Journal of The Malacological Society of London Molluscan Studies Journal of Molluscan Studies (2013) 79: 95–111. doi:10.1093/mollus/eys039 Advance Access publication date: 29 January 2013 OBSERVATIONS ON LAND-SNAIL SHELLS IN NEAR-ULTRAVIOLET, VISIBLE AND NEAR-INFRARED RADIATION Downloaded from https://academic.oup.com/mollus/article/79/2/95/1072615 by guest on 23 September 2021 ENRICO SAVAZZI1 AND TAKENORI SASAKI2 1School of Geosciences, Monash University, Building 28, Victoria 3800, Australia; and 2The University Museum, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan Correspondence: Enrico Savazzi, Hagelgra¨nd 8, 75646 Uppsala, Sweden; e-mail:
[email protected] (Received 18 March 2013; accepted 28 November 2012) ABSTRACT The shells of a broad range of land snails were digitally imaged in the near-ultraviolet (NUV), visible range (VIS) and near infrared (NIR). NIR images were recorded in both incident and trans- mitted illumination. In most cases, shell and periostracal pigmentation observed in the VIS was com- pletely translucent in the NIR, while its contrast was enhanced in the NUV. Exceptions to the above rule fit into four main categories. (1) Snails with green or tan shells or periostraca, presumably func- tional as camouflage among vegetation, were often highly absorbing in the NUV, thus matching the optical characteristics of green vegetation in this range. (2) Pigmented spiral stripes in the shells of several Camaenidae and Helicidae were adjacent to nonpigmented areas that display a heightened reflectivity and reduced translucence in the VIS and NIR. This enhanced the contrast of the colour pattern in the VIS, but appeared to lack functions in the NIR.