Zoology

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Entry Category: Zoology

Acanthocephalans

aka: Spiny-Headed Worms
aka: Thorny-Headed Worms
These cylindrical metazoan worms, superficially similar to nematodes, belong to the phylum Acanthocephala and include four classes, ten orders, twenty-six families, and about 1,300 species. Recent molecular studies suggest that Rotifera (rotifers) and Acanthocephala are phylogenetically related sister groups. Adult members are highly specialized, dioecious (having distinct male and female colonies, as opposed to hermaphroditic) parasites of the intestinal tract of a variety of vertebrates (but not generally humans). They cause serious disease fairly rarely. The life cycle involves at least two hosts, either an aquatic intermediate host (Amphipoda, Copepoda, Isopoda, and Ostracoda) or terrestrial intermediate hosts including insects, crustaceans, and myriapods. Fishes, amphibians, reptiles, birds, and mammals serve as definitive hosts. Acanthocephalans range from 0.92 to 2.4 millimeters long …

Alligator Snapping Turtle

The alligator snapping turtle (Macrochelys temminckii) is North America’s largest freshwater turtle. This turtle is found primarily in major rivers, streams, swamps, and oxbow lakes throughout much of the south-central United States—all around the states of Arkansas and Mississippi and in portions of Texas, Oklahoma, Kansas, Missouri, Illinois, Iowa, Georgia, and Florida. Alligator snapping turtles have distinct morphological features that distinguish them from their closest cousin, the snapping turtle (Chelydra serpentina). For example, the dorsal shell, or carapace, of the alligator snapping turtle has three prominent keels (ridges on the carapace), whereas the keels of the snapping turtle are low and become less conspicuous with age. The tails of both species have three rows of tubercles (warty projections), but these scales …

American Alligator

The American alligator (Alligator mississippiensis) belongs to the class Reptilia, order Crocodylia, superfamily Alligatoroidea, and family Alligatoridae. There are seven species in the family endemic to the New World tropics, with an eighth species occurring in the warmer temperate regions of China. The American alligator is endemic to the southeastern coastal plain of the United States, where it inhabits freshwater wetlands such as streams, reservoirs, ponds, lakes, coastal marshes, bayous, oxbows, and cypress swamps associated with larger rivers in parts of Alabama, Arkansas, Florida (and some Florida Keys), Georgia, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina, Texas, and Virginia; it also occurs in the lower Rio Grande Valley of Texas south of San Antonio, and farther south into the thornscrub …

American Eel

The American eel (Anguilla rostrata) belongs to the order Anguilliformes and family Anguillidae. Common names include Atlantic eel, common eel, freshwater eel, silver eel, yellow-bellied eel, green eel, black eel, bronze eel, elver, whip, and easgann. This family includes about eighteen facultative catadromous species of eels. The American eel ranges from Greenland and Iceland and all the drainages of eastern North America along the Atlantic and Gulf slopes west to New Mexico and south to Venezuela and islands of the Caribbean and West Indies across a latitudinal range of 5 to 62° N. In North America, A. rostrata occurs inland from eastern Canada to the Great Lakes, in the headwaters of many Atlantic and Gulf slope rivers, and in the …

Amphibians

Arkansas has within its borders a modest assemblage of salamanders, frogs, and toads, which are taxonomically grouped in the class Amphibia and, therefore, are commonly called amphibians. Amphibians were the first tetrapods (four-legged vertebrates) to walk on land, having come from an early-evolving group of lobe-finned fishes nearly 360 million years ago. Today’s amphibians possess a mostly bony skeleton with a strong “backbone” comprising a series of interlocking vertebrae. Salamanders are termed caudates because they possess a tail in both the juvenile and adult forms, whereas frogs and toads (collectively called anurans) lack tails as adults even though the larvae (tadpoles) possess them. The study of amphibians has been traditionally linked with the study of reptiles in the professional field …

