Zasphinctus sahyadriensis

This species was found in a tropical evergreen forest floor. Five workers were collected from a subterranean tunnel under a small rock, near the buttress of a tree (Image 11). The workers were moving in the narrow tunnel which happened to get opened when the rock was removed. The movement was army ant-like, fast, irregular, and the ants were averse to light. In captivity, workers accepted brood of a Pheidole species as food. The species is restricted to Ponmudi hills in Agasthyamalai region of southern Western Ghats in Kerala state of southern India as far as is known.

Identification
Zasphinctus sahyadriensis is easily differentiated from the sympatric Eusphinctus furcatus Emery, 1893, occurring in the same habitat. Although superficially similar, Z. sahyadriensis has 12-segmented antennae, a shallow pronotomesopleural suture, smaller size (TL 3.04–3.33), and shiny black color, while E. furcatus has 11-segmented antennae, a deep pronotomesopleural suture, larger size (TL 6.85– 6.90 mm), and dark brown integument coloration. Additonally, E. furcatus was recorded above 900 m, while the highest elevation for Z. sahyadriensis was 700 m.

Analysis of AntWeb (2021) images revealed morphological similarities between Zasphinctus sahyadriensis and other shiny black Afrotropical species (Z. sarowiwai Hita Garcia, 2017, Z. obamai Hita Garcia, 2017, and Z. wilsoni Hita Garcia, 2017). The presence of the conspicuous tooth in the median clypeal area distinguishes the new species from Z. obamai and Z. wilsoni Hita Garcia. From Z. sarowiwai, the new species is diagnosed by the irregular occipital margin of the former. With the sole Asian species Z. siamensis, the new taxon Z. sahyadriensis shares the median clypeal tooth and the regular occipital margins; but the new species is easily distinguished by the black integumental coloraton (brown on Z. siamensis) and the sparsely punctate head sculpture (densely foveolate on Z. siamensis).

Distribution based on Regional Taxon Lists
Oriental Region: India.

Nomenclature

 * . Zasphinctus sahyadriensis Kripakaran & Sadasivan, 2022: 21376, figs. 7A-C (w.) INDIA (Kerala).

Type Material

 * Holotype: NRC-AA-3760, 15 October 2015, Worker, Ponmudi, Agasthyamalai, Thiruvananthapuram District, Kerala State, India, at 600 m, coll. Manoj Kripakaran, collected under a small rock, in the forest floor of a mixed evergreen forest, deposited in the insect collection facility of the NCBS (National Centre for Biological Sciences), Tata Institute of Fundamental Research, GKVK, Bellary Road, Bengaluru, Karnataka 560065, India. Earlier, the holotype was with number TARG-1011, mounted for study and preserved as wet specimen in absolute alcohol, deposited in the research collections facility at the TNHS, Thiruvananthapuram, Kerala.
 * Paratype workers (n = 3) (Images 8,9):
 * NRC-AA-3761, Worker with the same collection data as holotype above. Earlier, the paratype was with number TARG-1012, wet specimen in absolute alcohol, currently deposited in the research collections facility at the TNHS, Trivandrum, Kerala.
 * Two other paratype workers both with the same collection data as paratype above. Of them one worker (TARG-1013), wet specimen in absolute alcohol, will be deposited in the insect collection of ZSI, Kozhikode, Kerala and the other worker (TARG-1014), wet specimen in absolute alcohol, will be retained as voucher specimen in collection facility of TNHS, Thiruvananthapuram, Kerala.

Description
Worker

Holotype

Measurements: HL 0.70, HW 0.40, SL 0.32, PH 0.40, PW 0.50, DML 0.90, WL 1.00, HFeL 0.42, PeL 0.32, PeH 0.23, PeW 0.50, A3L 0.35, A3W 0.43, A4L 0.30, A4W 0.58, A5L 0.30, A5W 0.59, A6L 0.30, A6W 0.60, CI 57.14, SI 45.71, DMI 50, DMI2 90, LMI 40, MFI 105, LPI 139, DPI 156, DA3I 123, DA4I 193, DA5I 197, DA6I 200.

