Field guide · Inclusion review · 10 October 2026

Historical v11 checkpoint. Latest curated Expert reference →

Six names off the roster, two kept

PBDB supplies the baseline guess roster. Documented evidence may exclude unavailable informal names, nonindependent historical identities, or exceptionally dubious material. Scientific disagreement, missing facts or uncertain age alone do not justify a cut. These eight cases do not complete a nomenclatural audit of every genus.

1,302 selected guesses; 2 specific answer holds remain. The six cuts are excluded from both independent guesses and hidden answers. The 36-genus live sample is unchanged; no expanded answer is released.

Genus	Guess status	Basis
Dachongosaurus	exclude	unavailable informal name
Oshanosaurus	exclude	unavailable informal name
Damalasaurus	exclude	unavailable informal name
Microdontosaurus	exclude	unavailable informal name
Ponerosteus	exclude	dubious material
Xuanhuasaurus	exclude	undescribed historical identity
Qijianglong	retain	diagnosed genus with uncertain age
Zigongosaurus	retain	conflicting taxonomic treatments

Dachongosaurus · exclude

Explicit nomen nudum for Dachungosaurus, with Dachongosaurus alternative spelling. Revision states remains undescribed although an in-situ photograph was published. A photographed skeleton alone is not an independently diagnosed genus.

Hidden answer: excluded with guess identity.

Reconsideration/release condition: A qualifying formal taxonomic publication that establishes an available name with differentiating characters and appropriate type-species fixation, or a demonstrated later validation. Additional locality or faunal-list mentions alone are insufficient.

Evidence access and limits

Original Zhao 1985 account not obtained; nomenclatural revision read directly.
No later validation surfaced in the targeted search; this is not an exhaustive literature search.
No synonym or occurrence transfer inferred.

Olshevsky, G. 1991. A revision of the parainfraclass Archosauria Cope 1869, excluding advanced Crocodylia. Mesozoic Meanderings 2.
Own read of existing full original PDF extraction; relevant Xuanhuasaurus entry printed p159. Web retrieval blocked by file-size limit.

iczn13
Official current Article13 read. Differentiating description or reference/replacement-name route required; genus additionally requires type-species fixation.

Original PBDB identity ↗

Oshanosaurus · exclude

Explicit nomen nudum. Revision states remains undescribed and appears in a faunal list. No later formal validation found. Do not assume Eshanosaurus synonymy or automatically redirect.

Hidden answer: excluded with guess identity.

Evidence access and limits

Original Zhao 1985 account not obtained; nomenclatural revision read directly.
No later validation surfaced in the targeted search; this is not an exhaustive literature search.
No synonym or occurrence transfer inferred.

iczn13
Official current Article13 read. Differentiating description or reference/replacement-name route required; genus additionally requires type-species fixation.

Original PBDB identity ↗

Damalasaurus · exclude

Explicit nomen nudum. Historical magnus/laticostalis usages do not establish available independently diagnosed genus. Zhao1983 p302 mentions Damalosaurus only as evolutionary example. Geographic disambiguation does not repair nomenclatural availability.

Hidden answer: excluded with guess identity.

Evidence access and limits

Original Zhao 1985 account not obtained; nomenclatural revision read directly.
No later validation surfaced in the targeted search; this is not an exhaustive literature search.
No synonym or occurrence transfer inferred.

iczn13
Official current Article13 read. Differentiating description or reference/replacement-name route required; genus additionally requires type-species fixation.

Zhao1983. Phylogeny and evolutionary stages of Dinosauria. APP28:295-306.
Original journal PDF read through web extraction; inspected pp302 and304.

Original PBDB identity ↗

Microdontosaurus · exclude

Explicit nomen nudum. Zhao1983 p304 provides only a brief evolutionary example. Geographic and Chaya locality data do not establish nomenclatural availability.

Hidden answer: excluded with guess identity.

Evidence access and limits

Original Zhao 1985 account not obtained; nomenclatural revision read directly.
No later validation surfaced in the targeted search; this is not an exhaustive literature search.
No synonym or occurrence transfer inferred.

iczn13
Official current Article13 read. Differentiating description or reference/replacement-name route required; genus additionally requires type-species fixation.

Zhao1983. Phylogeny and evolutionary stages of Dinosauria. APP28:295-306.
Original journal PDF read through web extraction; inspected pp302 and304.

Original PBDB identity ↗

Ponerosteus · exclude

Olshevsky 2000 naming-author statement calls the genus and species nomina dubia and doubtfully dinosaurian. A specimen which cannot securely establish even dinosaur affinity or an independently diagnosable genus is unsuitable as a separate playable genus.

Hidden answer: excluded with guess identity.

Reconsideration/release condition: Published modern redescription establishes dinosaur affinity and diagnostic identity from the type or securely associated material.

Evidence access and limits

Do not claim definitely non-dinosaurian.
Do not claim the formal 2000 checklist was read.
Historical locality and period evidence remain in the research record; they do not establish diagnostic identity.

