Triassic and Jurassic Rhynchonellacea (Brachiopoda) from New Zealand and New Caledonia.
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A systematic study of the Triassix and Jurassic rrhynchonellides of New Zealand and New Caledonia has led to the recognition in the area of four Pacific or cosmopolitan genera: Sakawairhynchia Tokuyama, 1957: Fissirhynchia Pearson. 1977: Timorhynchia Ager. 1968 and Furcirhynchia Buckman. 1818: and the proposal of twelve new genera. More than fifty species are recognised, all apparently endemic. All belong to the family Rhynchonellidae. and most to the subfamilies Cyclothyridinae and Tetrarhynchiinae. Cryptorhynchia kawhiana (Trechmann) probably represents a new genus within the Acanthothyridinae. While the rhynchonellides are dominantly endemic at the generic level there are affinities to western North America. China and Siberia.
Rhynchonellides are present in all the New Zealand Triassic and Jurassic stages. They are particularly abundant and diverse in the Etalian, Oretian, Arataura and Ururoan. and can be used to refine the biostratigraphy of those stages. They are a minor part of the Late Jurassic marine fauna. Significant changes in the rhychonellide fauna with extinctions and appearances of new taxa, occur at the Etalian-Kaihikuan, Kaihikuan-Oretian, Otapirian-Aratauran and Ururoan-Temaikan boundaries: changes between these boundaries are more gradual.
All Late Triassic and most Jurassic species of rhynchonellide recognised in New Caledonia are also present in New Zealand. The rhynchoneltides of the dominantly non-calcareous, clastic parts of the Torlesse Supergroup closely resemble those of the Murihiku Supergroup. In the calcareous Torlesse rocks of Marlborough, Canterbury and the southern North Island. Burmirhynchia warreni Campbell and Halorella ruahinensis Campbell indicate a Tethyan influence absent in other regions.
Ecologically. the rhynchonellides can be grouped into a "nearshore" assemblage dominated by the subfamily Cyclothyridinae, and a more diverse "offshore" assemblage dominated by Tetrarhynchiinae.
Rhynchonellides are present in all the New Zealand Triassic and Jurassic stages. They are particularly abundant and diverse in the Etalian, Oretian, Arataura and Ururoan. and can be used to refine the biostratigraphy of those stages. They are a minor part of the Late Jurassic marine fauna. Significant changes in the rhychonellide fauna with extinctions and appearances of new taxa, occur at the Etalian-Kaihikuan, Kaihikuan-Oretian, Otapirian-Aratauran and Ururoan-Temaikan boundaries: changes between these boundaries are more gradual.
All Late Triassic and most Jurassic species of rhynchonellide recognised in New Caledonia are also present in New Zealand. The rhynchoneltides of the dominantly non-calcareous, clastic parts of the Torlesse Supergroup closely resemble those of the Murihiku Supergroup. In the calcareous Torlesse rocks of Marlborough, Canterbury and the southern North Island. Burmirhynchia warreni Campbell and Halorella ruahinensis Campbell indicate a Tethyan influence absent in other regions.
Ecologically. the rhynchonellides can be grouped into a "nearshore" assemblage dominated by the subfamily Cyclothyridinae, and a more diverse "offshore" assemblage dominated by Tetrarhynchiinae.
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xv, 438p. :30cm
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1985MacFarlan
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MacFarlan, D.A.B., “Triassic and Jurassic Rhynchonellacea (Brachiopoda) from New Zealand and New Caledonia.,” Otago Geology Theses, accessed December 7, 2024, https://theses.otagogeology.org.nz/items/show/189.