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An order in the class Lycopsida that diverged from the Lepidodendrales in the Late Devonian. These two groups have several characters that are not found in other lycopsids, notably a centralized, shootlike rooting structure (rhizomorph) that allows finite growth, wood production, and tree-sized dimensions. Isoetaleans evolved from trees as an increasingly specialized and reduced lineage; all but the earliest are small-bodied shrubs and pseudoherbs. A reduced morphology characterizes the only living isoetalean genus, <i>Isoetes</i>.
Industry:Science
An order in the cnidarian class Scyphozoa that is probably the most recently evolved, most species-rich, and possibly most morphologically diverse.
Industry:Science
An order included in the Dictyoptera, and comprising 3500–4000 insect species, commonly known as roaches. The fossil record extends back some 400 million years, and roaches were found in abundance in the Carboniferous age. Blattaria are grouped with orders Isoptera (termites) and Mantodea (mantids) within the Dictyoptera. In fact, recent studies support the notion that termites are social roaches; Isoptera appear to be a sister group of roach species in the genus <i>Cryptocercus</i> that, like termites, digest wood with the aid of symbiotic intestinal protozoans.
Industry:Science
An order of about 219 species of teleost fishes ranked in four suborders. The order is distinguished by certain skeletal specializations of the gill arches that are unknown in other teleost fishes. They share characters with the order Myctophiformes (lanternfishes) to the extent that they are combined under the ordinal name Myctophiformes by some authors. In both orders the premaxilla excludes the maxilla from the gape of the mouth; the mouth is not protractile; an adipose fin is usually present; the caudal fin is forked; pelvic fins are usually abdominal; light-producing organs are often present; a swim bladder, if present, is physoclistous (not connected to the gut); and some families have hermaphroditic species with self-fertilization.
Industry:Science
An order of Acantharia. In this group of protozoa, skeletons typically include a latticework shell, although the characteristic skeletal rods are recognizable. The latticework may be spherical or ovoid, is fused with the skeletal rods, and is typically concentric with the central capsule. The body is usually covered with a single or double gelatinous sheath through which the skeletal rods emerge. Myonemes (usually a specific number) extend from the gelatinous sheath to each skeletal rod. These marine forms live mostly below depths of 150–200 ft (45–60 m). The order includes <i>Coleaspis, Diploconus, Dorotaspis</i>, and many other genera.
Industry:Science
An order of actinopterygian (ray-finned) fishes that comprise, with the Beloniformes and Cyprinodonti-formes, the series Artherinomorpha. Atherinimorphs are more or less intermediate between typical soft-rayed and spiny-rayed fishes, but are not thought to be the ancestry of the latter. The order Atheriniformes, consisting of about 285 species in six families, are relatively small fishes, usually with an elongate body; opercular and preopercular margins lacking spines or serrations; lateral line absent or nearly so; usually two dorsal fins, with the first, if present, having weak spines; an anal fin larger than the soft dorsal fin and usually preceded by one spine; and usually abdominal pelvic fins, but subthoracic or absent in some (see family Phallostethidae below).
Industry:Science
An order of actinopterygian fishes in the subclass Chondrostei, which probably originated from palaeonisciform ancestors during the Triassic or Jurassic periods. Acipenseriformes, the only extant order of about 10 orders of chondrosteans, are characterized by a largely cartilaginous skeleton, heterocercal tail, fins with more than one ray per pterygiophore, spiral valve intestine, myodome and preopercle reduced or absent, and gular plate absent. The cartilaginous skeleton of Acipenseriformes, long regarded as primitive, was taken as indicative of an alliance with the Chondrichthyes; however, cartilage is secondary and the true relationship is with bony fishes.
Industry:Science
An order of actinopterygian fishes in the subclass Neopterygii. Amiiformes plus several related fossil orders comprise the Halecomorphi, a well-developed group known from the middle Mesozoic. The Amiiformes comprise several families that persisted into the Cenozoic era; but only one, the Amiidae, survived to the present and it consists of a single species, <i>Amia calva</i>, the bowfin. The fossil amiids are from freshwater deposits, the oldest of which are of Jurassic age. The other halecomorphs were marine species.
Industry:Science
An order of actinopterygian fishes in the subdivision Elopomorpha, along with Elopiformes, Anguilliformes, and Saccopharyngiformes, all of which have a leptocephalous larval stage. Albuliformes, comprising three families, eight genera, and 30 species, are distinguished from other Elopomorpha by an open mandibular sensory canal in the dentary and angular bones. Two suborders are recognized, Albuloidei and Notacanthoidei, the latter of which was recognized previously as the order Notacanthiformes.
Industry:Science
An order of actinopterygian fishes in the superorder Ostariophysi with about 2700 species, which ranks second in number only to the Perciformes. Cypriniformes is the largest order of freshwater fishes in the world. Six families of cypriniforms occupy the freshwaters of most of the major landmasses of the world, but are notably absent from South America, Madagascar, and the Australian realm. North America is represented by two native families, Cyprinidae and Catostomidae.
Industry:Science
