Martha Angélica Gutiérrez-Aguirre

FRESHWATER COPEPODA (CRUSTACEA) FROM THE CHIHUAHUAN DESERT WITH COMMENTS ON BIOGEOGRAPHY

Abstract The zooplankton fauna of freshwater systems of the Chihuahuan Desert was surveyed 2005–2008. Samples were obtained from habitats including natural lakes, ephemeral waters, springs, and reservoirs. Copepods were sorted and identified to species. Including previous surveys, a total of 38 species occur in the Chihuahuan Desert, the checklist includes 6 calanoids (1 Temoridae, 5 Diaptomidae), 24 cyclopoids (12 Eucyclopinae, 12 Cyclopinae), and 8 harpacticoids. These species were assigned to different biogeographic categories (i.e., cosmopolitan, Nearctic, Neotropical, potential endemics). Results indicated that the Chihuahuan Desert, a transitional biogeographic region in Mexico with both Nearctic and Neotropical influences, represents an interesting geographic and environmental realm characterized by a balanced mixture of elements from different origins and affinities. There is a relatively high proportion (23%) of species that probably are endemic.

An Example of How Barcodes Can Clarify Cryptic Species: The Case of the Calanoid Copepod Mastigodiaptomus albuquerquensis (Herrick)

Background The freshwater calanoid Mastigodiaptomus is a genus with high richness in the Americas and is composed of nine species, seven recorded in Mexico and four that are apparently endemic to small areas. Mastigodiaptomus albuquerquensis is a common, widely distributed species ranging from the southern USA to Central America. This species can be easily identified by a notable butterfly-like sclerotization on the basis of the right fifth leg of males. Nevertheless, morphological differences observed among populations throughout this species distributional range have led to the description of several related species or subspecies, such as M. albuquerquensis patzcuarensis from Lake Pátzcuaro in the Central Plateau of Mexico. Methods Genetic results based on barcodes, morphology based on scanning electron and light microscopy images, and morphometric analyses were used to describe cryptic species within the M. albuquerquensis complex. Results The morphological analyses coincided partially with the genetic markers, suggesting the existence of at least two sibling species: M. albuquerquensis s. str. and M. patzcuarensis. A third species was genetically separated but was morphologically indistinguishable from the M. patzcuarensis group. Conclusions Hidden diversity has been a major problem in establishing real patterns of species distribution and genetic acquisition from megadiverse hotspots such as Mexico, where the Nearctic and the Neotropical regions of the Americas meet. Barcodes can help taxonomists to reveal and formally name these new species. Here, we describe two of three potential species highlighted by the use of barcodes: M. albuquerquensis s. str. in the northern semi-desert and M. patzcuarensis on the Central Plateau at more than 2000 m above sea level.

The neotropical species of Mesocyclops (Copepoda, Cyclopoida): an upgraded identification key and comments on selected taxa

In this work we present an analysis of upgraded characters used in the taxonomy of cyclopine copepods to provide a new key for the identification of the members of the freshwater genus Mesocyclops recorded in the neotropical region. This analysis, which included revision of type and museum specimens, resulted also in the clarification of the taxonomical status of two nominal species not previously revised, M. varius Dussart, 1987 and M. venezolanus Dussart, 1987. These two species are recognized herein as junior synonyms of M. brasilianus Kiefer, 1933. Considering the addition of new records (introduced Afro‐Asian or Asian forms), the designation of M. araucanus Campos et al., 1974 to species rank, and the conflict of determining the taxonomical status of M. annulatus diversus, the number of taxa recognized in the region includes 20 species and one variety. A general morphological analysis of the Old and New World species allowed us to contrast and evaluate some of the differential characters of these two groups. We propose several characters that can be considered as potentially valuable to separate reliably both female and male specimens of the neotropical species. The distribution of selected species or species groups of Mesocyclops is also revised in light of this new frame.

Diversity of freshwater copepods (Maxillopoda: Copepoda: Calanoida, Cyclopoida) from Chiapas, Mexico with a description of Mastigodiaptomus suarezmoralesi sp. nov.

In Mexico the knowledge of the freshwater copepod fauna is largely incomplete; after a field expedition to survey the Calanoida and Cyclopoida richness in Chiapas (southeastern Mexico), three species increase the full inventory in the country (of around 86 species). In this manuscript the first record of the genus Metacyclops in Mexico and a new record of Acanthocyclops einslei are reported. In addition, a full description of specimens of a new species assignable to the genus Mastigodiaptomus (M. suarezmoralesi sp. nov.) is presented. This research provides a full morphological description of adult males and females of the new species as well as comments on the morphology of Aglaodiaptomus clavipes. The new records were compared with previous taxonomic reports. Detailed analysis and illustration of the copepod morphology have been performed with the aid of camera lucida, light microscopy and scanning electron microscopy. Most of the species recorded show Neotropical affinity. http://www.zoobank.org/urn:lsid:zoobank.org:pub:4E3C5C42-F73E-4D91-A85F-E5794B146734

Morphology Of Elaphoidella Grandidieri (Guerne & Richard, 1893) (Copepoda, Harpacticoida) From Mexico With Notes On Fecundity In Culture Conditions

Samples collected from ponds in central Mexico contained male and female specimens of the harpacticoid copepod Elaphoidella grandidieri (Guerne & Richard, 1893). Field-collected ovigerous females were transported to the laboratory where several isofemale lines were established. Cultures were established from a single female and maintained on a mono-algal diet in moderately hard water. Specimens of both sexes, particularly the less known males, were analysed morphologically and compared with records from different geographical regions. Differences among these populations are subtle and not geographically consistent. Variations were found in the relative length of setal elements and ornamentations of swimming legs 1, 2, and 4, the proportions and armature of the exopod of the female leg (P) 5, among other characters. The specimens from Mexico have 1-2 long spines near the posteroventral margin of the anal somite; this character has been described only from a North African population. Our analysis supports the notion that this widespread pantropical species shows a considerable degree of variability in various characters. Since a clonal population of this parthenogenetic species could be established, molecular techniques are recommended to evaluate this variability and determine if E. grandidieri represents a species complex with morphologically similar taxa. The finding of E. grandidieri as an harpacticoid with high reproductive rates suggests that this copepod has an outstanding potential in aquaculture.