Mastigodiaptomus Light, 1939

Elías-Gutiérrez, Manuel, Jerónimo, Fernando Martínez, Ivanova, Natalia V., Valdez-Moreno, Martha & Hebert, Paul D. N., 2008, DNA barcodes for Cladocera and Copepoda from Mexico and Guatemala, highlights and new discoveries, Zootaxa 1839 (1), pp. 1-42 : 13

Genus Mastigodiaptomus Light, 1939

Three lineages of Mastigodiaptomus were found in a single small pond in the Yucatan. One of these lineages was Mastigodiaptomus reidae Suárez-Morales & Elías-Gutiérrez , described from a site near this locality (Suárez-Morales & Elías-Gutiérrez, 2000). The other two forms are closely related to this species, one lineage with 3% COI divergence also shows a differing shape of the male fifth thoracopod. The third lineage of Mastigodiaptomus seems to represent another undescribed species, with small but consistent morphological differences. This is the first report of three species of a single calanoid genus, similar in shape and size, coexisting in a single small habitat.

Another species within the same genus, Mastigodipatomus albuquerquensis (Herrick) , is one of the most morphologically distinctive species of freshwater copepods in the southern United States and Mexico (Suárez-Morales & Elías-Gutiérrez 2000). Any specimen with a butterfly-like sclerotization of the male second basipod of the right fifth leg has traditionally been assigned to this species, but barcoding confirmed earlier suspicions of overlooked diversity. For example, Kiefer (1938) assigned the population in Patzcuaro Lake to a different subspecies, D. albuquerquensis patzcuarensis and Pearse (1904) described Diaptomus lehmeri from Mexico City, although it was later synonymized by Marsh (1907) with D. albuquerquensis . Our data suggest the occurrence of at least two (or even three) sibling species with disjunct distributions in Mexico ( Fig. 1.6 ). The first species, M. albuquerquensis , was only found in the northern semi-desert region while the second (and possibly third), M. cf. albuquerquensis ( lehmeri ?), was apparently restricted to the Central Plateau, in localities close to Patzcuaro Lake, suggesting that they could actually be M. lehmeri . On the other hand, due to its broad geographic range, Bowman (1986) suggested that M. albuquerquensis was the original form which dispersed phoretically to the Caribbean islands, giving rise to another species, Mastigodiaptomus nesus Bowman. Another barcode lineage, present near the Pacific coast was morphologically close to M. nesus , but some subtle variations were noticed. Cervantes-Martínez et al. (2005) reported size differences between M. nesus from the Yucatan and the Caribbean islands. Possibly these could be different species whose status can be clarified by barcoding and other molecular analyses. Although the ID tree is not considered a hypothesis on evolutionary history, some clues about the relationships (especially on branching patterns at the tips of the tree) can be inferred from it, and M. cf. nesus appears close to M. albuquerquensis .

Figures

FIGURE 1. 1.1 Sampling localities for all taxa; 1.2 Distribution of C. rigaudi complex: ⊕ C. cf. rigaudi 1, ∧ C. cf. rigaudi 2, ′ C. cf. rigaudi 3; 1.3 Distribution of C. cf. dubia; 1.4 Moina micrura group: M. cf. micrura 1, M. cf. micrura 2, ® M. cf. micrura 3; 1.5 Arctodiaptomus dorsalis: ℜ A. cf. dorsalis, ρA. dorsalis, A. cf. dorsalis 1 from Lachua Lake, ′ A. cf. dorsalis 2; 1.6 Mastigodiaptomus albuquerquensis: ♦M. albuquerquensis, ⊕ M. cf. albuquerquensis.