Aenictus kadalarensis

Aenictus kadalarensis
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Dorylinae
Genus:	Aenictus
Species group:	pachycerus
Species:	A. kadalarensis
Binomial name
	Aenictus kadalarensis; Sahoo, Ramakrishnaiah, Dharma Rajan & Datta-Roy, 2023

The only known specimens of this species were collected in the Southern Western Ghats, India. They were from the ground where a few workers were seen on a rotten log and more individuals were present under the log. The collection was made in the month of May, prior to the monsoon. The type locality is a tea and cardamom plantation surrounded by evergreen forest. The forest vegetation is mostly comprised of Cullenia exarillata, Mesua ferrea, Palaquium ellipticum trees along with other tree species like Diospyros sylvatica, Drypetes elata, Cinnamomum keralense, Syzygium gardneri, Dimocarpus longan, Aglain jainii, and Litsea oleoides (Pascal, Ramesh, & De Franceschi, 2004). This area is part of the Southern Western Ghats biodiversity hotspot.

Photo Gallery

Sahoo et al. (2023), Fig. 1. Aenictus kadalarensis worker (holotype). Head in full-face view.
Sahoo et al. (2023), Fig. 2. Aenictus kadalarensis worker (holotype). Body in dorsal view.
Sahoo et al. (2023), Fig. 3. Aenictus kadalarensis worker (holotype). Mandibles.
Sahoo et al. (2023), Fig. 4. Aenictus kadalarensis worker (holotype). Body in lateral view.
Sahoo et al. (2023), Fig. 5. Aenictus kadalarensis worker (holotype). Petiole with subpetiolar process.

Identification

Sahoo et al. (2023) - A member of the Aenictus pachycerus species group. Aenictus kadalarensis is unique in the following combination of features: #Head longer than broad with subparallel margins.

Masticatory margin with a broad apical tooth followed by seven denticles.
Dorsal side of propodeum and petiole microreticulate.
Declivity of propodeum concave.
Subpetiolar process present, anteroposteriorly angulate.

The Aenictus pachycerus species group comprises 17 species (Antwiki, 2023; Jaitrong, Yamane, & Tasen, 2012; Jaitrong & Wiwatwitaya, 2013; Jaitrong & Yamane, 2011; Yamane & Wang, 2015), of which 4 species are present in India; Aenictus aitkenii, Aenictus dentatus, Aenictus pachycerus and Aenictus punensis (status of Aenictus aratus in India is dubious (Shattuck, 2008)) (Bharti et al., 2016).

A. kadalarensis can be distinguished from these species by having a smooth pronotum (microreticulated in A. aitkenii and A. dentatus) and the lack of longitudinal rugulae on propodeum dorsum (present in A. punensis). Aenictus kadalarensis is similar to Aenictus carolianus, known from Cebu island (Philippines), in general morphology and body measurements. Aenictus kadalarensis can be differentiated from the latter by the following characters.

Presence of subpetiolar process in A. kadalarensis (Fig. 6-1), which is absent in A. carolianus (Fig. 6-2).
Dorsal propodeum and dorsal petiole are microreticulate in A. kadalarensis (Fig. 7-1), while smooth in the latter (Fig. 7-2).
A. kadalarensis has a mandible with a large apical tooth followed by seven denticles, whereas A. carolianus has a mandible with a large apical tooth followed by only around five denticles.

Sahoo et al. (2023), Fig. 6-1. Aenictus kadalarensis worker (holotype). Subpetiolar process present.
Sahoo et al. (2023), Fig. 6-2. Aenictus carolianus. Subpetiolar process absent (modified and taken from Zettel & Sorger, 2010).
Sahoo et al. (2023), Fig. 7-1. Aenictus kadalarensis worker (holotype). Dorsal propodeum and dorsal petiole microreticulate.
Sahoo et al. (2023), Fig. 7-2. Aenictus carolianus. Smooth dorsal propodeum and dorsal petiole (modified and taken from Zettel & Sorger, 2010).

Keys including this Species

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: 10.1° to 10.1°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: Sahoo et al., 2023

Distribution based on Regional Taxon Lists

Oriental Region: India (type locality).

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

Explore Overview of Aenictus biology

Little is known about the biology of Aenictus kadalarensis. The genus is comprised of species that live an army ant lifestyle. Aenictus typically prey on other ants, from other genera, or other insects such as wasps or termites. There are reports of Aenictus preying on other insects as well and even have been observed collecting honeydew from homopterans (Santschi, 1933; Gotwald, 1995) but this appears, at least from available evidence, to be uncommon. Foraging raids can occur day or night across the ground surface. Occasionally raids are arboreal. During a raid numerous workers attack a single nest or small area, with several workers coordinating their efforts to carry large prey items back to the nest or bivouac. Aenictus have a nomadic life style, alternating between a migratory phase in which nests are temporary bivouacs in sheltered places above the ground and a stationary phase where semi-permanent underground nests are formed. During the nomadic phase bivouacs move regularly, sometimes more than once a day when larvae require large amounts of food. Individual nests usually contain up to several thousand workers, although nest fragments containing only a few hundred workers are often encountered. Queens are highly specialised and look less like workers than in most ant species. They have greatly enlarged gasters (dichthadiform) and remain flightless throughout their life. New colonies are formed by the division of existing colonies (fission) rather than by individual queens starting colonies on their own.

