科研之友
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摘要
A Late Triassic chimaeroid egg capsule from the South Island of New Zealand is described as Chimaerotheca reperepe, a new ichnospecies. The fossil egg capsule is preserved as a positive impression on a block of very fine sandstone from the Murihiku Terrane of the South Island, which is dated as Warepan or Otapirian in the local New Zealand stage system, equivalent to late Norian or Rhaetian internationally. The egg capsule impression is spindle-shaped and consists of a narrow flask-like central embryo chamber surrounded by a ribbed membrane, or collarette. Morphologically, the fossil is strikingly similar to egg capsules of the extant chimaeroid Callorhinchus, with which it shares several features in the context of a recent phylogenetic analysis of chondrichthyan egg capsules. The specimen represents the oldest formally described record of a chondrichthyan from New Zealand, and extends the southern Gondwanan fossil record of chimaeroids by approximately 100 million years. In terms of chimaeroid palaeobiology, this fossil occurrence provides clear evidence that Callorhinchus-like chimaeroids have employed a highly conserved reproductive mode throughout at least the last 200-plus million years of the group's history, and further demonstrates that Callorhinchus or a Callorhinchus-like chimaeroid was present by the Late Triassic along the eastern margin of Gondwana. [GRAPHICS]
- 出版日期2015-5-4
