Vollenhovia yasmeenae, Akbar & Bharti & Schifani & Wachkoo, 2023

Akbar, Shahid Ali, Bharti, Himender, Schifani, Enrico & Wachkoo, Aijaz Ahmad, 2023, Overview of the ant genus Vollenhovia (Hymenoptera, Formicidae) in India and Sri Lanka, with an illustrated key and the description of a new species, European Journal of Taxonomy 908, pp. 77-107 : 96-99

Vollenhovia yasmeenae sp. nov.

urn:lsid:zoobank.org:act:B34A100E-9543-45E4-BFAF-86D662F0BE33

Fig. 12

Diagnosis

Among the species of the region, V. yasmeenae sp. nov. can be separated based on some unique qualitative morphological features. It can be immediately distinguished from V. escherichi by its dark brown to blackish pigmentation as opposed to pale yellow, and from V. oblonga laevithorax by its sculptured as opposed to smooth mesosoma, and from V. pfeifferi by the absence of dentiform propodeal spines. Unlike V. keralensis and V. karimalaensis , its anterior clypeal margin is emarginate and has no median tooth, while the presence of a smooth area on the dorsum of the mesosoma separates it from V. gastropunctata , V. mawrapensis , and V. taylori . Finally, it differs from V. terayamai in having a much reduced smooth median area on the head and lacking the fine punctate sculpture on the sides of the petiole that characterizes the latter. The dorsal promesonotal sculpture appears relatively well-distinct and with a clear longitudinal orientation.

Etymology

The specific epithet is a Latinized noun in genitive, derived from the first name of Jammu and Kashmir’s first female Director of Colleges, Dr Yasmeen Ashai, for her service to higher education in the region.

Type material

Holotype INDIA • worker; Kerala, Silent Valley National Park ; 11°09′ N, 76°44′ E; alt. 900 m; 25 Sep. 2011; Winkler extraction method; S.A. Akbar leg.; PUAC0038 .

Paratypes INDIA • 3 workers; same collection data as for holotype: PUAC0039 to PUAC0041 • 3 workers; Kerala, Silent Valley National Park, near Badriya Juma Masjid, Mukkali ; 11°06′ N, 76°53′ E; alt. 700 m; 20 Dec. 2013; Winkler extraction method; S.A. Akbar leg.; PUAC0042 to PUAC0044 .

Worker measurements & indices (7 specimens, 2 colonies, 2 localities)

CL 0.61–0.65 (0.63), CW 0.54–0.57 (0.55), CS 0.57–0.6 (0.59), EL 0.14–0.16 (0.15), ML 0.80–0.82 (0.81), PEH 0.34–0.36 (0.35), PEL 0.16–0.19 (0.18), PEW 0.19–0.20 (0.19), PPH 0.20–0.23 (0.22), PPL 0.17–0.19 (0.18), PPW 0.23–0.24 (0.24), PW 0.38–0.41 (0.39), SL 0.38–0.39 (0.38). Indices: CL/ CW 1.09–1.21 (1.14), EL/ CS 0.23–0.27 (0.25), ML / CS 1.34–1.39 (1.37), PEH/ CS 0.57–0.61 (0.59), PEL/ CS 0.28–0.32 (0.30), PEW / CS 0.32–0.35 (0.33), PPH/ CS 0.35–0.39 (0.37), PPL/ CS 0.28–0.32 (0.30), PPW/ CS 0.39–0.42 (0.40), PW / CS 0.64–0.71 (0.67), SL/ CS 0.63–066 (0.65).

Description

Head in full-face view, subrectangular or subquadrate (CL/CW 1.09–1.21), posterior margin with a median concavity; posterolateral corner of head roundly convex, lateral margin broadly convex; clypeus emarginate; anterior clypeal margin laminate; mandible broad, masticatory margin consisting of 5–6 well-defined teeth, apical tooth strongly falcate; antenna 12-segmented; antennal scape short reaches about two-thirds the head length (SL/CS 0.63–0.66); eye prominent, protruding, placed well below midline of head (EL/CS 0.23–0.27).

In lateral view, dorsal outline of mesosoma flat; mesopleuron demarcated from lateral face of pronotum and propodeum by distinct sutures; posterior face of propodeum rounded and smooth; viewed dorsally, pronotal humeri rounded and smooth, and wider than the rest of the mesosoma; posterior propodeal margin convex; promesonotal suture absent; metanotal groove visible as a slight disruption in the surface sculpture, mesonotum and propodeum completely fused and lateral margins converging evenly to the propodeal declivity, no propodeal spines.

Petiole in lateral view, subquadrate with longer anterior face and shorter posterior face, dorsum concave; subpetiolar process well developed, subquadrate in shape (almost as long and as high, 0.09 mm); postpetiole dorsally rounded, much wider than long; sub-postpetiolar process pointed, peg-like, leaning anteriorly; gaster elliptical.

Surface sculpture throughout the body punctate-reticulate; punctures on head coarse; middle area of the head with a small smooth and unsculptured band in the middle of the head with few longitudinal striations running posteriorly, almost reaching the posterior margin; mandible smooth and shiny, with a few punctures present along masticatory margin; clypeus colliculate; mesosoma punctate-reticulate with longitudinally striations on dorsum; propodeal declivity colliculate; petiole and postpetiole sides minutely colliculate, dorsum mostly smooth with few punctures; gaster mostly smooth and shiny with fine punctures on first segment.

Whole body covered with abundant long, sub-erect, whitish pilosity.

Body black, appendages ferruginous to dark brownish.

Distribution

India (Kerala).

