World Congress of Malacology Antwerp ... - Unitas Malacologica

Evaluation of Neogastropoda of the Cretaceous, their taxonomy and relation based on the
morphology of their protoconch
Bandel, Klaus
Geologisch Paläontologisches Institut, University of Hamburg, Hamburg, Germany,
Email: klausbandel@yahoo.com
Traditionally many families of the Neogastropoda have been recognized among the fossil Late
Cretaceous species based on the morphology of their adult shell. The excellent preservation of shells
from the Campanian and Maastrichtian Ripley Formation of Mississippi and Tennessee allowed to
examine the protoconch of many of these taxa. In those species with shell of a planktotrophic veliger
a comparison with larvae of different families of modern Latrogastropoda provides no evidence for a
close relation between fossil and recent species. Obviously the closeness in morphology in adult shell
shape is due to convergence. The study also revealed that many of the taxa of the Ripley Formation
have no living counterparts but represent groups that have become extinct since, mostly connected to
the K/T event. The Pyrifusidae are united by the character of their protoconch and may represent
stem group Neogastropoda. They can be split into several subfamilies according to the shape of their
teleoconch. Their larval shells resembles in general shape and ornament some found among modern
species of Muricidae, Buccinidae or Conidae with little ornament and a median projection of the final
apertural outer lip, but they differ from the modern species by an indistinct apertural margin and
gradational transition of larval shell into the teleoconch. Some of the fossil taxa that have been
assumed to represent Neogastropoda are actually related to groups of the Neomesogastropoda. The
protoconch of Sarganidae and Moreidae is for example lowly coiled with rounded whorls and its
apertural margin not lobed, in contrast to the elongate conical protoconch of most modern
Neogastropoda as well as that of the Pyrifusidae. Similar shapes are found among modern Ficidae,
Capulidae or Eratiodae of the Neomesogastropoda. Cretaceous Paladmetidae have a larval shells that
connect in shape and ornament of rectangles to that of the Tonnoidea, but also to the problematic
fossil Colombellinidae. The early appearance of the Naticidae, Cypraeidae and Calyptraeidae during
the Late Cretaceous provides evidence of the origin of the Latrogastropoda and both their branches
Neogastropoda and Neomesogastropoda before Aptian/Albian time about 100 Million years ago. But
their representatives are conspicuously absent from all well known Early Cretaceous faunal
assemblages. Stem group Latrogastropoda have been suggested in the Maturifusidae of the Jurassic to
Cretaceous and the Purpurinidae of the Jurassic to Triassic, but their protoconch is not close to that of
the Ripley gastropods. The Pyrifusidae of the Late Cretaceous may have given rise to some of the
modern groups of the Neogastropoda such as Volutidae still during the Late Cretaceous, while many
of the taxa of the Neogastropoda appear within the Paleogene and their fossil species are usually
recognized by the characters of their protoconch.
Comparative anatomy of selected Philippine Cone snails (Neogastropoda)
Baoanan, Zenaida Gutay 1 , Cruz, Lourdes J. 2 ; Pagulayan, Roberto C. 3 ;
Lagunzad, Daniel A. 4
1. Faculty, Department of Biology, College of Science, University of the Philippines
Baguio, Baguio City and Ph.D. Candidate, Institute of Biology, College of Science,
University of the Philippines Diliman, Quezon City, Philippines,
Email: zbaoanan@yahoo.com
2. Marine Science Institute, College of Science, University of the Philippines
Diliman, Quezon City, Philippines,
Email: lulycruzj@yahoo.com
3. Angeles University Foundation, Angeles City, Pampanga, Philippines,
Email: roberto_pagulayan@yahoo.com
4. Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City,
Philippines,
Email: dalagunzad@yahoo.com
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