Keys to Leptanillinae

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Griebenow (2024) provides keys to workers and males of Leptanillinae. These include keys to genera and species groups of Leptanillinae (one for workers, one for males), along with keys to species groups (one set for each gender).

These keys include:

Worker-based key to genera and species groups and selected species of Leptanillinae

Most subclades of the Leptanillinae show strong morphological conservatism in the worker caste. It is consequently difficult to assess the scope of intraspecific phenotypic variation in workers, and the sparseness of collected specimens prevents algorithmic species delimitation using molecular data. Therefore, morphospecies known only from a single specimen are excluded from the following keys, even if phylogenomic data are available therefrom.

1

  • Abdominal segment III not petiolate (Fig. 34A); occiput visible in full-face view (Opamyrmini) => Opamyrma hungvuong (VIETNAM: Ha Tinh, Son La; CHINA: Hainan, Guangxi)
  • Abdominal segment III petiolate (Fig. 34B, C); occiput not visible in full-face view (Leptanillini) => 2
  • pxGriebenow (2024), Figure 34. Abdominal segments II–III of female Leptanillinae, profile view. Abdominal tergite II outlined in red; anterior of abdominal segment III outlined in blue. A, Opamyrma hungvuong (AKY05vii17-06) (Yamada et al. 2020: fig. 1C), worker. B, Protanilla gengma (CASENT0179564), worker. C, Protanilla id01 (MCZENT00728282), gyne. Scale bars: 0.5 mm (A); 0.2 mm (B, C).

2

  • Clypeus extending posteriorly between antennal toruli (Fig. 22A); epistomal sulcus present medially (Protanilla) => 3
  • Clypeus not extending posteriorly between antennal toruli (Fig. 22B); epistomal sulcus indistinct medially (Leptanilla) => 6
  • Griebenow (2024), Figure 22. Condition of the worker frontoclypeal margin in Protanilla (A) and Leptanilla (B). A, Protanilla beijingensis (CASENT0842639). B, Leptanilla laventa (CASENT0842746). Scale bars: 0.5 mm (A); 0.1 mm (B).

3

  • Abdominal tergite II without distinct posterior face (Fig. 34C); clypeus oblate-trapezoidal in full-face view; peg-like chaetae absent from mandible => Protanilla taylori species group
  • Abdominal tergite II with distinct posterior face (Fig. 34B); clypeus campaniform in full-face view; peg-like chaetae present on mandible => 4
  • pxGriebenow (2024), Figure 34. Abdominal segments II–III of female Leptanillinae, profile view. Abdominal tergite II outlined in red; anterior of abdominal segment III outlined in blue. A, Opamyrma hungvuong (AKY05vii17-06) (Yamada et al. 2020: fig. 1C), worker. B, Protanilla gengma (CASENT0179564), worker. C, Protanilla id01 (MCZENT00728282), gyne. Scale bars: 0.5 mm (A); 0.2 mm (B, C).

4

  • Clypeus oblate-trapezoidal in outline, elevated above frons posteriorly (Fig. 35A); mandible bowed along anteroposterior axis of cranium => Protanilla izanagi (JAPAN: Honshu)
  • Clypeus campaniform in outline (Fig. 1B), not elevated above frons posteriorly (Fig. 35B); mandible straight => 5
  • Griebenow (2024), Figure 35. Anterior of the worker head in Protanilla, full-face view. A, Protanilla izanagi (CASENT0842850). B, Protanilla jongi (CASENT0842693). Scale bars: 0.1 mm.

5

6

  • Anterior margin of cranium with median process => 7
  • Anterior margin of cranium without median process => 10

7

  • Frontoclypeal process entire; length of abdominal tergite IV usually less than combined length of abdominal tergites V–VII in dorsal view, sometimes subequal => Leptanilla revelierii species group (in part)
  • Frontoclypeal process emarginate; length of abdominal tergite IV usually greater than combined length of abdominal tergites V–VII in dorsal view, sometimes subequal => 8

8

  • Leong et al. (2018), Fig. 13A: L. havilandi (CASENT0907032), petiole in dorsal view (worker, arrow indicates posterior margin of petiolar node).
  • Leong et al. (2018), Fig. 13D: L. escheri (CASENT0907607), petiole in dorsal view (worker, arrow indicates posterior margin of petiolar node).
  • Leong et al. (2018), Fig. 13E: L. hypodracos (from Wong & Guénard 2016), petiole in dorsal view (worker, arrow indicates posterior margin of petiolar node).
  • Leong et al. (2018), Fig. 13F: L. clypeata (from Wong & Guénard 2016), petiole in dorsal view (worker, arrow indicates posterior margin of petiolar node).

9

  • In full-face view, mandible with most proximal tooth long and well-defined; petiolar node almost twice as long as wide in dorsal view; postpetiolar node longer than wide in dorsal view => Leptanilla hypodracos (SINGAPORE)
  • In full-face view, mandible without most proximal tooth long and well-defined; length and width of petiolar node subequal in dorsal view; postpetiolar node distinctly wider than long in dorsal view => Leptanilla clypeata (INDONESIA: Java)

10

11

  • Anterior margin of cranium with anterolateral frontoclypeal projections; abdominal sternites II-III projecting a subequal distance ventrad craniocaudal axis => Leptanilla kebunraya (INDONESIA: Java)
  • Anterior margin of cranium entire; abdominal sternite II projecting distinctly lower than abdominal sternite III => Leptanilla butteli (MALAYSIA: Selangor)


Worker-based key to the Protanilla bicolor species group

1

  • Cranium black-brown; anterior face of petiolar node sloping in profile view => Protanilla gengma (CHINA: Yunnan; INDIA: Mizoram; VIETNAM: Dong Nai, Bac Giang, Ninh Binh)
  • Cranium yellowish; anterior face of petiolar node subvertical in profile view => Protanilla bicolor (CHINA: Yunnan)


Worker-based key to the Protanilla rafflesi species group

Protanilla schoedli is known only from the gyne (Baroni Urbani and de Andrade 2006) and is excluded from the key. Dias et al. (2019) described the putative worker; however, given known morphological variation in the worker caste among described species of Protanilla, I here consider this as representing an undescribed species, related to Protanilla flamma.

