Leptanilla Emery 1870
Creators: name: Griebenow, Zachary Hayes
name: Richter, Adrian
name: Economo, Evan P.
name: Dang, An Van
name: Yamada, Aiki
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Formicidae
Leptanilla

description: Genus Leptanilla Emery, 1870
Leptanilla Emery, 1870: 196.
Scyphodon Brues, 1925: 93, fig. 1. Synonymy by Griebenow (2024: 128).
Phaulomyrma Wheeler & Wheeler, 1930: 193, figs 1–2. Synonymy by Griebenow (2021: 630).
Leptomesites Kutter, 1948: 286, figs 1–7. Synonymy by Baroni Urbani (1977: 433).
Noonilla Petersen, 1968: 582, figs 6–8. Synonymy by Griebenow (2024: 128).
Yavnella Kugler, 1987 (“1986”): 52, figs 14–22. Synonymy by Griebenow (2024: 128).
Diagnosis
Worker
1–4 medial mandibular teeth present. Ventromedial mandibular margin lacking teeth. Peg- or pencil-like chaetae absent from labrum. Dorsal mandibular articulation not visible in full-face view. Palp formula 1–2,1. Clypeus indistinct, not extending visibly between antennal toruli. Pair of medial chaetae absent from second protarsomere. Meso-metapleural suture absent; or if present, then unsculptured.Abdominal segments III–IV narrowly joined. Cuticular microsculpture present, scabriculous to areolate.
Gyne
Compound eyes repressed or present; if present then with 1–4 ommatidia. Mandible often falcate, rarely (Leptanilla belantan Griebenow, 2024) with distinct masticatory margin; edentate, or with 1–2 subapical teeth. Wings and alar sclerites absent. Abdominal segment III not petiolate.
Male
Palp formula 1–2,1. Ocelli present or absent; if present, then almost always set on tubercle. Notauli absent. Pterostigma absent. Hindwing 1A absent. Volsellae present or absent; if present, then parossiculus and lateropenite insensibly fused. Cupula present or absent; if present, then annular. Penial sclerites medially fused, rarely (Leptanilla astylina Petersen, 1968; Leptanilla TH 03) articulated.
Key to Leptanilla workers of the Eastern Palaearctic and Indo-Malaya
Condensed from Griebenow (2024: 148–149, 152–154), with the addition of taxa described since that publication (Qian et al. 2024; Zhong 2024).
1. Clypeus with median process (Fig. 3C) ............................................................................................ 2
– Clypeus without median process (Fig. 3A) .................................................................................... 16
2. Clypeal process entire; length of abdominal postsclerites IV<combined length of abdominal postsclerites V–VIII .......................................................................................................................... 3
– Clypeal process emarginate to bilobed; length of abdominal postsclerites IV≥combined length of abdominal postsclerites V–VIII ........................................................................................................ 5
3. Posteriorly recurved subpetiolar process absent; PPI = 80–86 ........................................................... ......................................................................... Leptanilla buddhista Baroni Urbani, 1977 (NEPAL)
– Posteriorly recurved subpetiolar process present; PPI = 122–138 ................................................... 4
4. CI = 72–74, SI = 49–56; outline of antennal torulus subcircular (Zhong 2024: fig. 3c) .................... ............................................................. Leptanilla macauensis Leong et al., 2018 (CHINA: Macau)
– CI = 67–70, SI = 63–66; outline of antennal torulus oblong, with protruding anteromedial angle (Zhong 2024: fig. 3b) .............................. Leptanilla sichuanensis Zhong, 2024 (CHINA: Sichuan)
5. Anterior margin of dorsal petiolar node emarginate in dorsal view (Leong et al. 2018: fig. 13e–f) .. ........................................................................................................................................................... 6
– Anterior margin of dorsal petiolar node entire in dorsal view (Leong et al. 2018: fig. 13a, d) ........ 7
6. Dorsal petiolar node almost twice as long as wide in dorsal view; postpetiolar node longer than wide in dorsal view ................................ Leptanilla hypodracos Wong & Guénard, 2016 (SINGAPORE)
– Length and width of dorsal petiolar node subequal in dorsal view; postpetiolar node distinctly wider than long in dorsal view ................... Leptanilla clypeata Yamane & Ito, 2001 (INDONESIA: Java)
7. Length of metasomal setae bimodal ................................................................................................. 8
– Length of metasomal setae unimodal ..............................................................................................11
8. Mandible with four teeth, with most proximal tooth truncate (Saroj et al. 2022: fig. 1e); ventromedian lamella of abdominal sternite II denticulate ....................................................................................... ............................................................... Leptanilla ujjalai Saroj et al., 2022 (INDIA: West Bengal)
– Mandible with three teeth, with most proximal tooth not truncate; ventromedian lamella of abdominal sternite II not denticulate .................................................................................................................. 9
9. Longitudinal subpetiolar lamella absent ............................................................................................. ............................................................. Leptanilla dehongensis Qian et al., 2024 (CHINA: Yunnan)
– Longitudinal subpetiolar lamella present ........................................................................................ 10
10. Lateral pronotal margins weakly convex in dorsal view; PPTI = 74–76 ............................................ ......................................... Leptanilla lamellata Bharti & Kumar, 2012 (INDIA: Himachal Pradesh)
– Lateral pronotal margins strongly convex in dorsal view; PPTI = 85–86 .......................................... .................................................................... Leptanilla escheri (Kutter, 1948) (INDIA: Tamil Nadu)
11. PI>85 .............................................................................................................................................. 12
– PI ≤ 85 .............................................................................................................................................. 15
12. Mandible with three teeth, most proximal tooth acute ....................................................................... ....................................................... Leptanilla kunmingensis Xu & Zhang, 2002 (CHINA: Yunnan)
– Mandible with four teeth, most proximal tooth blunt ..................................................................... 13
