I am a graduate student (Master Degree), at the University of Sao Paulo
(USP/SP), Brazil, working on polychaete systematics, under the
supervision of Dra. A. Cecilia Z. Amaral, from University of Campinas
(UNICAMP/SP), Brazil. I have some questions about the eunicid family and I
really would be grateful for any contribution about this matter.
According to traditional genera identification keys, 'Marphysa',
'Lysidice', and 'Nematonereis' are mainly distinguishable based on
occipital antennae number. The genus 'Marphysa' possesses other relevant
features at a specific level as type and distribution of the compound setae
and branchiae, that allow identification.
In 1983, a new eunicid genus was erected, 'Lysibranchia' ('Lysibranchia
paucibranchiata' Cantone, 1983 type-species). This genus was described as
having three antennae, compound spiniger and falciger setae, and branchiae.
But, the same characters appear in 'Marphysa mauritanica' Gillet, 1990 and
'Marphysa unibranchiata' Knox & Cameron, 1970.
According to researches on 'Marphysa' larval development and growth, the
median occipital antenna appears first on very young specimens, followed by
the first lateral pair, and finally by the second lateral pair. The setae
change according to the stage, and the branchiae appear just in a latter
In this view, Parapar et. al., 1993 (Aportaciones a la taxonomia y
autoecologia de los anelidos de la Peninsula Iberica: poliquetos de la Ria
de Ferrol. Cah. Biol. Mar., 34) pointed out that 'L. paucibranchiata' and
'Marphysa mauritanica' specimens are juveniles of 'Marphysa bellii'and
'Marphysa sanguinea', respectively.
Considering the aspects mentioned above, I would like to know how to
discern 'Marphysa' juveniles from 'Lysidice' and 'Lysibranchia' species,
supposing that 'Lysibranchia' is a valid genus? Would be body length and
width and setiger number (informations sometimes lack) good indicators to
discern among them, too?
Anybody has some information about this matter?
Thank you in advance for your attention.
- Tatiana Menchini Steiner Depto. de Zoologia - IB UNICAMP - Barao Geraldo
13083-970 - Campinas, SP BRASIL FAX - 55 19 2893124
<tatims at unicamp.br>
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