1

  • Abdominal sternite III linear to slightly concave in profile view; abdominal segments III–IV broadly conjoined, with abdominal tergite III lacking a distinct posterior face => 2
  • Abdominal sternite III convex in profile view; abdominal segments III–IV not broadly conjoined, with abdominal tergite III having a distinct posterior face => 3

2

  • Anterior margin of abdominal tergite IV emarginate in dorsal view; two ventrolateral teeth present on mandible => Protanilla furcomandibula (CHINA: Yunnan)
  • Anterior margin of abdominal tergite IV entire in dorsal view; one ventrolateral tooth present on mandible => Protanilla jongi (TAIWAN)

3

  • Anterior face of petiolar node concave in profile view => 4
  • Anterior face of petiolar node linear in profile view => 5

4

  • In profile view anterodorsal corner of petiolar node projecting anteriorly; larger species (WL > 0.8 mm) => Protanilla rafflesi (SINGAPORE; MALAYSIA: Sabah, Sarawak)
  • In profile view anterodorsal corner of petiolar node not projecting anteriorly; smaller species (WL 0.70–0.80 mm) (n = 2) => Protanilla wardi (INDIA: Kerala)

5

  • In dorsal view petiolar node breadth and length subequal; postpetiolar node not inclined anteriorly in profile view => 6
  • In dorsal view petiolar node distinctly broader than long; postpetiolar node inclined anteriorly in profile view => 9

6

  • Coloration castaneous (Fig. 22A); larger species (HL = 0.63–0.70 mm; WL = 0.99 mm) (n = 1) => Protanilla beijingensis (CHINA: Beijing; PAKISTAN: Khyber Pakhtunkhwa)
  • Coloration coppery or yellowish; smaller species (HL = 0.42–0.59 mm; WL = 0.64–0.94 mm) (n = 16) => 7
  • Griebenow (2024), Figure 22. Condition of the worker frontoclypeal margin in Protanilla (A) and Leptanilla (B). A, Protanilla beijingensis (CASENT0842639). B, Leptanilla laventa (CASENT0842746). Scale bars: 0.5 mm (A); 0.1 mm (B).

7

  • Scape not extending beyond occipital vertex of cranium in full-face view (SI ≤ 90); coloration coppery => Protanilla flamma (INDIA: Goa)
  • Scape extending beyond occipital vertex of cranium in full-face view (SI > 90); coloration yellowish (Fig. 4A–C) => 8

8

  • Larger species (WL ≥ 0.75 mm) (n = 2); postpetiolar node prominent in profile view, with anterior and posterior declivities equally rounded (Fig. 6A) => Protanilla lini (TAIWAN; JAPAN: Okinawa, Ryukyu Islands; Senkaku Islands)
  • Griebenow (2024), Figure 6. Leptanilla belantan, holotype (MCZ:Ent:00728278), worker. A, profile view. B, dorsal view. C, full-face view. Scale bars: 0.2 mm.
  • Smaller species (WL < 0.75 mm) (n = 14); postpetiolar node shallow in profile view, with posterior declivity more gradual than anterior declivity (Fig. 5B) => Protanilla wallacei (MALAYSIA: Sabah, Selangor)
  • Griebenow (2024), Figure 5. Worker petiole of Protanilla lini (a) and Protanilla wallacei (b), profile view. Abbreviation: dpn = petiolar node.

9

  • Lateral margin of head with acute dorsal mandibular articulation in full-face view; anteroventral corner of sub-post-petiolar process obliquely truncated => Protanilla tibeta (CHINA: Xizang)
  • Lateral margin of head without dorsal mandibular articulation apparent in full-face view (Fig. 24A); anteroventral corner of sub-post-petiolar process rounded => 10
  • Griebenow (2024), Figure 24. Worker cranium of Protanilla concolor (A) and Protanilla bicolor (B), diagrammatic full-face view, redrawn from Xu (2002: figs 18, 21). Abbreviation: dma = dorsal mandibular articulation.

10

  • Meso-metapleural furrow deeply excavated in profile view; very large species (HW = 0.82–0.84 mm) (n = 3) (Satria et al. 2023) => Protanilla eguchii (INDONESIA: Sumatra)
  • Meso-metapleural furrow shallowly excavated in profile view; smaller species (HW = 0.48 mm) (n = 1) => Protanilla concolor (CHINA: Yunnan)


Worker-based key to the Leptanilla revelierii species group

1

  • Anterior margin of cranium with median process => 2
  • Anterior margin of cranium without median process => 4

2

3

  • Posteriorly recurved subpetiolar process present; PPI = 122–138 (n = 5) => Leptanilla macauensis (CHINA: Macau)
  • Posteriorly recurved subpetiolar process absent; PPI = 80–86 (n = 2) => Leptanilla buddhista (NEPAL)

4

  • Meso-metapleural groove present, impressed on dorsum of mesosoma => Leptanilla hunanensis (CHINA: Hubei, Hunan, Yunnan)
  • Meso-metapleural groove absent from dorsum of mesosoma, sometimes faintly impressed on sides => 5

5

  • Anterior margin of cranium with median emargination => 6
  • Anterior margin of cranium entire, linear to convex => 9

6

  • Four mandibular teeth; greatest width of petiolar node in dorsal view distinctly posterior to midlength => Leptanilla vaucheri (MOROCCO)
  • Three mandibular teeth; greatest width of petiolar node in dorsal view not distinctly posterior to midlength => 7

7

  • Length of abdominal segment II subequal to that of abdominal segment III in dorsal view; abdominal tergite IV narrowed anteriorly in dorsal view (Fig. 36A) => Leptanilla taiwanensis (TAIWAN; CHINA: Beijing)
  • Abdominal segment II longer than abdominal segment III in dorsal view; abdominal tergite IV not narrowed anteriorly in dorsal view (Fig. 36B) => 8

8

  • Outline of abdominal segment III campaniform in dorsal view; frontoclypeal margin convex => Leptanilla oceanica (JAPAN: Ogasawara Islands)
  • Outline of abdominal segment III subrectangular in dorsal view; frontoclypeal margin linear => Leptanilla swani (AUSTRALIA: Western Australia)

