Aenictus kodaguensis, Sahoo & Sahanashree & Priyadarsanan & Datta-Roy, 2024

Sahoo, Bikash, Sahanashree, Ramakrishnaiah, Priyadarsanan, Dharma Rajan & Datta-Roy, Aniruddha, 2024, Aenictus kodaguensis sp. nov. (Hymenoptera: Formicidae), a unique species from India, Asian Myrmecology (e 017003) 17, pp. 1-7 : 2-6

Aenictus kodaguensis sp. nov.

http://zoobank.org/ 8052F8C8-E72B-4B76-B06C-5C182C2843F7

( Figs. 1 (A-D), 2B)

Type material. Holotype worker ( AIMB /Hy/ Fr 250014). India, Karnataka, Kodagu, Pushpagiri Wildlife Sanctuary , 12.662°N 75.687°E, 1476m, 26.iv.2022, aspirator, Bikash Sahoo leg., colony code KN32.

Paratypes: 101 paratype workers, same data as holotype .

Non-type material examined. 87 workers. India, Karnataka, Kodagu, Honey Valley private estate, 12.2186°N 75.6577°E, 1185m, 19.iv.2022, aspirator, Bikash Sahoo leg., colony code KN27 .

Holotype and paratypes are deposited in AIMB, India.

Measurements and indices. Holotype: HL, 0.82; HW, 0.67; SL, 0.68; WL, 1.08; PL1, 0.3; PL2, 0.27; GL, 1.1; TL, 3.57; CI, 81.7; SI, 101.49.

Paratypes: HL, 0.81- 0.88; HW, 0.70- 0.76; SL, 0.76- 0.81; WL, 1.19- 1.28; PL1, 0.32- 0.37; PL2, 0.32- 0.36; GL, 1.15- 1.36; TL, 3.89- 4.21; CI, 82- 90; SI, 104-114.

Diagnosis Aenictus kodaguensis sp. nov. can be distinguished from other members of A. pachycerus species group by the combination of these characters: head rectangular, longer than broad; head, mesosoma, petiole, and postpetiole entirely microreticulate; lateral mesonotum, propodeum, and petiole with irregular rugulae; a peculiar transverse carina present across the lateral mesosoma. First gastral tergite shagreened.

Worker description

In full-face view, head rectangular, longer than broad, with lateral margins slightly convex; posterior margin straight to weakly convex; parafrontal ridge well developed, reaching almost midlength of the head (ca. 0.28mm). Antennae 10 segmented; scape long, reaching posterior margin of the head; anterior clypeal margin convex, produced in the middle and without teeth; mandible sub-triangular and thick, its masticatory margin with a large apical tooth followed by 5 denticles of similar size ( Fig. 1A ).

In profile, mesosoma compact; dorsal outline of promesonotum convex; metanotal groove weak; a groove separates the mesonotum from the mesopleuron; a distinct transverse carina present across the lateral mesosoma, dividing the mesopleuron from the metapleuron ( Fig. 1B ); propodeum lower to promesonotum; dorsal outline of propodeum weakly convex; declivity concave, encircled with a rim.

In profile, both petiole and postpetiole globular; slightly longer than broad, while in some paratypes, length and height are the same; dorsum convex, with dorsal outline elevated posteriorly. Petiole subsessile; subpetiolar process present but indistinct, reduced with a straight ventral outline; petiolar spiracle, small, located anteriorly on lateral surface; post petiolar spiracle small, located near the middle on lateral surface. Gaster oval ( Fig. 1D ).

Head entirely microreticulate; mandibles with striation and few punctures; mesosoma, petiole, and postpetiole entirely microreticulate. Lateral mesonotum, propodeum, petiole with few distinct, irregular superficial rugae, and postpetiole with light rugae ( Fig. 1A, D ). Dorsum promesonotum, propodeum, petiole, and postpetiole with light superficial rugae ( Fig. 1C ). Rugae absent on lateral pronotum ( Fig. 1B ). First gastral tergite superficially shagreened with smooth and shinning interspaces; legs and antennae finely microreticulate ( Fig. 1D ).

Whole body with sparse, suberect hairs; longer hairs present on scape, occiput, dorsum of petiole, and postpetiole; relatively shorter hairs present on lateral sides of mesosoma, petiole, postpetiole and short decumbent hairs on gaster. Hairs relatively denser on the gaster, funiculus of antenna, tibia, and tarsus. ( Fig. 1A, C, D ).

Head and mandible dark reddish brown; head with a black patch on vertex; body dark reddish brown to black; gaster black with yellow apical end; legs and antennae light brown ( Fig. 1A, C, D ).

Etymology The species is named after its type locality, the district Kodagu in Karnataka state, where Pushpagiri Wildlife Sanctuary is situated.

Distribution India (Karnataka). Known only from the type locality and nontype locality so far.

Natural history

Pushpagiri Wildlife Sanctuary is a significant forest area in Karnataka situated within the central Western Ghats, features a distinctive landscape comprising evergreen forests and grassland shola habitat, typical of the higher elevations of the Western Ghats. Annual rainfall is 6000- 7000 mm, with an average annual temperature ranging from 10- 34°C ( Mallesha 2008).

In the type locality, specimens were collected from under a large rotting log where the bivouac was present. The non-type specimens from the Honey Valley estate were collected from leaf litter. Both collections were made in April, prior to the monsoon season.

