Placostylus ambagiosus | |
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A shell of the subspecies Placostylus ambagiosus priscus | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Mollusca |
Class: | Gastropoda |
Subclass: | Heterobranchia |
Order: | Stylommatophora |
Family: | Bothriembryontidae |
Genus: | Placostylus |
Species: | P. ambagiosus
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Binomial name | |
Placostylus ambagiosus |
Placostylus ambagiosus is a species of flax snail (Māori: pūpū whakarongotaua[4]), a large air-breathing land snail, a terrestrial pulmonate gastropod mollusc in the family Bothriembryontidae.
This snail has a large (43–97 millimetres or 1.7–3.8 inches long)[5] shell, which is heavily calcified. The size of the adult shell is habitat dependent,[5] but the shell shape is not plastic.[4] Placostylus ambagiosus is highly valued by Te Aupōuri me Ngāti Kurī (the indigenous people of northern New Zealand) as a food source, musical instrument and in the past this snail provided alarm calls at night warning of approaching invaders.[6]
This land snail species occurs in New Zealand. It is restricted to a small fragmented area of Northland Region, including the Aupouri Peninsula and Motuopao Island.[7] In the past local Māori moved and propagated populations of Placostylus ambagiosus,[8][9] so today at least three extant populations are found on old pā sites (fortified settlements), along with other species that were cultivated such as karaka (Corynocarpus laevigatus) and harakeke (Phormium tenax).[10][11]
This snail feeds at night on fallen leaves on the forest floor.[5] A favorite plant species is hangehange (Geniostoma ligustrifolium). Placostylus ambagiosus needs year round moisture provided by deep leaf-litter. Eggs are laid in clutches (average 43 eggs) in the shallow hollows in the soil.[5] The species is slow-growing with a lifespan of 10–22 years and strong site fidelity[12] The same individual snail has been found under the same food plant for 12 years.[5] The species is endangered due to predation from rats[13] and birds,[14] habitat damage by pigs and horses and competition from introduced snails.[13]
Based on molecular phylogeny (mtDNA) and shell morphology research it was suggested in 2011 by Buckley et al.[15] that there are no subspecies of Placostylus ambagiosus.[15] However, in the past, what were thought to be eight extant subspecies and a number of undescribed but distinct populations, were named;[7] six of these "subspecies" are now extinct[16] (marked with a †); conservation statuses were given according to the New Zealand Threat Classification System for the extant taxa: "nationally critical" and "nationally endangered":[17] At least five subspecies of Placostylus ambagiosus can be recognized using shell shape (not size or location) of individuals snails suggesting these represented distinct populations that require protection.[4]