Entries - Entry Category: Zoology

Nematomorpha

aka: Horsehair Worms
aka: Hairworms

Horsehair worms belong to the phylum Nematomorpha and are typically obligate parasites of terrestrial arthropods (e.g., beetles, crickets, cockroaches, locusts, grasshoppers, and mantids). As adults, however, they are free-living in aquatic environments. These worms are sometimes found in coiled clusters termed “Gordian knots” from the intricate legendary knot of Greek mythology. Another myth is related to the common name given these worms, “hairworms” or “horsehair worms,” originating from the idea that horse hairs that fell into water became worms. This belief was not disproved scientifically until American anatomist and paleontologist Joseph Leidy (1823–1891) noted in 1870 that horse hairs placed in water for many months did not come to life. The first published report of a horsehair worm from Arkansas …

Nemertea

aka: Ribbon Worms

The phylum Nemertea is an invertebrate phylum that contains over 1,000 species within 250 genera of mostly marine organisms known variously as ribbon, proboscis, or nemertean worms. Only a few taxa inhabit freshwater, and there are several terrestrial species. Most are free living; however, a few are known to be parasitic. The name means one of “Nereis” (unerring one), which refers to the unerring aim of the proboscis. Ribbon worms are unique in having an eversible muscular proboscis that is used for grasping prey. It lies free inside of a cavity above the alimentary canal known as the rhynchocoel. This muscular tube can be swiftly thrust out to catch prey items. This phylum is also occasionally called the Rhynchocoela, which …

Neuropterans

aka: Net-Winged Insects

Neuropterans belong to the Phylum Arthropoda, Class Insecta, and Order Neuroptera. The Neuroptera (antlions, lacewings, mantidflies, and their relatives) and allied orders Megaloptera (dobsonflies, alderflies) and Raphidioptera (snakeflies) together make up the clade Neuropterida. There are three suborders (Osmyloidea, Hemerobiiformia, and Myrmeleontiformia) and nine extinct and fifteen extant families. There are about 6,400 species in the group worldwide, with about 450 found in the United States and Canada. Neuropterans can be found on all continents except Antarctica. There are several types of neuropterans in Arkansas. In the fossil record, neuropterans first appeared during end of the Permian period (251 million years ago), which ended in the largest mass extinction the Earth ever experienced, as shown by fossils of the Permithonidae …

Northern Snakehead

aka: Channa argus
aka: Snakehead

The northern snakehead (Channa argus) is a modern bony fish belonging to the family Channidae. It is native to China, eastern Russia, and parts of the Korean peninsula. The fish was discovered in Arkansas in 2008, leading to attempts to eradicate it. The northern snakehead has an elongate body, with long dorsal and anal fins, and a truncated tail. Coloration is dark tan to brown with darker spots laterally, extending above and below the midline. The jaws have sharp, pointed teeth. The fish can reach a size of one meter and weigh as much as eight kilograms. The northern snakehead breathes with gills but also possesses a suprabranchial organ, which consists of chambers filled with folded tissue that allow atmospheric …

Odonates

aka: Dragonflies
aka: Damselflies

Odonates belong to the Phylum Arthropoda, Subclass Pterygota (winged insects), Class Insecta, and Order Odonata. The famous entomologist Johan Christian Fabricius (1745‒1808), who was the first to provide the name Odonata, apparently used that name because they have “teeth” on their mandibles. Odonates are considered a wide-ranging, primitive order of carnivorous aquatic insects. About 102 species have been documented in Arkansas. One of the two extant suborders of the Odonata (the order to which dragonflies and damselflies belong) is the Epiprocta. This new classification was proposed relatively recently to accommodate the inclusion of the suborder Anisozygoptera. The latter taxon has been shown not to be a natural suborder but somewhat of a paraphyletic collection of lineages, so it has been …

Official State Dinosaur

aka: Arkansas Dinosaur
aka: Arkansaurus fridayi

In August 1972, Joe B. Friday discovered the remains of the right hind foot of a dinosaur in a shallow pit on his land in Lockesburg (Sevier County). He found the bones in rocks belonging to the Lower Cretaceous Trinity Group, which consists of deposits of clay, sand, gravel, limestone, and the evaporite minerals gypsum and celestite. Friday donated the bones to the University of Arkansas (UA) in Fayetteville (Washington County), where they are kept in the University Museum Collections at the Arkansas Archeological Survey. UA professor James Harrison Quinn gave the bones the informal name “Arkansaurus fridayi” in 1973. He cleaned and assembled the bones and compared them to the feet of two similar-appearing dinosaurs previously described in the …

