Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Edificio de Posgrado, Planta baja (Costado sur de la Torre II de Humanidades), Circuito Interior Cd. Universitaria, Coyoacán 04510, Mexico City, Mexico.
*Correspondence author: E. Mail: sarma@servidor.unam.mx
1Laboratorio de Zoología Acuática, División de Investigación y Posgrado, Edificio UMF, Universidad Nacional Autónoma de México, Campus Iztacala, C.P. 54090, Tlalnepantla, Edo. de México, Mexico.
Changes in the morphometry (dorsal and ventral plates and posterior spine lengths of lorica) of Lecane stokesii were quantified with or without the presence of allelochemical asplanchnin from the predatory rotifer Asplanchnopus multiceps. As in many other species of Lecane, the dorsal plate of L. stokesii is wide, the ventral plate is long (total lorica length, excluding spines 130–138 μm) and there is a linear relation between the length and the width of lorica. Compared to the size of L. stokesii lorica cultured without asplanchnin, animals cultured in a medium with this allelochemical showed significant increase (up to 10%) in the size of lorica. The posterior spines of L. stokesii grew 25% longer, when cultured with asplanchnin than those cultured without asplanchnin. However, we did not observe significant changes in the anterior spine lengths of L. stokesii, when cultured with or without asplanchnin in the medium. The presence of two posterior spines of lorica appeared as a stable taxonomic character of L. stokesii that distinguished it from L. ohioensis or L. ludwigii.
Asplanchnidae, lecane, morphometry, rotifera, spine-induction
