Layahima chiangi Banks, 1941

Zheng, Yuchen, Tu, Yuezheng, Badano, Davide & Liu, Xingyue, 2025, New insights into diversity and evolution of the Oriental antlion genus Layahima Navás, 1912 (Neuroptera: Myrmeleontidae), with description of new species and new larvae from China, Arthropod Systematics & Phylogeny 83, pp. 543-571 : 543-571

Layahima chiangi Banks, 1941

Figures 2 A, B , 3 , 4 , 5 A – E , 6 , 7

Layahima chiangi Banks 1941: 1 (type locality: China: Yunnan, “ Loutsechiang ”; holotype in AMNH). Stange 1976: 310 ( Layahima). Stange 2004: 92 ( Layahima). Wan et al. 2006: 38 ( L. qilin sp. nov. misidentified as L. chiangi). Wang et al. 2018: 61 ( L. qilin sp. nov. misidentified as L. chiangi). Zheng et al. 2023: 48 ( L. qilin sp. nov. misidentified as L. chiangi but included type photo of the latter species).

Diagnosis.

Adult: Body pale yellowish brown with some black and dark brown markings, parts with numerous black dots at base of setae. Both vertex and postgena each with a pair of distinct black spots (Fig. 3 B, C ). Frons and clypeus with six black spots (Fig. 3 B ). Pronotum medially with a black spot and laterally with four pairs of black spots. Forewing rhegma present as two indistinct brownish markings (Figs 3 C , 5 A – C ). Male sternum 9 wide, posterior part narrowed and short (Fig. 3 E ); gonocoxites 9 as a pair of wide, oblate trapezoid plates, twice as wide as long; gonocoxites 11 are triangularly arched (Figs 3 H – L , 5 D ). Female pregenital plate shaped as an indistinct tiny sclerite (Fig. 5 E ). Gonocoxites 8 short and wide, digitiform (Fig. 3 F, G ). — 1 st instar larva: Head generally brown and dark brown (Fig. 7 A, B ). Antenna short and robust. Thoracic setiferous processes tubercular; anterior mesothoracic setiferous processes larger than others (Fig. 7 C ). Abdomen greenish brown, with many dark markings; dorsal abdominal segment 1 with a pair of large transversal dark markings (Figs 6 , 7 D ).

Re-description of adult.

Size. Head width: 2.27–3.22 mm; forewing length: 28.11–32.24 mm; hindwing length: 28.08–32.20 mm. — Head. Vertex and postgena with a pair of dark brown spots. Scape mostly dark brown; pedicel pale yellowish brown with a dark brown circular marking; antenna mostly yellowish brown, non-swollen part of flagellomeres each basally dark brown, swollen part of flagellum distally dark brown. A dark brown marking present around scapes, anteriorly concaved. Frons and clypeus with six black spots. Labrum pale yellow. Mandibles pale yellowish brown with distal half dark reddish brown. Maxillary palpus yellowish brown. Labial palpus generally yellowish brown, distal palpomere fusiform (Figs 3 B, C , 5 A – C ). — Thorax. Pronotum medially with a black spot and laterally with four pairs of black spots. Mesoprescutum mostly black, anteriorly with a pair of pale yellowish-brown spots; mesonotum pale yellowish brown, with three pair of black stripes and a pair of black spots, pale yellowish-brown part with some black dots; mesoscutellum anteriorly black, mostly pale yellowish brown, variation present in different individuals. Metanotum pale yellowish brown and black; metascutellum dark brown, laterally with a pair of pale yellowish-brown spots. Pleurae pale yellowish-brown and black (Figs 3 B, C , 5 A – C ). — Legs. Short, as long as thorax at most, with many black and pale setae. All tibial spurs slightly curved; tarsomeres each generally pale yellow with distal part dark brown; tarsomere 5 pale yellow, with distal part dark brown, nearly as long as entire length of tarsomeres 2–4; pretarsal claws curved, dark reddish brown. Foreleg: coxa pale yellow with a black spot; femur dorsally brown to dark brown, ventrally pale yellowish brown; tibia pale yellow with a dark anterior marking, distal part dark brown; tibial spurs reaching base of tarsomere 3. Midleg: Coxa pale yellowish brown, black basally; femur mostly yellowish brown, distally dark brown; tibia pale yellow, with some black dots, distal part dark brown; tibial spurs reaching basal of tarsomere 3. Hind leg: Coxa mostly pale yellowish brown, black basally; femur yellowish brown, with distal part dark brown; tibia pale yellow, distally dark brown; tibial spurs reaching tip of tarsomere 1; tarsomere 1 longer than that of fore- and midleg (Fig. 3 A ). — Wings. Mostly hyaline, distally rounded. Banksian lines absent. Pterostigma pale. Forewing slightly longer than hindwing. Forewing costal space with an indistinct brown spot proximal to pterostigma; subcostal area hyaline; radial area with some indistinct brown spots; mediocubital area with a few indistinct brown spots; rhegma as two indistinct brown markings; cubital area with a basal indistinct dark brown marking; costal crossveins generally simple on basal 1 / 3 part, while distal 2 / 3 part each connect with a short oblique veins; RP originates proximally to MP fork; four to five presectoral crossveins present, with from two to three biareolate cells; RP with eight to nine branches. Hindwing rhegma indistinct; presectoral area with only one crossvein; RP originates anteriorly to MP fork (Figs 2 A, B , 3 ). — Abdomen. Pale yellowish brown with some dark brown markings. Tergum 1 generally pale yellowish brown; tergum 2 with a dark brown marking; terga 3–8 each dark brown on posterior margin. — Male genitalia. Sternum 9 basal half wide, posterior part narrow, narrowed part as long as wide (Fig. 3 E ); gonocoxites 9 shaped as a pair of widely short trapezoid plates, twice as wide as long; gonocoxites 11 triangularly arched; gonostyli 11 slightly prominent (Figs 3 H – L , 5 D ). Ectoproct slightly protruded (Fig. 3 D ). — Female genitalia. Pregenital plate weakly sclerotized. Gonocoxites 8 rounded, short digitiform; gonapophyses 8 rounded. Gonocoxites 9 with many tapered stout setae, slightly curved. Ectoproct rounded on distal margin (Fig. 3 F, G ).