Opalinids

Opalinids are a small group of peculiar cosmopolitan organisms that belong to the kingdom Protista. Recent classification places the opalinids as heterotrophic stramenopiles (heterokonts) within the phylum Placidozoa, class Opalinea, and order Slopalinida. There are over 200 species, and, although opalinids are typically endocommensals (that is, living within the host without affecting it) in the large intestine and cloaca of anurans (frogs and toads), they have also been reported from fish, salamanders, reptiles, and some invertebrates (mollusks and insects). They are of no medical or economic importance, but they are interesting because their reproductive cycles are apparently controlled by the host’s hormones. In addition, opalinids are routinely encountered in dissections of frogs in college biology laboratories, and most students are …

Opossums

aka: Possums
aka: Didelphis virginiana

Arkansas opossums (commonly referred to as “possums”) are of the Virginia opossum species Didelphis virginiana and can be found in both rural and urban habitats. The Arkansas Game and Fish Commission tracks opossum populations and oversees an opossum hunting season during the winter months. As the only marsupials found in North America, opossums have existed for 70–80 million years. They are highly adaptable omnivores who eat a variety of foods including insects, rodents, berries, grasses, leaves, and carrion. The females can have twenty to twenty-five babies in one litter and carry their young in their pouches for up to three months. Opossums have opposable thumbs on their rear feet and can also grasp with their tails. Contrary to popular belief, …

Ostracods

aka: Seed Shrimps
aka: Mussel Shrimps

Ostracods belong to the Class Ostracoda within the Subphylum Crustacea and Phylum Arthropoda. Commonly called “seed or mussel shrimps,” the class encompasses over 33,000 described species and subspecies, and many more remain unknown to science and await formal description. There are two subclasses with living representatives: the Myodocopa and Podocopa. The former is exclusive to marine environments but occupies the benthos as well as the plankton, whereas podocopans occur in marine, brackish, and freshwater environments and occupy almost exclusively the benthos (but also the benthopelagic zone). The main orders are the Archaeocopida, Leperditicopida, Palaeocopida, Podocopida, and Myodocopida. As of 2019, there is no comprehensive list of extant ostracods in Arkansas. Ostracods are important fossil organisms, as they are the most …

Ouachita Streambed Salamander

The Ouachita streambed salamander (Eurycea subfluvicola) is a species belonging to the Class Amphibia, Order Caudata, and Family Plethodontidae. It is a relatively newly described Arkansas endemic species, found at a single locality in the Ouachita Mountain physiographic province, and has one of the smallest, perhaps the smallest, known geographic distribution of any North American salamander. The original specimen was collected in May 2011 by researchers from the Arkansas Game and Fish Commission and Tulsa University in Oklahoma. Because the specimen was similar in morphology to the larvae of many-ribbed salamanders (Eurycea multiplicata), which are common in the area and inhabit the same stream, collectors did not initially realize they might have a new species in hand. Once they returned …

Ozark Cavefish

aka: Amblyopsis rosae

The Ozark cavefish (Amblyopsis rosae) is found in the Springfield Plateau of the Ozark Mountains. Its geographic distribution covers approximately 8,200 square miles (21,000 square kilometers), comprising an area drained by the White River on the south and the east, the Neosho River (Arkansas River basin) on the west, and the Osage River (Missouri River basin) to the north. This species has been reported in at least fifty-two caves over three states: Missouri, Arkansas (originally in ten but now in seven sites in Benton County), and northeast Oklahoma. It has been proposed that there are two subspecies of this fish: Amblyopsis rosae whitae for the White River drainage region and Amblyopsis rosae arkansasus for the middle Arkansas River drainage region. …

Ozark Hellbender

aka: Cryptobranchus alleganiensis bishopi

The salamander called the Ozark hellbender (Cryptobranchus alleganiensis bishopi) is one of two subspecies of hellbender (Cryptobranchus alleganiensis). Historically, the eastern hellbender (C.a. alleganiensis) is found throughout much of the upland areas of the United States east of the Mississippi River; it also inhabits northern portions of the Ozark Mountains of Missouri. The Ozark hellbender occurs in several southern-flowing streams of the Ozark Mountains of Missouri and has a very restricted range in Arkansas, occurring only in the upper reaches of the Spring River, in portions of the Eleven Point River in Randolph County, and in the White River at Batesville (Independence County) and near the town of Norfork (Baxter County). The hellbender, North America’s largest salamander, sometimes grows to …

