Zoology

Subcategories:
  • No categories
Clear

Entry Category: Zoology

Mayflies

aka: Ephemeropterans
Mayflies belong to the Phylum Arthropoda, Class Insecta, and Order Ephemeroptera. They are a small, wide-ranging, primitive order of insects that is well known to entomologists, biologists, naturalists, and fly fishermen. There are approximately 3,000 species of mayflies described worldwide; these are grouped into over 400 genera within forty-two families. As of 2019, approximately 676 species within twenty-one families were recognized from North America. The southeastern United States has nearly 400 mayfly species, which is more than half of those known from the United States and almost half of those known from North America alone. No single study summarizing mayflies exists specifically for Arkansas, but an investigation from 2010 noted about 117 species of mayflies reported from the state. The …

Megaloptera

aka: Alderflies
aka: Dobsonflies
aka: Fishflies
Megaloptera is an order that is included within the Phylum Arthropoda and Class Insecta. There are about 300 extant species of megalopterans, and these include the alderflies, dobsonflies, and fishflies. There are six families: Corydalidae, Corydasialidae (extinct), Euchauliodidae (extinct), Nanosialidae (extinct), Parasialidae (extinct), and Sialidae. Megalopterans can be found in several Arkansas counties. The Megaloptera were once regarded as a part of a group of insects called Neuroptera, together with the lacewings and snakeflies; however, they are now generally considered to be separate orders, with Neuroptera only referring to the lacewings and their relatives (formerly Planipennia). The former Neuroptera, particularly the lacewing group, are very closely related to each other, and the new name for this group is Neuropterida. This …

Millipedes

There have been around 7,000 species of millipedes (sometimes spelled millipeds) described scientifically, with a projected estimate of possibly 80,000 total species occurring around the globe. Around 900 species have been described from the United States and Canada. However, the family Parajulidae, the largest group from North America, has not been studied thoroughly, suggesting that numerous more species exist in North America. Arkansas has a diverse array of millipede species. Some of them are fairly common, while others are rare. Millipedes—their name meaning “thousand feet”—make up a group of invertebrates (lacking a backbone) in the phylum Arthropoda. Within the Arthropoda phylum, millipedes belong in the subphylum Myriapoda, which includes four classes: Chilopoda (centipedes), Diplopoda (millipedes), Paurapoda (paurapods), and Sumphyla (symphylans). …

Mites

Mites are small arthropods (Phylum Arthropoda) belonging to the Class Arachnida (Subclass Acari) with two or three Superorders as follows: Acariformes (or Actinotrichida), Parasitiformes (or Anactinotrichida), and Opilioacariformes. There are four Orders, Mesostigmata, Prostigmata, Orbatida, and Astigmata. Among the more well-known mites are ticks (Ixodida). There are an estimated 48,200 species of described mites. The phylogeny of the Acari is still debatable, and several different taxonomic schemes have been proposed for their classification. The diversity of the Acari is extraordinary, and its fossil history goes back to at least the early Devonian Period (about 419 million years ago). Mites are very common in Arkansas, with chiggers being a particular pest of humans during warmer months. Historically, references to mites/chiggers go …

Moles

The mammalian family Talpidae includes seventeen genera and forty-two species of moles worldwide in the order Eulipotyphla. Of these, there are four genera and seven species in North America alone. Moles are found in most parts of North America, Asia, and Europe. The family contains all the true moles, and some of their close relatives—including desmans, but these are not normally called “moles” and belong to the subfamily Talpinae. Those species called “shrew moles” denote an intermediate form between the moles and their shrew ancestors. There are three subfamilies of moles, including the Scalopinae (New World moles) with five genera, Talpinae (Old World, desmans, and shrew moles) with nine genera, and Uropsilinae (Asian shrew-like moles) with a single genus. The …

