Entries - Entry Category: Zoology - Starting with E

Earwigs belong to the Phylum Arthropoda, Class Insecta, and Order Dermaptera. It is one of the comparatively species‐poor insect orders, as there are about 2,200 extant species within eleven families. About twenty-five species occur in North America, sixty in Australia, and forty-five in Europe. Earwigs are found on all continents except Antarctica and occur in northern latitudes as far north as Greenland. Earwigs exhibit their major diversity in the tropics and have a strong preference for warm and moist environments; few survive winter outdoors in cold climates. The overwhelming majority of earwig species are in the suborder Forficulina, grouped into nine families of 180 genera, including the common European earwig, Forficula auricularia. As of 2020, no earwigs have been reported …

Among the many success stories involving wildlife in Arkansas, a high-profile example is the elk of the Buffalo National River country. Wiped out in pioneer and early settlement days, the elk were brought back beginning in 1981, and, since then, the big animals have become well enough established that they can be hunted on a limited basis. The elk have also become a reliable tourist attraction in Newton County and the surrounding area. Elk were native to Arkansas but were wiped out by changing habitat, mostly the clearing of land. The variety in the area in the early days was the eastern subspecies of elk, which is extinct. By the time Arkansas became a state in 1836, elk were dwindling, …

Forty species/subspecies of darters live in Arkansas; many of them are beautifully colored, especially males during the breeding season. Of these forty, five species are endemic to Arkansas, meaning that they occur nowhere else on the planet. Those five endemic darters are the beaded darter (Etheostoma clinton), strawberry darter (Etheostoma fragi), yellowcheek darter (Etheostoma moorei), paleback darter (Etheostoma pallididorsum), and the most recently described Ouachita darter (Percina brucethompsoni). The beaded darter, Etheostoma clinton (named after Bill Clinton, the forty-second president of the United States) was described (elevated) by Richard Mayden of St. Louis University in Missouri and Steven Layman of Kennesaw, Georgia, from specimens collected in the upper Ouachita and Caddo rivers. It was formerly known as the speckled darter …

Isopods belong to the Phylum Arthropoda, Subphylum Crustacea, Class Malacostraca, and Order Isopoda, and include pillbugs, sowbugs, woodlice, and their relatives. Isopods are cosmopolitan organisms that inhabit saltwater and freshwater habitats, including subterranean waters, but they can also be found in terrestrial environments. There are over 10,000 species of isopods worldwide in eleven suborders with about 4,500 species found in marine environments, 500 species in freshwater environments, and 5,000 species on land. Their fossil record dates back to the Carboniferous Period of the Paleozoic (some 300 million years ago) when they lived in shallow seas. Isopods range in length from thirty micrometers (microcerberid isopods) to 500 mm (19.7 in.) for the giant Antarctic isopod (Bathynomus giganteus). The majority of North …

Two miniature catfishes are endemic to Arkansas—that is, they occur only in Arkansas and nowhere else on Earth. Both of these endemic fishes, the Ouachita madtom (Noturus lachneri) and the Caddo madtom (Noturus taylori), are taxonomically placed in the genus Noturus, the madtoms, which are contained within the catfish family Ictaluridae. Noturus lachneri was originally described by William Ralph Taylor in 1969 from the type locality of the Middle Fork of Saline River at State Highway 7, 11.2 miles (18.1 kilometers) north of Mountain Valley in Garland County. It was believed to be confined to the upper Saline River drainage until a Northeastern Louisiana University graduate student discovered it in a small tributary of the main Ouachita River just below …

Esocids belong to the order Esociformes and family Esocidae. They were endemic to the Northern Hemisphere of North America and Eurasia during the Paleogene (66 to 23 million years before present). The only living genus is Esox (pikes and pickerels) and it includes seven species; four of those species occur in North America, and five (one introduction) of the seven can be found in Europe and Asia. In the United States, the natural range of esocids is restricted to regions east of the Rockies; however, many introductions have been made in the west. In Arkansas, there are four species: the grass pickerel (Esox americanus), northern pike (E. lucius), muskellunge (E. masquinongy), and chain pickerel (E. niger). Two of these, E. …

An exotic (or invasive) species is any plant or animal that is not native to an ecosystem and that can potentially cause economic or environmental harm, as well as damage to native animal or human health. Several species of exotic fishes in Arkansas have the capability to cause significant economic losses to fisheries and reduce opportunities for effective uses of valued aquatic natural resources. These include seven species within the minnow family Cyprinidae (now considered Leuciscidae), five species in the trout and salmon family Salmonidae, a single species of cichlid (Cichlidae), snakehead (Channidae), smelt (Osmeridae), and yellow perch (Percidae), and two species of pikes (Esocidae). CYPRINIFORMES: CYPRINIDAE (LEUCISCIDAE) Rudd or pearl roach (Scardinius erythrophthalmus). This fish apparently entered the United …

Arkansas has undergone many changes over geologic time. The climate has ranged from tropical, supporting dinosaurs in the Mesozoic period, to the cold period at the end of the Cenozoic period, known as the Pleistocene epoch. The most recent drastic climate change began about 1.6 million years ago during the Pleistocene epoch, the planet’s most recent ice age. Glaciers covered much of North America. They did not reach Arkansas but occurred as far south as the Missouri River. During warm periods, the glaciers melted and sent millions of gallons of water through Arkansas on its way to the sea. Many types of animals that lived here have disappeared. If they had a hard shell or a bony skeleton, fossil records …

Fossils and sedimentary rock layers contribute to current knowledge of the animals that lived in Arkansas in the geologic past. A careful examination of these layers and the types of fossils contained in them reveals clues about the age of the rock and the different environments of the past. In the older deposits, evidence indicates that all of Arkansas was covered by the ocean at various times; fossils of marine animals are found as well as sequences of rock that display patterns only found in marine sedimentary deposits. In some of the most recent deposits, the remains of land animals that walked the earth just a few thousand years ago have been found. All but the most recent of the …