Diversity and antibiotic resistance profiles of bacteria isolated from the oral cavity of captive snakes

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  Diversity and antibiotic resistance profiles of bacteria isolated from the oral cavity of captive snakes Abstract Venomous snake bites are a global public health issue, causing between 81 000 and 138 000 annual deaths and 400 000 permanent disabilities. This study investigated the oral bacterial diversity and antibiotic resistance profiles in captive  Viperidae  snakes. Oral swabs from 48 specimens across four species ( Porthidium lansbergii ,  Bothriechis nigroviridis ,  Cerrophidion sasai , and  Bothrops asper ) were analyzed using culture-dependent methods. Bacterial isolation and identification using the VITEK 2 automated system revealed 41 strains from 12 genera, predominantly Gram-negative bacteria, including  Morganella morganii  (11 isolates) and  Providencia rettgeri  (10 isolates). Antibiotic susceptibility testing demonstrated significant resistance patterns, with 100% resistance to cephalothin and cefazolin i...

Grassland expansions promoted global diversification of the Pardosa wolf spiders during the late Cenozoic (Araneae, Lycosidae)

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Grassland expansions promoted global diversification of the Pardosa wolf spiders during the late Cenozoic (Araneae, Lycosidae)

Abstract

The spiders in the genus Pardosa C.L. Koch, 1847, are a young lineage of the family Lycosidae Sundevall, 1833, that exhibit high species diversity and widespread distribution. Pardosa is abundant in open and disturbed environments. In fact, most of its species live in grasslands, and the few that live in forests switched habitats relatively recently. The genus markedly prefers grasslands with a broad range of climates. Thus, its origin and diversification were probably associated with grassland expansions during the late Cenozoic. To test this hypothesis, we developed a global phylogenetic hypothesis that helps reconstruct the biogeographic patterns of the genus Pardosa using three nuclear (18S, ITS2, and H3) and four mitochondrial (12S, 16S, NADH1, and COI) loci. Our phylogenetic analyses cover 133 (125 described and 8 as yet undescribed) grassland species of Pardosa using Trochosa ruricola (De Geer, 1778) and Lycosa coelestis L. Koch, 1878, as outgroups. The results show that our selection of species in the genus is divided into four major clades: Clade I includes only P. crassipalpis Purcell, 1903, from South Africa; Clade II consists of a north-east African group (2 species) and a south-east Asian group (21 species); Clade III contains only P. sutherlandi (Gravely, 1924) from SE Asia; and Clade IV includes five species groups from Asia, Europe, and the Americas. The spiders of the genus probably originated in southern Africa or southern and eastern (SE) Asia at the Middle Miocene Climatic Optimum, about 19.40–14.18 Ma, and then expanded northwards to North America via the Bering Strait, as well as southwards to north-east Africa via the Arabian Peninsula, and westwards to Europe via western Asia between about 10.59 and 5.28 Ma. At least three exchanges occurred between North America and SE Asia, and at least two between Europe and North America. The biogeography of Pardosa in the past 14.18 Ma, associated with the evolution of grasses, suggested a late Cenozoic diversification of the genus as grasslands expanded.

Liu L, Fu D, Luo Y (2024) Grassland expansions promoted global diversification of the Pardosa wolf spiders during the late Cenozoic (Araneae, Lycosidae). Zoosystematics and Evolution 100(4): 1287-1296. https://doi.org/10.3897/zse.100.128885