Zoology

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Entries - Entry Category: Zoology

Reptiles

Arkansas’s reptilian biodiversity includes four groups—turtles, lizards, snakes, and the American alligator—each with a sharply different body morphology. By closely examining the morphology of these varied groups within the class Reptilia, today’s phylogenetic taxonomists (individuals who study the evolutionary relationships among species) have found that members of this class share several recently derived features (such as skull characteristics) with birds. Because of this modern understanding of the evolutionary relationships among reptilian ancestors and their descendents, which include dinosaurs and birds, some taxonomists have proposed a new class (Eureptilia) to include dinosaurs, birds, crocodylians, all of their close diapsid relatives (including lizards and snakes), and a number of extinct groups. However, the classical taxonomic designation for the class Reptilia includes turtles, …

Riddle’s Elephant and Wildlife Sanctuary

Opened in 1990 by Scott and Heidi Riddle, Riddle’s Elephant and Wildlife Sanctuary, located on 330 acres outside of Greenbrier (Faulkner County), provides a permanent home for African and Asian elephants in need of sanctuary for any reason, regardless of age, sex, species, health, or temperament. Elephants come from private owners, circuses, or zoos. The 501(c)(3) nonprofit sanctuary—which raises money through grants and donations—houses up to a dozen elephants at any given time, with three baby elephants born at the facility as of 2010. Maximus, an African elephant born at the sanctuary in 2003, starred in Animal Planet’s television show Growing Up Elephant. Scott and Heidi Riddle met while both were working at the Los Angeles Zoo, and they married …

Rotifers

aka: Wheel Animals
The Phylum Rotifera (“wheel animals”) contains over 2,100 nominal taxa of microscopic and near microscopic species of unsegmented, bilaterally symmetrical pseudocoelomate invertebrates. They were originally named in 1696 by Anglican priest John Harris (1666–1719) and studied in 1703 by Antoine van Leeuwenhoek (1632–1723). Several surveys of Rotiferans have been done in Arkansas, although there is no summation of the species as of 2019. Because they are minute and mostly composed of soft bodies, rotifers are not commonly supported for fossilization. Their only hard parts, their jaws, are sometimes preserved in the fossil record, but their size makes detection challenging. However, fossils of Habrotrocha angusticollis have been found in Pleistocene (2.5 million to 11,700 years ago) peat deposits of Ontario, Canada. …

Salmonids

aka: Trout
aka: Salmon
Salmonids include chars, graylings, salmon, trout, and freshwater whitefishes, all of which belong to the superorder Protacanthopterygii, order Salmoniformes, family Salmonidae, three lineages or subfamilies (Coregoninae, Thymallinae, and Salmoninae), eleven extant genera, and about 120 species. There are thirty-nine species known in North America. The family is widely distributed, with various species found north of the equator in Asia, Europe, and North America. Some important North American genera include Coregonus, Oncorhynchus, Prosopium, Salmo, Salvelinus, and Thymallus. Although no members are native to Arkansas, salmonids have been introduced, primarily for purposes of sports fishing. The family initially appears in the fossil record in the middle Eocene (48 to 38 million years ago) from fossils found in central British Columbia, Canada. A …

Scorpionflies

aka: Mecopterans
Scorpionflies belong to the Phylum Arthropoda, Class Insecta, Superorder Endopterygota, and Order Mecoptera. There are about 605 species within thirty-four genera and nine families worldwide. There are also 400 known fossil species in about eighty-seven genera, which are more diverse than even the extant members of the order. Sixteen species representing three families of scorpionflies occur in Arkansas. Most mecopterans live in moist environments, although adults of a few species are found in hotter semi-desert habitats and may be active and noticeable only for short intervals of the year. Those in the family Panorpidae generally inhabit broad-leaf woodlands with abundant damp leaf litter. Snow scorpionflies (family Boreidae) appear in winter and are often seen on snowfields and on moss; the …

