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 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]
Hypothetical subspecies
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]
^ abcdeParrish, G. Richard; Stringer, Ian A. N.; Sherley, Greg H. (2014). "The biology of Placostylus ambagiosus (Pulmonata: Bulimulidae) in New Zealand: Part 1. Behaviour, habitat use, abundance, site fidelity, homing and the dimensions of eggs and snails". Molluscan Research. 34 (3): 139–154. doi:10.1080/13235818.2014.888980. ISSN1323-5818. S2CID85060133.
^Stringer, Ian Alexander Noel; Parrish, Glen Richard; Sherley, Gregory Howard (2018). "Homing, dispersal and mortality after translocation of long-lived land snails Placostylus ambagiosus and P. hongii (Gastropoda: Bothriembryontidae) in New Zealand". Molluscan Research. 38 (1): 56–76. doi:10.1080/13235818.2017.1323368. ISSN1323-5818. S2CID89729069.
^ abBuckley T. R., Stringer I., Gleeson D., Howitt R., Attanayake D., Parrish R., Sherley G. & Rohan M. (2011). "A revision of the New Zealand Placostylus land snails using mitochondrial DNA and shell morphometric analyses, with implications for conservation". New Zealand Journal of Zoology38(1): 55-81. doi:10.1080/03014223.2010.527997.
