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An order of eel-like fishes in the class Actinopterygii, commonly called swamp eels. Synbranchiforms are among the most highly specialized fishes. They are characterized by a usually scaleless eel-like body lacking pelvic fins with pectoral fins present or absent; gill openings entirely ventral and often confluent across the breast; premaxillae lacking ascending processes and nonprotrusible; ectopterygoid bones enlarged; endopterygoids reduced or absent; swim bladder present or absent; and gills poorly developed, with respiration in some species accomplished in part by highly vascularized buccopharyngeal pouches. The order has no fossil record and comprises three families, 15 genera, and about 99 species, all but three of which are freshwater inhabitants. Synbrachiformes are thought to form a monophyletic group with the smegmamorphs.
Industry:Science
An order of Eognasthostomata which exhibits various stages in the backward migration of the anus out of the apical system. They have four genital pores, noncrenulate tubercles, and simple ambulacral plates. All members are referred to a single family, the Pygasteridae. They apparently arose from Triassic Pedinidae and occur in the Jurassic and Cretaceous of the Northern Hemisphere. They were formerly classified with other bilaterally symmetrical echinoids in the artificial assemblage Irregularia.
Industry:Science
An order of extinct flightless birds known from Paleocene and Eocene deposits in North America, Europe, and Asia. They are believed to have dispersed across the North Atlantic via a land bridge when those continents were connected in the Eocene. These were giant, 2-m-tall (7-ft) birds with large heads, huge laterally compressed bills, broad cervical vertebrae, wide pelves, massive legs with relatively short tarsi and heavy toes suggestive of a slow-moving gait, and reduced wings that were evidently too short to permit flight.
Industry:Science
An order of extinct plants that formed a conspicuous part of the landscape during the Triassic, Jurassic, and Cretaceous periods. The Cycadeoidales (or Bennettitales) had unbranched or sparsely branched trunks with a terminal crown of leaves (family Cycadeoidaceae), or they were branched, at times profusely (family Williamsoniaceae).
Industry:Science
An order of extinct, free-sporing plants (cryptogams) that lived during the Late Devonian through Early Mississippian. The order includes the genera <i>Archaeopteris</i> which has been extensively investigated, <i>Actinoxylon</i>, <i>Actinopodium</i>, <i>Svalbardia, Eddya</i>, and <i>Siderella</i>.
Industry:Science
An order of extremely elongate, limbless fossil amphibians in the subclass Lepospondyli from Permo-Carboniferous rocks of North America and the British Isles. The order includes three families: Lethiscidae (<i>Lethiscus</i>), Ophiderpetontidae (<i>Coloraderpeton Ophiderpeton</i>), and Phlegethontiidae (<i>Aornerpeton, Phlegethontia, Sillerpeton</i>). All genera are monotypic with the exception of <i>Ophiderpeton</i> (six species) and <i>Phlegethontia</i> (possibly three species). In seeming contrast to their derived state, aistopods are among the very oldest of all known fossil tetrapods.
Industry:Science
An order of extremely rare arachnids, also known as the Podogona, with a body less than 1 in. (25 mm) in length. Superficially, they resemble ticks in general appearance and movement, and are found only in tropical Africa and in the Americas, from the Amazon to Texas. The two anterior pairs of appendages are chelate. The terminal segments of the third legs of the male are modified as copulatory structures. Less than 25 modern species are known. The occurrence of several fossils from Carboniferous time suggests that the group was formerly more common. Virtually nothing is known about the reproduction, growth, and ecology of the Ricinulei.
Industry:Science
An order of filamentous fresh-water green algae (Chlorophyceae) with unique morphological features including (1) an elaborate method of cell division that results in the accumulation of apical caps, (2) zoospores and antherozoids with a subapical crown of flagella, and (3) a highly specialized type of oogamy. There is a single family, Oedogoniaceae, comprising three genera.
Industry:Science
An order of fishes also known as Lampridiformes and Allotriognathi. Although the families of Lampriformes appear very dissimilar, they share the following combination of characters that distinguish them from other orders of actinopterygian (ray-finned) fishes: notably compressed body, often ribbonlike; no true spines in fins, rays only; thoracic pelvic fins, if present; swim bladder, if present, physoclistous; and small cycloid scales, commonly absent. In addition, lampriforms have a unique type of protrusible upper jaw, by which the premaxilla excludes the maxilla from the gape, and the maxilla, instead of having a ligamentous attachment to the ethmoid and palatine bones, slides in and out with the highly protractile premaxilla. Most species are large and colorful; some have inspired sea-serpent stories.
Industry:Science
An order of fishes containing the cods, codlings, codlets, grenadiers, and hakes. The Gadiformes plus the orders Ophidiiformes (pearfishes, cusk-eels, and brotulas), Batrachoidiformes (toadfishes), and Lophiiformes (anglerfishes), collectively called the Anacanthini, are thought by some authors to be a monophyletic lineage but the concept is doubted by others. The group is characterized by the absence of a myodome (a cavity in the postorbital region of the skull in which lodge the muscles of the eye; actinopterygian fishes typically have a well-developed myodome); absence of parapophyses (singular parapophysis; a long, transverse process arising from the abdominal vertebral centrum, which serves to support epipleural ribs and, in Gadidae, the gas bladder; also called transverse process) on at least the first three vertebrae; and insertion of the first few pairs of ribs in cavities of the vertebral centra rather than on the parapophyses.
Industry:Science