Sculpins

aka: Cottids
Sculpins belong to the order Scorpaeniformes and superfamily Cottoidea. There are about 11 families, 149 genera, and 756 species. They reach their maximum diversity in the northern Pacific Ocean. The family Cottidae is the largest family, with approximately 258 species; the second-largest family is the Agonidae (marine poachers), with 47 species. The most speciose genus, Cottus (freshwater sculpins), is confined to North America and Eurasia. It includes about 68 taxa that are native to the Northern Hemisphere (Palearctic and Nearctic realms). There is fossil material similar to Cottus that dates to at least the Miocene Epoch (23 to 5.3 million years ago). Most sculpins are generally less than 15 centimeters (6 inches) in length, although a few species can reach …

Shrews

Shrews are very small, secretive, mouse-like mammals that inhabit moist, shady woodland areas. Generally, they have long, flexible, pointed snouts and very small eyes and ears. Their fur is soft and dense, and most species have prominent scent glands. All shrews belong to the Family Soricidae (subfamilies Soricinae, Crocidurinae, Myosoricinae) and Order Eulipotyphia, which also includes moles, shrew-like moles, desmans, gymnures, hedgehogs, and solenodons. True shrews, talpids, and solenodons were formerly grouped in the clade Soricomorpha; however, Soricomorpha has been found to be paraphyletic (descended from a common evolutionary ancestor or ancestral group, but not including all descendant groups). Members of this order are nearly cosmopolitan in distribution, with the exception of Australia, New Zealand, Antarctica, extreme southern South America, …

Shrimps

aka: Prawns
Arkansas shrimps belong in the cosmopolitan Family Palaemonidae (subfamily Palaemoninae) and Order Decapoda, which also contains the crayfishes. Taxonomically, shrimps are differentiated from crayfishes by their first pair of legs with chelae and the abdomen laterally compressed, while crayfishes have the first three pairs of legs with chelae and their abdomens dorsoventrally flattened. The Palaemonidae is a large family (950 species within 137 genera) and is distributed on all the continents except in the deep oceans, in temperate and tropical regions, and having representatives in marine, brackish, and fresh water. Representatives of this family are mainly carnivores that feed on small invertebrates. The most prominent genus in the family is Macrobrachium, with over 240 species that include commercially fished species; …

Silverfish

aka: Bristletails
Silverfish are small, wingless insects in the order Zygentoma (formerly Thysanura). There are four families: Lepidotrichidae (single species), Lepismatidae (about 200 species), Maindroniidae (three species), and Nicoletiidae (about twenty species). In the late twentieth century, it was recognized that the two suborders were not sister taxa; therefore Thysanura was paraphyletic, and the two suborders were each elevated to the status of an independent monophyletic order, with Archaeognatha the sister taxon to the Dicondylia, including the Zygentoma (fishmoths, firebrats, and silverfish). A nicoletiid, Speleonycta ozarkensis, occurs in eight different cave systems in Arkansas in Benton and Newton counties and in Oklahoma in Adair, Cherokee, and Delaware counties. In concert with jumping bristletails (Order Microcoryphia), the predecessors of silverfish are considered the …

Smelts

aka: Osmerids
Smelts belong to the family Osmeridae and order Salmoniformes. There are seven genera and about eleven species. Fishes of the genus Osmerus, to which the rainbow smelt (O. mordax) belongs, include the following: a North Pacific and Arctic species, O. dentex; the European smelt (O. eperlanus) of the Eastern North Atlantic; and the landlocked pygmy smelt (O. spectrum) of eastern Canada and New England, which some authorities suggest is not a valid species. In general, smelts are north circumpolar in geographic distribution, and they occur in marine and freshwater habitats in Asia, Europe, and North America. They date to the Paleocene Epoch (over 55 million years ago). The closest relatives are galaxioid (Protacanthopterygiid) fishes, and the marine argentinoid fishes are …

Southern Cavefish

aka: Typhlichthys subterraneus
The southern cavefish (Typhlichthys subterraneus) is one of the two species of blind cave fishes found in Arkansas. The other is the Ozark cavefish. The southern cavefish is found in the subterranean waters of two major non-overlapping ranges separated by the Mississippi River: in the Ozark Plateau of central and southeastern Missouri and northeastern Arkansas and in the Cumberland and Interior Low plateaus of northwest Alabama, northwest Georgia, central Tennessee, and Kentucky. They are usually found at considerable depths (mostly between 175 and 240 meters below the land surface). This species, which can grow as long as ninety millimeters, has a large, broad head. The caudal fin has from zero to two rows of sensory papillae (one on the upper …

