Phylogeny, Systematics and Biogeography of Short-Tailed Opossums (Didelphidae: Monodelphis)

Short-tailed opossums (genus Monodelphis) comprise the most species-rich genus of New World marsupials, with 25 currently recognized species. Monodelphis comprise small, terrestrial species collectively widespread in South America, which makes the group potentially informative about biogeographic processes that have shaped the continental fauna. The genus exhibits striking variation in several phenotypic characters, notably pelage coloration, behavior, and reproductive strategies. This diversity is unique among Neotropical marsupials, and makes the group particularly interesting to investigate the evolution and the adaptive significance of phenotypic trait variation. Despite this potential, missing knowledge on phylogeny and basic taxonomy precludes broader studies on evolution and biogeography on this group. To remedy this situation this thesis is centered on undertaking a comprehensive phylogenetic analysis and taxonomic revision of Monodelphis. In chapter one (published in collaboration with Dr. Sharon A. Jansa and Dr. Robert S. Voss) we present the first phylogenetic analyses of Monodelphis based on dense taxonomic sampling—23 of the 25 currently recognized species—and multiple genes—one mitochondrial gene (CYTB), two autosomal exons (IRBP, BRCA1), one autosomal intron (SLC38), and one X-linked intron (OGT). Parsimony, maximum-likelihood and Bayesian analyses of this dataset (110 terminals, 4983 aligned sites) strongly support the monophyly of Monodelphis and recover six major clades within the genus. Additionally, the analyses suggest that several nominal taxa are synonyms of other species in the genus (M. “sorex” of M. dimidiata, M. “theresa” of M. scalops, M. “rubida” and M. “umbristriata” of M. americana, and M. “maraxina” of M. glirina). By contrast, four unnamed genetic lineages recovered by the analyses may represent new species. Reconstructions of ancestral states of two discrete characters—dorsal pelage color pattern and habitat—suggest that the most recent common ancestor of Monodelphis was uniformly colored (with unpatterned dorsal pelage) and inhabited moist forest. Whereas most dorsal pelage patterns (e.g., reddish sides and reddish head-and-rump) appear to have evolved homoplastically in Monodelphis, dorsal stripes may have had a unique historical origin in this genus. In chapter two (also published in collaboration with Dr. Sharon A. Jansa and Dr. Robert S. Voss) we infer historical-biogeographic patterns and processes in South America based on estimated divergence times and ancestral distributions for this diverse clade of marsupials. The dating analysis suggests that the diversification of Monodelphis was not restricted to a narrow time interval, such that speciation cannot be attributed to a single causal historical factor. In particular, speciation within the Atlantic Forest biome appears to have occurred in the Neogene, whereas most Amazonian speciation events are Pleistocenic. Amazonia and the Atlantic Forest hosted most of the diversification events in Monodelphis and were estimated as the historical sources of lineages that subsequently colonized other areas (e.g., Tepuis, Andes, Cerrado) during the Pliocene and Pleistocene. Model selection suggests an important role for founder-event speciation, a process seldom accounted for in previous biogeographic analyses of continental clades. These results, together with others recently reported from analyses of South American datasets suggest that dispersal-mediated cladogenesis has been an important process in the evolution of Neotropical vertebrate faunas. Possible mechanisms for founder-event speciation in low-vagility terrestrial vertebrates such as Monodelphis include historically transient connections between currently disjunct biomes and rapid reproductive isolation of populations colonizing adjacent but ecologically disparate biomes. In the following chapter (to be published in collaboration with Dr. Robert S. Voss), an integrative approach—phylogenetic information together with phenotypic data from external and craniodental morphology— is used to provide a revised subgeneric classification of Monodelphis, intended to serve as the basis for future revisionary research at the species level. Over 2000 specimens of Monodelphis were analyzed for morphology, including representative material of all species currently recognized as valid, together with all undescribed forms discussed in the previous chapters. Discrete characters found to be useful for diagnosing monophyletic groups of species previously established by molecular research are defined and illustrated. Five subgenera are formally recognized, for which morphological diagnosis, comparisons, and patterns of geographical distribution and sympatry are provided. In chapter four, a paper (already published) describing a new species of Monodelphis from Atlantic Forest in Brazil is presented

MARE, Microcalorimeter Arrays for a Rhenium Experiment: A detector overview

Abstract We describe and discuss the features of MARE, an experiment based on arrays of rhenium low temperature microcalorimeters that have the potential to bring the sensitivity to the neutrino mass down to 0.2 eV, by studying the beta spectrum of Re 187 ( Q -value = 2.47 keV)

Results from the Cuore Experiment

The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay that has been able to reach the 1-ton scale. The detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers, each of them made of 52 crystals. The construction of the experiment was completed in August 2016 and the data taking started in spring 2017 after a period of commissioning and tests. In this work we present the neutrinoless double beta decay results of CUORE from examining a total TeO2 exposure of 86.3kg yr, characterized by an effective energy resolution of 7.7 keV FWHM and a background in the region of interest of 0.014 counts/ (keV kg yr). In this physics run, CUORE placed a lower limit on the decay half- life of neutrinoless double beta decay of 130Te > 1.3.1025 yr (90% C. L.). Moreover, an analysis of the background of the experiment is presented as well as the measurement of the 130Te 2vo3p decay with a resulting half- life of T2 2. [7.9 :- 0.1 (stat.) :- 0.2 (syst.)] x 10(20) yr which is the most precise measurement of the half- life and compatible with previous results

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

Design, Synthesis and Characterization of N-oxide-containing Heterocycles with In vivo Sterilizing Antitubercular Activity

Tuberculosis, caused by the Mycobacterium tuberculosis (Mtb), is the infectious disease responsible for the highest number of deaths worldwide. Herein, 22 new N-oxide- containing compounds were synthesized followed by in vitro and in vivo evaluation of their antitubercular potential against Mtb. Compound 8 was found to be the most promising compound, with MIC90 values of 1.10 and 6.62 μM against active and non- replicating Mtb, respectively. Additionally, we carried out in vivo experiments to confirm the safety and efficacy of compound 8; the compound was found to be orally bioavailable and highly effective leading to the reduction of the number of Mtb to undetected levels in a mouse model of infection. Microarray-based initial studies on the mechanism of action suggest that compound 8 blocks the process of translation. Altogether, these results indicated benzofuroxan derivative 8 to be a promising lead compound for the development of a novel chemical class of antitubercular drugs