisticated nets. Causal historical claims need fishing tools, environment, comparable recovery and meaningful dating.

Set two hypothetical assemblages with identical fish species but different predicted size ranges. The class should propose alternative fishing grounds, trade selection and preservation pathways before declaring a technical change. A strong conclusion may remain a pattern of reconstructed sizes plus a testable equipment hypothesis.

25. Chronology is not built into the pectoral girdle

A cleithrum does not carry a calendar date merely because it is diagnostic. Archaeological age must come from the sediment, associated datable material or appropriate independent techniques, each with uncertainty. Fish parts can also be transported and redeposited from earlier contexts into later ones. A size change in successive deposits cannot be assigned to one exact historic event without sufficient temporal resolution.

Present a fictional flood lens and two occupation layers with overlapping age ranges. Ask whether a cleithrum in the flood sediment belongs to the original source habitat or the final buried event. Students should distinguish source age, fish capture, discard, transport and burial rather than compressing them into one date.

26. Use a marine osteology manual responsibly

Marine Fish Osteology: A Guide for Archaeologists and the Archaeological Fish Resource both provide comparative illustrations and descriptive starting points for identifying cranial and pectoral-girdle elements. Their geographic and taxonomic coverage is broad but not exhaustive. Using a manual responsibly means recording the actual anatomical characters that match and the taxa it cannot exclude, not merely finding a roughly similar photograph.

Have students cite a labelled modern bone reference and write which features were compared, then name at least one alternative species in the same habitat that also needs consideration. A well-maintained reference library should grow as new collections and revised taxonomies become available.

27. Document an auditable specimen and data trail

A publishable archaeological report should include unique specimen ID, site context, anatomical element and side, completeness, diagnostic landmarks, photographs with scale, measurement definitions, modern references and any fitted equation with prediction limits. Counts should distinguish physical fragments, reconstructed elements and minimum individuals. A separate field should record the proposed cultural interpretation and supporting evidence.

Give one group a bare spreadsheet column labelled ‘cleithrum length’. A second group must discover which bone, landmark and length unit the values refer to. If it cannot reproduce the calculation, the dataset needs correction before publication. Archiving is not optional paperwork; it is the mechanism by which another researcher can verify a historical inference.

28. Respect destructive sampling and collection stewardship

Fish bones may belong to protected archaeological collections. Cutting, cleaning, collagen analysis or destructive testing can remove evidence and may require curatorial and heritage permissions. Most introductory anatomy and reasoning skills can be taught using licensed reference images and synthetic numbers without consuming irreplaceable material. Good research balances expected information gain against the object’s future scientific value.

Students prepare a one-page analysis request explaining which uncertainty a proposed sample would resolve, which non-destructive methods have been tried, whether the data can be compared with valid modern references and how remaining material will be preserved. A legitimate decision may be to avoid a test that cannot improve the claim.

29. Write a bounded conclusion that readers can use

For the fictional Harbour Reach measurements, the only secure arithmetic is that the toy complete cleithra generate toy length-model outputs when assumptions are met, and East has twice West’s recovered fragments per kilogram under the invented protocol. Neither result establishes a real fish population, specific fishing technology or named historical trade route. The next research question should target identification, model calibration, recovery differences or context depending on the greatest uncertainty.

The gold standard of teaching cleithrum analysis is a learner who recognises the anatomical element, preserves its diagnostic context, measures only valid landmarks, understands species-specific modelling and states exactly when an archaeological inference remains open.

Twenty-two independent archaeological decision cases

Each short case is a fictional teaching exercise focused on a different anatomical, measurement or historical inference problem. None of the case counts is a published discovery.

1. Curved bone misidentified as a rib

A pale narrow fragment resembles a rib but retains a cleithral articulation. Students compare whole pectoral girdle references and explain the feature that supports its correct skeletal category before choosing a species.

2. Scapula attached to the cleithrum

One recovered object contains portions of two joined bones. The catalogue mistakenly records the total as a single complete cleithrum measurement. Learners identify the boundary and decide which reference landmarks remain genuinely measurable.

3. Modern Ossubtus image as a fossil

A lesson labels the 2016 Ossubtus anatomical figure as a Neolithic excavation find. Students correct the title, publication, license, fish species and reference-only purpose. Scientific illustration must not become invented documentary evidence.

4. Right and left are not two species

Mirror-imaged cleithra from one taxon are sorted into different types because orientation was not recorded. Students verify side and views before doing a biodiversity comparison.

5. The sturgeon formula applied to carp

An analyst takes a sturgeon cleithrum regression and applies it to a common-carp fragment. Students explain why species-specific shape and growth invalidate the numerical transfer even when both bones are correctly identified.

6. The measured endpoint broke away

A fossil lacks the anterodorsal process required by the relevant cleithrum measurement. Students preserve the surviving dimension, mark the lost landmark and withhold the incompatible body-length prediction.

7. The high R-squared trap

A modern calibration reports a strong fit, but an archaeological bone lies beyond the reference size range. Students distinguish training correlation from validated prediction and request a suitable larger reference sample.