Ozark Pocket Gopher

aka: Geomys bursarius ozarkensis

The Ozark pocket gopher is a small mammal that belongs to the family Geomyidae (pocket gophers) and the order Rodentia (rodents). It is endemic to Arkansas, occurring in Izard County. The common name “pocket gopher” comes from the fur-lined cheek pouches that these animals use to carry food. Two species of pocket gophers live in Arkansas. Geomys bursarius can be found from southern Manitoba southward through the central plains of the United States toward Arkansas and Texas, with the subspecies G. b. ozarkensis found in the southwestern one-third of Izard County in Arkansas. Although a few individuals have been captured on the southern side of the White River in adjacent Stone County, no current population resides in any other county …

Paddlefish

aka: Spoonbill Catfish

Paddlefish belong to the family Polyodontidae and order Acipensiformes. There are six known species—four are extinct (three from western North America, one from China) and known only from fossil remains, while two extant species include the paddlefish (Polyodon spathula), which is native to the Mississippi River basin in the United States, and the gigantic critically endangered Chinese paddlefish (Psephurus gladius) endemic to the Yangtze River Basin in China, where they lived primarily in the broad-surfaced main stem rivers and shoal zones along the East China Sea. Paddlefish are basal Chondrostean ray-finned fish; they are archaic and have been referred to as “primitive fish” because they have evolved with few unique morphological changes since the earliest fossil records of the late …

Parasitic Crustaceans

The Subphylum Crustacea (Phylum Arthropoda) represents a diverse group of animals with members within several classes and orders, including the Amphipoda, Branchiura, Cirripedia, Copepoda, Isopoda, and Tantulocarida. (The Pentastomida, composed of parasites, are sometimes included in this subphylum and sometimes considered a separate phylum.) There are two classes with parasites: the Maxillopoda and Malacostraca. The majority of crustaceans are aquatic, living in either marine environments or fresh water, but a few groups have adapted to a terrestrial existence, such as some species of crabs and woodlice. Most crustaceans move about independently and live a free existence, although some are parasitic (about 30,000 named species) and live attached as ectoparasites to their hosts, including fish, sea, and whale lice, as well …

Passenger Pigeons

aka: Ectopistes migratorius

The passenger pigeon (Ectopistes migratorius) was a North American bird species in the order Columbiformes (pigeons and doves) that became extinct in the early twentieth century. The fate of the passenger pigeon serves as a graphic lesson in the misuse of natural resources, as the species went from an almost indescribable abundance to extinction in only a few decades. The decline came primarily as a result of relentless persecution of its breeding colonies by market hunters, largely for meat, with no (or ineffectual) regulation that might have maintained a stable population. The passenger pigeon had the same general body shape as the common and familiar mourning dove (Zenaida macroura) but was larger and somewhat more colorful, with areas of slate-blue …

Pauropoda

Pauropods belong to the Phylum Arthropoda, Subphylum Labiata, Superclass Myriapoda, and Class Pauropoda. They are small, pale, millipede-like arthropods. There are about 830 species in twelve families worldwide, and they live under rocks in moist soil, leaf mold, and woodland litter. Only a single species, Eurypauropus spinosus, has been reported from Arkansas, but there are likely more that would be uncovered with further research. The only known fossil pauropod is Eopauropus balticus, a prehistoric species known from mid-Eocene Baltic amber (40 to 35 million years ago). Because pauropods are normally soil-dwelling, their presence in amber (fossilized tree sap) is unusual, and they are the rarest known animals in Baltic amber. They appear to be an old group closely related to …

Pentastomes

aka: Tongue Worms

The phylum Pentastomida (some consider it a class) includes four orders, seven families, and about 144 species, including eight extinct species from the Paleozoic Era. They are wormlike obligate parasites, meaning that they cannot complete their life cycle without a host. As adults, they inhabit the respiratory tract (lungs and nasal passages) of vertebrates. Four species are known from intermediate host insects (three coprophagus cockroaches and one coleopteran). In addition, fishes are common intermediate hosts for pentastomes occurring in crocodilians and piscivorous chelonians, and rarely for some species of snakes. Definitive hosts include amphibians (few hosts) but mainly reptiles (lizards, snakes, freshwater turtles, and crocodilians), the latter making up about seventy percent of hosts. The most common genera of reptilian …