Arachnids

Arachnids belong to Chelicerata, one of four groups of living arthropods. The other three groups are Crustacea, Myriapoda (centipedes and millipedes), and Hexapoda (insects and relatives). There are eleven living arachnid orders, and Arkansas has representatives of five of these including Scorpiones (scorpions), Pseudoscorpiones (pseudoscorpions), Opiliones (harvestmen), Aranea (spiders), and Acari (mites). Overview of Arachnids Arachnid bodies are divided into two main regions called the prosoma (cephalothorax) and opisthosoma (abdomen). These regions have been subdivided in some groups (e.g., solifugids, scorpions). The prosoma holds six pairs of appendages. Unlike in all other arthropods, the first appendages in chelicerates are not sensory antennae but pincer-like mouthparts known as chelicerae (hence the subphylum name). Behind the chelicerae, there are two pedipalps that …

Arkansas Darter

aka: Etheostoma cragini
Arkansas darter (Etheostoma cragini) populations are scattered among some small, spring-fed tributaries of the Arkansas River basin in Colorado, Kansas, Oklahoma, Missouri, and Arkansas. This fish species is rare in Arkansas, being found only in a few spring runs in the Illinois River basin of Benton and Washington counties. The small streams occupied by Arkansas darters are characterized by slow current and silt substrates. The darters shelter in watercress and other aquatic plants, overhanging or flooded terrestrial vegetation, and even in the loose silt of the stream bottom. In some places, they have been observed to move down into larger streams, but this has not been so in Arkansas. They grow to a maximum size of around two inches and …

Arkansas Entomological Society

The Arkansas Entomological Society (AES) was founded in May 1991 by entomology educators, researchers, and industry professionals under the guidance of Dr. William Yearian, former chair of the Entomology Department at the University of Arkansas (UA) in Fayetteville (Washington County). The first president of the society, Dr. Timothy Kring, drafted the society’s constitution with the purpose of fostering entomological accomplishment among its members as well as bringing about closer coordination and understanding among research, regulatory, educational, and commercial entomologists. Entomology is the study of insects and related organisms. Meetings of the society have been held annually since its founding, with locations and dates varying, but most often held on the first Friday and Saturday in October. Every other year, the …

Arkansas Fatmucket

aka: Lampsilis powellii
The Arkansas fatmucket is a bivalve mollusk belonging to the family Unionidae, commonly referred to as freshwater mussels, naiads, or clams. Each freshwater mussel is composed to two halves (valves) of a hard outer shell, with the living animal (soft tissues) residing securely inside. The Arkansas fatmucket (Lampsilis powellii) was described as a species new to science in 1852 by Isaac Lea, a naturalist and publisher by trade residing in Philadelphia, Pennsylvania. Lea based his description on specimens provided to him by Dr. Josiah Hale and Professor W. Byrd Powell from the Saline River at Benton (Saline County). Adults rarely reach a length of four inches (100 millimeters), and males and females are sexually dimorphic—that is, they have slightly different …

Audubon Arkansas

Audubon Arkansas was established in 2000 as the twenty-fifth state office of the National Audubon Society through a seed grant from the Winthrop Rockefeller Charitable Trust. Audubon Arkansas’s mission is to inspire and lead Arkansans in environmental education, resource management, habitat restoration, bird conservation, and enlightened advocacy. In 2003, Audubon Arkansas was recognized as “Conservation Organization of the Year” by the Arkansas Wildlife Federation. Robert Shults was the founding board chairman of Audubon Arkansas. Shults, an Arkansan, served on the National Audubon Society board of directors from 1980 to 1986. The chairman of the National Audubon Society at the time was Donal C. O’Brien. O’Brien and Shults both served on the board of trustees of the Winthrop Rockefeller Charitable Trust. …

Audubon, John James

John James Audubon, a frontier naturalist and artist, is famous for illustrating and writing The Birds of America. He visited Arkansas Territory in 1820 and 1822 and documented Arkansas’s birds, including the Traill’s flycatcher, also known as the willow flycatcher, which is the only bird originally discovered in Arkansas. John Audubon was born Jean Rabin on April 26, 1785, in Saint-Domingue (Haiti). He was the illegitimate child of Jean Audubon, a ship’s captain, and Jeanne Rabin, a French chambermaid. His mother died in 1785 or 1786, and Jean Audubon and his children returned to France after a slave revolt. Along with his sister, he was adopted by his father and stepmother in 1794. Audubon stayed with his father and stepmother …

