Zoology

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Entry Category: Zoology

Cyprinids

The Cyprinidae is a diverse family of mainly freshwater fishes belonging to the ostariophysian order Cypriniformes, collectively called cyprinids. They include carps, true minnows, and their relatives. The Cyprinidae is the largest and most diverse fish family and, in general, the largest vertebrate animal family, with about 3,160 species, of which only 1,270 are extant, divided into about 376 genera. The family occurs in Africa, Eurasia, and North America (northern Canada to southern Mexico). Only two species of cyprinids occur in true marine waters, daces (Tribolodon brandtii and T. sachalinensis) from eastern Asia, and a few stray into brackish water only very rarely. More than sixty-two species of cyprinids are known from Arkansas, which represents almost a third of the …

Dellinger, Samuel Claudius

Samuel Claudius Dellinger was curator of the University of Arkansas Museum in Fayetteville (Washington County) and head of the Department of Zoology for over thirty years. As curator, he built the museum’s archaeology collection into one of the best in the nation. In Dellinger’s view, the museum was, first and foremost, an educational resource for the people of Arkansas, and he worked to generate interest in it from the university community and the general public. Samuel Dellinger was born on January 14, 1892, in Iron Station (later Lincolntown), North Carolina, to Robert H. and Laura Loftin Dellinger. After graduating from high school, Dellinger attended Trinity College (later Duke University), where he was a varsity wrestler and swimmer. Dellinger earned his …

Diplurans

aka: Two-Pronged Bristletails
The primitive insects known as diplurans belong to the phylum Arthropoda, subphylum Hexapoda, class Insecta and order Diplura. They are considered to have three lineages: the Campodeoidea, Japygoidea, and Projapygoidea. These superfamilies are defined morphologically by three different types of cerci (paired appendages) found across all the dipluran families. There are ten families in this cosmopolitan order distributed from the tropics to the temperate zones. Diplurans belong to one of the four groups of Hexapoda, with other primitive apterygote insects, including springtails (Collembola) and coneheads (Protura). There are about 800 described species, of which around seventy (9%) occur in North America, twelve (2%) in the United Kingdom, and two (0.3%) in Australia. In 2016, species of diplurans were reported from …

Dipteran Parasites

aka: Parasitic Dipterans
aka: flies
aka: mosquitos
aka: gnats
The order Diptera belongs to the Phylum Arthropoda and Class Insecta. The order ranks number two among all insect orders—only behind beetles (Coleoptera)—with about 125,000 described species (there are an estimated 1,000,000 total species), many of which are considered parasitic or serve as vectors for diseases. There are two main groups (suborders): the Nematocera with seven infraorders and Brachycera with six infraorders. Dipterans—including the sixty species of mosquitoes that occur in Arkansas and Missouri—can be irritating to humans and harmful to livestock and other animals. A major repository of voucher specimens of dipterans in Arkansas is the Entomology Arthropod Museum at the University of Arkansas in Fayetteville (Washington County). It houses the largest research and reference collection of insects and …

Dipterans

aka: True Flies
The order Diptera belongs to the Phylum Arthropoda, Subphylum Labiata, Superclass Hexapoda, and Class Insecta. Among all insect orders, the order is number two in total number of species, ranked only behind beetles (Coleoptera), with about 125,000 described species (and an estimated 1,000,000 total species). They include house flies, blow flies, mosquitoes, gnats, black flies, midges, crane flies, horseflies, fruit flies, and others. Arkansas is home to many of these species. The first true fossil dipterans are known from the Middle Triassic Period (about 240 million years ago [mya]), and became more widespread during the Middle to Late Triassic. Although modern flowering plants did not appear until the Cretaceous (around 140 mya), the original dipterans may have had a different …

Dog Heartworms

aka: Dirofilaria immitis
The canine heartworm (Dirofilaria immitis) is a filarial parasite that belongs to the Phylum Nematoda, Class Secertenea, Order Spirurida, and Family Onchocercidae. There are two subgenera: Dirofilaria and Nochtiella. This parasite is often found in wild and domestic canids throughout the world, especially in the United States where it is endemic from the East to the Midwest, the southeastern Atlantic seaboard, and the southern Gulf Coast. Transmission of the parasite occurs throughout the United States (even Alaska) and in the warmer regions of Canada. In the United States, the highest infection rates are found within 241 km (150 mi.) of the coast from Texas northeast to New Jersey, and along the Mississippi River Valley and its major tributaries. The parasite …

Earwigs

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 …

Elk

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, …

Endemic Darters

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 …

Endemic Isopods

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 …

Endemic Madtoms

aka: Ouachita Madtoms
aka: Caddo Madtoms
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

aka: Pikes
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. …

Exotic Fish

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 …

Extinct Animals [Historic Period]

