Strumigenys economoi, Booher & Prebus & Lubertazzi, 2019

Booher, Douglas B., Prebus, Matthew & Lubertazzi, David, 2019, A taxonomic revision of the Strumigenys nitens and simulans groups (Hymenoptera: Formicidae), two Caribbean radiations of leaf litter ants, Zootaxa 4656 (2), pp. 335-358 : 353-355

Strumigenys economoi sp. nov.

( Fig. 10 )

urn:lsid:zoobank.org:act:24571A74-9B2E-47E5-B8A4-5F70C2974430

Holotype worker: DOMINICAN REPUBLIC: Distrito Nacional. Jardín Botánico Nacional , Santo Domingo. 18.49361 -69.95397 20m. 45 m elev. July 13, 2017. Navarro ant diversity study. Mature lowland forest. Winkler sample: T41 Q6 (DL-Form00001) [ IIBZ].

Diagnosis. The two simulans group species S. economoi and S. simulans are the only Antillean species sharing the combined traits of four antennal segments and triangular shaped mandibles having interlocking teeth. Strumigenys economoi can be separated from S. simulans by pilosity and anterior outline of the clypeus when the head is in full frontal view. Strumigenys simulans has short standing curved setae on the dorsum of head and mesosoma, and a pair of elongate differentiated erect setae on the mesonotum, whereas S. economoi has only extremely short adpressed pilosity on these regions. The anterior outline of S. simulans between mandible insertions is shallowly concave whereas in S. economoi the outline is sinuate with anterior and posterior borders similarly shaped.

Holotype worker measurements. HL = 0.52; HW = 0.37; ML = 0.07; PW = 0.23; SL = 0.22; FL = 0.28; HT = 0.21; EL = 0.04; TL = 2.22; WL = 0.48; CI = 71.1; MI = 12.8; SI = 60.7.

Worker description. Mandibles in full face view and at full closure triangular. Mandibles relatively short; MI 12.8. In profile, base mandibles flat and inclined above dorsal profile of clypeus then abruptly arching ventrally with the apex of mandibles directed ventrally. Basal process of mandibles divided by a deeply incised transverse carina that fits into the dorsal anterior edge of clypeus when shut; the basal half a translucent thin lamella that fits under the anterior clypeal edge and the apical half a heavily sclerotized opaque process; inner margin truncate and flattened across basal (ventral) and apical (dorsal) portions. Basal process followed by ten teeth, three to four teeth along the basal flattened portion that are slightly smaller (≤0.01) than the 6–7 following teeth along apical arched portion (0.01–0.02). Angle of mandibles opening when basal process of mandibles rests in complementary labral pocket 59.6. Labral lobes truncate with a medial concave impression separating them. Anterior border of lobes with translucent spoon-shaped setae. Head in full face with lateral margins evenly converging from posterior scrobal margin to anterolateral corners of clypeus. Head elongate CI 71.1. Anterior margin curving posteriorly from mandible insertions towards the midline with a small medial concave impression where mandibles meet; the outline of the anterior and posterior borders similarly contoured. Eye smaller than maximum width of antennal scape (EL 0.04, scape thickness 0.06), but obviously larger than greatest length across propodeal spiracle (0.03). In profile ventral margin of head with deeply and broadly incised postbuccal groove with outline of anterior and posterior ventral portions diverging. Scapes relatively short SI 60.7. Exposed disc of postpetiole 1.99 times as broad as long. Mesosoma elongate: WL 2.07 times PW. Mesosoma evenly convex in profile. Propodeal spines developed (0.07) as lamellate triangular appendages that up-curve at their apices in profile. Cuticular flange on declivitous face of propodeum narrows evenly below spine to bulla of metapleural gland. Petiolar node narrow, 0.56 times as broad as postpetiole in dorsal view. Head, mesosoma, and gaster uniformly dark reddish brown. Appendages lighter brown.

Sculpture. Medial and postero-medial portion of dorsum of head without sculpture and shining. Anterior clypeus and lateral portions of frontal lobes with fine punctate to punctate-striolate sculpture. In profile view, punctate sculpture weak to absent between the compound eye and the postbuccal impression. Dorsum and side of mesosoma mostly without sculpture, when present sculpture is faint superficial punctations and sparse striations. Petiolar peduncle covered in dense punctate sculpture. Dorsal surfaces of petiolar nodes and first gastral tergite evenly covered with extremely faint superficial punctations. Basigastral costulae limited to extremely fine striations on the lateral portions of first gastral tergite.

Pilosity. Dorsum of head with sparse minute simple to adpressed and shallowly expanded spatulate setae. No standing setae anywhere on head, mesosoma, legs, petiole, postpetiole, or gaster. Ground pilosity on these surfaces similar to those on head.

Color dark piceous-brown.

Distribution and ecology. This species is only known from the Jardín Botánico Nacional, Santo Domingo. The holotype worker, currently the only specimen of this species, was collected in a mini-Winkler sample of forest litter from the botanical garden’s mature lowland forest.

Taxonomic notes. Etymology: Named after myrmecologist and biodiversity scientist Dr. Evan Economo in recognition of his work on evolutionary patterns of biomechanically complex trap-jaws in Strumigenys .

Figures

FIGURE 10. Holotype worker of Strumigenys economoi (DL-Form00001): a) dorsal view b) profile view c) full-face view. Scale bars 0.2 mm.