Ecology

Specimens were collected from the Silent Valley National Park ( Fig. 12D ), a primary tropical rainforest in Kerala, using the Winkler extraction method. Leaf litter samples of approximately 2 cm thickness were taken near tree trunks at two different locations in the National Park, one in the buffer zone (Mukkali) and one in the core region (Sairandhri). The species appears to be locally rare and may have a restricted distribution, although further research extending to other areas is required.

Remarks

Vollenhovia yasmeenae sp. nov. is the fourth species of the genus to be described from the Western Ghats region, further stressing its importance as a biodiversity hotspot for ants.

Worker-based key to the species of Vollenhovia Mayr, 1865 from India and Sri Lanka

1. Light colored, yellowish-brown with coarse alveolate head sculpture ( Fig. 13A–B ); small species (CW <0.4 mm), only known from Sri Lanka ( Fig. 13A ) ........................... V. escherichi Forel, 1911

– Dark brown to black ( Fig. 13C–D ), India......................................................................................... 2

2. Anterior clypeal margin convex, forming a single median tooth ( Fig. 13E ) .................................... 3

– Anterior clypeal margin emarginate with no median tooth ( Fig. 13F ) ............................................. 4

3. Body generally foveolate; mandible with 8 teeth; subpetiolar process lamellar wall distinctly longer than high ( Fig. 13G–I ) ................................................. V. keralensis Kripakaran & Sadasivan, 2022

– Body generally punctate; mandible with 7 teeth; subpetiolar process elongate and sickle-shaped ( Fig. 13H–J ) ........................................................................... V. karimalaensis Dhadwal et al., 2023

4. Mesosoma smooth and shiny, with few delicate, scattered punctures anteriorly, very evident metanotal depression ( Fig. 13K ) .......................... V. oblonga laevithorax Emery, 1889 or a member of the V. penetrans complex sensu Wang et al. (2022)

– Mesosoma strongly sculptured throughout ( Fig. 13L ) ..................................................................... 5

5. Propodeal spines dentiform; declivity carinate ( Fig. 13M ) ................. V. pfeifferi Bharti et al., 2023

– No propodeal spines; declivity smoothly rounded ( Fig. 13N ) ......................................................... 6

6. Mesosoma dorsum with a smooth and shiny central area ( Fig. 14A ) .............................................. 7

– Mesosoma dorsum dorsally entirely sculptured, with no central smooth region ( Fig. 14B ) ............ 8

7. Head with a broad smooth median band ( Fig. 14C ), postpetiole narrower and dorsally smooth, Eastern India ( Fig. 14E ) ...................................................................... V. terayamai Rilta et al., 2023

– Entirely sculptured ( Fig. 14D ), postpetiole wider and dorsally sculptured, Western Ghats ( Fig. 14F ) ......................................................................................................... V. yasmeenae sp. nov.

8. Body size small (CL: 0.44–0.50; CW: 0.40–0.44; ML: 0.54–0.60) ................................................. 9

– Body size larger (CL: 0.56; CW: 0.49; ML: 0.73–0.75) ..................................................................... ............................................................................................ V. gastropunctata Bharti & Kumar, 2013

9. Mandible with 7 teeth, mesosoma dorsum more finely and densely sculptured, mesopleuron transversely striate ( Fig. 14G–H ) ........................................... V. mawrapensis Dhadwal et al., 2023

– Mandible with 6 teeth, head, and mesosoma characterized by a coarse punctate sculpture, mesopleuron coarsely punctate ( Fig. 14I –J ) ................................................................... V. taylori Rilta et al., 2023

Figures

Fig. 12. Vollenhovia yasmeenae sp. nov., holotype worker from India (PUAC0038, photographer: Shahid Ali Akbar). A. Head, full face view. B. Habitus, lateral view. C. Habitus, dorsal view. D. Type locality of the new species.

Fig. 13 (see next page). Characters used in the identification key. A–B. Yellowish-brown (syntype worker of V. escherichi Forel, 1911 from Sri Lanka: CASENT0908656, photographer: Will Ericson). C–D. Dark brown to black (worker of V. keralensis Kripakaran & Sadasivan, 2022). E. Convex anterior clypeal margin with a single median tooth (worker of V. keralensis). F. Emarginate anterior clypeal margin with with no median tooth (holotype worker of V. gastropunctata Bharti & Kumar, 2013). G, I. Generally foveolate body with mandible having 8 teeth (worker of V. keralensis). H, J. Generally punctate body with mandible having 7 teeth (H. Worker of V. piroskae Forel, 1912; CASENT0159915, photographer: Michele Esposito. J. Holotype worker of V. karimalaensis). K. Mesosoma smooth and shiny (syntype worker of V. oblonga laevithorax, CASENT0904539). L. Mesosoma strongly sculptured throughout (holotype worker of V. taylori). M. Declivity carinate, dentiform (worker of V. pfeifferi). N. No propodeal spines; declivity smoothly rounded (holotype worker of V. yasmeenae sp. nov.).

Fig. 14. Characters used in the identification key. A. Mesosoma dorsum with a smooth and shiny central area (holotype worker of V. terayamai). B. Mesosoma dorsum dorsally entirely sculptured (holotype worker of V. taylori). C, E. Head with broad median smooth band with postpetiole narrower and dorsally smooth (holotype worker of V. terayamai). D, F. Head entirely sculptured with wider postpetiole, dorsally sculptured (holotype worker of V. yasmeenae sp. nov.). G–H. Mandible with 7 teeth, mesopleuron transversely striate (holotype worker of V. mawrapensis). I–J. Mandible with 6 teeth, mesopleuron coarsely punctuate (holotype worker of V. taylori).