9

  • Mandible with four teeth (subapical tooth sometimes difficult to distinguish) => 10
  • Mandible with three teeth => 18

10

  • Propodeum angular in profile view, with distinct posterior and dorsal faces => Leptanilla ortunoi (SPAIN: Ceuta)
  • Propodeum rounded in profile view, without distinct posterior and dorsal faces => 11

11

  • Abdominal sternite II emarginate in profile view, with narrow trough-like indentation (Fig. 37A) => Leptanilla poggii (ITALY: Pantellaria)
  • Abdominal sternite II linear in profile view (Fig. 37B) => 12
  • GGriebenow (2024), Figure 37. Profile condition of the petiole in the Leptanilla revelierii species group. A, Leptanilla poggii (after Mei 1995: fig. 4). B, Leptanilla theryi (after Mei 1995: fig. 6).

12

  • Frontal margin of cranium convex in full-face view; scape strongly constricted at base => Leptanilla nana (TUNISIA)
  • Frontal margin of cranium linear in full-face view; scape moderately constricted at base => 13

13

  • Abdominal sternite II with planar face in profile view => 14
  • Abdominal sternite II with rounded face in profile view => 15

14

  • Most proximal mandibular tooth large and distinct; abdominal tergite IV distinctly narrowed anteriorly in dorsal view => Leptanilla tanakai (JAPAN: Yakushima)
  • Most proximal mandibular tooth small and indistinct; abdominal tergite IV not distinctly narrowed anteriorly in dorsal view => Leptanilla japonica (JAPAN: Honshu, CHINA: Hong Kong)

15

  • Height of metafemur in anterior view 0.5× metafemoral length in anterior view; coloration beige => Leptanilla charonea (SPAIN)
  • Height of metafemur in anterior view < 0.5× of metafemoral length in anterior view; coloration yellowish => 16

16

  • Larger species (HL = 0.32–0.36 mm) => 17
  • Smaller species (HL = 0.22–0.28 mm) (López et al. 1994) => Leptanilla zaballosi (SPAIN)

17

18

  • Abdominal sternite II sinuate in profile view => Leptanilla doderoi (ITALY: Sardinia)
  • Abdominal sternite II linear to convex in profile view, never sinuate => 19

19

  • Petiole distinctly wider than long => Leptanilla yunnanensis (CHINA: Yunnan)
  • Petiole not distinctly wider than long => 20

20

  • Frontal margin convex in full-face view => 21
  • Frontal margin linear in full-face view => 22

21

22

  • Length of abdominal tergite V > 0.5× length of abdominal tergite IV => Leptanilla revelierii (FRANCE: Corsica; ITALY: Sardinia; SPAIN; PORTUGAL; MOROCCO)
  • Length of abdominal tergite V ≤ 0.5× length of abdominal tergite IV => 23

23

  • Pedicel distinctly longer than wide; abdominal sternite II linear in profile view => Leptanilla kubotai (JAPAN: Shikoku)
  • Pedicel length and width subequal; abdominal sternite II convex in profile view => 24

24


Worker-based key to the Protanilla taylori species group

Note: Protanilla taylori and the undescribed Protanilla id01 are known only from the gyne, and thus excluded from this key. It does not appear that either P. taylori or Protanilla id01, which are known only from Borneo, represent the gyne of Protanilla boltoni or Protanilla helenae (Borowiec et al. 2011).

1

  • Cranium, pronotum and mesopleuron puncticulate to roughly sculptured; subpetiolar process lacking fenestra in profile view => Protanilla boltoni (MALAYSIA: Perak)
  • Cranium, pronotum and mesopleuron glabrous; subpetiolar process with fenestra in profile view => Protanilla helenae (PHILIPPINES: Palawan)


Worker-based key to the Leptanilla thai species group and Leptanilla havilandi species group

This key has been updated to include Leptanilla voldemort.

1

  • SI > 100; length of petiole > 3× greater than maximum breadth in dorsal view (Griebenow et al. 2022: fig. 6B) => 1a
  • SI ≤ 100; length of petiole ≤ 3× greater than maximum breadth in dorsal view (Fig. 6A) => 2
  • Griebenow et al. (2022), Fig. 6. Leptanilla laventa, holotype (CASENT0842746). (a) Profile view. (b) Dorsal view. (c) Full-face view. Scale bars: a, b, 0.5 mm; c, 0.1 mm.
  • Griebenow (2024), Figure 6. Leptanilla belantan, holotype (MCZ:Ent:00728278), worker. A, profile view. B, dorsal view. C, full-face view. Scale bars: 0.2 mm.

1a

  • In dorsal view, petiole and postpetiole less elongate (PI = 29–32; PPI = 59–64.7); in lateral view, propodeal declivity weakly convex and gently rounded; in full-face view, axis of the basal mandibular tooth recurved, with tip of the tooth forming a 60–70° angle with medial mandibular margin; larger (WL = 0.74–0.85 mm) => Leptanilla laventa (IRAN: Fārs)
  • In dorsal view, petiole and postpetiole more elongated (PI = 25; PPI = 39); in lateral view, propodeal declivity strongly convex and distinctly angular; in full-face view, axis of the basal mandibular tooth extends almost perpendicular to mandibular margin, with tip of the tooth forming an 80–90° angle with medial mandibular margin; smaller (WL = 0.59–0.61 mm) => Leptanilla voldemort (AUSTRALIA: Western Australia)

2

  • Length of metasomal setae bimodal => 3
  • Length of metasomal setae unimodal => 5

3

  • Mandible with four teeth, with most proximal tooth truncate (Saroj et al. 2022: fig. 1E); ventromedian lamella of abdominal sternite II denticulate => Leptanilla ujjalai (INDIA: West Bengal)
  • Mandible with three teeth, with most proximal tooth not truncate; ventromedian lamella of abdominal sternite II not denticulate => 4
  • Saroj et al. (2022), Fig. 1A–E. Leptanilla ujjalai, holotype worker. (A) Body dorsal view. (B) Body lateral view. (C) Head full face view showing mandibles, (D) Mandible showing the truncate tooth at basal margin, (E) Mandible; diagrammatic sketch.