Description of 1 st instar larva.

Size. Body length (excluding mandible): 2.13–3.22 mm; head length: 0.65–0.78 mm; head width: 0.69–0.82 mm; mandible length: 0.75–0.89 mm. — Head. Nearly rectangular in dorsal view, wider than long, generally brown and dark brown. Dolichasters thick, distally swollen and truncate, dark and pale, present on clypeo-labrum, dorsal head, and basal mandible. Dorsal head dark brown posteromedially and laterally. Ventral head mostly brown, lateral margin dark brown. Antenna short and robust, dark brown. Ocular tubercles well prominent. Mandible dark brown, basally with 3–4 interdental mandibular setae; first tooth shorter than second tooth; second tooth nearly as long as third tooth; two short interdental mandibular setae between first and second teeth; no seta between second and third teeth. Labial palpi dark brown (Figs 6 A, B , 7 A, B ). — Thorax. Thoracic setiferous processes tubercular, with many pale setae and few dark setae. Pronotum dark brown and yellowish brown, with some dark and pale dolichasters. Mesothorax with spiracles present on short stout brown sclerotized tubercle; anterior process longer than posterior process. Metathorax medially with many dark dots; metathoracic setiferous processes equal in length (Figs 6 A , 7 C ). — Legs. Pale brown, with many slender and short tapered setae (Fig. 6 B, C ). — Abdomen. Greenish brown, with many dark markings; dorsal abdominal segment 1 with a pair of large transversal dark markings. Abdomen dorsally covered with dark setae, laterally covered with pale setae. Sternum 9 ventrally with seven to eight tapered setae of uneven size; rastrum distally with four pair of tapered digging setae (Figs 6 , 7 D ).

Type material.

Holotype ♂, “ Loutsechiang, Yunnan, China. Accession No. 24141 ”, the Nujiang dry hot river valley around the Cawarong region near Yunnan ( AMNH) .

Additional material examined.

Adult: 18 ♂ 10 ♀, CHINA: Xizang, Nyingchi, Zayu County [察隅县], Cawarong Township [察瓦龙乡], Ridong [日东], 1930 m, 27–29. VI. 2023, Yuchen Zheng ( CAU) . 4 ♂ 4 ♀, same information as above ( IZCAS) . 1 ♀, same locality as above, 1930 m, 11. VIII. 2021, Xingyue Liu ( IZCAS) . 2 ♂ 1 ♀, same locality as above, 1900 m, 30. VII. 2020, Yejie Lin ( CAU) . 1 ♂ 1 ♀, same locality as holotype ( AMNH) . 12 ♂, “ Thibet ” = [ CHINA: Xizang], Coll. Lacroix ( MNHN) . — Larva: 5 1 st larvae, hatched from the eggs, four preserved in 95 % ethyl alcohol, one is still rearing, same locality as above, 27–29. VI. 2023, Yuchen Zheng ( IZCAS) .

Distribution.

China ( Xizang) (Fig. 18 ).

Biology.

The larvae were obtained from eggs laid by field-collected females, so their natural habitat remains unknown. In the artificial settings, the larvae showed a preference for the bare environment rather than burying under sand like most antlions. The larvae fed on termites and springtails around them or crawling over their bodies, catching them with mandibles.

Remarks.