‎

Castes

Queen and male unknown.

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

kadalarensis. Aenictus kadalarensis Sahoo, et al. 2023: 617, figs. 1-5, 6.1, 7.1 (w.) INDIA (Kerala).
- Type-material: holotype worker, 64 paratype workers.
- Type-locality: India: Kerala, Idukki District, Kadalar tea estate, nr Munnar, 10.1330°N, 76.9977°E, 1416 m., 19.v.2022 (B. Sahoo); paratypes with same data.
- Type-depository: ATRE.
- [Notes (i): the authors comment that the holotype + 2 paratypes, initially deposited ATRE, will be transferred later to ZSIK; (ii) depositories of the remaining 62 paratypes are not given.]
- Distribution: India.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Holotype HL, 0.72; HW, 0.6; SL, 0.47; WL, 1; PL1, 0.24; PL2, 0.26; GL, 1; TL, 3.22; CI, 83.3; SI, 78; PHL, 0.20.

Paratype (n=10) HL, 0.71-0.76; HW, 0.66-0.68; SL, 0.47-0.56; WL, 1- 1.1; PL1, 0.24-0.27; PL2, 0.22-0.27; GL, 0.95-1; TL, 3.20-3.36; CI, 88-94.3; SI- 70.1-84.8; PHL, 0.20-0.26.

Monomorphic body.

Head: Subrectangular in frontal view, longer than broad, posterior margin concave; lateral sides subparallel. Antennae with 10 segments; scapes short, not reaching beyond the posterior region of head. Anterior clypeal margin convex, without teeth; angularly produced in the middle. Typhlatta spot absent. Parafrontal ridge present, extending 1 ⁄ 3 of the head length (ca 0.25 mm), with a small tooth between antennal sockets. Mandibles triangular, a large apical tooth followed by seven denticles of similar size.

Mesosoma: Elongated, dorsal outline almost straight in profile view, pronotum moderately convex in lateral view, mesonotum straight; metanotum continuous; metanotal groove slightly impressed. Mesonotum continues with mesopleuron. Mesopleuron demarcated from metapleuron by a shallow impression. Propodeum acutely angulate. Dorsal outline of propodeum is almost straight but slightly downcurved at the most posterior part. Propodeal declivity shallowly concave, encircled by a thin rim.

Metasoma: Both petiole and postpetiole are almost the same length in profile; petiole slightly higher than postpetiole in width. Dorsal outline of petiole slightly tapered towards the posterior side. Postpetiole dorsally convex. Subpetiolar process low, quadrilateral shape, and anteroposteriorly angulate not developed as a process. In lateral view, gaster oval with 4 tergites, sting distinct apically.

Sculpture: Head smooth and shining except for hair pits in frontal view. The area between the parafrontal ridges micro-reticulate. Area beside parafrontal ridge reticulate with sparse rugae. Mandibles with longitudinal striation with scattered punctures and flagellomeres microreticulate with punctures. Reticulation on occiput is feeble (Fig. 1). Dorsally, areas behind occiput densely reticulate. Dorsum of pronotum and mesonotum smooth and shiny. Anterior most pronotum reticulate. Dorsal face of propodeum and declivity microreticulate. Dorsum of petiole microreticulate. Subpetiolar process microreticulate. Dorsum of postpetiole smooth medially and feebly microreticulate. Gaster smooth and shiny except hair pits. In lateral view, pronotum smooth posteriorly and microreticulate anteriorly. In some individuals, lateral pronotum microreticulate posteriorly as well. Mesonotum, petiole, and postpetiole microreticulate in lateral view. Mesopleuron and metapleuron microreticulate along with moderate longitudinal striation. Legs feebly reticulate.

Pilosity: Whole body with sparse, suberect long hairs. Long hairs present on scape, occiput, dorsum of petiole, postpetiole, and gaster. Short hairs present on lateral mesosoma, petiole, and postpetiole. Relatively denser and short hairs on funiculus of antenna, tibia, and tarsus of legs.

Color: Dark reddish brown to black. Head and antennae dark reddish brown. Occiput and mandible black. Mesosoma, petiole, and postpetiole reddish brown to black. Gaster is black except the apical part, which is yellowish. Legs light yellow to black.

Type Material

Holotype worker (AIMB/Hy/ Fr 25004). India, Kerala, Munnar, Idukki, Kadalar tea estate, 10.1330°N 76.9977°E, 1416 m, 19.v.2022, aspirator, coll. Bikash Sahoo.
Paratypes, 64 workers, same data as holotype.

Etymology

The name of the species is derived from the type locality, Kadalar tea estate, Munnar, Kerala. The species is known only from the type locality.

References

Sahoo, B., Ramakrishnaiah, S., Rajan, P.D., Datta-Roy, A. 2023. A new species of army ant genus Aenictus (Hymenoptera: Formicidae) from India. Journal of the Entomological Research Society 25(3), 615-622 (doi:10.51963/jers.v25i3.2504).