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Marc G.M. van Roosmalen

  • Biodiversity Journal, 7 (1): 117-198 - MONOGRAPH

    Marc G.M. van Roosmalen & Tomas van Roosmalen
    On the origin of allopatric primate species

    ABSTRACT
    Here we present a theory on the origin of allopatric primate species that follows - at least in Neotropical primates - the irreversible trend to albinotic skin and coat color, called “metachromic bleaching”. It explains why primates constitute such an exceptionally diverse, species-rich, and colorful Order in the Class Mammalia. The theory is in tune with the principle of evolutionary change in tegumentary colors called “metachromism”, a hypothesis propounded by the late Philip Hershkovitz. Metachromism holds the evolutionary change in hair, skin, and eye melanins following an orderly and irreversible sequence that ends in loss of pigment becoming albinotic, cream to silvery or white. In about all extant sociable Neo- tropical monkeys we identified an irreversible trend according to which metachromic varieties depart from the saturated eumelanin (agouti, black or blackish brown) archetypic form and then speciate into allopatric taxa following the trend to albinotic skin and coat color. Speciation goes either along the eumelanin pathway (from gray to silvery to cream to white), or the pheomelanin pathway (from red to orange to yellow to white), or a combination of the two. The theory represents a new and original evolutionary concept that seems to act indefinitely in a non-adaptive way in the population dynamics of male-hierarchic societies of all sociable primates that defend a common territory. We have successfully tested the theory in all 19 extant Neotropical monkey genera. Our theory suggests the trend to allopatry among metachromic varieties in a social group or population to be the principal behavioral factor that empowers metachromic processes in sociable Neotropical monkeys. It may well represent the principal mechanism behind speciation, radiation, niche separation, and phylogeography in all sociable primates that hold male-defended territories. We urge field biologists who study primate distributions, demography and phylogeography in the Old World to take our theory to the test in the equally colorful Catarrhini.

  • Biodiversity Journal, 6 (1): 219-244 - MONOGRAPH

    Marc G.M. van Roosmalen
    Hotspot of new megafauna found in the Central Amazon: the lower Rio Aripuanã Basin
    Proceedings of the 2nd International Congress “Speciation and Taxonomy”, May 16th-18th 2014, Cefalù-Castelbuono (Italy)

    ABSTRACT
    Here I announce the discovery of a whole new ecosystem in the central-southern part of the Brazilian Amazon: the Rio Aripuanã Basin. Overall, it seems to have created more ecological niches than any other river basin in the Amazon, in particular so to aquatic and non-volant terrestrial mammals. This is plausibly explained for by the unique geo-morphological history of the region. During the Pliocene and Early Pleistocene the entire area to the southeast of the Rio Madeira contained one huge clear-water system that was drained toward the south into the Atlantic Ocean. In the course of several million years a biome quite different from the rest of Amazonia could evolve in this drainage system. Living relicts from ancient times that happened to survive in isolation here, are: a dwarf manatee here described as Trichechus pygmaeus n. sp., a dolphin locally called “boto roxo” that is suspected to be closer related to marine Rio Plata dolphins Pontoporia blainvillei (Gervais et d'Orbigny, 1844) than to Amazonian dolphins of the genus Inia (d'Orbigny, 1834), a black dwarf tapir (Tapirus pygmaeus Van Roosmalen, 2013, with T. kabomani Cozzuol et al., 2013 as junior name), a dwarf marmoset Callibella humilis Van Roosmalen et Van Roosmalen, 2003, a new mono-specific genus of Callitrichidae that stands at the base of the phylogenetic tree of all extant marmosets (i.e., Cebuella Gray, 1866, Mico Lesson, 1840, and Callithrix Erxleben, 1777), a giant striped paca here described as Agouti silvagarciae n. sp., and an arboreal giant anteater spotted in the wild but remains to be collected and described (Myrmecophaga n. sp.). A number of other, more advanced mammalian species discovered in the Rio Aripuanã Basin, among which a third species of brocket here described as Mazama tienhoveni n. sp., evolved after a dramatic vicariance took place about 1-1.8 MYA (million years ago), the break-through of the continental watershed by the proto-Madeira River during one of the glacial epochs of the Middle Pleistocene. It marked the birth of the modern fast-flowing Rio Madeira, in terms of total discharge the biggest tributary of the Amazon proper and the second strongest river barrier in the entire Amazon Basin. Furthermore, current threats to the environment in this sparsely inhabited and poorly explored river basin will be addressed. We intend to have this ‘lost world’ preserved as a UNESCO Natural World Heritage Reserve through the divulgation of new, hitherto not yet identified mammals that it appears to harbor.

  • Biodiversity Journal, 6 (1): 119-120 - MONOGRAPH
    Marc Van Roosmalen & Mason Fisher
    Speciation and Taxonomy: Neotropical Primate diversity
    Proceedings of the 2nd International Congress “Speciation and Taxonomy”, May 16th-18th 2014, Cefalù-Castelbuono (Italy)