Speckled Pocketbook

aka: Lampsilis streckeri
The speckled pocketbook 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 speckled pocketbook, scientific name Lampsilis streckeri, was described as a species new to science in 1927 by Lorraine Screven Frierson, a naturalist and landowner/merchant/planter residing south of Shreveport in the company town of Frierson, Louisiana. Frierson named the species in honor of his friend, colleague, and fellow naturalist John K. Strecker of Waco, Texas. Adults may reach a length of slightly more than 3.5 inches (or more than 90 millimeters), with a maximum life expectancy …

Sponges

The phylum Porifera, which contains the sponges, is a highly successful group of metazoan animals that includes about 8,600 living species of marine and freshwater forms as well as some that inhabit brackish waters. The majority are marine, but there are about 150 species of freshwater sponges, including twenty-seven to thirty species found in North America north of Mexico. The family Spongillidae is the most speciose and widespread group of freshwater sponges and includes twenty-two genera and more than 130 species from a wide variety of habitats. Seven species of freshwater sponges have been documented in Arkansas. Sponges are an ancient group of asymmetrical invertebrates with a fossil record preceding the early Cambrian period (541 million years ago), and even …

Stoneflies

Stoneflies (Phylum Arthropoda, Class Insecta, Order Plecoptera) are a group of aquatic insects well known to fishermen and biologists worldwide. The name Plecoptera means “braided-wings” from the Ancient Greek plekein and pteryx, which refers to “wing.” The name refers to the complex venation of their two pairs of wings, which are membranous and fold flat over their body. Generally, stoneflies are not strong fliers, and several species are entirely wingless. Stoneflies are called “indicator species” because finding them in freshwater environments generally indicates relatively good water quality, as they are quite intolerant of aquatic pollution. They are also prized and imitated by anglers as artificial tied-flies in trout fishing, particularly on Arkansas rivers such as the Eleven Point, Spring, and …

Strepsiptera

aka: Twisted Wing Parasites
aka: The Stylops
The order Strepsiptera, or twisted wing parasites, belongs to the class Insecta, phylum Arthropoda. It is a very small, cosmopolitan order of bizarre parasitoids containing about 624 named species of minute endopterygote insects with nine extant families. They parasitize thirty-four families and several orders of Insecta, including Blattodea (cockroaches), Diptera (flies), Homoptera (leafhoppers), Mantodea (mantises), Hemiptera (true bugs), Orthoptera (grasshoppers and crickets), Zygentoma (silverfish and firebrats), and Hymenoptera (ants, bees, and wasps). Three species of strepsiptera (halictophagids) have been reported from Arkansas hosts (all leafhoppers, Cicadellidae). Strepsiptera have two major groups: the Stylopidia and Mengenillidia. The former, which has endoparasitic females with multiple genital openings, includes seven families: the Bohartillidae (one extant and two fossil species), Corioxenidae (forty-six extant and …

Striped Bark Scorpions

aka: Centruroides vittatus
The striped bark scorpion, Centruroides vittatus, is the only scorpion species recorded from Arkansas, where it is most abundant in the western part of the state. It is the most widely distributed scorpion species in the United States, having been recorded from Missouri, Arkansas, and Louisiana west to eastern Colorado and New Mexico and south to northeastern Mexico. The front body region, which bears the yellowish-brown pedipalps (pincers) and legs below, has a somewhat triangular median dark spot on top pointing backward and extending beyond the eyes. The wide body region that follows has a distinctive pair of broad, dark, longitudinal bands on top. The slender tail-like postabdomen is uniformly yellowish brown, except for the tip of the stinger, which …

Sturgeons

Sturgeons (primitive Acipenseriform) are an ancient group of fishes dating back to the Triassic Period some 245 to 208 million years ago. True sturgeons appear in the fossil record during the Upper Cretaceous (101 to 66 million years ago). There are about twenty-five species of sturgeons, and all belong to the Family Acipenseridae, Order Acipenseriformes. Sturgeons can be found in subtropical, temperate, and sub-Arctic rivers, lakes, and coastlines of North America, with the greatest diversity in Eurasia. In North America, there are eight species that range along the Atlantic Coast from the Gulf of Mexico to Newfoundland, as well as along the West Coast in major rivers from California and Idaho to British Columbia, Canada. The family contains four genera …