4

  • Lateral pronotal margins weakly convex in dorsal view; PPTI = 73.68–76.47 (n = 11) => Leptanilla lamellata (INDIA: Himachal Pradesh)
  • Lateral pronotal margins strongly convex in dorsal view; PPTI = 84.62– 85.71 (n = 6) => Leptanilla escheri (INDIA: Tamil Nadu)

5

  • Petiolar length ≥ 2× width => 6
  • Petiolar length ≤ 1.5× width => 8

6

  • Meso-metapleural furrow absent; mandible with four teeth, most proximal tooth distally recurved, apex expanded => Leptanilla belantan (MALAYSIA: Selangor)
  • Meso-metapleural furrow present; mandible with three teeth, most proximal tooth acute => 7

7

  • Abdominal sternite III no more anteroposteriorly compressed than abdominal tergite III => Leptanilla kunmingensis (CHINA: Yunnan)
  • Abdominal sternite III more anteroposteriorly compressed than abdominal tergite III => Leptanilla judaica (WEST BANK)

8

  • Subpetiolar process present, angular; torulus without areolate sculpture (Fig. 27B) => Leptanilla havilandi (SINGAPORE; MALAYSIA: Sabah)
  • Subpetiolar process absent; torulus with medial and anterior areolate sculpture (Fig. 27A) => Leptanilla thai (THAILAND: Khao Chong)
  • Griebenow (2024), Figure 27. Antennal torulus in Leptanilla thai (A) and Leptanilla havilandi (B), worker. Scale bars: 0.04 mm (A); 0.05 mm (B).


Male-based keys

The following keys are corrected and extended from Griebenow (2020), with updated generic assignments for undescribed morphospecies; concordances of these morphospecies identifiers with previous publications are provided in Table 1. Respective male-based keys to each of the major subclades are subsequently provided.

These keys include all described species for which males are known, and all undescribed male morphospecies for which molecular data are or soon will be available, except for Leptanilla ZA01 (for which only genital morphology is known), Leptanilla TH07 and Leptanilla zhg-mm14 (for which genital morphology is unknown). Based on phylogenetic inference from both molecular and morphological data (Griebenow 2021; pers. obs.), these three morphospecies belong to the Leptanilla revelierii species group, the Leptanilla bethyloides species group, and the Leptanilla thai species group, respectively. Leptanilla zhg-au04 and zhgau06, of the Leptanilla revelierii species group, are also excluded due to lacking observations of the gonopodital apex, making it impracticable to include these morphospecies in the male-based key to that clade.

Male-based keys include the following:

Male-based key to the major subclades and species of the Leptanillinae

1

  • Rs+M and 1m-cu present (Fig. 38A); parossiculus (=cuspis in part) and lateropenite (=digitus) distinct, articulated (Opamyrmini) => Opamyrma hungvuong (VIETNAM: Ha Tinh, Son La; CHINA: Hainan, Guangxi)
  • Rs+M and 1m-cu absent (Fig. 38B–D); if volsella discernible, parossiculus and lateropenite distinct or indistinct, if distinct then inarticulate (Leptanillini) => 2
  • Griebenow (2024), Figure 38. Exemplars of male wing venation across the Leptanillinae, diagrammatic B, C are typological generalizations of male wing venation in the clades that they represent. A, Opamyrma hungvuong. B, Protanilla. C, Leptanilla najaphalla species group. D, Leptanilla javana. Abbreviation: pts = pterostigma.

2

  • Pterostigma present (Fig. 39B); ocelli present, with ocellar tubercle absent (Fig. 40A); parossiculus and lateropenite distinct (Protanilla) => 3
  • Pterostigma absent (Fig. 39A, C); ocelli present or absent, if present then set on ocellar tubercle (Fig. 40B, C), tubercle rarely absent (e.g., Leptanilla najaphalla); parossiculus and lateropenite not distinct (Leptanilla) => 5
  • Griebenow (2024), Figure 40. Condition of the male ocelli in the Leptanillini, profile view. A, Protanilla lini (OKENT0011097). B, Leptanilla indica (CASENT0106366). C, Leptanilla argamani (CASENT0235253). Scale bars: 0.25 mm (A); 0.1 mm (B, C).

3

  • MaL < 0.5× ML; apex of mandible acuminate => Protanilla zhg-th02 (THAILAND: Chaiyaphum)
  • ML ≥ 0.5× ML; apex of mandible rounded => 4

4

  • Abdominal segment III petiolate; abdominal segment IV equal in length to combined length of abdominal segments V–VIII (Protanilla bicolor species group) => Protanilla TH03 (THAILAND: Chiang Mai)
  • Abdominal segment III not petiolate; length of abdominal segment IV subequal to, or less than, respective lengths of abdominal segments V–VII => Species of the Protanilla rafflesi species group

5

  • Propodeum concave in profile view (Fig. 41A); anteromedian ocellus directly dorsal to compound eye in profile view; pronotum and mesoscutum not posteriorly prolonged => Species of the Leptanilla thai species group
  • Propodeum not concave in profile view (Fig. 41B, C); anteromedian ocellus posterad compound eye in profile view, rarely directly dorsal (Leptanilla copiosa); pronotum and mesoscutum posteriorly prolonged => 6
  • Griebenow (2024), Figure 41. Propodeal outline in profile view across male Leptanillini, after Griebenow (2021: fig. 17). Propodeum outlined in black in Fig. 16A–C. A, Leptanilla zhg-bt03 (CASENT0106384). B, Leptanilla zhg-my02 (CASENT0106456). C, Protanilla lini (OKENT0011097). Scale bars: 0.15 mm (A, C); 0.2 mm (B).