Bachman’s Warbler

aka: Vermivora bachmanii
Bachman’s warbler (Vermivora bachmanii) was a small, yellow-and-black bird of the American wood-warbler family (Parulidae) that formerly nested in the southeastern United States, including Arkansas. In winter, Bachman’s warblers migrated south to spend the winter on the island of Cuba. Preferring swampy bottomland habitat, the species suffered severe population decline in the early twentieth century when that habitat began disappearing and is now believed by most ornithologists to be extinct. Bachman’s warbler was discovered in 1832 near Charleston, South Carolina, by the Reverend John Bachman, a skilled amateur naturalist. Bachman (pronounced BACKman) was a close friend to John James Audubon, the famed naturalist and artist. Audubon painted a pair of the birds based on skins (prepared specimens) and named the …

Baerg, William J.

William J. Baerg was a naturalist, entomologist, and teacher who served as head of the Department of Entomology at the University of Arkansas (UA) in Fayetteville (Washington County) for thirty-one years. His research on black widow spiders, tarantulas, scorpions, and other arthropods led to descriptions of their behavior, biology, and natural history that had previously been largely ignored by biologists and entomologists. William Baerg was born in Hillsboro, Kansas, to Johann and Magaretha (Hildebrand) Baerg on September 24, 1885. His parents, who had left Russia in 1874, worked as field hands on a Kansas wheat farm. The family later acquired a small piece of land for their own. Baerg was the sixth of seven children. Baerg began school at age seven. At …

Banded Pygmy Sunfish

The banded pygmy sunfish (Elassoma zonatum) belongs to its own family (Elassomatidae) and the Order Perciformes. It is a diminutive sunfish that is about 25 to 40 mm (1.0 to 1.5 in.) in total length. This fish is endemic to the United States, where it ranges in the Mississippi River drainage from Indiana and Illinois south to Texas and east along the Atlantic Coast from North Carolina south to Florida. There are six additional species of Elassoma, including spring pygmy sunfish (E. alabamae), Carolina pygmy sunfish (E. boehlkei), Everglades pygmy sunfish (E. evergladei), Gulf Coast pygmy sunfish (E. gilberti), bluebarred pygmy sunfish (E. okatie), and Okefenokee pygmy sunfish (E. okefenokee). Interestingly, E. zonatum was described by the “Father of American …

Bats

Bats belong to the class Mammalia and the order Chiroptera. There are two suborders: the Yinpterochiroptera (formerly Megachiroptera), which includes the horseshoe and Old World fruit bats (megabats), and the Yangochiroptera (formerly Microchiroptera), the remainder of bats. Worldwide, there are eighteen families, 202 genera, and more than 1,100 species of bats with only about four percent (at least forty-five species) occurring in the United States. This mammalian order is second only in number of species behind the rodents (order Rodentia). Sixteen bat species occur in Arkansas. Much of the past research on bats in Arkansas was conducted by Michael J. (Mick) Harvey (1934–2015) of Tennessee Technical University in Cookeville. His research on several endangered bats in Arkansas was instrumental in …

Big Arkie

Big Arkie was a thirteen-foot-long alligator caught in 1952 near Hope (Hempstead County). He was the Little Rock Zoo’s main attraction for eighteen years. Weighing 500 pounds, Big Arkie was considered to be the largest alligator in captivity in the western hemisphere. Big Arkie was spied by a young boy in a flooded pasture by Yellow Creek, which is west of Hope. Ed Jackson, caretaker of a local hunting club, was alerted and, with some companions, wrapped Big Arkie in a fifty-foot-long cable attached to a tractor. The alligator spent one night in Hope’s public children’s pool, encased in chicken wire. On the following day, he was delivered to the Little Rock Zoo, doubled up in a crate. When the …

Birds

The birdlife of Arkansas (its avifauna) comprises just over 400 species, although that number includes more than forty species that have been extirpated (that is, they no longer occur) in the state, are completely extinct, or are rarities that have strayed into Arkansas fewer than a half dozen times. Around 350 species, then, can be found in Arkansas with some regularity. About 145 species nest within the state. Others nest north of Arkansas and spend the winter here or pass through the state in spring and fall as they migrate to and from nesting grounds to the north and wintering areas to the south. Arkansas’s location in the south-central United States means that its avifauna is generally typical of North …

