Prionopelta laurae Overson & Fisher

Overson, Rick & Fisher, Brian L., 2015, Taxonomic revision of the genus Prionopelta (Hymenoptera, Formicidae) in the Malagasy region, ZooKeys 507, pp. 115-150 : 126-128

Taxon classification Plantae Hymenoptera Formicidae

Prionopelta laurae Overson & Fisher sp. n. Fig. 7

Type material.

Holotype, pinned worker, MADAGASCAR, Antsiranana, Parc National de Marojejy, Manantenina River, 28.0 km 38° NE Andapa, 8.2 km 333° NNW Manantenina, 14.43667°S, 49.775°E, 450 m, rainforest, sifted litter (leaf mold, rotten wood), collection code: BLF08722, 12.xi.2003 (B.L. Fisher et al.) (CASC: CASENT0046149). Paratypes, nine pinned workers with same data as holotype (BMNH: CASENT0046153; CASC: CASENT0046141; CASENT0046142; CASENT0046143; CASENT0046147; CASENT0046151; MCZC: CASENT0046150; MHNG: CASENT0046140; NHMB: CASENT0046148).

Diagnosis.

Prionopelta laurae is the only Malagasy Prionopelta with workers that possess nine antennal segments (all others possess twelve). Additionally, it is the smallest of all the Malagasy species with HL <0.4 mm and HW <0.3 mm (HL and HW of all other species is greater than 0.4 mm and 0.3 mm respectively).

Worker measurements

(N=16). HL 0.33-0.38 (0.35); HW 0.24-0.27 (0.26); SL 0.16-0.18 (0.17); WL 0.34-0.4 (0.38); PetL 0.09-0.11 (0.1); PetW 0.13-0.15 (0.14); T1W 0.19-0.23 (0.21); CI 67.55-75.64 (72.71); PI 120.18-152.75 (135.44); SI 61.62-69.05 (65.06).

Worker description.

Head much longer than wide with lowest cephalic index on average of all Malagasy Prionopelta (mean CI 72.71); posterior head margin straight in full-face view; cephalic foveae small and very dense, with no space for additional cephalic foveae present; median cephalic band devoid of foveae is long and thin and appears slightly swollen or raised above the surrounding integument, forming a scarlike suture; apical tooth of the mandible over four times the length of third tooth in full-face view; nine antennal segments; eye greatly reduced, appearing as a tiny, dark gray patch; majority of marks on pronotum are densely spaced, tiny punctures; mesonotum and propodeum consisting of tiny shallow foveae; metanotal groove visible dorsally; smallest of the Prionopelta from Malagasy region; body distinctly pale yellow in color.

Etymology.

The name of this species is a patronym dedicated to Laura D. Steger for her continual support during the course of this work and her either completely genuine-or expertly feigned-enthusiasm for being endlessly bombarded by information about ants.

Distribution and ecology.

This species has been collected in leaf litter primarily in rainforest with some collections from littoral rainforest and one in tropical dry rainforest, at elevations between 10-600 meters. Its range is restricted to eastern Madagascar and is seemingly disjunct, with most individuals collected from the northeast and only two locales known from the southeast near the coast. No individuals have been collected between Sahafina Forest in the north and Mahabo forest in the south, a distance of 500 km (Fig. 13). The current range of Prionopelta laurae is such that it may once have been distributed along the entire eastern coast of Madagascar.

Taxonomic notes.

This species of Prionopelta is unmistakable as it is the only Malagasy species with nine antennal segments. It is also the smallest known species of Malagasy Prionopelta and is a distinct pale yellow color, which is much lighter than the fully-sclerotized workers of any other Malagasy species.

Non-type material.

MADAGASCAR: Antsiranana, Ambondrobe, 41.1 km 175° Vohemar, 13.7153°S, 50.1017°E, 10 m, littoral rainforest, 29.xi.2004 (B.L.Fisher); Antsiranana, Forêt Ambanitaza, 26.1 km 347° Antalaha, 14.6793°S, 50.1837°E, 240 m, rainforest, 26.xi.2004 (B.L.Fisher); Antsiranana, Forêt de Binara, 7.5 km 230° SW Daraina, 13.255°S, 49.6167°E, 375 m, tropical dry forest, 1.xii.2003 (B.L.Fisher); Fianarantsoa, Réserve Forestière d’Agnalazaha, Mahabo, 42.9 km 215° Farafangana, 23.1938°S, 47.723°E, 20 m, littoral rainforest, 19.iv.2006 (B.L. Fisher et al.); Toamasina, 19 km ESE Maroantsetra, 15.4833°S, 49.9°E, 350 m, rainforest, 22.iv.1989 (P. S. Ward); Toamasina, Montagne d’Akirindro 7.6 km 341° NNW Ambinanitelo, 15.2883°S, 49.5483°E, 600 m, rainforest, 17.iii.2003 (Fisher, Griswold et al.); Toamasina, Nosy Mangabe, 15.5°S, 49.7667°E, 300 m, rainforest, 18.iv.1989 (P. S. Ward); Toamasina, Parc National Mananara-Nord, 7.1 km 261° Antanambe, 16.455°S, 49.7875°E, 225 m, rainforest, 14.xi.2005 (B.L.Fisher et al.); Toamasina, Reserve Betampona, Camp Rendrirendry 34.1 km 332° Toamasina, 17.924°S, 49.1997°E, 390 m, rainforest, 28.xi.2005 (B.L.Fisher et al.); Toamasina, Reserve Betampona, Camp Vohitsivalana, 37.1 km 338° Toamasina, 17.8867°S, 49.2025°E, 520 m, rainforest, 1.xii.2005 (B.L.Fisher et al.); Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, 16.7727°S, 49.2655°E, 450 m, rainforest, 20.ii.2010 (B.L.Fisher et al.); Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, 16.8175°S, 49.295°E, 360 m, rainforest, 25.ii.2010 (B.L.Fisher et al.); Toamasina, Sahafina forest 11.4 km W Brickaville, 18.8145°S, 48.962°E, 140 m, rainforest, 13.xii.2007 (B.L.Fisher et al.); Toliara, 2.7 km WNW 302° Ste. Luce, 24.7717°S, 47.1717°E, 20 m, littoral rainforest, 9.xii.1998 (B.L.Fisher, J.-Baptiste).