Holocenic small rodents of northeastern Rio Grande do Sul, Brazil: Diversity changes through time and paleo-environmental reconstruction

• Grant number: 16/20693-9
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: October 16, 2017
• End date: April 15, 2018
• Field of knowledge: Biological Sciences - Zoology - Taxonomy of Recent Groups
• Principal Investigator: Alexandre Reis Percequillo
• Grantee: Paulo Ricardo de Oliveira Roth
• Supervisor: Jessica Lynn Blois
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Institution abroad: University of California, Merced (UC Merced), United States
• Associated to the scholarship: 14/19126-7 - Holocene small rodents in Northeastern Rio Grande do Sul: describing communities and their responses to environmental changes, BP.DD

Abstract

The preservation of small vertebrates as subfossils or fossils is extremely rare, because it is necessary the congruence of chemical, physical, geological and biological factors to avoid destruction of bones and teeth by the process of decomposition and weathering. Although rare, testimonies of such fauna are found with some frequency in excavations in rock shelters or caves, representing windows to past faunas and their habitats, since many species of small mammals have different environmental requirements and different species occupy very specific niches. The identification of species in past communities also favors the understanding the environmental and climatic history of a region. The availability of remnants of ancient communities also is a unique opportunity to, through morphological analysis, investigate the responses of populations to environmental and climate changes of the past to understand the present distribution pattern of the species. Furthermore, when the remnants are not completely mineralized, there is extraordinary opportunity to access genetic information to investigate their phylogenetic relationships with recent population or species. I sampled 13,617 post-cranial bones (whole and fragmented) and 1,484 skulls parts and teeth of small rodents obtained at two archaeological sites in northeastern Rio Grande do Sul state whose ages range from 12,430 until 1,390 years before present. Among this sample were identified 30 taxa, among which three are locally extinct (Gyldenstolpia cf. fronto, Necromys cf. obscurus and Pseudoryzomys simplex) and two have no recent representatives (Clyomys cf. riograndensis and Dicolpomys fossor). Based on these specimens, I aim to recognize the diversity of small rodents in different periods of the Holocene through the identification of taxa supported by descriptive analysis and evenness, richness and abundance estimates. These data, along with stable isotopic information, will allow me to reconstruct the habitats occupied by these changing assemblages through time. I also intend to apply aADN extraction methods in bone parts of rare and extinct taxa to perform phylogenetic analyses. To reach these goals, I believe that the best opportunity to acquire these skills will be at the Blois Paleoecology Lab (UC Merced/ CA), with Jessica Blois, as she have expertise in to interpret relations between climatic changes and assemblage structure changes. Moreover, her laboratory and staff are perfecting methods on aADN extractions, and I believe I will also benefit on their expertise. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

DALAPICOLLA, JERONYMO; DE OLIVEIRA ROTH, PAULO RICARDO; PERCEQUILLO, ALEXANDRE REIS. First record of albinism in spiny rats of genus Proechimys (Rodentia: Echimyidae) from Western Amazon. MAMMALIA, v. 84, n. 6, p. 605-609, NOV 2020. (16/20055-2, 09/16009-1, 15/02853-6, 14/19126-7, 16/20693-9)