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 …

Extinct Animals [Prehistoric Period]

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 …

Fairy Shrimps

aka: Anostraca
The Order Anostraca (Phylum Arthropoda, Subphylum Crustacea, Class Branchiopoda) includes the fairy or brine shrimps. Worldwide, there are 300 species within twenty-six genera placed in eight families: Artemiidae (one genus, nine species), Branchinectidae (one genus, forty-five species), Branchipodidae (five genera, thirty-five species), Chirocephalidae (nine genera, eighty-one species), Parartemiidae (one genus, thirteen species), Streptocephalidae (one genus, fifty-six species), Tanymastigidae (two genera, eight species), and Thamnocephalidae (six genera, sixty-two species). In Arkansas, seven anostracan species are known: Eubranchipus neglectus, E. serratus, E. moorei, Branchinecta packardi, Thamnocephalus platyurus, Streptocepalus sealii, and S. texanus. Fairy shrimps are very primitive organisms believed to have diverged during the Ordovician period from the main line of the Branchiopoda. Their fossil record dates back to the Devonian, although …

Fish

Arkansas fishes are a combination of abundant and rare species—primitive and ancestral, commercial and sport, game and non-game, native and introduced, and transplanted and exotic. There are approximately 233 fish species in Arkansas. Arkansas has a relatively rich fish fauna compared to neighboring states (which range between 148 and 319 fish species). Some species, such as the western mosquitofish (Gambusia affinis), are common statewide, whereas other species, such as the yellowcheek darter (Etheostoma moorei), have more restricted distributions. Distinct differences in topography and geology between northwestern (upland) and southeastern (lowland) Arkansas have led to distinctly different groups of fish species developing in each of these regions. For example, because of an abundance of clear, gravel-bottom, flowing streams in northwestern Arkansas, …

Fleas

Fleas are small, wingless, hematophagous (blood-feeding) ectoparasites that belong to the Phylum Arthropoda, Class Insecta, and Order Siphonaptera. There are four recognized suborders—Ceratophyllomorpha, Hystrichopsyllomorpha, Pulicomorpha, and Pygiopsyllomorpha—with about 246 recognized genera and over 2,500 described species within sixteen families. Adult fleas feed on blood of mostly mammals (about ninety-four percent of known species), including dogs, cats, and humans, with the remainder of species parasitizing birds. Fleas are an important component of the worldwide biota. In addition, they can be nuisance biters, and some serve as vectors or intermediate hosts of flea-borne disease agents and parasites. The most recent summary listed twenty-nine species of fleas in Arkansas. Fleas are most closely related, evolutionarily speaking, to insects in the orders Diptera (true …

Fourche Mountain Salamander

aka: Plethodon fourchensis
The Fourche Mountain salamander (Plethodon fourchensis) is a slender, large (115–178 millimeters in total length) terrestrial salamander that is one of twenty or so members of the caudate family Plethodontidae that can be found in Arkansas. This species is one of three endemic salamanders known to exist in Arkansas and is confined to Fourche Mountain and Irons Fork Mountain in the south-central region of the Ouachita Mountains. Normally, these salamanders can be found beneath the surface rock of hillsides and valleys within these mountains; however, they can also be found under rotting logs on the forest floor. Adults of this species possess two longitudinal rows of large, white blotches on the back; the dorsal body color is, otherwise, uniformly black. …

Freshwater Drum

aka: Grunter
aka: Gaspergou
The freshwater drum (Aplodinotus grunniens) belongs to the order Perciformes and family Sciaenidae; it is the only freshwater member of the family. Freshwater drum are endemic to freshwater environs of the Americas, and their distributional range extends as far north as the Hudson Bay of Canada and reaches as far south as the Usumacinta River Basin of Guatemala. In the United States, eastward distribution includes the eastern Appalachians westward as far as Kansas, Oklahoma, and Texas. This fish appears to have the greatest latitudinal range of any freshwater fish in North America. In Arkansas, A. grunniens occurs throughout the state but mainly is found in the larger lakes and rivers. The closest living relatives of A. grunniens are a group …

Gars

aka: Garfish
aka: Garpikes
Gars are a primitive group of euryhaline fishes dating back to the late Jurassic to early Cretaceous Period, about 150 million years ago. Gars are one of the most recognizable fishes because of their slender torpedo-shaped bodies, ganoid scales, and long snouts with numerous teeth. Dorsal and anal fins are set far back on the body, and the caudal fin is rounded, with a condition known as abbreviate-heterocercal. Gars are unusual among fishes in that their vascularized swim bladders can function as lungs; they must surface periodically to take a gulp of air. Arkansas hosts four gar species: the alligator gar (Atractosteus spatula), spotted gar (Lepisosteus oculatus), longnose gar (L. osseus), and shortnose gar (L. platostomous). Fossilized gar specimens have …

