Paleodiversity Of Philippine Conus (Gastropoda: Conidea)
As Viewed Under Ultraviolet Light

Tomoki Kase

Department of Geology, National Science Museum, Tokyo, Japan

Yolanda Maac-Aguilar

Petrolab, Mines and Geosciences Bureau, Quezon City

The distribution of color pigmentations (color patterns) on the surface of shells is an important character for species-level taxonomy in mollusks. These features are particularly important for species-level classifications of conid gastropods in tropical seas especially in shells of similar morphologies. Such color patterns usually disappear in fossilized shells due to diagenetic alteration of color pigments and recrystallization of the original shells. Ultraviolet –light (UV-light) photography is a well known method applied in order to retrieve and reconstruct the original color patterns in fossil mollusks, but this nonetheless has not been employed rigorously in previous taxonomic studies of fossil conids. Previous UV-light photography was simply done to irradiate UV-light in fossil shells that often yielded unsuccessful results. In this case, modified techniques are herein applied on late Miocene and Pliocene conids from various localities in the Philippines and Indonesia in order to verify biodiversities of this gastropod group in the fossil records of tropical Indo-western Pacific. The shells were immersed in strong bleaching solutions before photography and then, photographed images were processed using computer graphics. With these methods, beautiful color pattern images of more than 30 conid species were obtained which is comparably better than previous attempts made by earlier authors. Preliminary results of color pattern examinations as well as shell morphology analyses showed that only few Philippine late Miocene to Pliocene conids are identical with modern forms. Likewise, only few Late Neogene Philippine species matches with contemporary species from Indonesian strata. These observations contradict with present day Indo-western Pacific Conus distribution which is rather wide in circulation yet highly diversified. Conids had probably evolved rapidly during Late Neogene times, however, what processes and environmental factors are involved are some topics that will be explored in the future.