Van Diemen Flax Snail (Maoristylus ambagiosus ssp. priscus)

The Van Diemen Flax snail was described in 1938 based on subfossil specimens.

This form is known from several disjunct populations: “Cape Maria van Diemen (Mainland) about three-quarters of a mile east of worthyi type locality in consolidated dunes (type); many former colonies on south and eastern slopes of Herangi, – 700 feet, down to Te Werahi Stream and Swamp; Twilight Beach between Cape Maria van Diemen and Scott’s Point …; one mile south of Te Paki Stream and one-quarter mile inland in consolidated dunes ….” [1]

Like most other now extinct populations, also this one died out at the end of the Pleistocene/beginning of the Holocene caused by natural reasons.

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The photo below is thought to show this form.

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syn. Placostylus ambagiosus ssp. priscus (Powell)

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References:

[1] A. W. B. Powell: On further colonies of Placostylus land snails from northernmost New Zealand. Records of the Auckland Institute and Museum 4(2): 134-140. 1951

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edited: 06.02.2024

Hinemoa Flax Snail (Maoristylus ambagiosus ssp. hinemoa)

The Hinemoa Flax snail was described in 1947 based on subfossil specimens.

This form was apparently restricted to Cape Maria van Diemen, the westernmost point of New Zealand’s North Island; however, the taxon’s author says: “Restricted to the Island.” [1], thus it appears that this form was probably restricted to the northernmost part of the cape, which is an island that is now joined to the rest of the area by drifting sand.

Again, this is very likely a case of natural extinction due to changes in climate at the end of the Pleistocene.

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syn. Placostylus ambagiosus ssp. hinemoa Powell

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References:

[1] A. W. B. Powell: On further colonies of Placostylus land snails from northernmost New Zealand. Records of the Auckland Institute and Museum 4(2): 134-140. 1951

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edited: 06.02.2024

Spirits Bay Flax Snail (Maoristylus ambagiosus ssp. spiritus)

This taxon was described in 1947 based on subfossil specimens that were recovered from loose dunes between the camp sites of Kapowairua and Pandora at the Spirits Bay in the far north of New Zealand’s North Island.

Like many other former populations of this snail species, also this one apparently disappeared at the Pleistocene/Holocene border due to natural causes.

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syn. Placostylus ambagiosus ssp. spiritus Powell

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References:

[1] A. W. B. Powell: On further colonies of Placostylus land snails from northernmost New Zealand. Records of the Auckland Institute and Museum 4(2): 134-140. 1951

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edited: 06.02.2024

Worthy’s Flax Snail (Maoristylus ambagiosus ssp. worthyi)

Worthy’s Flax Snail was described in 1947; it is known from subfossil remains only.

“Cape Maria van Diemen (Mainland), on north-eastern side of headland, formerly an island but now linked to the mainland by a tombolo of consolidated and drifting sand (type); on a small island, accessible by wading at low tide, half a mile south of type locality …; in loose sandy humus, with Austrosuccinea remains; on a former islet 3/4 mile south of type locality and just off the western escarpment of the “priscus block,” in coarse cemented shell sand.” [1]

Worthy’s Flax Snail is one of several flax snail populations separated from each other by geographical barriers that have developed into distinct forms over time; it disappeared sometimes during the Late Pleistocene/Early Holocene due to climatic changes.

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syn. Placostylus ambagiosus ssp. worthyi Powell

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References:

[1] A. W. B. Powell: On further colonies of Placostylus land snails from northernmost New Zealand. Records of the Auckland Institute and Museum 4(2): 134-140. 1951

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edited: 06.02.2024