The Anterior Dentition Of Sivapithecus-parvada, With Comments On The Phylogenetic Significance Of Incisor Heteromorphy In Hominoidea
Anthropology; clade; dentition; east-africa; evolution; Evolutionary Biology; hominids; hominoid phylogenetics; incisors; kenya; middle miocene; miocene hominoid; orangutan; origin; pakistan; pongo; sivapithecus; specimens
A premaxillary fragment of Sivapithecus parvada preserving the germs of the right central and lateral incisors is described. The specimen was recovered in situ during excavation at locality Y311 in the upper Nagri Formation (ca. 9.2 m.y.a.) of the Siwalik Sequence, Potwar Plateau, Pakistan. The central incisor is approximately 35% larger than the next largest Sivapithecus incisor, in keeping with the very large size of S. parvada compared to other Sivapithecus species, and is exceptionally long mesiodistally in relation to its breadth. It is also morphologically distinct, having a sharply angled distal margin and a distinct lingual tubercle. However, previous descriptions of Sivapithecus upper central incisors as having a continuous lingual shelf are in some cases erroneous and ignore the morphological variation present in the sample. In several features of anterior tooth size, morphology and proportionality, S. parvada resembles Pongo more than do other species of Sivapithecus. The I1/I2 length ratio of the new specimen is 2.12, the largest size disparity reported for any fossil catarrhine, and greater than any single value in a large sample of Pongo pygmaeus. Very great size disparity between upper central and lateral incisors is widely considered to be a synapomorphy of the orang-utan lineage. We conclude, however, that descriptions of upper incisor size heteromorphy in Pongo have in general been exaggerated and have failed to recognize substantial differences in this character between Bornean and Sumatran orang-utans. We further conclude, based on examination of a variety of Miocene hominoids and other Miocene catarrhine primates, that the character of I1/I2 proportionality has little if any phylogenetic utility within Hominoidea.
Kelley J; Anwar M; McCollum M A; Ward S C
Journal of Human Evolution
1995
1995-06
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1006/jhev.1995.1039" target="_blank" rel="noreferrer noopener">10.1006/jhev.1995.1039</a>
Morphine, Opioids, And The Feline Pulmonary Vascular Bed
Anesthesiology; cat; fentanyl; histamine receptor; lung; meperidine; morphine; opioid receptor; remifentanil; sufentanil; vasodepressor
Background: Opioid-induced vasodepressor responses have been reported in a variety of species and laboratory models. The aim of this study was to ascertain the relative potencies of different clinically relevant opioids compared with traditional vasodepressor agents in the feline pulmonary vascular bed. A second aim was to study the effects of morphine and to identify the receptors involved in the mediation or the modulation of these effects. Methods: This was a prospective vehicle-controlled study involving an intact chest preparation of adult mongrel cats. The effects of various opioids, morphine, fentanyl, remifentanil, sufentanil, and meperidine were compared with other vasodepressor agents. Additionally, the effects of L-N(5)-(1-iminoethyl) ornithine hydrochloride (L-NIO) (nitric oxide synthase inhibitor), nimesulide [selective cyclooxygenase (COX)-2 inhibitor], glibenclamide (ATP-sensitive K 1 channel blocker), naloxone (non-selective opioid receptor antagonist), and diphenhydramine (histamine H(1)-receptor antagonist) were investigated on pulmonary arterial responses to morphine and other selected agonists in the feline pulmonary vascular bed. The systemic pressure and lobar arterial perfusion pressure were continuously monitored, electronically averaged, and recorded. Results: In the cat pulmonary vascular bed of the isolated left lower lobe, morphine, remifentanil, fentanyl, sufentanil, and meperidine induced a dose-dependent moderate vasodepressor response and it appeared that sufentanil was the most potent on a nanomolar basis. The effects of morphine were not significantly altered after administration of L-NIO, nimesulide, and glibenclamide. However, the vascular responses to morphine were significantly attenuated following administration of naloxone and diphenhydramine. Conclusion: The results of the present study suggest that sufentanil appears to have slightly more potency and morphine the least of the five opioid agonists studied on a nanomolar basis. Morphine-induced vasodilatory responses appeared to be mediated or modulated by both opioid receptor and histamine-receptor-sensitive pathways.
Kaye A D; Hoover J M; Kaye A J; Ibrahim I N; Fox C; Bajwa A; Anwar M; Fields A M; Baluch A; Huffman S; Chilian W
Acta Anaesthesiologica Scandinavica
2008
2008-08
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1111/j.1399-6576.2008.01595.x" target="_blank" rel="noreferrer noopener">10.1111/j.1399-6576.2008.01595.x</a>