Morphometrics of Leptoplastides marianus (Hoek) (Trilobita, Olenidae) from the Tremadocian of Northwestern Argentina: taxonomic implications

MONTI, DANIELA S.

JOURNAL OF SYSTEMATIC PALAEONTOLOGY

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2017

1477-2019

Morphometrics can be an important tool insystematic studies providing taxonomists with strong elements of quantificationand formal hypotheses testing. In the present work, the contribution of thesetools was tested in a particular case of Northwestern Argentina.  Leptoplastidesmarianus (Hoek) was described on the basis of three deformed specimens fromwest Tarija, Bolivia. Following the conclusions of Harrington & Leanza, awide range of morphological variation is accepted for this species, and thename was applied to a large number of specimens from Northwestern Argentina.Based on specimens collected from the quebrada Moya (Huacalera, Jujuy), as wellas on material of the Harrington & Leanza collections in the University ofBuenos Aires, traditional morphometrics and geometric morphometrics methodswere used to evaluate the variation of the cranidial shape of L. marianus sensu Harrington &Leanza. The results allow the discrimination between two clearly differentmorphotypes and a discussion of their diagnosis. The name L. marianus should be restricted to the type specimens, given thedeformation of these materials. Also L. argentinensisand L. granulosus are both validnames for the two morphotypes recognized in the present paper. This workconstitutes a new example of the contribution of morphometrics to taxonomystudies.