Vega, Y. | Search bioRxiv

bioRxiv2026

The Taxonomic Status and Phylogenetic Relationships of Toxorhynchites (Diptera: Culicidae) Species from Panama

Mosquitoes in the Toxorhynchites genus (Theobald, 1901) are specialized predators of container-breeding mosquito larvae, including major Aedes disease vectors. Despite their biological control potential, species boundaries and phylogenetic relationships remain poorly understood. Utilizing country-wide sampling across Panama, we evaluated the taxonomic status and diversity of local Toxorhynchites species. We collected 147 specimens from artificial and natural containers, yielding 97 cytochrome c oxidase subunit I barcodes from 101 sequenced individuals. A Panama-only Neighbor-Joining analysis revealed four distinct, well-supported clusters (I - IV) exhibiting high mean inter-cluster genetic divergence (4.8 - 20.2%), alongside morphological and ecological segregation. A subsequent global Neighbor-Joining analysis incorporating BOLD and GenBank sequences recovered Toxorhynchites as a strongly supported monophyletic group (99.0% bootstrap support) and revealed deep phylogenetic divergence separating Old World Toxorhynchites (Toxorhynchites) (Clades A and B) from New World Toxorhynchites (Lynchiella) (Clades C - G) lineages. Panamanian Clusters I and II formed two distinct groupings within Clade G, nesting as sisters to Subclade G1 characterized by severe taxonomic discordance involving sequences labeled as Tx. moctezuma, Tx. theobaldi, and Tx. rutilus. Cluster III nested within Tx. hypoptes (1.5% divergence) in Clade E, whereas Cluster IV associated with Tx. haemorrhoidalis s.l. (>5.0% divergence) in Clade C. The high degree of taxonomic uncertainty or cryptic diversity uncovered within Clades C, D, and G underscores an urgent need for formal taxonomic revision to accurately delimit species boundaries. Due to its widespread peri-urban distribution, Cluster I (within the Tx. moctezuma s.l. complex) shows the greatest promise for mass-rearing and Aedes biocontrol applications in Panama.

evolutionary biology↗

bioRxiv2024

Distribution, ecology, and natural history of the recently rediscovered and critically endangered Santa Marta Sabrewing

The Santa Marta Sabrewing is a critically endangered (CR) hummingbird endemic to the Sierra Nevada de Santa Marta, Colombia. Prior to 2022, there were only three documented sightings of the sabrewing since it was described in 1879, including only one record between 1946 and 2022. As a result, this "lost" species has long been one of the most poorly-known birds in Colombia. We located a resident population of Santa Marta Sabrewing along the Guatapuri River near the Chemesquemena and Guatapuri villages in July 2022, and at its type locality, San Jose, in January 2023. Based on historical data and newly-collected field observations, we assess the species status and describe aspects of its natural history and ecology. Our review indicates the species has been frequently misidentified in the past, and that to date, documented evidence of its presence is limited to five localities, almost all of them restricted to the south-eastern slope of the Sierra Nevada de Santa Marta, along the mid Guatapuri river basin. Consequently, this bird appears to represent a case of microendemism. Following IUCN criteria, our data suggest that Santa Marta Sabrewing should remain listed as CR. Field observations indicate that the species is highly associated with watercourses, where males hold year-round territories and form leks. We obtained records of males in mid-elevation habitats (1,150-1,850 m) for 16 consecutive months between July 2022 and October 2023, suggesting that the species might not be an elevational migrant, as previously speculated. More information is needed to understand the species ecology so that effective conservation actions can be designed in collaboration with the indigenous communities with which the species coexists.

ecology↗