6

  • Propodeum with lateral longitudinal carinae on dorsum; penial sclerites lateromedially compressed => Leptanilla palauensis (PALAU)
  • Propodeum without lateral longitudinal carinae on dorsum; penial sclerites sometimes lateromedially compressed, more often not => 7

7

  • Dorsal propodeal face long, parallel to craniocaudal axis (Fig. 41B); mulceators present; protibial comb present (Fig. 42A) => Species of the Leptanilla najaphalla species group
  • Dorsal propodeal face short, with propodeal outline in profile view convex, if long and parallel to craniocaudal axis then upper metapleuron distinct from metapectal-propodeal complex; mulceators absent; protibial comb absent (Fig. 42B) => 8
  • Griebenow (2024), Figure 41. Propodeal outline in profile view across male Leptanillini, after Griebenow (2021: fig. 17). Propodeum outlined in black in Fig. 16A–C. A, Leptanilla zhg-bt03 (CASENT0106384). B, Leptanilla zhg-my02 (CASENT0106456). C, Protanilla lini (OKENT0011097). Scale bars: 0.15 mm (A, C); 0.2 mm (B).
  • Griebenow (2024), Figure 42. Protibia in male Leptanilla, posterior view. A, Leptanilla zhg-my11 (CASENT0842593). B, Leptanilla zhg-my04 (CASENT0842555). Scale bars: 0.05 mm (A); 0.2 mm (B).

8

  • Procoxa with distal transverse carina (Fig. 29A); phallotreme surrounded with decumbent setae, rarely bare (Leptanilla zhg-ph01); if lower metapleuron distinct from metapectal-propodeal complex then upper metapleuron not distinct => Species of the Leptanilla havilandi species group
  • Procoxa without distal transverse carina (Fig. 29B); phallotreme bare; lower metapleuron usually indistinct from metapectal-propodeal complex, if distinct then upper metapleuron distinct => 9
  • Griebenow (2024), Figure 29. Condition of the male procoxa in Leptanilla, anterior view. Distal procoxal carina outlined in red. A, Leptanilla cf. copiosa (CASENT0842844). B, Leptanilla zhg-my04 (CASENT0842567). Abbreviation: pcx = procoxa. Scale bars: 0.1 mm.

9

10


Male-based species-level key to the Leptanilla bethyloides species group

1

  • Mesoscutellum produced into recurved posterior process (Griebenow 2021: fig. 16B); LF2 > SL => Leptanilla zhg-th01 (THAILAND: Chiang Mai)
  • Mesoscutellum not produced into recurved posterior process; LF2 ≤ SL => 2
  • Griebenow (2021), Fig. 16. Presence (B: Leptanilla zhg-th01; CASENT0842619) versus absence (A: Yavnella zhg-th01; CASENT0842620) of the posterior prolongation of the mesoscutellum in male Leptanillini. Scale bar: 0.3 mm.

2

  • Penial sclerites lateromedially compressed, with dorsomedian carina => Leptanilla TH01 (THAILAND: Chiang Mai)
  • Penial sclerites dorsoventrally compressed, without dorsomedian carina; gonopodital apex bifid => 3

3

  • Smaller species; abdominal postsclerites V–VII anteroposteriorly compressed relative to those of III–IV => Leptanilla zhg-mm05 (BURMA: Taninthayi)
  • Larger species; abdominal postsclerites V–VII with anteroposterior lengths subequal to those of III–IV => Leptanilla bethyloides (CHINA: Hong Kong)


Male-based species-level key to the Leptanilla havilandi species group

1

  • ML > SL, with mandible flattened and paddle-like; lower metapleuron indistinct => Leptanilla anomala (INDONESIA: Sumatra, Kalimantan Barat)
  • ML ≤ SL, with mandible nub-like; lower metapleuron distinct => 2

2

  • Mandalus not extending to mandibular apex; anteromedian ocellus orthogonally dorsal to compound eye in profile view (Fig. 57A) => Leptanilla copiosa (PHILIPPINES: Palawan)
  • Mandalus extending to mandibular apex; anteromedian ocellus positioned posterodorsal to compound eye in profile view (Fig. 57B) => 3
  • Griebenow (2024), Figure 57. Position of the male anteromedian ocellus relative to the compound eye in Leptanilla, diagrammatic, after Griebenow (2020: fig. 12B). A, Leptanilla copiosa. B, Leptanilla zhg-my10.

3

  • Gonostylus longer than gonocoxite (Fig. 58A) => Leptanilla zhg-my10 (MALAYSIA: Sabah)
  • Gonostylus shorter than, or subequal in length to gonocoxite (Fig. 58B) => 4
  • Griebenow (2024), Figure 58. Male genitalia in the Leptanilla havilandi species group, profile view, diagrammatic, after Griebenow (2020: fig. 13A). Figures to scale. A, Leptanilla zhg-my10. B, Leptanilla zhg-my11.

4

  • Penial apex produced into two ranks of aculeate processes; phallotremal rim glabrous => Leptanilla zhg-ph01 (PHILIPPINES: Camarines Sur; Quezon)
  • Penial apex produced into robust ventral carina, without process dorsad to carina; phallotremal rim with vestiture => 5

5

  • Penial apex entire => Leptanilla zhg-my14 (MALAYSIA: Sabah)
  • Penial apex cleft => Leptanilla zhg-my11 (MALAYSIA: Sabah)


Male-based species-level key to the Leptanilla najaphalla species group

1

  • Phallotreme at penial apex => 2
  • Phallotreme proximad penial apex, anatomically ventral => 3

2

  • Penial sclerites dorsoventrally compressed at apex, without dorsomedian lamina (Fig. 53A) => Leptanilla zhg-my03 (MALAYSIA: Sabah, Sarawak)
  • Penial sclerites lateromedially compressed at apex, with dorsomedian lamina (Fig. 53B) => Leptanilla zhg-my04 (MALAYSIA: Sabah)
  • Griebenow (2024), Figure 53. Male genitalia in the Leptanilla najaphalla species group, profile view. Abbreviation: lam = dorsomedian lamella of penial sclerites. A, Leptanilla zhg-my04 (CASENT0842558). B, Leptanilla zhg-my03 (CASENT0842545). Scale bar: 0.2 mm.

