Rhachitomi is a group of temnospondyl amphibians that includes all temnospondyls except edopoids and dendrerpetontids.
 It was established as a clade name by German paleontologist Rainer R. Schoch in 2013, although the name had first been established in 1919 by British paleontologist D. M. S. Watson to encompass an evolutionary grade of temnospondyls leading to the group Stereospondyli.
 American paleontologist Alfred Romer used the term in a similar sense, grouping most Permian and Triassic temnospondyls under Rhachitomi.
 A similar name that appeared earlier in the scientific literature is Rachitomi, which was named by American paleontologist Edward Drinker Cope in 1882.
 Rachitomi was commonly used in the late nineteenth and early twentieth century to include early amphibians such as "Eryops" and "Archegosaurus" that had rhachitomous vertebrae.
 Many early tetrapods have vertebrae that are split into two parts below the notochord: a pleurocentrum and an intercentrum.
 In rhachitomous vertebrae, the intercentrum is large and semicircular, while the pleurocentrum divided into two smaller paired elements.
 Schoch defined Rhachitomi as a node-based taxon to include four major and well-supported clades of temnospondyls: Dvinosauria, Eryopidae, Stereospondyli and a clade formed by Zatracheidae and Dissorophoidea.
 Not all members of Rhachitomi have rhachitomous vertebrae; the largest subgroup, Stereospondyli, lacks pleurocentra.
 Below is a cladogram from Schoch's analysis showing the placement of Rhachitomi within Temnospondyli:
Paranthodon ( ) is a genus of extinct stegosaurian dinosaur that lived in South Africa during the Early Cretaceous, between 145.5 and 136.4 million years ago.
 Discovered in 1845, it was one of the first stegosaurians found.
 Its only remains, a partial skull and isolated teeth, were found in the Kirkwood Formation.
 British paleontologist Richard Owen initially identified the fragments as those of the pareiasaur "Anthodon".
 After remaining untouched for years in the British Museum of Natural History, the partial skull was identified by South African paleontologist Robert Broom as belonging to a different genus; he named the specimen "Palaeoscincus africanus".
 Several years later, Hungarian paleontologist Franz Nopcsa, unaware of Broom's new name, similarly concluded that it represented a new taxon, and named it "Paranthodon owenii".
 Since Nopcsa's species name was assigned after Broom's, and Broom did not assign a new genus, both names are now synonyms of the current binomial, "Paranthodon africanus".
 The genus name combines the Ancient Greek "para" (near) with the genus name "Anthodon", to represent the initial referral of the remains.
Nathaniel Southgate Shaler (February 20, 1841 – April 10, 1906) was an American paleontologist and geologist who wrote extensively on the theological and scientific implications of the theory of evolution.
In his youth, Sargent's family moved to a ranch in San Bernardino, California.
 In 1892, he became principal of a San Bernardino grammar school.
 The next year he went to study at Harvard University, where he obtained his bachelor's (1896) and masters (1897).
 Among the professors who influenced him were William James, Nathaniel Shaler, Charles Eliot Norton, and William Gilson Farlow.
 After graduation, Sargent taught school in Cambridge, and did graduate research on neurology, publishing 10 scientific papers, but quitting before he received his doctorate.
 For a decade beginning in 1904, Sargent ran a travel school for boys, in which he led tours to Europe and other parts of the world.
Ruhuhuaria is an extinct genus of owenettid procolophonoid reptile known from the Middle Triassic Manda Beds of southwestern Tanzania.
 "Ruhuhuaria" is known solely from the holotype CAMZM T997, poorly preserved but complete skull and mandible recently re-discovered in the collections of the Cambridge Museum of Zoology.
 It was collected by the English paleontologist Francis Rex Parrington in the early 1930s from the Lifua Member of Manda Beds of the Ruhuhu Basin in Songea Urban District of southwestern Tanzania, which dates back to the late Anisian stage of the Middle Triassic.
 "Ruhuhuaria" was first described and named by Linda Akiko Tsuji, Gabriela Sobral and Johannes Müller in 2013 and the type species is "Ruhuhuaria reiszi".