Gastrotrichs

aka: Hairybacks
The Phylum Gastrotricha (commonly called “hairybacks”) comprises about 800 species of marine, brackish, and freshwater microscopic invertebrates. Twelve genera and fewer than 100 species of freshwater gastrotrichs are known from North America. However, in North America, perhaps 75 to 90 percent of the probable diversity of freshwater gastrotrichs species are undescribed. Gastrotrichs are widely distributed cosmopolitan organisms that are divided into two orders: the Macrodasyida (with nine families), which, except for two freshwater species (Marinellina flagellata and Redudasys fornerise), are marine, and the Chaetonotida (seven families), some of which are marine, estuarine, and semi-terrestrial forms, while others are primarily found in freshwater. The Chaetonotida can be further broken down into two suborders: the Multitubulatina (Nesodasys) and the Paucitublatina (Chaetonotus, Dasydytes, …

Geckos

Geckos are lizards that belong to the Class Reptilia, Order Squamata, Suborder Sauria (Lacertilia), and Infraorder Gekkota within seven families, including Carphodactylidae (seven genera, thirty species), Diplodactylidae (twenty-five genera, 137 species), Eublepharidae (six genera, thirty species), Gekkonidae (fifty-four genera, 1,264 species), Pygopodidae (eight genera, thirty-five species), Phyllodactylidae (nine genera, 100 species), and Sphaerodactylidae (twelve genera, 200 species). By far, the true geckos (Gekkonidae) are the largest family of lizards. Many common geckos are members of this family, including dtellas (Gehyra), house geckos (Hemidactylus), true geckos (Gekko), and day geckos (Phelsuma). Geckos are cosmopolitan in distribution and are particularly species-rich in the tropics. At least one type of gecko is found in Arkansas. Geckos probably evolved in the Lower Cretaceous, and …

Goldeyes and Mooneyes

aka: Mooneyes and Goldeyes
aka: Hiodontid Fishes
North American freshwater fishes of the family Hiodontidae (order Hiodontiformes or Osteoglossiformes) include the goldeye (Hiodon alosoides) and mooneye (H. tergisus). The goldeye ranges from James Bay (bordering the provinces of Ontario and Quebec) in Canada and the Mississippi River basins from the Northwest Territory to western Pennsylvania and Ohio south to Louisiana. In Arkansas, H. alosoides is found sporadically in lakes and the larger turbid rivers of the state, including the Arkansas and Mississippi, and the smaller Black River. The mooneye (also called the “freshwater tarpon”) ranges from the St. Lawrence–Great Lakes, Mississippi River, and Hudson Bay basins from Quebec and Alberta, Canada, east to western North Carolina and south to Louisiana. In Arkansas, H. tergisus occurs in large …

Grotto Salamander

aka: Eurycea spelaea
aka: Ghost Lizard
aka: Ozark Blind Salamander
The grotto salamander (Eurycea spelaea) is a species of lungless salamander in the Phylum Chordata, Subphylum Vertebrata, Class Amphibia, Order Caudata, and Family Plethodontidae. It was originally described as Typhlotriton spelaeus but is now considered a member of the genus Eurycea. It is endemic to wet caves, sinkholes, and karst regions beneath the Springfield and Salem Plateaus of the Ozark Mountains of 120 individual sites in northern Arkansas, 124 sites in southwestern Missouri, forty-three sites in northeastern Oklahoma, and one county (Cherokee) in extreme southeastern Kansas. Its natural habitats are freshwater springs, inland karsts, and caves. It is not listed by the federal government as endangered or threatened, but it is vulnerable to changes in groundwater quality and a reduction …

Haemogregarines

Haemogregarines are protist parasites that belong to the Phylum Apicomplexa, Class Conoidasida, Order Eucoccidiorina, and Suborder Adeleorina, and include the following seven families: Adeleidae, Dactylosomatidae, Haemogregarinidae, Hepatozoidae, Karyolysidae, Klossiellidae, and Legerellidae. There are two major genera, Haemogregarina and Hepatozoon, in addition to several minor ones, including Babesiosoma, Bartazoon, Cyrilia, Dactylosoma, Desseria, Hemolivia, and Karyolysus. As a group, these parasites are cosmopolitan in their range of infected hosts (such as turtles, crocodiles, birds, reptiles, and mammals) and geographic distribution. In general, haemogregarines sensu lato (meaning, in a broad sense) are elongate to fusiform ovoidal organisms that occur within the erythrocytes (red blood cells) of various animals, mostly poikilothermic vertebrates (animals whose internal temperatures vary widely). They form a group of diverse …