Thewissen, Johannes G. M.

8 publications

Thewissen, Johannes G. M. (detail)
1985Cephalic evidence for the affinities of Tubulidentata.
Mammalia 49(2): 257-284. 1 tab. 5 figs.
—Considers the evidence weak for ungulate relationships of tubulidentates; compares their brain and skull morphology and cranial foramina with, among others, Eocene sirs. (265, 268-269, 271-274, 279).
Thewissen, Johannes G. M.; Domning, Daryl Paul (detail)
1992The role of phenacodontids in the origin of the modern orders of ungulate mammals.
Jour. Vert. Pal. 12(4): 494-504. 2 tabs. 2 figs. Dec. 15, 1992.
—Concludes that the mirorder Pantomesaxonia (including Sirenia, Desmostylia, Proboscidea, Hyracoidea, and Perissodactyla) and the order Phenacodonta are sister groups together making up the superorder Paenungulata, but the relationships within the Pantomesaxonia remain unresolved.
Thewissen, Johannes G. M. (detail)
1993Eocene marine mammals from the Himalayan foothills.
Research & Exploration (National Geographic Society) 9(1): 125-127. Figs. 9-12. Winter 1993.
—Reports a sir. rib and skull fragments of a supposed sir. from the Early to Middle Eocene Kuldana Formation of Pakistan. The skull was later determined not to be sirenian.
Savage, Robert Joseph Gay; Domning, Daryl Paul; Thewissen, Johannes G. M. (detail)
1994Fossil Sirenia of the West Atlantic and Caribbean region. V. The most primitive known sirenian, Prorastomus sirenoides Owen, 1855.
Jour. Vert. Pal. 14(3): 427-449. 3 tabs. 12 figs. https://doi.org/10.1080/02724634.1994.10011569 Sept. 7, 1994.
—Italian transl.: https://www.mumat.it/gpt/notizie/.
Spoor, F.; Bajpai, Sunil; Hussain, S. Taseer; Kumar, K.; Thewissen, Johannes G. M. (detail)
2002Vestibular evidence for the evolution of aquatic behaviour in early cetaceans.
Nature 417: 163-166. 1 tab. 3 figs. May 9, 2002.
—Graphs the relationship of semicircular canal curvature to body mass in Dugong dugon and other mammals; it lies within the range for terrestrial species.
Bajpai, Sunil; Thewissen, Johannes G. M.; Kapur, Vivesh Vir; Tiwari, Brahma N.; Sahni, Ashok (detail)
2006Eocene and Oligocene sirenians (Mammalia) from Kachchh, India.
Jour. Vert. Pal. 26(2): 400-410. 2 tabs. 6 figs. June 12, 2006.
—Describes Eotheroides babiae, n.sp. (Middle Eocene) and Bharatisiren indica, n.sp. (Late Oligocene), in addition to other reported taxa.
Thewissen, Johannes G. M.; Bajpai, Sunil (detail)
2009A new Miocene sirenian from Kutch, India.
Acta Palaeontologica Polonica 54(1): 7-13. 2 tabs. 3 figs. Mar. 2009.
—Describes Domningia sodhae, n.gen. n.sp. urn:lsid:zoobank.org:pub:7E63EF87-F843-42DB-B113-892B6664C2C2
Kim, Sora L.; Thewissen, Johannes G. M.; Churchill, Morgan M.; Suydam, Robert S.; Ketten, Darlene R.; Clementz, Mark T. (detail)
2014Unique biochemical and mineral composition of whale ear bones.
Physiological & Biochemical Zoology 87(4): 576-584. 3 tabs. 4 figs. DOI: 10.1086/676309. Aug. 2014.
—ABSTRACT: Cetaceans are obligate aquatic mammals derived from terrestrial artiodactyls. The defining characteristic of cetaceans is a thick and dense lip (pachyosteosclerotic involucrum) of an ear bone (the tympanic). This unique feature is absent in modern terrestrial artiodactyls and is suggested to be important in underwater hearing. Here, we investigate the mineralogical and biochemical properties of the involucrum, as these may hold clues to the aquatic adaptations of cetaceans. We compared bioapatites (enamel, dentine, cementum, and skeletal bone) of cetaceans with those of terrestrial artiodactyls and pachyosteosclerotic ribs of manatees (Sirenia). We investigated organic, carbonate, and mineral composition as well as crystal size and crystallinity index. In all studied variables, bioapatites of the cetacean involucrum were intermediate in composition and structure between those of tooth enamel on the one hand and those of dentine, cementum, and skeletal bone on the other. We also studied the amino acid composition of the cetacean involucrum relative to that of other skeletal bone. The central involucrum had low glycine and hydroxyproline concentrations but high concentrations of nonessential amino acids, unlike most bone samples but similar to the tympanic of hippos and the (pachyosteosclerotic) ribs of manatees. These amino acid results are evidence of rapid bone development. We hypothesize that the mineralogical and amino acid composition of cetacean bullae differs from that of other bone because of (1) functional modifications for underwater sound reception and (2) structural adaptations related to rapid ossification.