Olshevsky, G. 2000. Dinosaur Genera List corrections #141. Dinosaur Mailing List, 10 May 2000. Contemporaneous explanation of the replacement name published in Mesozoic Meanderings 3.
Own read of full primary naming-author statement via web. Formal Mesozoic Meanderings 3 original not obtained.

Original PBDB identity ↗

Xuanhuasaurus · exclude

Zhao et al. 2006 p467 explicitly labels the earlier Xuanhuasaurus niei nomen dubium while stating no holotype, diagnosis or description was provided. Olshevsky 1991 p159 labels Xuanhuasaurus nomen nudum. An undescribed historical name for the material later formally described as Xuanhuaceratops; retained in the history, not counted as a separate playable genus.

Hidden answer: excluded with guess identity.

Reconsideration/release condition: Original or later formal evidence establishes Xuanhuasaurus as an independently available and diagnostic genus, rather than this historical undescribed label.

Evidence access and limits

Do not silently change the primary paper’s nomen dubium label to nomen nudum.
Do not claim original Zhao1985 was obtained.
Do not make a live alias or transfer PBDB fossils in this evidence report.
Printed p468 describes horizon as probably Late Jurassic and mentions earliest Cretaceous ages for upper Tuchengzi; verified name identity does not independently settle period approval.

Zhao, X., Cheng, Z., Xu, X. & Makovicky, P.J. 2006. A New Ceratopsian from the Upper Jurassic Houcheng Formation of Hebei, China. Acta Geologica Sinica 80(4):467–473.
Full original author-upload PDF downloaded. Printed p467 visually inspected and OCR read; printed p468 OCR read.

International Code of Zoological Nomenclature, Article 13. Names published after 1930.
Official primary rule retrieved through search; description/definition or other specified availability requirements.

Original PBDB identity ↗

Qijianglong · retain

Original description defines a specimen-based unique character combination including several autapomorphies. Two 2025 descriptions retain and compare Qijianglong independently. Its unresolved formation/age is a clue-certainty issue, not demonstrated taxonomic invalidity.

Hidden answer: hold.

Reconsideration/release condition: Direct specimen-specific type-quarry horizon/date evidence, or an approved uncertainty-aware period clue that cannot falsely eliminate a credible interpretation.

Evidence access and limits

No newly published specimen-specific remapping or date found. Formation alternatives must not become two occurrences. Retain hidden-answer hold until period clues can handle credible uncertainty; inclusion review alone does not approve release.

xing2015 · primary description/revision
Read holotype and diagnosis: QJGPM1001 preserves skull and partly articulated axial material, with four diagnostic features marked autapomorphies. The original horizon is Suining, Beidu/Qijiang, Chongqing.

wei2025 · primary description/revision
Compares Tongnanlong with Zigongosaurus fuxiensis ZDM00251 and CQMNHCV025011: scapular proximal plate proportions and oval coracoid. References8 and38 are Peng2005 and Hou1976. This is anatomical comparison and independent usage; it is not a modern revision demonstrating the coherence of original material.

Earlier four-case research and specimen evidence
Preserved scientific checkpoint; current inclusion decisions supersede six earlier retentions.

Original PBDB identity ↗

Zigongosaurus · retain

Taxonomic validity remains disputed, but it is not merely an undocumented name: the 2005 primary monograph publishes a diagnosis and the 2025 Tongnanlong description makes named specimen comparisons. These positive treatments make an unqualified truly-dubious cut insufficiently secure. PBDB retains the genus while its type-species opinion is nomen dubium.

Hidden answer: hold.

Reconsideration/release condition: A specimen-based modern revision/catalog concordance establishing diagnostic type material and justified referrals. Composite series alone does not establish unidentifiability; 2025 comparison alone does not remove current association doubts.

Evidence access and limits

Full Wang 2019 taxonomic argument remains unread; PBDB records its doubtful-species opinion.
Positive later comparisons do not establish coherence of original composite material.
No imposed synonym or fossil transfer.

peng2005 · primary description/revision
Primary monograph English synopsis publishes a genus/type-species diagnosis, rather than only listing the name. Existing resolution dossier inspected the synopsis and identifies CV02501 as a composite holotype. This turn initially fetched the monograph, but subsequent targeted reads hit a bot wall; full diagnosis cannot be independently re-read now.

Earlier four-case research and specimen evidence
Preserved scientific checkpoint; current inclusion decisions supersede six earlier retentions.

Original PBDB identity ↗

Does the revised roster still narrow fairly?

482 retained supported locality targets rechecked across 21,014 reaching guesses. None stays blind above five after informative navigation. These comparisons still use provisional source facts and the working evidence overlay; they do not approve absence, an Expert tree or a hidden answer.

What stays on record

All frozen identities and fossils remain preserved.
No fossils or ancestry are transferred.
Xuanhuaceratops 153948 remains selected; Xuanhuasaurus is not a second animal.
No live alias or expanded answer is activated.

Earlier screening pages reproduce their labelled v10 checkpoint. This inclusion review and the roster desk report the current v11 selection. The exclusions are individual decisions, not a blanket rule excluding every disputed genus.