Molluscs

aka: Mollusks
The phylum Mollusca is a major invertebrate group known commonly as “molluscs” (sometimes spelled “mollusks”), which includes about 85,000 living species (although this number varies), with another 60,000 to 100,000 additional fossil species. This phylum is ranked second only to the Phylum Arthropoda in number of living species. Included within the diverse phylum are snails, slugs, cowries, squids, clams, mussels, limpets, oysters, scallops, octopi, cuttlefish, and a myriad of additional groups such as the little-known chitons, monoplacophorans, and tusk shells. Malacology is the scientific study of molluscs, and a specialist who studies them is known as a malacologist. Two classes of molluscs inhabit Arkansas: the Gastropoda and the Bivalvia. Approximately eighty-five species of bivalves are known from the state, while …

Monogeneans

The class Monogenoidea is a fairly large group of parasitic flatworms belonging to the phylum Platyhelminthes. Monogeneans are generally found on bony fishes in freshwater and marine habitats. Although some are endoparasites in the urinary bladder and eyes, most monogeneans are ectoparasites that attach to their host’s skin or gills by a special posteriorly positioned attachment organ called a haptor. The class contains about nine orders, fifty families, and 4,000–5,000 species. The genus Dactylogyrus is one of the largest genera, with nearly 1,000 species. Some taxonomists divide the Monogenoidea into two or three subclasses based on the complexity of their haptor. Those in the subclass Monopisthocotylea have one main part to the haptor, often with hooks or a large attachment …

Mullets

aka: Gray Mullets
aka: Flathead Gray Mullets
Fishes commonly known as mullets, of the Family Mugilidae and Order Mugiliformes, are a group of more than seventy mostly marine species within some fifteen to twenty-five genera. The genus Mugil is cosmopolitan in distribution except in upper latitudes, and at least five species occur in North America. The latest evidence suggests that mullets are most closely related to atherinomorph fishes (silversides and topminnows). Although most mullets are strictly marine, the striped mullet (Mugil cephalus) has the physiological ability to travel between freshwater and salt water, spending much of its life in streams. It is a cosmopolitan resident of estuaries, temperate and tropical oceans, salt marshes, and shoreline areas along the Atlantic Coast of Nova Scotia south to Mexico and Brazil. …

Mysid Shrimps

aka: Opossum Shrimps
Mysida is an order of small, shrimp-like crustaceans in the Class Malacostraca and Superorder Peracarida, with two families, Mysidae (nine subfamilies) and Petalopthalmidae (two subfamilies); 178 genera; and 1,132 species. Most are marine species, but there are about 72 freshwater species, being predominantly found in the Palearctic and Neotropical biogeographical realms. The first report of a species of mysid shrimp documented in Arkansas was in 2012. Species within the order are found throughout the world across a broad range of habitats, such as subterranean, freshwater, and brackish. They can also be found in shallow coastal waters and in surface to deep-sea habitats. In marine waters, they can be benthic (living on the seabed) or pelagic (living in mid-water), but they …

Myxozoans

Myxozoans are a group of microscopic, oligocellular, obligate endoparasites that belong to the Phylum Cnidaria, which also includes sea anemones, box jellies, corals, true jellies, sea pens, and hydrozoans. There are two parasitic classes, the Malacosporea and Myxosporea, and more than 2,200 nominal species of myxozoans classified into sixty-four genera and seventeen families. Myxozoans were, for years, placed within their own phylum (Myxozoa). Similarities to cnidarians had been noted at various times but not firmly until 2007. Although morphological and genetic evidence support placement of the Myxozoa as cnidarians, and this taxonomy has been followed by some authorities, others have not reached the same conclusion; exactly where the Myxozoa fit in this taxonomic scheme is not yet entirely known. Less …

Nematodes

aka: Roundworms
The phylum Nematoda includes three classes (Anoplea, Chromodorea, and Rhabditida), sixteen to twenty orders, and about 27,000 described species (and possibly up to one million) of mostly dioecious, elongate, bilaterally symmetrical pseudocoelomate worms. They can be found in abundance in nearly every habitat on Earth, with a diverse array of species existing in both marine and terrestrial habitats. Most are free-living, with less than half considered to be parasitic. Nevertheless, many species threaten the health of plants and animals (including humans) on a global scale. Nematodes are variable in size from less than one millimeter to more than one meter in length. They have been in existence for an estimated one billion years, having evolved from simple animals some 400 …

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 …

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, …