Janet W. Reid

The distribution of species of the genusThermocyclops (Copepoda, Cyclopoida) in the western hemisphere, with description ofT. parvus, new species

The distribution and ecology of species of cyclopoid copepods of the genusThermocyclops in the western hemisphere are reviewed. These are:Thermocyclops brehmi (Kiefer),T. crassus (Fischer),T. decipiens (Kiefer),T. hastatus antillensis Herbst,T. inversus (Kiefer),T. minutus (Lowndes),T. tenuis (Marsh),T. tenuis longifurcatus Pesce, andT. parvus, new species.T. brehmi is known from microlimnotopes in a restricted region in northern Argentina and Uruguay, whileT. crassus has been reliably recorded only from small ponds in Costa Rica.T. decipiens, with many records from northern Argentina to Costa Rica, Guatemala and the Antilles, is often numerous in mesotrophic and eutrophic lakes and reservoirs. The range ofT. minutus extends over tropical and subtropical lowlands of South America from northern Argentina to Venezuela; this species prefers oligotrophic and mesotrophic conditions in larger lakes.T. inversus may prefer mildly carbonate waters and inhabits large and small reservoirs, natural lakes, ponds, wells and caves from northeastern Brazil to Mexico and the Antilles.T. tenuis ranges from northern Argentina to the Antilles and the southern United States, inhabiting large and small, natural and artificial bodies of water.T. tenuis longifurcatus is known only from two wells on Bonaire,T. hastatus antillensis from a well on the island of Guadeloupe, andT. parvus only from plankton samples from the Florida Everglades. Knowledge of population dynamics, feeding and reproductive biology of several planktonic species is reviewed.

A human challenge: discovering and understanding continental copepod habitats

Copepods have invaded an astonishing variety of aquatic and humid continental environments and microhabitats. The historical process of discovery and investigation of copepods in ephemeral, acid and thermal waters, subterranean waters and sediments, phytotelmata, humid soils, leaf litter, human-modified and artificial habitats, and other situations extends over about 130 years. The methods developed to collect in and study these habitats range from simple nets to elaborate pumping systems and diving techniques. Investigations of non-lacustrine continental environments have contributed greatly to the understanding of aspects of copepod biology such as reproduction, diapause and population dynamics. Questions regarding faunistics and biological diversity, biogeography, evolution, transport and introductions of alien species have also been informed by such studies. This article briefly reviews these topics, and provides detailed lists of records from some of the less well-known kinds of habitats.

Diapause in copepods (Crustacea) from ephemeral habitats with different hydroperiods in Everglades National Park (Florida, U.S.A.)

Water management practices in the Everglades have severely stressed the natural system, particularly by reducing the hydroperiods of much of the region. During the dry season of 1999, we investigated the influence of hydroperiod on the species composition and dormancy patterns of freshwater copepod communities in seasonal wetlands of Everglades National Park, Florida, U.S.A. The habitats were characterized by an annual dry season, from December through June. We sampled at two locations: the Long Pine Key area of the Rocky Glades region (short hydroperiod, ca. 4–5 months), and western Taylor Slough (intermediate hydroperiod, ca. 8–10 months). Both areas have experienced a reduction in natural hydroperiods and an increase in the frequency of dry-down. We collected weekly plankton samples from Rocky Glades solution holes to assess the potential species pool of copepods. To document the taxa capable of surviving dry-down by resting, we performed three immersion trials in which we rehydrated, in laboratory aquaria, sediment patches from solution holes and surface soils from all stations. Only a subset of the planktonic species collected emerged from the dried sediments. The cyclopoids Microcyclops rubellus and Paracyclops poppei were dominant. This is the first record of diapause for P. poppei. Species distributions from the different hydroperiod soil patches indicated that more diapausing species occurred at the sites that dried for shorter periods. Emerging individuals of M. rubellus and P. poppei were mainly ovigerous females, demonstrating a resting strategy seldom before recorded. The cyclopoid Diacyclops nearcticus had not been previously reported to diapause, but they emerged from the dried sediments in our trials. Our collections included six new records for Florida: Diacyclops nearcticus, Megacyclops latipes, Orthocyclops modestus, Elaphoidella marjoryae, Bryocamptus sp. and Bryocamptus cf. newyorkensis. Paracyclops poppei, Macrocyclops fuscus and Arctodiaptomus floridanus are new records for Everglades National Park. Clearly, diapause is an important strategy for the persistence of copepods in short-hydroperiod wetlands. The duration of the dry period appears to be inversely related to the number of species that emerge from diapause.

Murunducaris juneae, New Genus, New Species (Copepoda: Harpacticoida: Parastenocarididae) from a Wet Campo in Central Brazil

ABSTRACT Specimens of a new parastenocaridid copepod were collected from a murundu mound and nearby soil in the central Brazilian highlands. Principal diagnostic features of Murunducaris juneae, new genus, new species, include, in both sexes, the posterior insertion of the spiniform seta of leg 4 exopodite article 1, and, in the male, the fifth legs with massive, fused basipodites, each with a large subconical terminal spine, and the posteriorly recurved process located on the ventral midline of the fused basipodites. Murunducaris, like some other neotropical parastenocaridid genera, is among the most highly evolved members of the family. Known patterns of integumental somitic windows in the Parastenocarididae are reviewed, and their possible significance for the systematics of the family is discussed.

