| Basic info | Taxonomic history | Classification | Included Taxa |
| Morphology | Ecology and taphonomy | External Literature Search | Age range and collections |
Taxonomy
Xenocrania was named by Chen and Rong (2019). Its type is Palaeocyclus haimei.
It was assigned to Craniidae by Chen and Rong (2019).
It was assigned to Craniidae by Chen and Rong (2019).
Species
Synonymy list
| Year | Name and author |
|---|---|
| 2019 | Xenocrania Chen and Rong |
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If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| Chen and Rong 2019 | Dorsal valve calcareous, punctate, encrusting, asymmetrical; outline very variable; small (1.3–9.9 mm wide); low, moderate sub‐conical, sub‐central beak located about 15–35% of valve length from posterior margin (Fig. 5). Ornament of radial ribs and spines with various morphologies, three types recognized (Figs 5–6, 5–6): Type A: basically continuous radial ribs with undulations on ribs, appearing like many spines linked; Type B: tubular hollow spines, radially aligned, continuously linked one by one, protruding from margins of concentric lamellae, hollow spines extending anteriorly to be almost aligned parallel to or obliquely to shell surface; and Type C: minute and short, hollow, isolated spines, radially arranged. Concentric laminae mainly seen in the type B; interspaces smooth, somewhat flat, wider than distinct, elevated ribs or spines, without any striations. Dorsal muscle fields generally not well impressed; anterior adductor scars in front of umbo, elliptical, larger than posterior ones (Fig. 7). Limbus entirely absent. Punctae very fine, radially aligned. Host ribbing rarely impressed. No ventral valves seen, possibly not calcified. |
Measurements
No measurements are available
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| Source: o = order, c = class, p = phylum | |||||
| References: Williams et al. 1996, Aberhan et al. 2004 | |||||
Age range: Hirnantian or 445.20000 to 443.10000 Ma
Collections (2 total)
| Time interval | Ma | Country or state | Original ID and collection number |
|---|---|---|---|
| Hirnantian | Myanmar (Northern Shan) | X. haimei (202727) | |
| Hirnantian | China (Yunnan) | X. haimei (203556) |