Suckers

aka: Catostomid Fishes
Suckers belong to the Family Catostomidae, Order Cypriniformes, and Class Actinopterygii. There are about seventy-two species and thirteen extant genera of these benthic (bottom-dwelling) freshwater fishes. In Arkansas, there are eighteen species in eight genera. Suckers are Holarctic in distribution and primarily native to North America north of Mexico, but the longnose sucker (Catostomus catostomus) occurs in both North America and northeastern Siberia from Alaska, and the Asiatic Sucker (Myxocyprinus asiaticus) is found in the Yangtze River basin in China. Sucker-like fossils are known from Eocene epoch (56 to 33.9 million years ago) deposits from central Asia, and the fossil genus Amyzon, with Ictiobus and Myxocyprinus affinities, occurs in middle Eocene and Oligocene Epoch (33.9 to 23 million years ago) …

Tarantulas

Tarantulas are the largest spiders in Arkansas and are among the most recognizable. Tarantulas are relative newcomers to Arkansas, having arrived in the state about 8,000 years ago. At that time, the climate of North America was much warmer and drier than it is today. Because of higher temperatures and lower amounts of rainfall, habitats more typical of the southwestern United States and the Great Plains expanded eastward into Arkansas and Missouri. Along with drier habitats came many of the animals associated with them, such as tarantulas and scorpions. As the climate became cooler and wetter about 4,000 years ago, these species did not retreat west. Instead, they became isolated within suitable patches of open, dry habitat surrounded by increasing …

Temperate Basses

aka: Moronids
The temperate basses are freshwater, brackish water, and marine species belonging to the Order Perciformes and Family Moronidae. They are represented by two genera and six species—the North American and northern African Morone (four species) and European Dicentrarchus (two species). In North America, two popular freshwater game fish species, white bass (Morone chrysops) and yellow bass (M. mississippiensis), are native, whereas two others, the anadromous striped bass (M. saxatilis) and brackish water white perch (M. americana), have been successfully introduced into several U.S. states. In Arkansas, M. chrysops, M. mississippiensis, M. saxatilis and, rarely, M. americana are found in various watersheds. In addition, hybrid M. saxatilis × M. chrysops have been cultured and stocked in several Arkansas reservoirs. Morphologically, in …

Thomas, Ruth Harris

Ruth Harris Thomas was a highly regarded amateur ornithologist whose column on birding in Arkansas was published by the Arkansas Gazette for about forty years. Her column not only documented area birds, but it also contributed to a growing appreciation for birds, birding, and habitat conservation. Ruth Harris was born in Kentucky on August 25, 1900, to Charles O. Harris and Columbia B. Cox Harris. She had two brothers. Majoring in English and journalism, Harris graduated from Louisiana State University in 1923, where she also edited the student newspaper. She moved to Little Rock (Pulaski County) in the autumn of 1923 to work as a reporter for the Arkansas Gazette newspaper. In 1927, she married Maine native Stanley Powers Rowland …

Ticks

Ticks belong to the phylum Arthropoda, class Arachnida, subclass Acari, suborder Parasitiformes, and order Ixodida (Metastigmata), which includes almost 900 recognized species. There are three families: Ixodidae, or the “hard” ticks (approximately 700 species); Argasidae, or the “soft” ticks (approximately 200 species); and Nuttalliellidae, containing only a single species, Nuttalliella namaqua, a tick found only in southern Africa. In Arkansas, nine genera and a total of nineteen species (three argasids and sixteen ixodids) are known. Another species, Rhipicephalus (Boophilus) annulatus, has been extirpated from Arkansas. Ticks are a highly specialized group of obligate, bloodsucking, nonpermanent ectoparasitic arthropods of vertebrates (mostly on reptiles, birds, and mammals) and are distributed throughout the world. In addition to being irritating to hosts and causing …

