World Congress of Malacology Antwerp ... - Unitas Malacologica

Unravelling a taxonomic tangle and a morphological mystery:
A molecular phylogeny of the Rapaninae (Neogastropoda: Muricidae)
Claremont, Martine 1 ; Reid, David G. 2 ; Williams, Suzanne T. 2
1. Natural History Museum, Cromwell Road, London, SW7 5BD, UK, and Imperial
College, London, South Kensington campus, London, SW7 2AZ, UK,
Email: m.claremont@nhm.ac.uk
2. Natural History Museum, Cromwell Road, London, SW7 5BD, UK,
Email: d.reid@nhm.ac.uk; s.williams@nhm.ac.uk
The Rapaninae are a large subfamily of taxonomically perplexing, carnivorous marine snails. This
perplexity arises, in part, from the prevalence of convergence within the rapanines and consequent
morphological similarity. Bayesian and parsimony analyses of one mitochondrial and one nuclear
gene in 15 species within the rapanines and an additional 20 species from across the Muricidae
disprove previous phylogenetic hypotheses based on morphological characters. At least five
monophyletic subfamilies are supported with the Muricidae: Rapaninae, Ocenebrinae, Ergalataxinae,
Muricinae and Muricopsinae. The only representative of the Trophoninae included in this study,
Trophon plicatus, falls within the Ergalataxinae, questioning the validity of the Trophoninae as a
subfamily. In contrast to morphological phylogenies, the Ergalataxinae are not contained within the
Rapaninae in any trees, nor is there any evidence to support the hypothesized sister relationship
between Rapaninae and Ocenebrinae. Relationships within the Rapaninae and Ergalataxinae are also
highly divergent from those hypothesized from morphological evidence, and two of the genera (Thais
and Morula) are polyphyletic.
Reproductive traits of Crepidula aculeata (Gastropoda: Calyptraeidae) from Argentina
Cledón, Maximiliano 1 ; Ocampo, Emiliano 1 ; Farias, Nahuel 2 ; Penchaszadeh, Pablo 3
1. Dpto. de Cs Marinas - Facultad de Cs. Exactas y Naturales - Universidad Nacional de Mar del
Plata - CONICET - Funes 3350 - Mar del Plata 7600 - Argentina,
Email: mcledon@mdp.edu.ar, eocampo@mdp.edu.ar
2. Dpto de Biología - Facultad de Cs. Exactas y Naturales - Universidad Nacional de Mar del Plata –
CONICET - Funes 3350 - Mar del Plata 7600 – Argentina,
Email:nfarias@mdp.edu.ar
3. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" - CONICET - Av. Angel Gallardo
490 - C1405DJR - Buenos Aires – Argentina,
Email: penchas@bg.fcen.uba.ar
C auleata reproductive traits for Argentina are presented here.Males present a conspicuous penis
when shell length (SL) is between 4.9 and 15.1mm. Sexchange can start at 8 mm in SL. Then penis
undergoes resorption as well as testis. Simultaneously female reproductive system develops. The
smallest brooding female found was 16.4 mm in SL. The reproductive season occurs in springsummer
but depends on the latitude. In Mar del Plata (38°02’22S, 57°31’38W) it extends from
September to April, while in San Antonio Oeste (40°43’38S, 64°55’57W) from end of October until
April. No latitudinal differences were found between broods of both latitudes. Broods contained 9 to
21 triangular egg capsules, which is more than in Venezuela. Egg capsules are 2.84 to 5.36 mm in
width. Egg diameter was 230 + 20 µm, which is the half of the diameter reported for Venezuelan C
aculeata. There were 217 to 664 embryos starting development synchronously, more than the double
than in the Venezuelan population. Between 6 and 21 reach juvenile size feeding from each other,
similar to Venezuelan population. The hatchlings were 850 to 1050 µm in SL, which is a similar size
to the reported in Venezuela. The number and diameter of eggs supports that the argentinean
population is in fact a different species than the Caribbean C aculeata. Results are compared with
other species of Crepidula with direct development show no coincidence.
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