This species is endemic to the Nujiang dry hot river valley near the Cawarong Region. According to Zheng et al. (2023), the absence of an anteromedial marking on pronotum of the holotype of L. chiangi is individual variability. However, a dozen specimens from Yunnan and western Sichuan preserved in CAU show some differences from the holotype, including the presence of the anteromedial markings, but the differences in all other characters are subtle. The type locality of L. chiangi is ambiguous (“ Loutsechiang, Yunnan ”, now called “ Nujiang ”, a watershed that throughs Xizang, Yunnan, Myanmar and Thailand), so it was not possible to locate the original collecting site, and the holotype and we can only refer to type photos for comparison.

Further collecting efforts in 2023 in the Nujiang dry hot river valley of Cawarong, Xizang, allowed to find further specimens of L. chiangi , which clarified the taxonomic status of this species through genital comparisons and molecular analyses. The morphology of these specimens is consistent with the holotype of L. chiangi , confirming that the specimens from Yunnan and Sichuan identified as this species in Zheng et al. (2023), belong to an undescribed taxon, i. e., L. qilin sp. nov.

L. chiangi is characterized by dark brown scape, pronotum lacking anteromedial marking, abdominal terga with reduced dark markings, male sternum 9 short and posteriorly narrowed, male gonocoxites 9 twice as wide as long, male gonocoxites 11 triangularly arched, female pregenital plate weakly sclerotized, and shorter female gonocoxites 8. Layahima qilin sp. nov. differs in the pronotum with anteromedial marking, abdominal terga with wide dark markings, male sternum 9 elongate and posteriorly narrowed, male gonocoxites 9 as long as wide, female pregenital plate shaped as an anterior sclerotized prominent papilla and a posterior ridge-like prominence, and female gonocoxites 8 longer than that of L. chiangi .

We also shed new light on the type locality of L. chiangi with better precision. This species inhabits the unique habitat of the Nujiang dry hot river valley in Cawarong. This area represents an isolated “ mountainous island ”, surrounded by snow-capped mountains and monsoon rainforests, characterized by many endemic species, such as the spoon-winged lacewing Sinonemoptera tibetana Zheng & Liu, 2024 ( Zheng and Liu 2024). Therefore, it is likely that the type locality of L. chiangi is the town of Cawarong or its environs, rather than Yunnan. All the examined specimens from the river valleys of belonged to L. qilin sp. nov. (Jinshajiang river valley and Lancangjiang river valley) and L. pixiu sp. nov. (Jinshajiang river valley). Finally, it is worth noting that the type locality of L. chiangi is labeled as “ Yunnan ” instead of “ Xizang ” or “ Tibet ”, because Cawarong Township is close to Gongshan County in western Yunnan Province, and both places are near the Nujiang River. Moreover, Cawarong was visited by European and American missionaries in the mid- 19 th early 20 th centuries ( Liu 2019), and they often collected insect specimens referring to the churches on the territory as geographic information, resulting in strongly biased locality data.

Figures

Figure 2. Habitus of Layahima spp. from China, adults: A L. chiangi Banks, 1941, male, Cawarong (Xizang); B L. chiangi, male, holotype (© D. Grimaldi from AMNH); C L. qilin sp. nov., male, holotype, Weixi (Yunnan); D L. haohani sp. nov., female, holotype, Puer (Yunnan); E L. pixiu sp. nov., female, holotype, Hutiaoxia (Yunnan); F L. zhitengi sp. nov., female, holotype, Fugong (Yunnan).

Figure 3. Layahima chiangi Banks, 1941, adult: A Habitus, female holotype; B head, frontal view; C head and thorax, dorsal view. D, E male terminalia: D Lateral view, E ventral view. F, G Female terminalia: F Lateral view, G ventral view. H – L Male genitalia: H Ventral view, I anteroventral view, J caudal view, K lateral view, L dorsal view.

Figure 4. Layahima chiangi Banks, 1941, living photos and its habitat: A Habitat, Cawarong (Xizang), B living adult. C Newly hatched first instar larva. D Well-fed first instar larva (photos by Y. Zheng).

Figure 5. Comparison of different individuals of Layahima chiangi Banks, 1941 and L. qilin sp. nov. A – E L. chiangi, F – J. L. qilin sp. nov. A – C, F – H Head-thorax, dorsal view; D, I male genitalia, ventral view; E, J female pregenital plate, ventral view. Location (A, B, D, E) Cawarong (Xizang). C Holotype, type locality “ Loutsechiang ”, probably near to Cawarong (© D. Grimaldi from AMNH). F Holotype, type locality “ Weixi, Zhonglu, Zhazidi ” (Yunnan). G, I Batang (Sichuan). H Pantiange (Yunnan). J Baimaxueshan (Yunnan).

Figure 6. Habitus of Layahima chiangi Banks, 1941, first instar larva: A Dorsal view, B ventral view, C lateral view.

Figure 7. Layahima chiangi Banks, 1941, first instar larva: A Head, dorsal view; B head, ventral view; C thorax, dorsal view, on black background; D abdominal segments 8–9, ventral view.

Figure 18. Distribution map of Layahima spp.