Eretmocera hafeetensis sp. nov., a moth in the family Scythrididae, is described and illustrated based on the examination of three male and 13 female specimens collected at the foot of Jebel Hafeet, an isolated 1,140 metres-high massif just south of Al Ain, after which the new species is named. The new species is distinct from congeners in details of its male and female genitalia and is also readily separated in the field from other Eretmocera species. The new addition brings the number of confirmed species in this genus represented in the UAE to three. The discovery of this species at Ain Al Waal, Jebel Hafeet highlights the conservation importance of this and similar nearby locations, which are beginning to reveal unique species among its already species-rich fauna at a time of huge human encroachment into the area.

Moths in the family Scythrididae are often small-sized and somewhat cryptic in appearance. Although represented in most parts of the world, until late last century, only a small minority of the species described had been recorded in the Middle East (Bengtsson 2014).

Knowledge of Scythrididae species in Arabia is mostly derived from work in Oman and Yemen at around the turn of the 21^st century, when Bengtsson (2002a, 2002b) described 45 new species and identified many others. Prior to that, some scythridids from Saudi Arabia had been recorded by Passerin d’Entrèves (1996).

In the UAE, knowledge of the fauna is less developed. Van Harten’s literature review (van Harten 2005) – that was compiled prior to embarking on the first of six volumes in the Arthropod Fauna of the UAE series – documented only two species. As part of that project, van der Wolf (2008) brought to 12 the number of species of the family recorded from the UAE, six of them having been among those described from Oman and Yemen.

Two genera in Scythrididae are represented in the UAE, namely Eretmocera Zeller, 1952 and the more species-rich genus Scythris Hübner, 1825. The genus Eretmocera consists of rather small species with wingspan in general of 8–12 mm and are often recognisable in resting position by their dark brown upper wings with brightly coloured markings, and abdomen coloured with varying extents of orange, yellow and black. Many species have partly thickened antennae, especially in males. There are 50 species in Eretmocera worldwide (BÅB, private database). Most species are found in the tropical zone, especially in Africa, but they also range to the Middle East, Asia and Australia.

Two species in the genus Eretmocera are known from the UAE, E. impactella (Walker 1864) and E. bradleyi (Amsel 1961), the former of which is found in small numbers on Jebel Hafeet. Two more, as yet unidentified species in the genus, have also been observed on the mountain with external markings quite distinct from each other, and different from E. bradleyi, E. impactella and E. hafeetensis.

The distinctively marked E. hafeetensis sp. nov. was first observed in 2010. Differences in its external appearance to other species in the region prompted discussion between the authors about its possible identity and led to specimens being collected for examination and dissection. Finding males among the specimens collected proved difficult, and indeed only females were present in the first two batches examined. The results bore confirmation that E. hafeetensis was indeed a new species, although it was not until later that males were found. A description of both male and female of the new species is provided here. The holotype is deposited in Natural History Museum, Abu Dhabi, UAE.

Figure 1. 

Type series of Ertemocera hafeetensis sp. nov. (pinned). Three males to the left (holotype at the top), the other specimens females.

Specimens were collected, using sweep nets over various plants. Collected specimens were preserved and pinned, or they were sent as dry specimens to the laboratory in Sweden, where they were relaxed and mounted for dissection and examination.

Field photographs were taken using Nikon D850, D3 and Z9 camera bodies, with Nikkor 105 mm lenses and Nikon’s R1 Wireless Close-Up Speedlight System. A stacked photograph (Fig. 6) was taken using Nikon D850 camera body using a 25mm f/2.8 Ultra-macro 2.5× -5.0× lens and a Cognisys Stackshot focus stacking rail. HELICON FOCUS 8.2.0 software was used for processing of the stacked image. Post processing was done using ADOBE PHOTOSHOP.

Genitalia slides (Figs 7a, b, 8a, b) were made according to the standard procedure described by Robinson (1976). The slides were photographed with Canon EOS 500D mounted on a compound microscope Euromex Arnheim EB No. 149508. The pictures were stacked with the software HELICON FOCUS Version 4.2.8 and then enhanced with ADOBE PHOTOSHOP Elements 2019.

Given that nearly all the specimens of this new species have been found at Ain Al Waal, its future prospects would appear to be closely tied up with that of the site itself. However, despite benefitting from an undisturbed environment so far, it is not guaranteed that the area will remain in its present state. While two layers of security have kept the area free of disturbance in recent years, the encroachment of a human residential area to within metres of the site is likely to be a constant threat in the coming years.

Away from the type locality, there are a few possible habitats for E. hafeetensis nearby. Despite many searches on the eastern side of the mountain, and to a species-rich wadi that intersects the mountain from the north (Wadi Tarabat), surprisingly, the species has not been found at those other locations. Ain Al Waal is different in some ways (e.g., has a steeper face, more permeable and fractured composition and hundreds of deep holes and caves), but those other parts of the mountain share much of the fauna and flora occurring at Ain Al Waal, so it is speculated that there is a good chance that the species may be found there as well with a more concerted search.

The other location where this species has been recorded is Ain Al Fayda’s Ladies’ and Children’s Park, 4 km further west, where a few of this species were observed in 2014. That location is no longer irrigated, and it is earmarked for development. That area is flat, and not a mountainside habitat, but the plant at which it was seen, Salvadora persica, is commonly planted and irrigated at roadsides. The new moth species may have dispersed away from the mountain, and this particular record does at least show that the species is not confined strictly to mountainside habitats.

Whether the new species might occur further away in the Hajar Mountain range in the northern Emirates (or Oman) is open to question. Between the two mountainous areas, there are differences climatically (the Hajars with more rainfall and cooler), geographically (at least 40 km separation), geologically (predominantly igneous rocks in the Hajars rather than tertiary sedimentary rock in Jebel Hafeet: Kirkham 2003) and in terms of the fauna and flora found in those areas. A large collecting effort by numerous entomologists over several years in recent times (van Harten 2008–2017) failed to discover this species among 12 scythridid species that they found during collections of tens of thousands of arthropod specimens, mostly in the Hajar range of mountains of the UAE.

The discovery of new species at Ain Al Waal will hopefully help to raise awareness of this site. A list of 800 terrestrial fauna species (Roberts unpublished) will show that it is an area that has a rich biodiversity.

Given that Eretmocera hafeetensis sp. nov. is not guaranteed to occur away from the mountain, hopes of its long-term survival are pinned on the mountain’s new status as a National Park, which it received in 2017. This may lead to greater monitoring of this and other mountainside sites. That may be necessary to protect this new species and hundreds of others that are only now starting to be revealed.

We would like to thank the Mohammed bin Zayed Species Conservation Fund for its support during the early years of the Ain Al Waal study. We gratefully acknowledge the support of the Societas Europaea Lepidopterologica in covering the Article Processing Charges (APCs). We would also like to thank the reviewers (editor David Lees, Lauri Kaila and Erik van Nieukerken) for their comments which helped to improve this article.