original description
Watson, R. B. (1897). On the marine Mollusca of Madeira; with descriptions of thirty-five new species, and an index-list of all the known sea-dwelling species of that island. <em>Journal of the Linnean Society of London, Zoology.</em> 26(19): 233-329, pl. 19-20., available online at http://www.biodiversitylibrary.org/page/31882661
page(s): 236-237; pl. 19 fig. 5, 5a [details]
additional source
Malaquias, M. A. (2004). The opisthobranch molluscs described by the Reverend Robert Boog Watson from the Madeira archipelago (Northeast Atlantic, Portugal). <em>Journal of Conchology.</em> 38(3): 231-240.
page(s): 238 [details] Available for editors [request]
additional source
Malaquias M.A.E., Ohnheiser L.T., Oskars T.R. & Willassen E. (2017 [Code-compliant e-publication published 2016]). Diversity and systematics of philinid snails (Gastropoda: Cephalaspidea) in West Africa with remarks on the biogeography of the region. <em>Zoological Journal of the Linnean Society.</em> 180(1): 1-35., available online at https://doi.org/10.1111/zoj.12478
note: listed as a possible synonym of P. intricata [details]
From editor or global species database
Type locality Ponta de São Lourenço and Santa Cruz, Madeira, and Porto Santo [details]