Head: Antennae with 12 segments and relatively short (SI 44–56), scapes reaching half of the height of the head in full-face view. Apical antennal segment is conspicuous, longer than two preceding segments combined. Head distinctly longer than broad (CI 56– 59). Parafrontal ridges present and well-developed but somewhat irregular. Torulo-postorular complex vertical reaching only below half of the height of the parafrontal ridges. Antennal scrobes absent. Median clypeal area with a single short but conspicuous tooth (Image 7C). Palp formula 3,3 (visible palpomeres). Mandibles elongate triangular and curved; masticatory margin almost plain, basal region with inconspicuous dentcles. Eyes and ocelli absent. Vertex concave. Head capsule with a well-differentiated vertexal margin with prominent lateral angles.

Mesosoma: Mesosoma in lateral view the profile is almost straight (LMI 40–44). Sides are rounded and not marginate (Images 7A). In dorsal view, slightly more than twice as long as broad (DMI2 88–93). Promesonotal suture completely fused. Pronotomesopleural suture absent. Mesometapleural groove not impressed. Transverse groove dividing mesopleuron absent. Pleural endophragmal pit concavity present. Mesosoma dorsolaterally immarginate. Metanotal depression or groove on mesosoma absent. Propodeal spiracle situated low below mid-height on the sclerite. Propodeal declivity almost vertical with an angle of 110 degrees to the dorsum. Propodeal declivity with distinct dorsolateral and lateral edge or margin, and declivity is nearly semi-circular in posterior view. Metapleural gland without bulla visible through the cuticle. Propodeal lobes developed.

Metasoma: Abdominal segment II (petiole) sessile, without peduncle. Petiolar node well-developed. In profle, petiolar tergum 1.4 tmes longer than high (LPI 136–139). Petiole anterodorsally marginate but blunt, dorsolaterally well rounded, and laterally above spiracle weakly marginate. Subpetolar process well-developed with strongly anteroventrally projecting “eagle beak” shaped with tp hooked posteriorly (Image 7A) The subpetiolar process without fenestra. Prora on the anterior aspect of the ventral part of abdominal segment III is simple and heart shaped. Spiracle openings of abdominal segments IV–VI circular. Abdominal segment III anterodorsally emarginate and dorsolaterally emarginate. Abdominal segment III distinctly longer than succeeding segment IV, in both dorsal and ventral views. Girdling constrictions of segments IV, V, VI present and distinct. Abdominal tergite IV not folding over sternite, and anterior portions of sternite and tergite equally well visible in lateral view. Pygidium large, with weakly impressed and hypopygium moderately concave proximally, with the posterior end bossed on its midline bearing the ventral part of the tiny sting. Legs: Pro-, tibia, meso-, and metatibiae with single pectinate spur. Tarsal claws simple. Metafemur moderately long (MFI 105-112).

Sculpture and Pilosity: The head, mandibles, mesosoma, legs and metasoma are generally smooth and shiny, with sparse piligerous punctae and a much lesser number of glabrous punctae. Sculpture on ventral margin of antennal scape, propodeal declivity and helcium imbricate to reticular. Most of body with numerous short to moderately long, decumbent to suberect setae. Few erect hairs present around the pygidium and hypopygium. Pygidium near the sting and the lateral margins armed with short and stout, tubiform to conical setae. Long semierect filiform setae present around the pygidium and hypopygium. The area between vertexal margin and occipital margin unsculptured.

Color: Mainly black, appendages and subpetiolar process amber brown. Mandibles dark amber brown. Hairs pale yellowish and translucent (Image 7)

Paratype Workers

Measurements: HL 0.68–0.72, HW 0.38–0.42, SL 0.31–0.32, PH 0.40–44, PW 0.49–0.54, DML 0.88–0.93, WL 0.98–1.10, HFeL 0.40–0.45, PeL 0.30–0.34, PeH 0.22– 0.25, PeW 0.48–0.54, A3L 0.32–0.38, A3W 0.42–0.45, A4L 0.30–0.32, A4W 0.56–0.59, A5L 0.28–0.32, A5W 0.56–0.60, A6L 0.28–0.32, A6W 0.58–0.61, CI 55.88– 58.33, SI 44.44–55.56, DMI 49–54, DMI2 88–93, LMI 40–44, MFI 105–107, LPI 136–139, DPI 156–160, DA3I 118–131, DA4I 184–193, DA5I 188–200, DA6I 191–207.