3

  • Gonostylus present, articulated, tusk-like and lacking setae (Fig. 54); penial sclerites with recurved apical hook (Fig. 55A) => Leptanilla zhg-id01 (INDONESIA: Kalimantan Barat)
  • Gonostylus absent; penial sclerites without recurved apical hook (Fig. 55B) => 4
  • Griebenow (2024), Figure 54. Male genitalia of Leptanilla zhg-id01 (CASENT0842625), ventral view. Gonostylus outlined in white. Scale bar: 0.1 mm.
  • Griebenow (2024), Figure 55. Penial sclerites of the Leptanilla najaphalla species group, profile view, diagrammatic. Base (left) partly concealed by gonocoxites in situ. A, Leptanilla zhg-id01. B, Leptanilla zhg-my05.

4

  • Apicolateral gonocoxital lamina subulate (Fig. 56A) => Leptanilla najaphalla (MALAYSIA: Sabah)
  • Apicolateral gonocoxital lamina lanceolate (Fig. 56B) => Leptanilla zhg-my05 (MALAYSIA: Sabah)
  • Griebenow (2024), Figure 56. Apicolateral gonocoxital laminae in the Leptanilla najaphalla species group, profile view. A, Leptanilla zhg-my02 (CASENT0106427). B, Leptanilla zhg-my05 (CASENT0842571). Scale bars: 0.3 mm (A); 0.5 mm (B).


Male-based species-level key to the Protanilla rafflesi species group

1

  • Antero-admedian signum present => Protanilla TH02 (THAILAND: Chaiyaphum)
  • Antero-admedian signum absent => 2

2

  • Gonostylar apex pointed (Fig. 43A) => Protanilla TH01 (THAILAND: Khon Kaen)
  • Gonostylar apex rounded (Fig. 43B) => 7
  • Griebenow (2024), Figure 43. Gonostyli in Protanilla, posterodorsal view. After Griebenow (2020: fig. 9C). A, Protanilla TH01 (CASENT0119776; Michele Esposito). B, Protanilla lini (OKENT0011097). Scale bars: 0.1 mm (A); 0.5 mm (B).

3

  • Anterior face of subpetiolar process nearly perpendicular to craniocaudal axis in profile view; abdominal tergite III slightly narrower than IV in dorsal view (TI1 62–92) (n = 13) (Fig. 44A) => Protanilla zhg-vn01 (VIETNAM: Vinh Phuc), Protanilla zhg-my01 (MALAYSIA: Sarawak)
  • Anterior face of subpetiolar process gently sloping relative to craniocaudal axis; abdominal tergite III much narrower than IV in dorsal view (TI1 50–55) (n = 4) (Fig. 44B) => Protanilla lini (TAIWAN; JAPAN: Ryukyu Islands, Senkaku Islands)
    • These morphospecies are recovered distantly within the Protanilla rafflesi species group by phylogenomic inference (pers. obs.), and so are presumed to be allospecific in the absence of further evidence.
  • Figure 44. Proportions of male abdominal tergites III-IV in Protanilla zhg-vn01 (A) versus Protanilla lini (B), diagrammatic. Abbreviation: AT = abdominal tergite.


Male-based species-level key to the Leptanilla revelierii species group

1

  • Gonostylus ellipsoid in outline (Griebenow 2020: fig. 11E); gonocoxites with complete ventromedian fusion => Leptanilla astylina (PHILIPPINES: Palawan)
  • Gonostylus not ellipsoid; gonocoxites without ventromedian fusion => 2
  • Griebenow (2020), Fig. 11: (A) profile view of mesosoma in (i) Yavnella zhg-bt01 and (ii) Noonilla zhg-my04, with pronotum marked in blue and mesoscutum marked in black; (B) male foreleg of (i) Yavnella zhg-th01 and (ii) Yavnella argamani, with basal constriction of the profemur in Yavnella zhg-th01 marked; (C) mesal view of volsella in (i) Yavnella zhg-th01 and (ii) Yavnella TH02 (after sketch by P.S. Ward); (D) posterodorsal view of penial sclerites in (i) Yavnella argamani (CASENT0235253) and (ii) Yavnella cf. indica (CASENT0106378); (E) ventral view of the male genitalia of Leptanilla astylina (after Petersen 1968: Fig. 3), with stylus in yellow and penial apex marked. Abbreviation: stl = stylus.

2

  • Protibial length 0.5× profemoral length => 3
  • Protibial length > 0.5× profemoral length => 4

3

  • Length of probasitarsal seta less than that of calcar => Leptanilla africana (NIGERIA)
  • Length of probasitarsal seta subequal to that of calcar => Leptanilla TH09 (THAILAND: Phetchabun)

4

  • Gonostylus bifurcated or emarginate => 5
  • Gonostylus entire, apex tapering or truncate => 14

5

  • Abdominal segment II broadly joined to abdominal segment III (Santschi 1907: fig. 3) => Leptanilla minuscula (TUNISIA)
  • Abdominal segment III narrowly joined to abdominal segment III => 6
  • Santschi (1907), Fig. 3. Leptanilla tanit, holotype male.

6

  • Ventromedial gonocoxital margin with sinuate process => Leptanilla tanit (TUNISIA)
  • Ventromedial gonocoxital margin entire => 7

7

  • Gonostylar apex with obtuse tooth subtending dorsal process => Leptanilla GR02 (GREECE: Rhodes)
  • Gonostylar apex lacking obtuse tooth subtending dorsal process => 8

8

  • Ventromedian margin of gonostylus excavated proximad apical furca => Leptanilla zhg-au02 (AUSTRALIA: New South Wales)
  • Ventromedian margin of gonostylus entire proximad apical furca => 9

9

  • Dorsal process of gonostylar apex acuminate => 10
  • Dorsal process of gonostylar apex rounded => 11

10

  • Processes of gonostylar apex large, with apex appearing deeply bifurcated => Leptanilla tenuis (TUNISIA)
  • Processes of gonostylar apex small, with apex appearing nearly truncate => Leptanilla zhg-mm02 (BURMA: Taninthayi)

11

  • Penial apex entire => 12
  • Penial apex emarginate => 13

12

  • PTL ≈ PTH => Leptanilla GR01 (GREECE: Rhodes)
  • PTL > PTH => Leptanilla zhg-id02 (INDONESIA: Sulawesi Tenggara)

