World Congress of Malacology Antwerp ... - Unitas Malacologica

can lead to erroneous beta taxonomy. Supposedly widely distributed species can be shown to
represent discrete species. Approximately 89 species remain to be named, most from the Indo-
Malayan Archipelago and New Zealand. Half of all lots and specimens are from the Indo-Pacific,
while sampling effort declines exponentially to 1000 m; thereafter the decline is much steeper. The
top nine of fifty collections assessed contain approximately 83% of all specimens and lots.
Recognition and verification of discrete species requires SEM, but in most cases identification of
established species can be done with a stereomicroscope. Advances in SEM technology (variable
pressure, environmental) allow type specimens to be imaged without coating. Automontage z-stack
integration does not work well for 1 mm white shells; compound microscopes do not adequately
resolve some necessary fine structure. Some type specimens have crumbled to dust due to
inappropriate storage conditions. A significant problem is the uncertain location and/or existence of
types. Restrictive loan requirements of some countries (Brazil) make de facto impossible to include
material from that area.
The evolution of small body size in Vetigastropoda
Geiger, Daniel L. 1 ; Thacker, Christine E. 2
1. Santa Barbara Museum of Natural History – Invertebrate Zoology, 2559 Puesta del Sol Road,
Santa Barbara, CA 93105, USA,
Email: geiger@vetigastropoda.com
2. Natural History Museum of Los Angeles County – Ichthyology Section, 900 Exposition Blvd., Los
Angeles, CA 90007, USA,
Email: thacker@nhm.org
Vetigastropoda includes a variety of lineages ranging in size from 0.6 to 300 mm, and inhabiting
depths of 0 to 6000 m. We use molecular phylogenetics, doubling the taxon sampling of our previous
40-taxon study of Vetigastropoda (Geiger & Thacker, 2005), to investigate the evolution of size and
ecology in the group. We assembled a matrix of more than 2600 base pairs, of which approximately
1000 positions were parsimony informative, composed of Histone 3, COI, and 18S rRNA. The
expanded data matrix includes several new and interesting lineages such as two skeneids, one
seguenziid, Gorgolepsis, Temnocinclis, Incisura, Sinezona and Sukashitrochus. We emphasize the
need of voucher specimens of small species, which usually harbor taxonomic uncertainty, and
illustrate how to process minute species to gain the maximum information from single specimens
(DNA, shell, radula). We apply continuous character state reconstruction to address size change and
vertical colonization of the ocean in Vetigastropoda; both variables exhibit changes over more than
three orders of magnitude. Three dimensional reconstruction with Amira 4.1 of the gonad of a
scissurellid is used to explain and predict the smallest size in Vetigastropoda, which agrees with the
smallest known Vetigastropoda.
Freshwater Hydrobiidae of Morocco (Mollusca: Gastropoda):
Inventory and preliminary red list at regional level
Ghamizi, Mohamed
University Cadi Ayad, Muséum d’Histoire Natrurelle de Marrakech, Faculté des Sciences Semlalia,
BP 2390 Marrakech, Morocco,
Email: mghamizi@yahoo.fr
Forty five species belonging to fourteen hydrobiid genera are recorded from the continental
freshwater hydrosystems of Morocco. Six genera with twenty three species are strictly stygobiont and
collected from wells and hyporheic water of the streams. All are micro molluscs of the Hydrobiidae
family, including forms that are not yet formally described. The restricted area of their habitat, in the
groundwater systems with less possibilities of the dispersion, provides radiation in forms and high
endemism.
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