Birdwatching

aka: Birding
Birdwatching, also commonly called birding, is the hobby of observing wild birds. Involvement in the pursuit ranges from enjoying birds on backyard feeders to traveling thousands of miles, nationally or internationally, to see new and different species. Birdwatching is usually considered to be distinct from ornithology, which is the scientific study of birds, although there is considerable overlap between the two. Birdwatchers often keep records of when and where they saw different species. Many people keep records simply for the personal satisfaction of remembering interesting and unusual sightings. Records kept by amateur birdwatchers, however, have made significant contributions to ornithology by helping with the knowledge of bird distribution and abundance. Most birdwatchers keep a life list—a record of all the …

Black Bears

aka: Ursus americanus
Black bears have a rich and varied history in Arkansas. Once giving to the state its unofficial nickname (the “Bear State”), bruins long shaped society and culture in Arkansas and continue to do so. Used for meat, fur, and fat, bears were a valuable commodity in the colonial period. By the early nineteenth century, although bears were still prized for their original uses, the bear-human relationship began to shift toward overt exploitation and bear hunting as a quest for masculine identity. By the first decades of the twentieth century, Arkansas black bears were at the brink of extirpation, but the population has since been revived. Native Americans were the first to hunt black bears in the region. Documented evidence of …

Bowfin

aka: Grinnell
Bowfin (Amia calva) belong to the primitive North American fish family Amiidae and Order Amiiformes. The family is monotypic and contains a single genus and species (A. calva). Bowfin are basal bony fishes related to gars in the infraclass Holostei. They are native to North America and are commonly found throughout much of the eastern United States, the St. Lawrence River, and Lake Champlain drainages of southern Ontario, and Quebec, Canada. Their range extends farther westward around the Great Lakes into Minnesota and south to the Colorado River in Texas. In Arkansas, A. calva is found in all major river drainages of the Gulf Coastal Plain lowlands and westward through the Arkansas River Valley; they are rarely found in the …

Branchiobdellidans

aka: Crayfish Worms
Branchiobdellidans, or crayfish worms, are leech-like, clitellate annelids belonging to the Phylum Annelida and Order Brachiobdellida (single family Brachiobdellidae) that form an obligate, ectosymbiotic association primarily with astacoidean crayfishes. They have long been known as “branchiobdellid worms” because they were considered a separate family of the oligochaetes; however, more recent treatment of these worms as a separate taxonomic order technically renders their epithet more correctly as “branchiobdellidan worms” or simply “branchiobdellidans.” Branchiobdellidans are a monophyletic clade of more than 150 ectosymbiont species within twenty-one genera found throughout North and Central America, Europe, and eastern Asia, of which about fifteen genera and 107 species have been reported from North America, including in Arkansas. However, branchiobdellid fauna in Arkansas need further study. …

Butterflies and Moths

Arkansas has long been an ideal place to see butterflies and moths, but an increase in public awareness has occurred since the mid-1990s with the publication of scientific papers and checklists, as well as the emergence of special events in state parks. Butterflies and moths are classified in the insect order Lepidoptera, meaning “scale-wing.” Of approximately 350,000 species of butterflies and moths on earth, approximately 15,000 species are butterflies. Butterflies are distinguished from moths by the thousands of microscopic scales that create the color patterns on both sides of the wings. During a typical year, 134 butterfly species may be sighted in Arkansas, including year-round residents, summer residents, and migrants; 94 of these species live on Mount Magazine. An estimated …

Caddisflies

aka: Trichopterans
Caddisflies (Phylum Arthropoda, Class Insecta, Order Trichoptera) make up the largest and most diverse group of aquatic insects. More specifically, caddisflies are a group of small to medium-sized (2 to 30 mm in length), moth-like insects with two pairs of hairy membranous wings; they have aquatic larval forms that metamorphose into terrestrial adults. The name for the order Trichoptera comes from the name Trichos, which means “hairy,” and ptera, which means “wings.” The word “caddis” dates back to The Compleat Angler, written by Izaak Walton (1594–1683) and published in 1653, in which “cod-worms or caddis” were named as being used for bait. Caddisflies are a favorite food of many fish, and therefore are attractive to anglers, particularly trout fly fishermen, …

