Tucetona wairarapaensis is an extinct species of bivalve, a marine gastropod in the family Glycymerididae. Fossils of the species date to the early Pleistocene strata of the Castlepoint Formation at Castlepoint, Wairarapa, New Zealand. The species may have descended from the Miocene (Waiauan stage) species T. monsadusta, and be ancestral to modern-day T. laticostata.
Description
In the original description, Powell described the species as follows:
The holotype of the species has a height of , a length of and a thickness of for a single valve. It can be distinguished from T. monsadusta due to having more numerous radial ribs and fewer ligamental chevrons, and from T. laticostata by being more oval and having a more convex shell, as well as by its narrowly arched massive hinge-plate.
Taxonomy
The species was first described by A.W.B. Powell in 1938, using the name Glycymeris (Grandaxinea) wairarapaensis. Due to morphological similarities, Powell believed that the species descended from the Miocene (Waiauan stage) species T. monsadusta, and is ancestral to modern-day T. laticostata. The holotype was collected by Powell from the Lighthouse Reef, Castlepoint, Wairarapa, New Zealand at an unknown date prior to 1924, and is held by the Auckland War Memorial Museum.
Distribution
This extinct marine species occurs in early Pleistocene (Waipipian, Nukumaruan and Castlecliffian stage) strata of New Zealand dating to between c. 3.70 and 1.63 million years ago, Fossils have predominantly been found in the Castlepoint Formation at Castlepoint, Wairarapa, New Zealand, with one known from Taranaki.
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