INVESTIGADORES
CASTRO VAZQUEZ Alfredo Juan
artículos
Título:
The calcareous egg capsule of the Patagonian neogastropod Odontocymbiola magellanica: Behavioral, morphological, and mineralogical correlates
Autor/es:
BIGATTI, G.; GIRAUD-BILLOUD, M.G; VEGA, I.A.; PENCHASZADEH, P.E; ALFREDO JUAN CASTRO VAZQUEZ
Revista:
JOURNAL OF MOLLUSCAN STUDIES
Editorial:
OXFORD UNIV PRESS
Referencias:
Año: 2009 vol. 76 p. 279 - 288
ISSN:
0260-1230
Resumen:
<!-- /* Font Definitions */ @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-1610611985 1107304683 0 0 159 0;} @font-face {font-family:"Times New"; panose-1:0 0 0 0 0 0 0 0 0 0; mso-font-charset:0; mso-generic-font-family:auto; mso-font-format:other; mso-font-pitch:variable; mso-font-signature:3 0 0 0 1 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:none; font-size:10.0pt; font-family:"Times New"; mso-fareast-font-family:"Times New Roman"; mso-bidi-font-family:"Times New Roman"; mso-ansi-language:ES-TRAD; mso-fareast-language:ES; layout-grid-mode:line;} .MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-size:10.0pt; mso-ansi-font-size:10.0pt; mso-bidi-font-size:10.0pt;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Odontocymbiola magellanica is the only known South American volutid depositing calcareous egg capsules.  The spawn is moulded and fixed to flat or convex surfaces by the female’s ventral pedal gland, during an hours long process in which the female adopts a stereotyped posture while it appears non-reactive to most external stimuli. Microscopically, the different cells of the ventral pedal gland show features suggesting their participation in the secretion of both the organic matrix and the calcium component of the calcareous layer. The latter consists mainly of numerous spherulites that are packed together around cylindrical, membranous septated spaces which traverse the spherulitic layer and attach to the membranous layers surrounding the capsule cavity. These septated spaces should ensure permeability of the capsule wall, which is needed for embryonic gas exchange and excretion. Notably, the calcareous layer is made of high-magnesium calcite, a calcium carbonate polymorph in which Ca is partially substituted by Mg in the calcite lattice. Mg substitution is thought to confer a greater crack resistance to the Ca mineral, it is commonly found in many invertebrates, but apparently has not been reported before in molluscs. O. magellanica is a long lived species, heavily investing in its egg capsules, and is a vulnerable, though commercially exploitable snail whose interesting morphological, behavioural and ecophysiological features deserve future studies.