METHODS EMPLOYED IN THE MORPHOLOGICAL STUDY OF THE ANTARCTIC LIMPET NACELLA CONCINNA: NEW TECHNIQUE SHOWS BETTER RESULTS?

MARTÍNEZ JJ; DE ARANZAMENDI MC; CASTILLO S

Biocell

Sociedad de Biología de Córdoba

Año: 2018 vol. 42

METHODS EMPLOYEDIN THE MORPHOLOGICAL STUDY OF THE ANTARCTIC LIMPET NACELLA CONCINNA: NEW TECHNIQUE SHOWS BETTER RESULTS?Castillo S. 1, de Aranzamendi M.C.1 y Martínez J.J. 21 IDEA, CONICET-UNC, Córdoba, Argentina; 2INECOA, CONICET-UNJu, Jujuy, Argentina.e-mail: santiagocastillo55@gmail.com Nacella concinna is one of themost abundant macro-invertebrates of the Antarctic Peninsula, where it can befound from littoral to 100 meters deep. Two morphotypes have been describedbased on the shell morphology and the platform zone in which they inhabit. Thelittoral morphotype has a tall and globose shell, while the sublittoralmorphotype shell is flatter. Traditionally, linear measurements were used todifferentiate between individuals of both morphotypes. However, EllipticFourier Analysis (EFA) based on the contour of shells has shown interestingresults in this and other species. In this work, we evaluated the differencesbetween these two usually used morphometric methodologies. The maximum high,maximum length and maximum width were measured in littoral and sublittoral individuals;EFA was performed in lateral and dorsal views. The results obtained were similarbetween traditional morphometry and lateral EFA, even though the latter presentsa better resolution. Dorsal EFA does not provide much useful information todifferentiate between morphotypes. Although the use of traditional morphometryproved to be a reliable tool to differentiate the morphs of this species, thelateral EFA would be the most appropriate methodology for the study ofmorphological variation and the distinction of morphotypes. This is because lateralEFA evaluates the plane formed by the maximum axes of variation between morphs,allowing a better characterization of the shape changes.