Thyasira bartrumi

Thyasira bartrumi
Temporal range:
Holotype from Auckland War Memorial Museum
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Bivalvia
Order: Lucinida
Family: Thyasiridae
Genus: Thyasira
Species:
†T. bartrumi
Binomial name
†Thyasira bartrumi
Synonyms[1][2]
  • Thyasira (Prothyasira) bartrumi A. W. B. Powell, 1935
  • Thyasira (Thyasira) bartrumi (A. W. B. Powell, 1935)

Thyasira bartrumi is an extinct species of bivalve, a marine mollusc in the family Thyasiridae.[2] Fossils of the species date to early Miocene strata of the west coast of the Auckland Region, New Zealand.

Description

In the original description, Powell described the species as follows:

Shell of moderate size, thin, very oblique and inequilateral, equivalve and inflated. Beaks at about anterior seventh, small, directed forwards and incurved at tips. Anterior end short, with a large, deeply excavated lunule which extends from just below the beaks to the angle with the ventral margin. The greatly produced posterior end has two deep arcuate furrows bordering the dorsal slope, and a very broad but only slightly raised medial fold which runs from the beaks to behind the anterior fourth on the ventral margin. Surface smooth except for regular microscopic concentric lines of growth. Interior not accessible in any of the specimens.[3]

The holotype of the species measures 15 mm (0.59 in) in height and width, and has a diameter of 10.75 mm (0.423 in) when measuring both valves.[3] The species can be differentiated from T. marwicki and T. motutaraensis due to its more deeply excavated lunule, by not being bordered by a furrow, and its very oblique outline.[3]

Taxonomy

The species was first described by A. W. B. Powell in 1935 as Thyasira (Prothyasira) bartrumi.[3] Its currently accepted name is Thyasira bartrumi, without a subgenus.[4][2] The holotype was collected at an unknown date prior to 1935 from between Powell Bay and Bartrum Bay, approximately 2 km (1.2 mi) south of Muriwai, Auckland Region (then more commonly known as Motutara), and is held in the collections of Auckland War Memorial Museum.[5][1]

In 2020, palaeontologists Steffen Kiel, Yolanda Aguilar and Tomoki Kase suggested that the fossil species may belong to the genus Channelaxinus, due to morphological similarities.[6]

Distribution

This extinct marine species occurs in early Miocene strata of the Nihotupu Formation of New Zealand, on the west coast of the Waitākere Ranges of the Auckland Region, New Zealand.[5]

  • Opposite valve of holotype
  • Side view of holotype
  • Side view of holotype

References

  1. ^ a b "Thyasira bartrumi". Collections Online. Auckland War Memorial Museum. Retrieved 19 January 2026.
  2. ^ a b c Thyasira bartrumi (A. W. B. Powell, 1935) †. Retrieved through: World Register of Marine Species on 19 January 2026.
  3. ^ a b c d Powell, A. W. B. (1935). "Tertiary Mollusca from Motutara, West Coast, Auckland". Records of the Auckland Institute and Museum. 1: 327–340. ISSN 0067-0464. JSTOR 42905961. Wikidata Q58676576. This article incorporates text from this source, which is under a CC BY 4.0 license.
  4. ^ Maxwell, P.A. (2009). "Cenozoic Mollusca". In Gordon, D.P. (ed.). New Zealand Inventory of Biodiversity. Volume one. Kingdom Animalia: Radiata, Lophotrochozoa, Deuterostomia. Christchurch: Canterbury University Press. p. 236. ISBN 978-1-877257-72-8.
  5. ^ a b Blom, Wilma M. (2025). "Annotated Catalogue of Fossil and Extant Molluscan Types in the Auckland War Memorial Museum". Bulletin of the Auckland Museum. 22. doi:10.32912/BULLETIN/22. ISSN 1176-3213. OCLC 1550165130. Wikidata Q135397912.
  6. ^ Kiel, Steffen; Aguilar, Yolanda; Kase, Tomoki (2020). "Mollusks from Pliocene and Pleistocene seep deposits in Leyte, Philippines". Acta Palaeontologica Polonica. 65. doi:10.4202/APP.00756.2020. ISSN 0567-7920. Wikidata Q104623761.

Further reading

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