Search

Cycloclasticus bacteria are ubiquitous in oil-rich regions of the ocean and are known for their ability to degrade polycyclic aromatic hydrocarbons (PAHs). In this study, we describe Cycloclasticus that have established a symbiosis with Bathymodiolus heckerae mussels and poecilosclerid sponges from asphalt-rich, deep-sea oil seeps at Campeche Knolls in the southern Gulf of Mexico. Genomic and transcriptomic analyses revealed that, in contrast to all previously known Cycloclasticus, the symbiotic Cycloclasticus appears to lack the genes needed for PAH degradation. Instead, these symbionts use propane and other short-chain alkanes such as ethane and butane as carbon and energy sources, thus expanding the limited range of substrates known to power chemosynthetic symbioses. Analyses of short-chain alkanes in the environment of the Campeche Knolls symbioses revealed that these are present at high concentrations (in the μM to mM range). Comparative genomic analyses revealed high similarities between the genes used by the symbiotic Cycloclasticus to degrade short-chain alkanes and those of free-living Cycloclasticus that bloomed during the Deepwater Horizon oil spill. Our results indicate that the metabolic versatility of bacteria within the Cycloclasticus clade is higher than previously assumed, and highlight the expanded role of these keystone species in the degradation of marine hydrocarbons.

An annotated checklist of the Sarcophagidae of Jamaica is presented based on material collected from 2018 to 2024, supplemented with specimens in museum collections as well as literature records. The checklist comprises 45 species from 21 genera, of which 23 species from 15 genera were collected during the present study and identified based on male terminalia. The following species are recorded from Jamaica for the first time: Bahamiola orbitalis Dodge, Peckia (Sarcodexia) dominicana (Lopes), Tapacura mariarum Tibana & Lopes, and Lepidodexia (Harpagopyga) diversipes (Coquillet). [ABSTRACT FROM AUTHOR]

Current knowledge of the global diversity of schizophoran flies, the megadiverse group that evolved during the episode of rapid dipteran radiations in the Early Cenozoic, is far from satisfactory. A significant part of this radiation is flesh flies (Sarcophagidae), which include about 3000 known species. Miltogramma Meigen, the largest genus of the flesh fly subfamily Miltogramminae, includes 119 known species with a peak of diversity in the Middle East and Central Asia. The taxonomy of the genus is acknowledged to be challenging, partly due to logistical issues associated with the deposition of type specimens in less accessible Russian institutions. Six new distinctive species of Miltogramma collected during recent expeditions to Iran and Uzbekistan are described using methods of integrative taxonomy: Miltogramma manouchehrii Szpila & Pape, sp. nov. , M. mikolajczyki Szpila & Pape, sp. nov. , M. rognesi Szpila & Pape, sp. nov. , M. soszynskii Szpila & Pape, sp. nov. , M. thompsoni Szpila & Pape, sp. nov. , and M. vervesi Szpila & Pape, sp. nov. Flies are characterized by secondary sexual dimorphism expressed in the form of species-specific chaetotaxy of the male fore tarsus, a character related to courtship behaviour. The reconnaissance surveys to both of the mentioned countries performed in the last decade brought information about a large number of potential new species of Miltogramma , despite the taxonomic work performed in this area in the past. Describing the majority of them requires extensive revisionary work, which involves accessing the type specimens and applying modern methods of species delimitation. [ABSTRACT FROM AUTHOR]

Recent studies on oestroidean Diptera (Brachycera) are providing a comprehensive and nuanced understanding of the evolutionary history of this remarkably diverse clade of holometabolous insects. The Oestroidea, which includes formidable pests such as various blowflies, botflies, and flesh flies that infest livestock, pets and humans, are mostly composed of beneficial species that act as scavengers or parasitoids on various pest insects. In our research, we used genomic methods to elucidate the phylogenetic position of Nesodexia corsicana  Villeneuve, 1911 (Diptera: Calliphoridae), a mysterious oestroid species endemic to Corsica and characterized by distinctive morphological features that have puzzled taxonomists for years. Contrary to initial hypotheses, our results place Nesodexia Villeneuve, 1911 within the Calliphoridae subfamily Rhinophorinae, a small lineage of terrestrial isopod parasitoids. Through detailed morphological analysis of adults of both sexes and eggs, we uncovered significant insights consistent with our phylogenomic reconstruction. The unique morphological features of the species, coupled with its restricted and fragmented habitat, highlight its potential conservation importance. We delineated the area of occupancy for N. corsicana and assessed its "threatened" category using specific IUCN Red List criteria. In addition, we mapped the available habitat within its range and determined potential key biodiversity areas (KBA) triggered by N. corsicana. New potential KBAs are only partially covered by the Corsican Regional Park. Finally, we mapped the distribution of habitats on the island to assess the potential distribution of the species beyond its currently known geographic range. [ABSTRACT FROM AUTHOR]

Detailed knowledge of the extent of post-genetic modifications affecting shallow submarine hydrocarbons fueled from the deep subsurface is fundamental for evaluating source and reservoir properties. We investigated gases from a submarine high-flux seepage site in the anoxic Eastern Black Sea in order to elucidate molecular and isotopic alterations of low-molecular-weight hydrocarbons (LMWHC) associated with upward migration through the sediment and precipitation of shallow gas hydrates. For this, near-surface sediment pressure cores and free gas venting from the seafloor were collected using autoclave technology at the Batumi seep area at 845 m water depth within the gas hydrate stability zone. Vent gas, gas from pressure core degassing, and from hydrate dissociation were strongly dominated by methane (> 99.85 mol.% of ∑[C1-C4, CO2]). Molecular ratios of LMWHC (C1/[C2 + C3] > 1000) and stable isotopic compositions of methane (δ13C = - 53.5‰ V-PDB; D/H around - 175‰ SMOW) indicated predominant microbial methane formation. C1/C2+ ratios and stable isotopic compositions of LMWHC distinguished three gas types prevailing in the seepage area. Vent gas discharged into bottom waters was depleted in methane by > 0.03 mol.% (∑[C1-C4, CO2]) relative to the other gas types and the virtual lack of 14C-CH4 indicated a negligible input of methane from degradation of fresh organic matter. Of all gas types analyzed, vent gas was least affected by molecular fractionation, thus, its origin from the deep subsurface rather than from decomposing hydrates in near-surface sediments is likely. As a result of the anaerobic oxidation of methane, LMWHC in pressure cores in top sediments included smaller methane fractions [0.03 mol.% ∑(C1-C4, CO2)] than gas released from pressure cores of more deeply buried sediments, where the fraction of methane was maximal due to its preferential incorporation in hydrate lattices. No indications for stable carbon isotopic fractionations of methane during hydrate crystallization from vent gas were found. Enrichments of 14C-CH4 (1.4 pMC) in short cores relative to lower abundances (max. 0.6 pMC) in gas from long cores and gas hydrates substantiates recent methanogenesis utilizing modern organic matter deposited in top sediments of this high-flux hydrocarbon seep area. © 2009 Elsevier B.V. All rights reserved.