13

  • Internal margins of apical penial cleft distinctly separated, ventral gonostylar process narrower than dorsal process => Leptanilla bifurcata (ISRAEL)
  • Internal margins of apical penial cleft adjacent, gonostylar processes subequal in breadth => Leptanilla israelis (ISRAEL)

14

  • Gonostylar apex not tapering => 15
  • Gonostylar apex tapering => 17

15

  • Gonostylus with expanded, rounded apex (Fig. 59A) => Leptanilla islamica (YEMEN; OMAN)
  • Gonostylus with apex not expanded (Fig. 59B) => 16

16

  • Outline of penial sclerites attenuate in posterodorsal view (Fig. 60A) => Leptanilla alexandri (UZBEKISTAN)
  • Outline of penial sclerites elliptical in posterodorsal view (Fig. 60B) => Leptanilla japonica (JAPAN: Honshu; CHINA: Hong Kong)
  • Griebenow (2024), Figure 60. Dorsal outline of the penial sclerites (red) in the Leptanilla revelierii species group, diagrammatic, after Griebenow (2020: fig. 13G). A, Leptanilla alexandri. B, Leptanilla japonica.

17

  • Gonostylar apex acuminate => 18
  • Gonostylar apex digitate => 25

18

  • Oblique mesopleural sulcus traversing posterior > 0.5× of mesopleuron => 19
  • Oblique mesopleural sulcus traversing posterior ≤ 0.5× of mesopleuron => 20

19

  • Penial sclerites broad in posterodorsal view, apex entire; Rsf1+Mf1 present => Leptanilla javana (INDONESIA: Java)
  • Penial sclerites narrow in posterodorsal view, apex emarginate; Rsf1+Mf1 absent => Leptanilla zhg-ke01 (KENYA: Laikipia)

20

  • Abdominal sternite II without distinct subpetiolar process (Fig. 61A) => Leptanilla zhg-bt02 (BHUTAN)
  • Abdominal sternite II with distinct subpetiolar process (Fig. 61B) => 21
  • Griebenow (2024), Figure 61. Presence (A) versus absence (B) of forewing 2s-rs+R+4-6 in males of the Leptanilla revelierii species group, diagrammatic.

21

  • 2s-rs+R+4-6 absent from forewing (Fig. 62A) => 22
  • 2s-rs+R+4-6 present in forewing (Fig. 62B) => 24
  • Griebenow (2024), Figure 62. Abdominal segment II in males of the Leptanilla revelierii species group, profile view. Abdominal sternite II outlined in red. A, Leptanilla zhg-bt01 (CASENT0842617). B, Leptanilla zhg-bt02 (CASENT0842612). Scale bars: 0.125 mm (A); 0.100 mm (B).

22

  • Posterior face of petiolar node shallower than anterior face; genital capsule subequal in overall dimensions to abdominal segment II => Leptanilla zhg-bt01 (BHUTAN)
  • Posterior face of petiolar node not shallower than anterior face; dimensions of genital capsule conspicuously greater than those of abdominal segment II => 23

23

  • Oblique mesopleural sulcus adjoining metapectal-propodeal complex => Leptanilla zhg-au03 (AUSTRALIA: Queensland)
  • Oblique mesopleural sulcus not adjoining metapectal-propodeal complex => Leptanilla zhg-ke02 (KENYA: Kakamega)

24

  • Apicolateral margins of penial sclerites emarginate; smaller species (WL = 0.37–0.44 mm) (n = 6) => Leptanilla charonea (SPAIN)
  • Apicolateral margins of penial sclerites entire; larger species (WL = 0.46–0.50 mm) (n = 3) => Leptanilla cf. zaballosi (SPAIN)

25

  • Penial sclerites broader than long (Fig. 63A) => Leptanilla GR03 (GREECE: Rhodes; TURKEY: Muğla), Leptanilla zhg-tr01 (TURKEY: Muğla)
  • Penial sclerites longer than broad (Fig. 63B) => 26
  • Griebenow (2024), Figure 63. Penial sclerites in the Leptanilla revelierii species group, outlined in black, posterodorsal view. A, Leptanilla GR02 (CASENT0106068). B, Leptanilla zhg-au01 (CASENT0758873). Scale bar: 0.1 mm.

26

  • Gonostylus not articulated to gonocoxite => Leptanilla exigua (TUNISIA)
  • Gonostylus articulated to gonocoxite => 27

27

  • Abdominal sternite II produced ventrally, forming curve in profile view => 28
  • Abdominal sternite II not produced ventrally, linear in profile view => 29

28

  • Gonocoxites with apicoventral laminae => Leptanilla zhg-au05 (AUSTRALIA: Queensland)
  • Gonocoxites without apicoventral laminae => Leptanilla zhg-au01 (AUSTRALIA: Queensland)

29

  • Oblique mesopleural sulcus present; Sc+R+Rs tubular => Leptanilla zhg-au07 (AUSTRALIA: Queensland)
  • Oblique mesopleural sulcus absent; Sc+R+Rs absent => Leptanilla australis (SOUTH AFRICA: Cape Province)


Male-based species-level key to the Leptanilla thai species group

1

  • Gonocoxites entirely fused medially, without suture; hypopygium with posteromedian filiform process => Leptanilla TH03 (THAILAND: Chiang Mai)
  • Gonocoxites partly to fully separate medially; hypopygium without posteromedian filiform process => 2

2

  • Ocelli absent (Fig. 45B); mandible articulated to gena (Fig. 46A) => Leptanilla zhg-bt03 (BHUTAN)
  • Ocelli present (Fig. 45A); mandible fused to gena (Fig. 46B), rarely articulate (Leptanilla TH04) => 3
  • Griebenow (2024), Figure 45. Condition of male ocelli in the Leptanillini, full-face view. A, Leptanilla TH02 (CASENT0119531; Shannon Hartman). B, Leptanilla zhg-bt03 (CASENT0106384). Scale bars: 0.1 mm.
  • Griebenow (2024), Figure 46. Articulation of the male mandible in the Leptanilla thai species group. A, Leptanilla indica (CASENT0106377). B, Leptanilla zhg-bt03 (CASENT0106384). Scale bars: 0.03 mm (A); 0.04 mm (B).