Caddo Mountain Salamander

aka: Plethodon caddoensis
The Caddo Mountain salamander (Plethodon caddoensis) is a slender, medium-sized (90–100 millimeters in total length) terrestrial salamander. It is one of twenty or so members of the caudate family Plethodontidae that can be found in Arkansas. Adults of this species possess numerous tiny white spots and/or brassy flecks on the back and tail; the dorsal body color is otherwise uniformly black. The lateral body surfaces are creamy white in appearance. The throat region is distinctly pale or white. Juveniles may lack much of the lateral body coloration. This species is one of three endemic salamanders known to exist in Arkansas and is primarily confined to the Caddo Mountains area of the southern Ouachita National Forest and several outlying areas in …

Centipedes

Centipedes (class Chilopoda) are myriapods that include two subclasses, five living orders, and about 2,800 described species (out of an estimated worldwide fauna of approximately 8,000 species) within about twenty-three families. Their fossil history dates back over 410 million years ago to the late Silurian Period of the Paleozoic Era. In terms of worldwide geographic distribution, centipedes are found north of the Arctic Circle and inhabit all subarctic regions but are most abundant in temperate, desert, and tropical areas, where they are common terrestrial invertebrates. Humans have unintentionally introduced several species onto most oceanic islands. However, one order (Craterostigomorpha) is endemic to New Zealand and Tasmania. Members of the families Oryidae and Scutigeridae and of the subfamily Otostigminae have been …

Central Mudminnows

aka: Umbrids
The central mudminnow (Umbra limi) is a small (51 to 132 mm [2 to 5 in.]) fish that belongs to the Family Umbridae and Order Esociformes. There are three other North American members of the family: the eastern mudminnow (U. pygmaea) of the Eastern Seaboard and Atlantic Coastal Plain, the Alaska blackfish (Dallia pectoralis) that occurs in Alaska and adjacent Siberia, and the Olympic mudminnow (Novumbra hubbsi) of the Olympic Peninsula of Washington. All of these are strictly Northern Hemisphere freshwater species. A third Umbra species, the European Mudminnow (U. krameri), occurs widely throughout Europe. Mudminnows are most closely related to esocids (pikes and pickerels). The fossil record includes specimens that date back to the Oligocene of Eurasia and North …

Cestodes

aka: Tapeworms
Cestodes (tapeworms) include flatworms belonging to the phylum Platyhelminthes, class Cestoidea, subclasses Cestodaria (two orders) and Eucestoda (sixteen orders), and about fifty-nine families. The subclass Cestodaria includes monozoic (unsegmented) tapeworms containing only a single set of male and female reproductive organs; these are parasitic in the intestinal tract and body cavity of fishes and turtles. The subclass Eucestoda is made up of polyzoic (segmented) or monozoic cestodes of varying structure and parasitic in the intestines of vertebrates. To date, there are more than 5,000 described species that, as endoparasites, infect all vertebrate classes. The classification of tapeworms remains ambiguous using classical morphological studies alone, and, although some studies have been done recently using molecular tools, further attention is needed to …

Chordate Parasites

aka: Parasitic Chordates
Although the majority of the world’s parasites are protists, helminths, invertebrates, and other miscellaneous groups of organisms, parasitism has also arisen within animals of the phylum Chordata (subphylum Vertebrata). All chordates, at some time in their development, possess five derived morphological characteristics as follows: (1) a dorsal tubular or hollow nerve cord, (2) a notochord, (3) pharyngeal gill slits or pouches, (4) an endostyle, and (5) a post-anal tail. Some examples of parasitic chordates are remoras (which attach to sharks and rays); the jawless fishes (lampreys and hagfishes), which prey upon other fishes; some birds that practice brood parasitism; and vampire bats. The Superclass Agnatha has both extinct groups and extant species, including the “jawless” fish (lamprey and hagfish) that …