Latitudinal diversity patterns of continental benthic copepod species assemblages in the Americas

The diversity, considered as richness (numbers) of genera and species, of continental benthic Copepoda of the Americas was examined. Thirty-three local lists of planktonic and benthic Cyclopidae (Eucyclopinae and Cyclopinae), 21 local lists of epibenthic Harpacticoida (Canthocamptidae), and 8 local lists of interstitial Harpacticoida (Parastenocarididae) were compared. Available data do not allow the rejection of the null hypothesis of no significant difference in diversity of tropical and temperate copepod faunas. For Cyclopidae, 6–15 genera and 6–44 species were recorded from local areas; linear regression analysis showed no significant correlation between latitude and number of genera and species. For Canthocamptidae, 1–13 genera and 3–43 species were recorded locally, with no significant correlation between latitude and number of species; for genera the correlation between latitude and number of genera was strongly positive, but the effect of latitude is small. No relationship between latitude and diversity of the Parastenocarididae was evident from inspection. Endemism of Cyclopidae and Canthocamptidae is significantly greater in South America, as shown by comparisons of Sorensen’s similarity coefficient between paired areas. Because of this high degree of endemism, conservation strategies for South American wetland invertebrates should emphasize preservation of many small sites.

NEW RECORDS OF BRYOCYCLOPS FROM THE CONTINENTAL U.S.A., PUERTO RICO, AND BRAZIL (COPEPODA: CYCLOPOIDA: CYCLOPIDAE)

Collections from Brazil, Puerto Rico, and the U.S.A. yielded new records of 3 species of Bryocyclops. Both sexes of Bryocyclops muscicola are described from a probably introduced population found in a plant nursery in Florida, U.S.A., and compared to material of B. muscicola from Java. This is the first record of the genus in North America. The known distribution of Bryocyclops campaneri in Brazil is considerably expanded, and new information provided on its morphology. Bryocyclops caroli, previously known only from Brazil, is recorded for the first time from Puerto Rico.

Semiterrestrial meiofauna inhabiting a wet campo in central Brazil, with special reference to the Copepoda (Crustacea)

The wet campo (“campo úmido”) marsh type is widely distributed in the cerrado region of central Brazil. These marshes develop on slopes along margins of gallery forests where the water table persists at or near the soil surface year-round. Their grass and sedge vegetation covers spongy, highly organic (not peaty) soils. Ground and surface water seeping through the wet campos tends to be slightly acidic (pH about 5), ion-poor (conductivity less than 10 µS cm−1) and well oxygenated.A typical freshwater meiofaunal community develops in those wet campos where soils remain moist throughout the year (moisture content more than about 60% of soil wet weight). Such a community was studied from 1979–1982 in a wet campo in a protected natural area on the Fazenda Água Limpa of the Universidade de Brasília. It was dominated by nematodes, rotifers and harpacticoid copepods, and included protozoans, turbellarians, cyclopoid copepods, cladocerans, ostracods, oligochetes, hydracarines and several families of aquatic insect larvae. This community was most fully developed in the wetter areas.Species richness of the copepod community is the highest yet recorded in a freshwater system. The 29 species of harpacticoid copepods and 4 species of cyclopoid copepods displayed pronounced zonation which seemed best correlated with soil moisture content and water regime.

ITOCYCLOPS, A NEW GENUS PROPOSED FOR SPEOCYCLOPS YEZOENSIS (COPEPODA: CYCLOPOIDA: CYCLOPIDAE)

Abstract We redescribe Speocyclops yezoensis Ito on the basis of specimens from Japan and from Alaska and Tennessee, U.S.A. The combination of the segmentation of the swimming legs; the lack of dimorphism in the structure of the swimming legs, except for the modified terminal spine of the leg 3 endopodite in the males of some populations; the partly fused proximal segment of leg 5; and, in the female, the peculiar structure of the seminal receptacle provide grounds to propose a new genus Itocyclops to accommodate this taxon. A new record from Tennessee is the first from the eastern U.S.A.

RHEOCYCLOPS, A NEW GENUS OF COPEPODS FROM THE SOUTHEASTERN AND CENTRAL U.S.A. (COPEPODA: CYCLOPOIDA: CYCLOPIDAE)

The new genus Rheocyclops is proposed to accommodate the cyclopoid copepods Diacyclops virginianus Reid, from Virginia, and the new species R. carolinianus from South Carolina, R. talladega and R. hatchiensis from Alabama, and R. indiana from Indiana, U.S.A. Most species were collected from the hyporheic zones of stream beds, except R. indiana which was found in a drip pool in a cave. The new genus is distinguished by a combination of characters: anal operculum produced; antennule 11-segmented; antenna lacking exopodite seta; rami of legs 1-4 all 3-segmented, or some rami 2-segmented; leg 5 with proximal segment fused to somite and reduced to small protrusion bearing seta inserted near distal (free) segment, and free segment cylindrical with 2 terminal setae.

Thermocyclops Crassus (Crustacea: Copepoda) Present in North America: A New Record from Lake Champlain

The cyclopoid copepod Thermocyclops crassus was collected in Missisquoi Bay, Lake Champlain, Vermont, U.S.A., in May and August 1991. Since this is the first confirmed record of the species in North America, the population is considered to be introduced. Thermocyclops crassus is widespread in temperate and tropical Eurasia and Africa, but, in the Americas, has been collected previously only in Costa Rica. It is planktonic and thermophilic, with a preference for eutrophic waters.