3

  • Gonopodite shorter than (Fig. 47A), or subequal in length to, penial sclerites => 4
  • Gonopodite distinctly longer than penial sclerites (Fig. 47B) => 6
  • Griebenow (2024), Figure 47. Proportions of the penial sclerites to the gonopodites in the Leptanilla thai species group. A, Leptanilla argamani. B, Leptanilla TH08. Abbreviations: stl = gonostyli; psc = penial sclerites. Scale bars: 0.2 mm (A); 0.1 mm (B).

4

  • Internal margins of apical penial cleft distinctly separated; posteroventral gonocoxital margin entire (Fig. 48B) => Leptanilla argamani (ISRAEL, LEBANON)
  • Internal margins of apical cleft of penial sclerites subparallel; posteroventral gonocoxital margin sinuate (Fig. 48A) => 5
  • Griebenow (2024), Figure 48. Outline of the gonopodites in Leptanilla indica (A) and Leptanilla argamani (B), ventral view, diagrammatic. Redrawn from Kugler (1987: figs 18, 22).

5

  • Color castaneous; posterior margin of compound eye linear in profile view => Leptanilla indica (INDIA: Kerala)
  • Color yellowish to pallid; posterior margin of compound eye convex in profile view => Leptanilla indica (SRI LANKA)

6

  • Dorsoventral margins of profemur not parallel (Fig. 49A) => 7
  • Dorsoventral margins of profemur parallel (Fig. 49B) => 10
  • Griebenow (2024), Figure 49. Male protrochanter, profemur, and protibia in the Leptanilla thai species group, diagrammatic. After Griebenow (2020: fig. 11B). A, Leptanilla zhg-th02. B, Leptanilla TH04.

7

  • Volsella bifid, ventral process bifurcated (Fig. 50A) => Leptanilla zhg-th02 (THAILAND: Phetchabun)
  • Volsella usually bifid, rarely not (Leptanilla zhg-mm11), if bifid then ventral process entire (Fig. 50B) => 8
  • Griebenow (2024), Figure 50. Volsella of the Leptanilla thai species group, medial view, diagrammatic, after Griebenow (2020: fig. 11C). Not to scale. A, Leptanilla zhg-th02. B, Leptanilla TH02.

8

  • Dorsal and ventral parossicular processes forming 90° angle; lengths of processes subequal => Leptanilla TH02 (THAILAND: Khon Kaen)
  • Dorsal and ventral parossicular processes forming acute angle; ventral parossicular process 3× longer than length of dorsal process => 9

9

  • Diameter of compound eye > 4× span of ocellar tubercle; gonopodital apices not recurved towards medial axis => Leptanilla zhg-th04 (THAILAND: Chaiyaphum)
  • Diameter of compound eye only slightly greater than span of ocellar tubercle; gonopodital apices sharply recurved towards medial axis => Leptanilla zhg-th05 (THAILAND: Chaiyaphum)

10

  • Gonostylar apex subtriangular, entire => 11
  • Gonostylar apex tapering, entire or bifid (Fig. 47B) => 14

11

  • Ventral margin of gonocoxites produced into two pairs of lobes (Fig. 51A); volsellae apparently not furcate (Fig. 52A) => Leptanilla zhg-mm11 (BURMA: Taninthayi)
  • Ventral margin of gonocoxites not so produced (Fig. 51B); volsellae furcate (Fig. 52B) => 12
  • Griebenow (2024), Figure 51. Gonopodital margins in the Leptanilla thai species group, ventral view. Gonocoxital lobes outlined in black. A, Leptanilla zhg-mm11 (CASENT0842848). B, Leptanilla zhg-mm13 (CASENT0842670). Scale bars: 0.15 mm (A); 0.06 mm (B).
  • Griebenow (2024), Figure 52. Volsellae in the Leptanilla thai species group, posterior view. Volsellar processes marked with arrows. A, Leptanilla zhg-mm11 (CASENT0842848). B, Leptanilla zhg-mm13 (CASENT0842670). Scale bar: 0.1 mm.

12

  • Bifid processes of volsella oriented along lateromedial axis relative to genital capsule, lateral process shorter than medial process => Leptanilla MM01 (BURMA: Rakhine)
  • Bifid processes of volsella oriented along dorsoventral axis relative to genital capsule, lengths of processes subequal => 13

13

  • Larger species (WL > 0.5 mm); gonopodital suture absent => Leptanilla zhg-mm13 (BURMA: Taninthayi)
  • Smaller species (WL ≤ 0.5 mm); gonopodital suture present, complete => Leptanilla cf. zhg-mm10 (BURMA: Taninthayi)

14

  • Head not broader than long in full-face view, including compound eyes; gonostylar apex bifurcated (Fig. 47B) => Leptanilla TH08 (THAILAND: Surat Thani)
  • Head broader than long in full-face view, including compound eyes; gonostylar apex entire => 15
  • Griebenow (2024), Figure 47. Proportions of the penial sclerites to the gonopodites in the Leptanilla thai species group. A, Leptanilla argamani. B, Leptanilla TH08. Abbreviations: stl = gonostyli; psc = penial sclerites. Scale bars: 0.2 mm (A); 0.1 mm (B).

15

  • Penial sclerites distinctly longer than broad; volsella entire => 16
  • Penial sclerites not distinctly longer than broad; volsella bifid => 17

16

  • Gonocoxite with distodorsal carina; dorsal process of volsella recurved dorsally => Leptanilla TH04 (THAILAND: Chiang Mai)
  • Gonocoxite without distodorsal carina; dorsal process of volsella recurved laterally => Leptanilla zhg-th05 (THAILAND: Chiang Mai)

17

  • Gonostylar apex lobate in outline, covered with dense vestiture; coloration castaneous => Leptanilla TH06 (THAILAND: Chiang Mai)
  • Gonostylar apex acuminate, glabrous; coloration beige => Leptanilla zhg-my16 (MALAYSIA: Selangor)

References

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