13. Meso-metapleural suture present laterally; PPI ≤ 87 ........................................................................... .................................................................... Leptanilla sapa Yamada sp. nov. (VIETNAM: Lao Cai)
– Meso-metapleural suture absent laterally; PPI>87 ........................................................................ 14
14. Proximal mandibular tooth recurved, apex expanded ........................................................................ ........................................................ Leptanilla belantan Griebenow, 2024 (MALAYSIA: Selangor)
– Proximal mandibular tooth sublinear, apex not expanded .................................................................. .............................................................. Leptanilla belantanoides sp. nov. (VIETNAM: Ninh Binh)
15. Subpetiolar process present, angular; torular rim without areolate sculpture (Griebenow 2024: fig. 27a) .............................. Leptanilla havilandi Forel, 1901 (SINGAPORE; MALAYSIA: Sabah)
– Subpetiolar process absent; torular rim with medial and anterior areolate sculpture (Griebenow 2024: fig. 27b)............................. Leptanilla thai Baroni Urbani, 1977 (THAILAND: Khao Chong)
16. Mandible with two teeth ................................................................................................................. 17
– Mandible with 3–4 teeth ................................................................................................................. 18
17. Anterior margin of cranium with anterolateral clypeal projections; ventral vertices of abdominal sternites II–III projecting a subequal distance ventrad craniocaudal axis .......................................... ...................................................... Leptanilla kebunraya Yamane & Ito, 2001 (INDONESIA: Java)
– Anterior margin of cranium entire; ventral vertex of abdominal sternite II distinctly lower on dorsoventral axis compared to ventral vertex of abdominal sternite III ............................................. ..................................................................... Leptanilla butteli Forel, 1913 (MALAYSIA: Selangor)
18. Meso-metapleural groove present, impressed on dorsum of mesosoma ............................................ ............................................................... Leptanilla hunanensis Tang et al., 1992 (CHINA: Hunan)
– Meso-metapleural groove absent from dorsum of mesosoma, sometimes impressed on sides ...... 19
19. Clypeus with median emargination ................................................................................................ 20
– Anterior clypeal margin entire, sublinear to convex ....................................................................... 23
20. Abdominal tergite IV not narrowed anteriorly in dorsal view (Griebenow 2024: fig. 36b); clypeal margin protruding well anterad antennal toruli .................................................................................. ........................................... Leptanilla oceanica Baroni Urbani, 1977 (JAPAN: Ogasawara Islands)
– Abdominal tergite IV narrowed anteriorly in dorsal view (Griebenow 2024: fig. 36a); clypeal margin not protruding well anterad antennal toruli .................................................................................... 21
21. Abdominal tergite II trapezoidal in dorsal view, narrowing posteriorly; abdominal sternite III nearly planar ................................................. Leptanilla qinlingensis Qian et al., 2024 (CHINA: Shaanxi)
– Abdominal tergite II rectangular in dorsal view, not narrowing posteriorly; abdominal sternite II convex ............................................................................................................................................. 22
22. Mandibular teeth equidistant (Zhong 2024: fig. 13a) ......................................................................... ........................................................................ Leptanilla taiwanensis Ogata et al., 1995 (TAIWAN)
– Proximal mandibular tooth slightly removed from remaining teeth (Zhong 2024: fig. 13b) ............. .............................................................. Leptanilla beijingensis Qian et al., 2024 (CHINA: Beijing)
23. Mandible with four teeth (subapical tooth sometimes difficult to distinguish) .............................. 24
– Mandible with three teeth ............................................................................................................... 25
24. Most proximal mandibular tooth large and distinct; abdominal tergite IV distinctly narrowed anteriorly in dorsal view .................. Leptanilla tanakai Baroni Urbani, 1977 (JAPAN: Yakushima)
– Most proximal mandibular tooth small and indistinct; abdominal tergite IV not distinctly narrowed anteriorly in dorsal view ..................... Leptanilla japonica Baroni Urbani, 1977 (JAPAN: Honshu)
25. Petiole distinctly wider than long .................. Leptanilla yunnanensis Xu, 2002 (CHINA: Yunnan)
– Petiole not distinctly wider than long ............................................................................................. 26
26. Anterior margin of clypeus convex in full-face view ..................................................................... 27
– Anterior margin of clypeus linear in full-face view ....................................................................... 28
27. Mesothorax anteriorly constricted in dorsal view .............................................................................. ................................................................. Leptanilla besucheti Baroni Urbani, 1977 (SRI LANKA)
– Mesothorax not anteriorly constricted in dorsal view ........................................................................ ................................................................ Leptanilla morimotoi Yasumatsu, 1960 (JAPAN: Kyushu)
28. Pedicel length and width subequal .... Leptanilla okinawensis Terayama, 2013 (JAPAN: Okinawa)
– Pedicel distinctly longer than wide ................................................................................................. 29
29. Meso-metapleural suture absent; subpetiolar process absent posteriorly, abdominal sternite II linear in profile view ...................................... Leptanilla kubotai Baroni Urbani, 1977 (JAPAN: Shikoku)
– Meso-metapleural suture present on side of mesosoma, absent from dorsum; abdominal sternite II convex in profile view ............................. Leptanilla phthirigyna sp. nov. (VIETNAM: Ninh Binh)
description: Published as part of Griebenow, Zachary Hayes, Richter, Adrian, Economo, Evan P., Dang, An Van & Yamada, Aiki, 2025, Four new species of Leptanillinae (Hymenoptera: Formicidae) from northern Vietnam described with phylogenomics and micro-computed tomography, pp. 98-145 in European Journal of Taxonomy 987 on pages 121-124, DOI: 10.5852/ejt.2025.987.2867, http://zenodo.org/record/15255273