Percidae

The Percidae is a family containing three subfamilies and approximately 250 species within eleven genera of perciform fishes found mostly in freshwater and brackish waters of the Northern Hemisphere. Most are found in the Nearctic realm. It is one of the largest families in North America, making up about one-fifth of all fish biota, only outnumbered by the Cyprinidae. There are also some Palearctic (Eurasian) species in the genera Gymnocephalus (four species), Percarina (two species), Romanichthys (single species), and Zingel (four species). The family includes the perches and their relatives, with some well-known species such as the ruffe, sauger, walleye, and three species of perch. However, much smaller fishes restricted to North America known as darters are also an integral …

Pillstrom Tongs

Pillstrom Tongs were invented by Lawrence G. Pillstrom MD for the safe capture of snakes for scientific research. The company eventually began shipping these unique, safe herpetological tools all over the world. They are used by zoos, animal control agencies, specialty animal handlers, collectors, and others. The company expanded upon the line of original snake tongs and modified them to be used for hunting frogs, pruning trees, cooking outdoors, picking up aluminum cans, and more. In 1953, as a young student at what is now the University of Arkansas for Medical Sciences (UAMS) in Little Rock (Pulaski County), Pillstrom began some early studies and medical research of snake venom and its effects. As a key part of his doctoral work, …

Pirate Perch

The pirate perch (Aphredoderus sayanus) belongs to the order Aphredoderiformes (or by some sources, Percopsiformes) and family Aphredoderidae. There are two subspecies, A. s. sayanus and A. s. gibbosus. It is the only living member of the family and ranges from the Atlantic and Gulf slopes from Michigan, Wisconsin, Minnesota, and New York south to the Gulf of Mexico and west to the Brazos River drainage, Texas. In Arkansas, A. sayanus occurs throughout the Coastal Plain physiographic region extending westward into the central areas of the state. It is quite rare in the Ozark uplands, and there are no records from the northwestern part of the state. The Aphredoderidae contains one fossil genus, Trichophanes, with possibly two of three valid …

Planarians

aka: Triclads

There are at least seven species of planarians found in Arkansas, on land and in water. Planarians belong to the superphylum Lophotrochozoa, phylum Platyhelminthes, subphylum Catenulidea, class Rhabditophora (some consider the artificial grouping Turbellaria), order Tricladida, suborder Paludicola, and families Dugesiidae, Kenkiidae, Planariidae, and Dendrocoelidae. These flatworms are often simply referred to as triclads or triclad worms. Currently, the order Tricladida is split into three suborders, including the marine forms (Maricola); those found mostly in freshwater habitats of caves, although at least one species occurs in surface waters (Cavernicola); and land planarians/freshwater triclads (Continenticola). Scientists have argued about the systematics of platyhelminths for many years, and with the advent of molecular approaches (18S and 28S ribosomal DNA sequences), older classification …

Proturans

aka: Coneheads

Proturans belong to the Phylum Euarthropoda, Class Entognatha, and Class Protura. The Protura constitute a taxon of hexapods that were previously thought to be insects and now are considered as a class on their own. Proturans are cosmopolitan in distribution (except for both polar regions and snow zones of mountains) with more than 800 described species belonging to three distinct orders (Acerentomata, Eosentomata, and Sinentomata) and seven families (Acerentomidae, Antelientomidae Eosentomidae, Fujientomidae, Hesperentomidae, Protentomidae, and Sinentomidae). As of 2019, seventy-six genera are known worldwide, with nearly 300 species contained within the single cosmopolitan genus, Eosentomon. There are about twenty-six species in North America, though there is no exact number of species reported, to date, from Arkansas. However, four species of …

Pseudoscorpions

aka: False Scorpions
aka: Book Scorpions

Pseudoscorpions belong to the phylum Arthropoda, class Arachnida, order Pseudoscorpionida, and two suborders (Epiocheirata and Iocheirata). There are more than 3,300 species within about 430 genera, with more described as new species regularly. They are cosmopolitan in distribution and occur in a variety of habitats from temperate to cold regions from Northern Ontario, Canada, and above the timberline in the Rocky Mountains of Wyoming in the United States to the karst system of the Jenolan Caves of New South Wales, Australia. However, pseudoscorpions are most dense with diverse populations in the tropics and subtropics, where they can be found on island territories such as the Canary Islands, where about twenty-five endemic species have been reported. There are also two endemic …