8. The 2018 predator assemblage

A cleithrum survives passage through a fish predator. The instructor calls it definitive proof of human fishing. Students consider predator taphonomy, anatomical survival and context before attributing human behaviour.

9. The Guye opercle comparison

At Guye, some opercles were abundant but too fragmented for desired measurements. Students explain why a less frequent but more measurable diagnostic element might be the better model input, rather than choosing bones by total count.

10. The toy thirty-nine-centimetre prediction

An invented cleithrum measurement of 6.0 mm is entered into a teaching equation giving 39 cm. Learners check units, target length and the fact that no real fish has been calibrated by this toy formula.

11. The substitute landmark error

A broken cleithrum receives a guessed remaining length of 6.5 mm instead of 6.0 mm. The toy model shifts by 2.5 cm. Students show why the correct response may be to withhold the estimate rather than average the two guesses.

12. The three-left-cleithra MNI case

Three confirmed left cleithra of the same taxon occur within one closed context. Students consider whether these support at least three individuals, then contrast ten unspecified fragments that may derive from far fewer fish.

13. The East-West fragment reversal

Fictional East contains 54 fragments in 1.8 kg and West 72 in 4.8 kg. Learners calculate 30 versus 15 objects per kg and explain why more raw objects do not mean more fish.

14. A coarse-screened size profile

Large cleithra dominate one site, which used coarse sieving. Students assess missing small-fish remains before claiming gear selection or ecosystem change.

15. An inland seabream bone

A marine seabream cleithrum appears in an inland town. The class maps possible imported fish, secondary refuse and depositional pathways rather than proposing the town once sat on the coast.

16. Human butchery or later burning

One cleithrum fragment is blackened, with no associated hearth context. Students distinguish cooking, secondary burning and natural fire, then propose the independent marks required to support human food preparation.

17. A wrongly named length metric

One article predicts fork length while another describes standard length. Students identify the anatomical landmarks and explain why values cannot be compared as one measure without justified conversion.

18. A mislabelled taxonomic photo

A comparative atlas image is of whiting, but students present it as cod. They check the species caption and diagnostic alternatives before describing an archaeological specimen.

19. The fracture-made false species

Breakage removes a species-diagnostic projection, making one cleithrum resemble another. Students preserve a broader classification and state what would need to survive for species-level confidence.

20. The unrecorded excavation mass

Two sites have cleithrum counts but different sampled areas and unknown sediment masses. Students explain why comparing absolute totals is a limited descriptive exercise until recovery denominators are supplied.

21. The complete fisheries story without dates

A report describes technological progress from two deposits with overlapping chronologies. Students separate the measured skeletal evidence from the unsupported temporal and causal explanation.

22. The rare specimen ethics gate

A curator offers a unique cleithrum for destructive collagen testing. Learners decide whether a reference photograph or non-destructive imaging would answer the question first and prepare a permission-based plan.

A three-session teaching plan

• Session 1 — anatomy and reference comparison: identify cleithrum, scapula and coracoid on genuine figures; recognise sides, orientations, attachment surfaces and damaged landmarks.
• Session 2 — measurement and quantitative reasoning: review modern species-specific length regressions, perform the fictional Harbour Reach examples, and distinguish fragments, original bones and minimum individuals.
• Session 3 — archaeology and scientific judgement: audit sieving, predator digestion, burial chemistry, trade, body-size selection, historical chronology and ethical specimen use.
• Assessment: submit labelled photographs with provenance, taxonomic confidence, defined linear measurements, explicit denominators, two formation histories, and a referenced evidence-limited conclusion.

Evidence-grade assessment rubric

Frequently asked questions

Primary research, image credit and related eduKate Gold Standard chapters

• Yu and Cui (2022): Late Neolithic Guye Chinese sea bass body-size and fishing analysis
• Hansel et al. (1988): diagnostic fish bones, survival after predation and length regressions, USGS
• Thieren, Wouters and Van Neer (2015): sturgeon bone identification and cleithrum references
• Davis et al. (2024): photographic atlas of European freshwater and migratory fish remains
• Archaeological hardhead-catfish bone-size regression from Maya Xcambó and Mayapán
• Archaeological Fish Resource, University of Nottingham: photographic cleithrum references
• Gilthead seabream cleithrum, lateral view, Archaeological Fish Resource
• Marine Fish Osteology, Simon Fraser University Archaeology Press
• Pectoral girdle anatomy of Ossubtus xinguense, Andrade et al. 2016
• Wikimedia Commons original pectoral girdle figure and CC BY 4.0 license
• Teaching Archaeological Fish Vertebra Analysis
• Teaching Archaeological Fish Pharyngeal Tooth Analysis
• Teaching Archaeological Fish Scale Analysis
• Teaching Zooarchaeology
• The Gold Standard master hub

The gold standard of teaching archaeological cleithrum analysis is a learner who can locate the bone, record what survives, choose species-appropriate comparisons and explain why identification confidence, measurable landmarks, archaeological recovery and historical inference each need separate evidence. A precise but unjustified historical story is weaker than a clear observation another researcher can reproduce.