Topminnows

aka: Fundulids
aka: Killifishes
Topminnows belong to the Family Fundulidae, Order Cypriniformes, and Class Actinopterygii. This family also includes some North American killifishes. There are approximately forty-four to forty-six species that are found in the lowlands of North and Central America from southeastern Canada to the Yucatan Peninsula of Mexico, including the Mississippi River drainage, and the islands of Bermuda and Cuba. Most (forty species) of topminnows belong to the genus Fundulus, and others are included in the genera Lucania (three species) and Leptolucania (a single species). The Family Fundulidae is a paraphyletic grouping of members of genera Fundulus and Lucania. There are six species of topminnows found in Arkansas. Topminnows occur in both freshwater and marine waters as well as brackish environments. They …

Trematodes

aka: Flatworms
aka: Flukes
Trematodes (flukes) include parasitic flatworms belonging to the phylum Platyhelminthes, class Trematoda, and subclasses Aspidogastrea (two orders, four families) and Digenea (ten orders, more than seventy-two families). The class numbers between 18,000 and 24,000 species; they are found primarily in a variety of animals, including humans and other vertebrates. Modern phylogenetic analysis reveals that the worms of class Monogenoidea (monogenetic flukes) are no longer included within the Trematoda and are more closely related to tapeworms. The modern mobility of human beings, combined with the international transportation of animals and foodstuffs that can be infected, means that diagnoses can occur well outside the areas where trematode species are endemic. However, while trematodes do occur in Arkansas, they do not pose a …

Turpentine Creek Wildlife Refuge

Turpentine Creek Wildlife Refuge near Eureka Springs (Carroll County) is a 501(c)(3) nonprofit organization providing lifetime homes for abandoned, abused, and neglected big cats and other endangered wildlife. With over 450 acres and more than 120 exotic cats, the refuge is one of the largest big cat sanctuaries in North America licensed by the U.S. Department of Agriculture (USDA). The sanctuary is rated a “Must See” attraction by the Arkansas Department of Parks and Tourism and is one of the most popular destinations in the Eureka Springs area. Don Jackson, a former employee of the Dallas Zoo, along with his wife, Hilda, and their daughter, Tanya Smith, founded the refuge in 1992. After a friend acquired a lion cub and realized …

Venomous Snakes

Arkansas hosts about forty-five species and subspecies of snakes, and six (thirteen percent) are species that use venom to obtain food and to defend themselves. There are two families of venomous snakes in the state: Elapidae (a single elapid species, the Texas coral snake) and Viperidae (five species of pitvipers). All of Arkansas’s venomous snakes inject venom through fangs via muscular contraction of paired venom glands. Texas Coral Snake The Texas coral snake, Micrurus tener tener (formerly Micrurus fulvius tenere) is a tricolored, medium-sized (maximum length = 122 centimeters), secretive elapid snake that primarily occurs in the southern and southwestern part of the state. Verified records are available for only five counties of the state in the Gulf Coastal Plain, …

Western Mosquitofish

aka: Gambusia
The western mosquitofish (Gambusia affinis) belongs to the order Cyprinodontiformes and family Poeciliidae. The name “mosquitofish” is appropriate for this fish because its diet sometimes consists of large numbers of mosquito larvae. The family contains about twenty-one genera and 160 species. There are eight other freshwater species of Gambusia similar in appearance in North America north of Mexico, including the eastern mosquitofish (G. holbrooki), Amistad gambusia (G. amistadensis), Big Bend gambusia (G. gaigei), largespring gambusia (G. geiseri), San Marcos gambusia (G. georgei), Clear Creek gambusia (G. heterochir), Pecos gambusia (G. nobilis), and blotched gambusia (G. senilis). Many of these Gambusia spp. are endemic and afforded protection, as populations are either listed as threatened or endangered. The similar western mosquitofish ranges …

Willow Flycatchers

aka: Empidonax traillii
The willow flycatcher (Empidonax traillii) is the only bird species that has been discovered in the geographic area that is now the state of Arkansas. The noted naturalist and painter John James Audubon found the bird in 1822 while he was traveling near the community of Arkansas Post (Arkansas County), in what was then Arkansas Territory. When Audubon described the species in print for science in 1828, he named it Traill’s flycatcher for his friend Dr. Thomas Traill of Edinburgh, Scotland. Ornithologists have since determined that “Traill’s flycatcher” is really two different species, willow and alder flycatchers, which have almost identical appearances but distinctive vocalizations. The form Audubon discovered is of the species that was renamed willow flycatcher in 1973. …