Entry Category: Science and Technology - Starting with S

Stern’s medlar (Mespilus canescens or Crataegus × canescens) is a rare shrub in the rose family known in the wild from about twenty-five individual plants at a single site near Slovak (Prairie County). It was first discovered in 1969 by Jane Stern but was not named until 1990, when it was formally described (as Mespilus canescens) by Dr. James Phipps of the University of Western Ontario. Its origin, taxonomic placement, and proper scientific name are a matter of debate among botanists and represent one of the most curious and persistent mysteries in North American botany. Stern’s medlar is a showy species with a number of desirable ornamental properties including dense groupings of quarter-sized white flowers, multiple trunks, arching branches, patchy …

Robert Blair Stobaugh was an authority on energy, international business, and corporate governance who served as a professor in the Harvard Business School. His 1979 book Energy Future: The Report of the Energy Project led to significant initiatives in energy policy by the Carter administration and became a New York Times bestseller. His article “The Bent Measuring Stick of the Multinational Enterprise” was voted one of the twenty best articles ever published on international business. A federal judge once referred to him as “one of the nation’s foremost experts on corporate governance,” and was quoted on the front page of the Wall Street Journal several times. Robert Stobaugh was born on October 15, 1927, in McGehee (Desha County) to Robert …

Stoneflies (Phylum Arthropoda, Class Insecta, Order Plecoptera) are a group of aquatic insects well known to fishermen and biologists worldwide. The name Plecoptera means “braided-wings” from the Ancient Greek plekein and pteryx, which refers to “wing.” The name refers to the complex venation of their two pairs of wings, which are membranous and fold flat over their body. Generally, stoneflies are not strong fliers, and several species are entirely wingless. Stoneflies are called “indicator species” because finding them in freshwater environments generally indicates relatively good water quality, as they are quite intolerant of aquatic pollution. They are also prized and imitated by anglers as artificial tied-flies in trout fishing, particularly on Arkansas rivers such as the Eleven Point, Spring, and …

The order Strepsiptera, or twisted wing parasites, belongs to the class Insecta, phylum Arthropoda. It is a very small, cosmopolitan order of bizarre parasitoids containing about 624 named species of minute endopterygote insects with nine extant families. They parasitize thirty-four families and several orders of Insecta, including Blattodea (cockroaches), Diptera (flies), Homoptera (leafhoppers), Mantodea (mantises), Hemiptera (true bugs), Orthoptera (grasshoppers and crickets), Zygentoma (silverfish and firebrats), and Hymenoptera (ants, bees, and wasps). Three species of strepsiptera (halictophagids) have been reported from Arkansas hosts (all leafhoppers, Cicadellidae). Strepsiptera have two major groups: the Stylopidia and Mengenillidia. The former, which has endoparasitic females with multiple genital openings, includes seven families: the Bohartillidae (one extant and two fossil species), Corioxenidae (forty-six extant and …

The striped bark scorpion, Centruroides vittatus, is the only scorpion species recorded from Arkansas, where it is most abundant in the western part of the state. It is the most widely distributed scorpion species in the United States, having been recorded from Missouri, Arkansas, and Louisiana west to eastern Colorado and New Mexico and south to northeastern Mexico. The front body region, which bears the yellowish-brown pedipalps (pincers) and legs below, has a somewhat triangular median dark spot on top pointing backward and extending beyond the eyes. The wide body region that follows has a distinctive pair of broad, dark, longitudinal bands on top. The slender tail-like postabdomen is uniformly yellowish brown, except for the tip of the stinger, which …

Sturgeons (primitive Acipenseriform) are an ancient group of fishes dating back to the Triassic Period some 245 to 208 million years ago. True sturgeons appear in the fossil record during the Upper Cretaceous (101 to 66 million years ago). There are about twenty-five species of sturgeons, and all belong to the Family Acipenseridae, Order Acipenseriformes. Sturgeons can be found in subtropical, temperate, and sub-Arctic rivers, lakes, and coastlines of North America, with the greatest diversity in Eurasia. In North America, there are eight species that range along the Atlantic Coast from the Gulf of Mexico to Newfoundland, as well as along the West Coast in major rivers from California and Idaho to British Columbia, Canada. The family contains four genera …

Suckers belong to the Family Catostomidae, Order Cypriniformes, and Class Actinopterygii. There are about seventy-two species and thirteen extant genera of these benthic (bottom-dwelling) freshwater fishes. In Arkansas, there are eighteen species in eight genera. Suckers are Holarctic in distribution and primarily native to North America north of Mexico, but the longnose sucker (Catostomus catostomus) occurs in both North America and northeastern Siberia from Alaska, and the Asiatic Sucker (Myxocyprinus asiaticus) is found in the Yangtze River basin in China. Sucker-like fossils are known from Eocene epoch (56 to 33.9 million years ago) deposits from central Asia, and the fossil genus Amyzon, with Ictiobus and Myxocyprinus affinities, occurs in middle Eocene and Oligocene Epoch (33.9 to 23 million years ago) …

Symphylans belong to the Phylum Arthropoda, Subphylum Labiata, Superclass Myriapoda, and Class Symphyla. About 200 species of symphylans are known worldwide, predominantly in the tropics. There are two families: Scutigerellidae with five genera and about 128 species, and Scolopendrellidae containing nine genera and approximately seventy-three species. There are few reports of symphylans in Arkansas, aside from a new endemic scutigerellid species described in 1992 in Polk County. Many taxa are yet to be discovered and described in the state. The fossil record of symphylans is poorly known; only five species have been recorded, all placed within living genera. They are ancestral arthropods dating back to the early Silurian approximately 430 million years ago, although the only fossil symphylans are known …