 The generic name is derived from the name of the Ruhuhu Basin.
 The specific name, "reiszi", honors the Canadian paleontologist Robert R. Reisz.
 Due to the poor preservation of the holotype, the phylogenetic position of "Ruhuhuaria" within Owenettidae is uncertain.
 "Ruhuhuaria" being the second youngest owenettid to date, supports the persistence of owenettids into the Middle Triassic and their coexistence with procolophonids.
Lyman Tower Sargent (born 9 February 1940) is an American academic, professor emeritus of political science at the University of Missouri-St.
 Louis.
 Sargent's main academic interests are in utopian studies, political theory, American studies and bibliography.
 He is one of the world's foremost scholars on utopian studies, founding editor of "Utopian Studies," serving in that post for the journal's first fifteen years, and recipient of the Distinguished Scholar Award from the Society for Utopian Studies.
 Sargent was educated as an undergraduate at Macalester College and as a graduate student at the University of Minnesota.
Charles Abiathar White (January 26, 1826 – June 29, 1910) was an American geologist, paleontologist, and writer whose publications total 238 titles.
 He was born at North Dighton, Massachusetts.
 He was the State geologist of Iowa in 1866-70, and professor of natural history in the State University of Iowa in 1867-73.
 He held a similar position at Bowdoin College in 1873-75, and was geologist and paleontologist of the United States Geological Survey between 1874 and 1892, and after 1895 was an associate in paleontology at the United States National Museum.
Phreatophasma is an extinct genus of tetrapod from the Middle Permian of European Russia.
 It includes only one species, Phreatophasma aenigmatum, which is itself known from a single femur found in a mine near the town of Belebei in Bashkortostan.
 "Phreatophasma" comes from a fossil assemblage that is latest Ufimian to earliest Kazanian in age under the Russian stratigraphic scheme, correlating with the Roadian Age (earliest Middle Permian, about 270 million years ago) under the international stratigraphic timescale.
 Because the species is based on a single specimen with few diagnostic anatomical features, uncertainty remains as to where it belongs in tetrapod phylogeny; originally interpreted in 1954 as an enigmatic "theromorph" synapsid (hence its species name "aenigmatum") by Soviet paleontologist Ivan Yefremov, "Phreatophasma" was later described as a therapsid "incertae sedis" by American paleontologist Alfred Romer in 1956 and then as a member of a basal synapsid family called Caseidae starting with Everett C. Olson in 1962.
 Olson's classification was later supported by Canadian paleontologist Robert Reisz in 1986 and American paleontologist Robert L. Carroll in 1988.
 Ivakhneneko "et al." (1997) and Maddin "et al." (2008) both considered "Phreatophasma" an indeterminate synapsid.
Jørn Harald Hurum (born November 4, 1967) is a Norwegian paleontologist and popularizer of science.
 He is a vertebrate paleontologist and holds an Associate Professor position at the Natural History Museum of the University of Oslo.
 He has studied dinosaurs, primitive mammals and plesiosaurs.
Euparkeriidae is a family of small basal archosauromorph carnivores which lived from the Early Triassic to the Middle Triassic (Anisian).
 While most other early archosauriforms walked on four limbs, euparkeriids were probably facultative bipeds that had the ability to walk on their hind limbs at times.
 The only definitive member of Euparkeriidae is the species "Euparkeria capensis", which was named by paleontologist Robert Broom from the Karoo Basin of South Africa in 1913 and is known from several nearly complete skeletons.
 The family name was first proposed by German paleontologist Friedrich von Huene in 1920; Huene classified euparkeriids as members of Pseudosuchia, a traditional name for crocodilian relatives from the Triassic (Pseudosuchia means "false crocodiles").
 Recent phylogenetic analyses place Euparkeriidae as a basal group of Archosauriformes, a position outside Pseudosuchia and close to the ancestry of both crocodile-line archosaurs and bird-line archosaurs (which include dinosaurs and pterosaurs).
 However, they are probably not direct ancestors of archosaurs.

Question: What is the name of the paleontologist and professor who influenced Porter Sargent?
Answer: Nathaniel Shaler