Comparative notes

The Aenictus pachycerus species group comprises 18 species ( Jaitrong & Yamane 2011; Jaitrong et al. 2012; Jaitrong & Wiwatwitaya 2013; Yamane & Wang 2015; Sahoo et al. 2023; Antwiki 2024), of which five species have been reported from India: A. pachycerus Smith, 1858 ; A. aitkenii Forel, 1901 ; A. punensis Forel, 1901 ; A. dentatus Forel, 1911 ; and A. kadalarensis Sahoo et al., 2023 (status of A. aratus Forel, 1900 in India is uncertain ( Shattuck 2008; Bharti et al. 2016; Sahoo et al. 2023). A table listing A. pachycerus group species and their distributions is provided ( Table 1 ).

Aenictus kodaguensis sp. nov. is different from all other Aenictus species reported from India by having a shagreened gaster and a peculiar transverse ridge in lateral mesosoma. It shares a close resemblance to A.paradentatus Jaitrong & Yamane, 2012 , by having a shagreened gaster. However, A. kodaguensis sp. nov. differs from A. paradentatus in having a shorter scape (measuring <0.82 mm; with SI <115) compared to A. paradentatus , which measures more than 0.92 mm, with SI>117. The masticatory margin of the mandible in the former bears 5 denticles, while the latter bears 11-12 denticles. Further distinctions lie in the absence of longitudinal rugae on the dorsal and lateral promesonotum of A. kodaguensis sp. nov., in contrast to the presence of multiple distinct longitudinal rugae on the dorsal and lateral promesonotum of the latter ( Fig. 2 ).

A. kodaguensis sp. nov. also exhibits similarities with A. dentatus Forel, 1911 and A. bobaiensis Zhou & Chen, 1999 by having a microreticulated head and mesosoma. However, A. dentatus can be differentiated by having a much longer scape (SI> 142) ( Jaitrong & Wiwatwitaya 2013) and a smooth first gastral tergite (Jaitrong et al. 2012), while A. kodaguensis sp. nov. has a shagreened gaster and a shorter scape (SI<115). Similarly, A. bobaiensis is a larger species (TL 4.85–5.10 mm; HW 0.90–0.98 mm) ( Jaitrong & Wiwatwitaya 2013) compared to A. kodaguensis sp. nov. (TL 3.57- 4.21; HW 0.67- 0.76).

Figures

Fig. 1. Aenictus kodaguensis sp. nov., worker (holotype). A. Head in full-face view B. Mesosoma with lateral carinae (marked with arrows); shagreened gaster C. Body in dorsal view D. Body in profile.

Fig. 2. A. A. paradentatus (image from Jaitrong & Yamane 2012), B. A. kodaguensis sp.nov.

Tables

Table 1. List of worker-based species of Oriental A. pachycerus species group and its distributions (type localities are marked with *).

Specific names	Distributions
A. aitkenii Forel, 1901	India (Karnataka *) and Sri Lanka ( Shattuck 2008)
A. aratus Forel, 1900	Australia (Mackay*, Queensland) ( Shattuck 2008)
A. bobaiensis Zhou & Chen, 1999	South China (Guangxi *, Hainan, and Hong Kong) and Vietnam ( Jaitrong & Wiwatwitaya 2013)
A. carolianus Zettel & Sorger, 2010	Philippines (Cebu *) ( Zettel & Sorger 2010)
A. dentatus Forel, 1911	Malay Peninsula (Southern part of Thailand and Malaysia *), Sumatra, Borneo (Sabah, Sarawak, Brunei, and Kalimantan), and Java (Jaitrong Wiwatwitaya 2013), India
A. kutai Jaitrong & Wiwatwitaya, 2013	Borneo (E. Kalimantan*) ( Jaitrong & Wiwatwitaya 2013)
A. levior Karavaiev, 1926	Borneo (Sabah, Sarawak and Brunei), Malay Peninsula ( Malaysia), and Buru Island* ( Jaitrong & Wiwatwitaya 2013)
	Philippines (Negros*, Luzon and Palawan), Sulawesi, and
A. nesiotis Wheeler & Chapman, 1930	Australia ( Jaitrong & Wiwatwitaya 2013)
A. pachycerus Smith, 1858	India (after Bingham 1903)
	Vietnam, Laos, Thailand (Chiang Mai prov*) (Jaitrong &
A. paradentatus Jaitrong & Yamane, 2012	Yamane 2012 )
A. philiporum Wilson, 1964	Australia (Iron range*, Queensland), Papua New Guinea ( Shattuck 2008)
A. powersi Wheeler and Chapman, 1930	Philippines (Negros*) ( Jaitrong & Wiwatwitaya 2013)
A. prolixus Shattuck, 2008	Australia (Northern Territory *) ( Shattuck 2008)
A. punensis Forel, 1901	India (Maharashtra *) ( Forel 1901)
A. reyesi Chapman, 1963	Philippines (Negros*) ( Jaitrong & Wiwatwitaya 2013)
A. sirenicus Yamane & Wang, 2015	E. Malaysia (Borneo*) ( Yamane & Wang 2015)
A.sulawesiensis Jaitrong & Wiwatwitaya, 2013	Sulawesi * ( Jaitrong & Wiwatwitaya 2013)
A. kadalarensis Sahoo et al., 2023	India (Kerala *) ( Sahoo et al. 2023)
A. kodaguensis sp. nov.	India (Karnataka *)