Triadobatrachus massinoti is a batrachian known from a single fossil from the Early Triassic of Madagascar that presents a combination of apomorphic salientian and plesiomorphic batrachian characters. Herein we offer a revised description of the specimen based on X-ray micro-tomography data. We report previously unknown caudal vertebrae, possible mentomeckelians, and hidden parts of other structures. We also confirm the presence of a ventrolateral ledge on the opisthotic, and we rectify some previous interpretations. There are no cervical ribs and the jaw may have had an angular. The presacral region is composed of 15 vertebrae with a unique atlas-axis complex instead of 14 vertebrae with a bipartite atlas. The configuration of the pelvic girdle is not very clear, although it is likely more plesiomorphic than the anuran-like condition previously assumed. Our re-assessment of the saltatorial performance of Triadobatrachus supports the traditional interpretation that this animal was not a specialised jumper. In order to assess the sequence of events in the early evolution of the salientian morphotype, we estimated the ancestral length of the trunk region of batrachians under different hypotheses of lissamphibian relationships and divergence times. Most of our results suggest that some trunk reduction took place before the divergence of caudates and salientians (presumably in the Permian), and that the trunk of Triadobatrachus mostly reflects this ancestral condition. Thus, trunk reduction possibly preceded the anteroposterior elongation of the ilia and the shortening of the tail seen in Triadobatrachus. We also provide an updated review of the data relevant for the use of Triadobatrachus as a calibration constraint in molecular divergence age analyses that meets recently-suggested standards.

Limited data are available on the contribution of wildlife to the spread of antibacterial resistance. We determined the prevalence of resistance to antibiotics in Escherichia coli isolates collected from wild animals in 2013 and 2014 and the genetic basis for resistance to third-generation cephalosporin in Guadeloupe. We recovered 52 antibioticresistant (AR) E. coli strains from 48 of the 884 (5.4%) wild animals tested (46 iguanas, 181 birds, 289 anoles, and 368 rodents at 163 sampling sites). Rodents had higher rates of carriage (n = 38, 10.3%) than reptiles and birds (2.4% and 1.1%, respectively, p < 0.001). A significant association (p < 0.001) was found between the degree of anthropization and the frequency of AR E. coli carriage for all species. The carriage rate of ciprofloxacin-and cefotaxime-resistant isolates was 0.7% (6/884) and 1.5% (13/884), respectively. Most (65.4%) AR E. coli were multi-drug resistant, and the prevalence of extended-spectrum beta-lactamase (ESBL)-producing E. coli was low (n = 7, 0.8%) in all species. Eight ESBL-producing E. coli were recovered, two genetically unrelated isolates being found in one bird. These isolates and 20 human invasive ESBL E. coli isolates collected in Guadeloupe during the same period were investigated by whole genome sequencing. bla CTX−M−1 was the only ESBL gene shared by three animal classes (humans, n = 2; birds, n = 2; rodents, n = 2). The bla CTX−M−1 gene and most of the antimicrobial resistance genes were present in a large conjugative IncI1 plasmid that was highly similar (>99% nucleotide identity) to ESBL-carrying plasmids found in several countries in Europe and in Australia. Although the prevalence of ESBL-producing E. coli

No abstract

No abstract