Razorback Hogs

Arkansas was known for its razorback hogs long before the University of Arkansas mascot came into being. These wild boars were called razorbacks because of their high, hair-covered backbone and ill-mannered temper. The razorback hog was considered ruthless and dangerous when backed into a corner. The true wild boar, also called the European or Russian boar, is not native to the United States. Christopher Columbus introduced their domesticated ancestors to the New World in 1493. Wild boars are thought to have arrived with explorer Hernando de Soto, who brought the original thirteen grunting hogs to the new world in 1539, though this theory has lately been cast into doubt by Charles Hudson, who reconstructs de Soto’s path in his book, …

Red-cockaded Woodpeckers

aka: Picoides borealis

With the exception of the recently rediscovered ivory-billed woodpecker, red-cockaded woodpeckers (Picoides borealis) are the rarest of Arkansas’s nesting woodpeckers. A century ago, the bird was common in mature, open pine stands. Its natural range included millions of acres of pine habitat throughout the southeast United States. An estimated ninety-nine percent of suitable habitat was lost because of logging, wildfire suppression, conversion to agricultural lands, and urbanization. Best estimates range-wide indicate an original population numbering over four million. By the time the bird was declared endangered, it had declined to an estimated 10,000. The Arkansas population dwindled to under 400 birds. The red-cockaded woodpecker was designated as endangered on October 13, 1970. It received formal legal protection with the passage …

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 was located on 330 acres outside of Greenbrier (Faulkner County). The sanctuary provided a permanent home for African and Asian elephants in need of sanctuary for any reason, regardless of age, sex, species, health, or temperament. Elephants came from private owners, circuses, or zoos. The 501(c)(3) nonprofit sanctuary—which raised money through grants and donations—housed up to a dozen elephants at any given time, with several baby elephants born at the facility. 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) …

Symphylans

aka: Glasshouse Symphylans
aka: Garden Centipedes
aka: Pseudocentipedes

Symphylans belong to the Phylum Arthropoda, Subphylum Labiata, Superclass Myriapoda, and Class Symphyla. About 200 species of symphylans are known worldwide, predominantly in the tropics. There are two families: Scutigerellidae with five genera and about 128 species, and Scolopendrellidae containing nine genera and approximately seventy-three species. There are few reports of symphylans in Arkansas, aside from a new endemic scutigerellid species described in 1992 in Polk County. Many taxa are yet to be discovered and described in the state. The fossil record of symphylans is poorly known; only five species have been recorded, all placed within living genera. They are ancestral arthropods dating back to the early Silurian approximately 430 million years ago, although the only fossil symphylans are known …

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 …

Tardigrades

aka: Water Bears
aka: Moss Piglets

Tardigrades (sometimes called water bears or moss piglets) are microscopic members of the Phylum Tardigrada, numbering more than sixty-seven subspecies, 1,018 species, four subgenera, 105 genera, fifteen subfamilies, twenty families, five orders, and three classes. Of these, there are fifty-four genera and 380 species known from the Americas, 245 species from the Nearctic ecozone, and 251 in the Neotropical ecozone. Several species of tardigrades can be found in Arkansas. Discovered in 1773 by the German entomologist and pastor Johann August Ephraim Goeze (1731–1793), they were nicknamed “water bears” because of their plump, bear-like appearance; legs with claws; and slow, lumbering gait. The name Tardigrada (“slow steppers”) was given in 1777 by the Italian Catholic priest, biologist, and physiologist Lazzaro Spallanzani …

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 …

Termites

aka: Isopterans

Termites belong to the Phylum Arthropoda, Class Insecta, Infraorder Isoptera, and Order Blattodea. They were formerly placed in a separate order (Isoptera) from the cockroaches (Blattodea), but Isoptera is currently classified at the taxonomic rank of infraorder. About 3,106 species are currently described within twelve families, with a few hundred more to still be described. There are several species of termites in Arkansas. Termites are among the most successful groups of insects on Earth, colonizing all continents except Antarctica. Comparatively speaking, the diversity of termite species is rather low in North America and Europe (fifty species are known from North America, and only ten species occur in Europe), but it is higher in South America, where over 400 species are …

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 …