Previously regarded as a subspecies of Campylopterus largipennis (HBW/BirdLife International 2018) but split following Lopes et al. (2017, 2020). Differs from C. l. largipennis by its longer ‘LTTs’ (light tail-tips) (effect size 2.39 for male LTT1; score 2); base of outer rectrices bright bronzy-green vs dark grey (1); totally different habitat (1); totally different voice, with the song a high tittering trill, quite unlike anything on Xeno-canto for largipennis (at least 4). For difference from C. calcirupicola, see that species. Monotypic.

This species's range is projected to contract over the next few decades as a result of climate change. The exact timing of this decline, and the rate of any population reduction over the next decade, are highly uncertain. In a worst-case scenario there may be a very rapid population decline over the next decade, but further evidence is required to confirm this. The species is therefore listed as Near Threatened.

Campylopterus diamantinensis is restricted to the Serra Espinhaço in Minas Gerais, southeast Brazil, including the Diamantina plateau, Serra dos Ferreiras, Serra do Caraça, Serra do Gavião, Serra do Cabral, Serra do Breu, Serra do Barão, Serra do Cipó and Sempre Vivas National Park (Vasconcelos and Melo Junior 2002; Vasconcelos 2009; Vasconcelos and Rodrigues 2010; Chaves 2014; Lopes et al. 2017).

The population size is unknown, but it is naturally rare. The species occurs on several upland areas and is unlikely to disperse over large distances, so there are likely to be multiple isolated subpopulations.

It occurs in high altitude campos rupestres (isolated rocky outcrops with dry, bushy vegetation) above 1,000 m (Vasconcelos and D'Angelo Neto 2007; Lopes et al. 2017).

The species's habitat is relatively intact (Vasconcelos and D'Angelo Neto 2007; Lopes et al. 2017). Potential threats include fires, mining, climate change, urbanisation and poorly-managed tourism (Vasconcelos and Melo-Junior 2001; Vasconcelos and D'Angelo Neto 2007; Vasconcelos et al. 2008; Vasconcelos and Rodrigues 2010). 

Fires are largely used to renew the grassland vegetation for use as natural pastures and may also be caused by conflict between people and protected areas, as well as by tourist campfires or by lightning (Ribeiro and Figueira 2011). Although the campo rupestre is adapted to fire, anthropogenic changes in the fire regime increase the frequency and intensity of fires, reducing the ability of the ecosystem to recover (Figueira et al. 2016). An analysis of fire history in the Serrado Cipo National Park and Morroda Pedreira Environment Protection Area found that 75% (983 km²) of the study area had been burned at least once between 1984 and 2014, and 48% of the area was burned every 1-2 years (Alvarado et al. 2017). In some years, the total burned area was more than 300 km² (Alvarado et al. 2017). However, fires in the Serrado Cipo National Park do not usually burn more than 1 km² (Figueira et al. 2016).

A significant proportion of the species's habitat is either directly or indirectly affected by mining (Pena et al. 2017). An analysis found that the combined impacts of climate change and mining may lead to the loss of over 80% of the campo rupestre habitat by 2070, although some of the areas where C. diamantinensis occurs (including Caraça and Serra do Cipó) appeared likely to persist (Wilson Fernandes et al. 2018).

Climate change is likely to pose a significant threat over future decades. The species's range has been variously projected to contract by c.66-75% by 2045-2060, relative to climatic conditions in 1990 (Marini et al. 2009), or by over 99% by 2050, also relative to climatic conditions in 1990 (Hoffman et al. 2020), as a result of climate change.

Grazing by cattle and horses degrades the quality of the campo rupestre habitat (Vasconcelos and D'Angelo Neto 2007). Small numbers of cattle are scattered along the Espinhaço mountains, but they are not present on the steep slopes or rocky areas (M. F. de Vasconcelos in litt. 2009).

Conservation Actions Underway
It occurs in several large conservation units (Lopes et al. 2017), including Sempre Vivas National Park and the RPPN Caraça.
An educational programme has been carried out in RPPN Caraça (Vasconcelos and Melo-Junior 2001).

Conservation and Research Actions Proposed
Carry out surveys across potentially occupied habitat to confirm the species range and to estimate the population density and population size. Monitor trends in the species's population size and range. Research the likely impact of threats such as climate change and mining.

Create new protected areas and improve enforcement at existing protected areas where the species occurs. Carry out an educational programme about the importance of the biodiversity of the region, to reduce the risk of fires. Ensure that a regional fire service is able to effectively control fires.