title: A new species ofMastigodiaptomusLight, 1939 from Mexico, with notes of species diversity of the genus (Copepoda, Calanoida, Diaptomidae).
abstract: A new species of the genusMastigodiaptomusLight, 1939, namedMastigodiaptomus cuneatussp. n.was found in a freshwater system in the City of Mazatlán, in the northern region of Mexico. Morphologically, the females of this new species are distinguishable from those of its congeners by the following combination of features: the right distal corner of the genital double-somite and second urosomite have a wedge-shaped projection, the fourth urosomite has no dorsal projection and its integument is smooth. The males are distinct by the following features: the right caudal ramus has a wedge-shaped structure at the disto-ventral inner corner; the basis of the right fifth leg has one triangular and one rounded projection at the distal and proximal margins, respectively, plus one hyaline membrane on the caudal surface close to the inner margin; the aculeus length is almost the width of the right second exopod (Exp2); and the frontal and caudal surfaces of the right Exp2 are smooth. Furthermore, the analysis of the COI gene ofMastigodiaptomus cuneatussp. n. has revealed thatMastigodiaptomus albuquerquensis(Herrick, 1895) is its nearest congener, with 18.64% of genetic distance. A key for the identification of the known species of the genus is provided.
authors.affiliation: Universidad de Quintana Roo (UQROO), Unidad Cozumel, Av. Andrés Quintana Roo s/n, 77600, Cozumel, Quintana Roo México.
authors.forename: Martha Angélica
authors.initials: MA
authors.lastname: Gutiérrez-Aguirre
authors.affiliation: Universidad de Quintana Roo (UQROO), Unidad Cozumel, Av. Andrés Quintana Roo s/n, 77600, Cozumel, Quintana Roo México.
authors.forename: Adrián
authors.initials: A
authors.lastname: Cervantes-Martínez
keywords: COI gene; Mexico; freshwater; morphology; taxonomy