A remarkable troglomorphic ant,

Abstract

The ant subfamily Leptanillinae (Hymenoptera: Formicidae) consists of minute soil-dwelling species, with several genera within this clade being based solely upon males, including Yavnella Kugler. The dissociation of males and workers has resulted in taxonomic confusion for the Leptanillinae. We here describe the worker caste of Yavnella, facilitated by maximum-likelihood and Bayesian inference from 473 partitioned ultra-conserved element loci, this dataset including 49 other leptanilline species, both described and undescribed. Yavnella laventa sp. nov. is described from seven worker specimens collected in south-western Iran from the Milieu Souterrain Superficiel, a subterranean microhabitat consisting of air-filled cavities among rock and soil fragments, which is subject to similar environmental conditions as caves. This species has bizarrely elongated appendages, which suggests that it is confined to cavities, in contrast with the soil-dwelling behaviour observed in other leptanilline ants. Based on its gracile phenotype relative to other Leptanillinae, Y. laventa shows remarkable adaptations for subterranean life, making it one of a very few examples of this syndrome among the ants. Moreover, the discovery of the worker caste of Yavnella expands our morphological knowledge of the leptanilline ants. We provide worker-and male-based diagnoses of Yavnella, along with a key to the genera of the Leptanillinae for which workers are known. The worker caste of Yavnella as known from this species is immediately recognisable, but the possibility must be noted that described workers of Leptanilla may in fact belong to Yavnella. Further molecular sampling is required to test this hypothesis.

Leptanilla voldemort sp. nov., a gracile new species of the hypogaeic ant genus Leptanilla (Hymenoptera, Formicidae) from the Pilbara, with a key to Australian Leptanilla

“…Specifically, the elongated antennae and petiole of workers in both L. voldemort sp. nov. ( SI = 128–139, PI = 25) and L. laventa ( SI = 160–163, PI = 29–32) are not observed in other Leptanilla species ( SI <100, PI >31) ( Griebenow et al 2022 ; Griebenow 2024 ; Qian et al 2024 ). Nonetheless, workers of L. voldemort sp.…”

“…nov. is unlike that of any other Leptanilla species except L. laventa from Iran. Interestingly, L. laventa was not collected from soil, but via subterranean pitfall traps buried 0.6–1 m belowground in the Milieu Souterrain Superficiel , an underground network of empty air-filled voids and cracks developing within multiple layers of rock fragments, located below the soil layer ( Mammola et al 2016 ; Griebenow et al 2022 ). We can only presently speculate whether L. voldemort sp.…”

“…A total of 33–72 images were taken and stacked together. Morphological measurements and indices were calculated following Griebenow et al (2022) . These are detailed below.…”