Atlantomyia nitida is a parasitoid fly endemic to the island of St Helena. Described from 14 specimens collected from Prosperous Bay Plain in 1967. This species is found both in coastal drylands and the cloud forest. This order has generally received less recording effort than other taxonomic groups and so further survey work is required for this species. From what is known about the ecology of related species it is likely that it will be found to be a parasitoid on grasshoppers and/or crickets, originally of one or more of the five endemic species for example on Prosperous Bay Plain there is an endemic grasshopper, Primnia sanctaehelenae. Threats to this species would be linked both to threats to the host species and direct threats to the species, such as climate change, habitat loss, competition for host resources from invasive non-native species and predation from non-native invertebrate species. Non-native vertebrate predators, such as rodents and the African Grass Frog (Strongylopus grayi), may also negatively impact this species. This species was last recorded in Sharks Valley in 2020. Its current known extent of occurrence (EOO) and area of occupancy (AOO) are both 20 km² (but it may be more widespread than currently known), it occurs in three different areas of habitat with unique threats, all of which are in decline due to the threats described above, but it is likely to occur in more than five locations. This species is assessed as Vulnerable.

Atlantomyia nitida is a parasitoid fly species endemic to the island of St Helena, in the South Atlantic. This species was thought to be restricted to Prosperous Bay Plain but was found in the Peaks across a range of altitudes from multiple sites, but only accounted for less than 1% of the samples (Mendel et al. 2008). One specimen was recorded in 2003 from Widow Slope at Prosperous Bay Plain and then in 2005 from the Depot and Cuckholds Point/Mt. Actaeon/Diana’s Peak and in 2006, from Prosperous Bay Plain and from Signal House, cliff-top Scrubwood site (four samples in total) (Mendel, Ashmole and Ashmole 2008). This species was not recorded in the Prosperous Bay survey by Pryce (2019) but was last seen in 2020, identified from photos in Sharks Valley.

Note: there are historical changes with the site names for Diana’s Peak, Cuckhold’s Point and Mt Actaeon and as such, we are including all the names in this assessment for the location of the records; see St Helena Government (2020).

This species is related to the widespread genus Ceracia (Ashmole and Ashmole 2000). Described from 14 specimens found at Prosperous Bay Plain in 1967 (Pryce 2019) and it was seen at Sharks Bay in 2020. This species was thought to be restricted to Prosperous Bay Plain but was found in the Peaks across a range of altitudes from multiple sites, but only accounted for less than 1% of the samples (Mendel et al. 2008). One specimen was recorded in 2003 from Widow Slope at Prosperous Bay Plain and then in 2005 from the Depot and Cuckholds Point/Mt. Actaeon/Diana’s Peak and in 2006, from Prosperous Bay Plain and from Signal House, cliff-top Scrubwood site (four samples in total) (Mendel et al. 2008). This species was not recorded in the Prosperous Bay survey by Pryce (2019) but was last seen in 2020, identified from photos in Sharks Valley.

Described from samples collected in Prosperous Bay Plain collected in 1967 (Alexander et al. 1977). This species is found both from coastal drylands and the cloud forest. From what is known about the ecology of related species it is likely that it will be found to be a parasitoid on endemic grasshoppers and/or crickets (Alexander et al. 1977, Ashmole and  Ashmole 2000). On Prosperous Bay Plain there is an endemic grasshopper, Primnia sanctaehelenae (Dutton et al. 2020), but in the cloud forest there are a number of species which might be a host. It is unknown whether it can also utilize any of the endemic, native or non-endemic species of Orthoptera as a host.

This species was last recorded in 2020 in Sharks Valley. This species is likely to be parasitic on Orthoptera and more information on the host species needs to be collected. This species could be under threat from climate change, invasive non-native predatory invertebrates, non-native vertebrate predators, such as rodents and the African grass Frog (Strongylopus grayi), invasive non-native species competing for host invertebrate prey and habitat loss.

This species is on the Environmental Protection Ordinance on St Helena, which indicates protected species. The Peaks and Prosperous Bay plain are currently within a protected area and part of the government’s Nature Conservation Area (NCAs). This species will benefit from the habitat improvement outlined in the Peaks National Park Management Plan (2019) and what will be proposed in the Prosperous Bay Plain Managment plan (in prep). There is currently no specific action plan for this species, but its conservation and further research will be supported through the St Helena Invertebrate Strategy 2023–2027 (St Helena National Trust and St Helena Government 2023).