Science and Medicine

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Entry Category: Science and Medicine

Nimrod Dam and Lake

Nimrod Dam in western Perry County is the oldest project of the U.S. Army Corps of Engineers in the state of Arkansas, created to control flooding along the Fourche La Fave River. Nimrod Lake, the reservoir created by the dam, stretches across the border of Perry and Yell counties and is a popular attraction for fishermen and duck hunters. The dam and lake take their names from the nearby community of Nimrod (Perry County), itself named after the biblical figure. The construction of Nimrod Dam was authorized by the Flood Control Act of 1938. Damming the Fourche La Fave was considered an economical means of protecting communities and valuable crop land in Yell and Perry counties, as well as lessening …

Nix, Joe Franklin

Joe Nix is a water chemist, environmentalist, naturalist, and educator considered by many to be the watchdog of Arkansas rivers and lakes with respect to water quality and usage patterns. His mission has been to have society use good scientific data in making decisions about environmental matters. Joe Franklin Nix was born on August 28, 1939, the only child of Frank and Era Nix, in Malvern (Hot Spring County). His father was a mechanic; his mother was a homemaker. He was a sickly child, so the doctor advised that he spend a lot of time outdoors. As a youth, he fell under the personal tutelage of family friend and former state geologist Joe Kimzey of Magnet Cove (Hot Spring County). …

Norfork Dam and Lake

Built on the North Fork River, just upstream from its confluence with the White River in Baxter County in north-central Arkansas, Norfork Dam and Lake are named after the nearby town of Norfork (Baxter County). The dam was authorized by Congress in the Flood Control Act of 1938, and construction began in the spring of 1941, making it one of the oldest U.S. Army Corps of Engineers’ multi-purpose concrete structures. The reservoir extends north from the dam site to near Tecumseh, Missouri, and covers portions of Baxter and Fulton counties in Arkansas and Ozark County in Missouri. The drainage area controlled by the reservoir is about 1,806 square miles. The project also contains a powerhouse that houses the generators and …

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 …

Novaculite

Novaculite is a hard, dense, white-to-grayish-black sedimentary rock, composed of microcrystalline quartz. It is translucent on its thin, sharp edges and usually breaks with a smooth conchoidal (shell-like) fracture. The word “novaculite” is derived from a Latin word meaning “razor stone.” Novaculite is found in the Ouachita Mountains in formations that are highly resistant to erosion. These formations range from about 250 to 900 feet in thickness. There are two categories of Arkansas novaculite classified by the abrasives industry. The “Washita” stone has the dull luster of unglazed porcelain. It is more porous and less dense than the “Arkansas” stone, which is extremely fine-grained with a waxy luster. There has been recent interest in the fine-grained novaculite as a lapidary …

Nuttall, Thomas

Thomas Nuttall, a preeminent and far-ranging field naturalist, participated in the early scientific exploration of Arkansas and is remembered both for identifying a number of the state’s plants and for his description of early Arkansas life. His notes on people living in the territory—both Native Americans and American settlers—have provided valuable information for historians and researchers ever since they were first published in 1821. Thomas Nuttall was born to James Nuttall and Margaret Hardacre Nuttall on January 5, 1786, in Long Preston, Yorkshire, England. He was the oldest of three siblings; he had two sisters, Susan (Susannah) and Elizabeth. He never married and had no children. After attending the village school, Nuttall worked as a journeyman printer for his uncle …

Obesity

Obesity is a complex issue impacting every segment of the population and having many roots. The drivers and health effects of obesity are not fully understood but may be contextualized within the United States’ transition from a farm-based to an industrialized economy. Arkansas consistently ranks as one of the most obese states in the United States. Historically, most efforts to combat obesity have focused on individual-level interventions. Arkansas Act 1220 of 2003, which created the Child Health Advisory Committee, was among the first and most comprehensive statewide legislative initiatives to combat childhood obesity by focusing on creating healthier public school environments. Similar initiatives have proliferated since obesity has become a global health issue. Although widely discussed as a major risk …

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 …

Ogden, Mahlon Dickerson

Mahlon Dickerson (M. D.) Ogden was a physician who cofounded Trinity Hospital of Little Rock (Pulaski County) in 1923. At Trinity, he pioneered the use of the health maintenance organization (HMO)—a form of health insurance in which member physicians provide medical care to subscribers for a fixed fee—in Arkansas. Born on December 5, 1881, in Little Rock, M. D. Ogden was the only son of railroad clerk Charles Cullen Ogden and his wife, Altamira Deason Ogden. An older cousin, Fred R. Bryson, was adopted into the family and became Ogden’s legal brother. Educated in the local schools, Ogden graduated from the Arkansas Medical School (now the University of Arkansas for Medical Sciences) in 1904. From 1905 to 1916, he taught …

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, …

Orto, Zaphney

Zaphney Orto, a prominent physician who helped discover the link between malaria and mosquitoes, was a U.S. army major and surgeon during the Spanish-American War, and the second president of Simmons First National Bank, founded in Pine Bluff (Jefferson County). Born to Leonidas Orto and Martha G. McElwee Orto in Somerville, Tennessee, in 1842, Zaphney Orto lived on a farm near Somerville until he was eighteen, then worked in a store for two years. He studied medicine with Dr. S. W. Thompson of Evansville, Indiana, and graduated from the Miami Medical College of Cincinnati, Ohio, in 1872. Shortly afterward, he moved to Arkansas, where he settled in Clover Bend (Lawrence County). He practiced medicine there for two years before moving …

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 Mountains Biological Station

The Ouachita Mountains Biological Station (OMBS) began serving the needs of colleges and universities as a research and education center in 1962. The OMBS was the vision of husband-and-wife team Dr. Richard K. (Dick) Speairs Jr. (1920‒2004) and Dr. Betty McKnight Speairs (1925‒2018), formerly of Louisiana State University and Centenary College (both in Shreveport, Louisiana), respectively. Together they founded the Speairs Charitable Foundation for the perpetual support of the OMBS. The station hosts collegiate groups, graduate students, faculty, and researchers for any aspect of field research and biological education. It is available at any time during the year by reservation only. The OMBS is located in the central part of the Ouachita Mountains of Arkansas, between the towns of Mena …

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 …

Paragould Meteorite

Two, possibly three, huge rocks from outer space put the Arkansas town of Paragould (Greene County) into the history and science books early in 1930. What is now known as the Paragould Meteorite was, at that time, the largest meteorite to ever have been seen falling and then recovered. A belt of rocks known as the asteroid belt, left over from the formation of the solar system, orbits the sun mainly between the orbits of planets Mars and Jupiter. Due to the gravity of nearby Jupiter, some of these rocks can stray inward and cross Earth’s orbit, even striking it. At 4:08 a.m. on February 17, 1930, the orbit of one of these rocks crossed Earth’s orbit, and two fields …

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 …