Variation in workers: No variation except in the subtle differences in body measurements indicated above.

Gyne Unknown

Male Unknown

Measurements

EL—Eye length: maximum length of eye measured in lateral view | HL—Head length: maximum measurable distance from the mid-point of the anterior clypeal margin to the mid-point of the posterior margin of head, measured in full-face view | HW—Head width: maximum head width directly behind the eyes, measured in full face view | SL—Scape length: maximum length of scape shaft excluding basal condyle | PH—Pronotal Height: the maximum height of the pronotum in profile | PW— Pronotal Width: the maximum width of the pronotum in dorsal view | DML—Dorsal Mesosoma Length: maximum length of mesosomal dorsum from anterio-dorsal margin of pronotum to dorsal margin of propodeal declivity | WL—Weber’s Length of Mesosoma: the maximum diagonal length of the mesosoma in profile, from the angle at which the pronotum meets the cervix to the posterior basal angle of the metapleuron | HFeL— Metafemur Length: the maximum straight-line length of the metafemur, measured in dorsal view | HTiL—Hind tbia length: maximum length of hind tibia measured on its external face | HBaL—Hind basitarsus length: maximum length of hind basitarsus measured along its external face | PeL—Abdominal Segment II (petiole) Length: the maximum length of abdominal segment II (petiole), measured in dorsal view | PeH—Abdominal Segment II (petiole) Height: the maximum height of the petiolar tergum in profile view, including laterotergite, excluding petiolar sternum | PeW—Abdominal Segment II (petiole) Width: the maximum width of abdominal segment II (petiole), measured in dorsal view | A3L— Abdominal Segment III Length: the maximum length of abdominal segment III, measured in dorsal view | A3W—Abdominal Segment III Width: the maximum width of abdominal segment III, measured in dorsal view | A3H—Postpetole Height: Maximum height of postpetiole in profile | A4L—Abdominal Segment IV Length: the maximum length of abdominal segment IV, measured in dorsal view | A4W—Abdominal Segment IV Width: the maximum width of abdominal segment IV, measured in dorsal view | LS4—Abdominal sternum IV length: maximum length of abdominal sternum IV in lateral view | A5L— Abdominal Segment V Length: the maximum length of abdominal segment V, measured in dorsal view | A5W— Abdominal Segment V Width: the maximum width of abdominal segment V, measured in dorsal view | A6L— Abdominal Segment VI Length: the maximum length of abdominal segment VI, measured in dorsal view | A6W— Abdominal Segment VI Width: the maximum width of abdominal segment VI, measured in dorsal view | WL— Weber’s length: diagonal length of mesosoma in lateral view from the anterior-most point of pronotal slope (excluding neck) to posterioventral margin of propodeal lamella or lobe

Indices

CI—Cephalic index: HW / HL × 100 | OI—Ocular index: EL / HW × 100 | SI—Scape index: SL / HL × 100 | DMI —Dorsal Mesosoma Index: PW / WL × 100 | DMI2 —Dorsal Mesosoma Index 2: DML / WL × 100 | LMI — Lateral Mesosoma Index: PH / WL × 100 | DPe (DPI)— Dorsal petole index: PeW / PeL × 100 | LPI —Lateral Petole Index: PeL / PeH × 100 | MFI —Metafemur Index: HFeL / HW × 100 | ASI—Abdominal segment index: A4L /A3L × 100 | IGR—Gastral reflection index: LS4 / A4L.

Etymology
The epithet ‘sahyadriensis’ is masculine and derived from the Sanskrit and regional Malayalam language word ‘Sahyadri’, denoting the Western Ghats.