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Late Quaternary Fossil Mammals And Last Occurrence Dates From Caves At Barahona, Puerto Rico, Donald A. Mcfarlane Dec 1999

Late Quaternary Fossil Mammals And Last Occurrence Dates From Caves At Barahona, Puerto Rico, Donald A. Mcfarlane

WM Keck Science Faculty Papers

Puerto Rico supported at least five genera of endemic terrestrial mammals in the late Quaternary, all of which are extinct. Whether these animals died out in the late Pleistocene, the mid-Holocene, or in post-Columbian time has not been established. This paper is the first attempt at radiometrically dating the 'last occurrences' of these taxa, together with the first unambiguous descriptions of localities reported by previous workers. Last occurrence dates for Nesophontes, Elasmodontomys and Heteropsomys are shown to be mid-Holocene and overlap with Amerindian occupation of the island. Acratocnus is known only from the late Pleistocene. No Puerto Rican taxon has …


Different Proctolin Neurons Elicit Distinct Motor Patterns From A Multifunctional Neuronal Network, Dawn M. Blitz, Andrew E. Christie, Melissa J. Coleman, Brian J. Norris, Eve Marder, Michael P. Nusbaum Jul 1999

Different Proctolin Neurons Elicit Distinct Motor Patterns From A Multifunctional Neuronal Network, Dawn M. Blitz, Andrew E. Christie, Melissa J. Coleman, Brian J. Norris, Eve Marder, Michael P. Nusbaum

WM Keck Science Faculty Papers

Distinct motor patterns are selected from a multifunctional neuronal network by activation of different modulatory projection neurons. Subsets of these projection neurons can contain the same neuromodulator(s), yet little is known about the relative influence of such neurons on network activity. We have addressed this issue in the stomatogastric nervous system of the crab Cancer borealis. Within this system, there is a neuronal network in the stomatogastric ganglion (STG) that produces many versions of the pyloric and gastric mill rhythms. These different rhythms result from activation of different projection neurons that innervate the STG from neighboring ganglia and modulate STG …


A Note On Sexual Dimorphism In Nesophontes Edithae (Mammalia: Insectivora), An Extinct Island-Shrew From Puerto Rico, Donald A. Mcfarlane Jan 1999

A Note On Sexual Dimorphism In Nesophontes Edithae (Mammalia: Insectivora), An Extinct Island-Shrew From Puerto Rico, Donald A. Mcfarlane

WM Keck Science Faculty Papers

The island-shrew, Nesophontes edithae Anthony 1916, Mean is the only Puerto Rican representative of the monogeneric family Nesophontidae.