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An order of actinopterygian fishes that comprise, with the Atheriniformes and Cyprinodontiformes, the series Artherinomorpha. These fishes are identified by the interarcural cartilage that connects the first and second gill arches; small second and third epibranchials; absence of interhyal; a nonprotrusible upper jaw; far posterior placement of the dorsal and anal fins; abdominal pelvic fins; and the lower caudal fin lobed with more principal rays than the upper lobe and significantly longer in needlefishes and flyingfishes. The order consists of 191 species in 38 genera and 5 families. Each family has distinctive features that make identification simple.
Industry:Science
An order of ancestrally wingless Hexapoda comprising about 800 species and variously considered as apterygotan insects or as their independent sister group. These insects are equipped with three pairs of thoracic legs and a pair of antennae on the head. They are slender and white, but unlike typical insects they have intrinsic muscles in the antennal segments beyond the basal one. All diplurans lack eyes, and have paired mandibles and maxillae largely enclosed by fused folds of the head so that only the tips are exposed for retrieving food. The integument is thin and unpigmented, and the posterior end of the abdomen is furnished with a pair of cerci, which may be multisegmented (for example, in the family Campodeidae) or single segmented and modified into a pair of stout, pigmented jaws or forceps (in the family Japygidae and allied families) resembling those of adult earwigs and used for catching prey or for defense. The dipluran body size is usually small, under 0.4 in. (1 cm) long, but some Australian <i>Heterojapyx</i> species reach 2 in. (5 cm).
Industry:Science
An order of ancestrally wingless insects (subclass Apterygota). The order is usually classified into four families in two suborders (Eosentomoidea and Acerentomoidea), and about 500 species are recognized.
Industry:Science
An order of ancestrally wingless insects, commonly known as bristletails, in the subclass Apterygota; about 350 species are known in the two families, Machilidae and Meinertellidae. All have slender, spindle-shaped bodies of about 0.4–0.8 in. (1–2 cm) in length, tapered tailward to a long, multisegmented median caudal filament and paired cerci. The relatively thin integument is covered with pigmented scales after the first instar. The antennae are long and filiform, without intrinsic musculature in the flagellum, as in all true insects; and large, contiguous compound eyes are accompanied by a trio of ocelli. The mandibles are exposed and attached to the cranium by a single joint (condyle), and the maxillary palpi are extended, with seven segments, while the labial palpi have only three segments. Each leg has a large coxa, two-segmented trochanter, femur, tibia, and a two- or three-segmented tarsus terminating in a two-clawed pretarsus. The posterior pair or two pairs of coxae and most of the ventral abdominal coxites bear styles, which may represent modified legs. Outwardly projecting vesicles that are apparently water absorbing also occur on most coxites. Internally, the gut is relatively simple, with small crop, digestive ceca, and a dozen or more Malpighian tubules. The nervous system is primitive, with three thoracic and eight abdominal ganglia and twin connectives. Tracheae are well developed.
Industry:Science
An order of animals, long considered the only order of the mammalian infraclass Metatheria.
Industry:Science
An order of aquatic and semiaquatic flowering plants, division Magnoliophyta (Angiospermae), in the subclass Alismatidae of the class Liliopsida (monocotyledons). The order consists of 10 families and a little more than 200 species. The Potamogetonaceae, with about 100 species, are the largest family of the order, and the name Potamogetonales is sometimes used instead of Najadales for the group. The Najadales are Alismatidae in which the perianth, when present, is not differentiated into evident sepals and petals. Usually the flowers are not individually subtended by bracts. The evolutionary history of the order is in large part a story of floral reduction, associated with progressive adaptation to aquatic and eventually marine habitats. The Zosteraceae of this order are unique among flowering plants in that they grow submersed in the ocean, albeit in shallow water near the shore. <i>Zostera marina</i>, or eelgrass, is a common member of the family.
Industry:Science
An order of aquatic flowering plants, division Magnoliophyta Angiospermae), in the subclass Alismatidae of the class Liliopsida (monocotyledons). The order consists of the single family Hydrocharitaceae, with about 100 species. Within the subclass the order is marked by its inferior, compound ovary with basically laminar placentation. The ovules are scattered over the walls of the individual carpels, which are weakly connate to form partial partitions (intruded placentas) in the ovary. The aquarium plant <i>Vallisneria spiralis</i>, called tape grass or eelgrass, is not a grass but belongs to the Hydrocharitaceae.
Industry:Science
An order of Arachnida with two families, Protoschizomidae (<i>Agastoschizomus</i>, <i>Protoschizomus</i>) and Schizomida (<i>Schizomus</i>, <i>Trithyreus</i>, <i>Megaschizomus</i>), including about 130 described species, mainly in the genus <i>Schizomus</i>. Schizomids occur in most tropical and warm temperate regions, but each species has a restricted distribution. Many undescribed species probably occur in tropical leaf litter and caves. Schizomids are most closely related to Uropygi, with which they share several evolutionary novelties.
Industry:Science
An order of arachnids, the tailed whip scorpions, comprising about 70 species from tropical and warm temperate Asia and the Americas. Most are dark reddish-brown, of medium to giant size, 0.72–2.6 in. (18–65 mm), the largest one being <i>Mastigoproctus giganteus</i> of the southern United States and Mexico. The elongate, flattened body bears in front a pair of greatly thickened, raptorial pedipalps set with many sharp spines and used to hold and crush insect prey. The first pair of legs is elongated and modified into feelers. The abdomen terminates in a slender, many jointed, whiplike flagellum. The uropygids are harmless, nocturnal creatures without poison glands that live in dark places and burrow into the soil. When disturbed, they expel a volatile liquid, with the strong odor of acetic acid, from a gland at the base of the tail. This accounts for the name “vinegaroon” given by many Americans to these much-feared animals.
Industry:Science
An order of articulated brachiopods consisting of a group of sessile, suspension-feeding, marine, benthic, epifaunal bivalves with representatives occurring from the Early Devonian Era. It is most diverse and abundant group of living brachiopods, which probably exhibits maximum diversity in present-day seas.
Industry:Science
