Strumigenys zemi, 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 : 348-349

Strumigenys zemi sp. nov.

( Figs. 7 & 8 )

urn:lsid:zoobank.org:act:43F84A3A-F960-4716-8721-B6F3D90EF48F

Holotype worker: DOMINICAN REPUBLIC: María Trinidad Sánchez: Loma Guaconejo , 19.29529 -69.94941 60m, 150 m, 23/ 24 July 2015, Lubertazzi/Prebus, Tr4 S#9, mature secondary broadleaf forest, sifted leaf litter (MCZ-ENT00036126) [ MCZC].

Paratypes: DOMINICAN REPUBLIC: María Trinidad Sánchez: same data as holotype dealate gyne (MCZ- ENT00595663) [ MCZC] ; same data as holotype, except Tr 4 S#8, 1 worker (MCZ-ENT00681482)) [ MCZC], 1 worker (DL-Form00003) [ MNHN]; Loma Guaconejo, 19.30372 -69.95536 60m, 295m, 22/ 23 July 2015, Lubertazzi/Prebus, Tr3 S#6, mature secondary broadleaf forest, sifted leaf litter 1 worker (CASENT0758244) [ MNHN- SD], 1 worker (CASENT0875769) [ UGCA] .

Non-type material. DOMINICAN REPUBLIC: Duarte: 12.5km NE San Francisco de Macoris , 19.35682 -70.14773 5m, 965m 5m, 25 July 2015, M.M. Prebus #02096, cloud forest, under moss mat on boulder, 1 worker (MCZENT00539558) [ MCZC], 1 worker (CASENT0755485) [ UCDC] .

Diagnosis. Strumigenys zemi can be distinguished from other Strumigenys in the nitens group by the dental count of seven and enlarged occipital lobes, which gives this species a distinctive sub-cordate head shape in full face view. Both of these characters independently separate S. zemi from all other members of the nitens group. This species can also be distinguished from S. convexiceps by the basigastral costulae, which extend only to the very anteriormost part of the first gastral tergite in S. zemi , while they extend beyond the basalmost quarter of the tergite in S. convexiceps . Additional characters that can be used to separate S. zemi from S. caiman and S. nitens are the comparatively broad petiolar node in dorsal view, which is approximately 2/3 of the width of the postpetiole (roughly 1/ 2 in S. caiman and S. nitens ), the lack of spatulate setae anywhere on the body, as well as the short mandibles (MI 28–32 vs. 31–39 in S. caiman and S. nitens ), short antennal scapes (SI 46–54 vs. 56–74), and compact mesosoma (WL approximately 1.8 times PW vs. 2.0–2.3).

Holotype worker measurements. HL = 0.43; HW = 0.38; ML = 0.13; PW =0.27; SL = 0.18; TL = 1.83; WL = 0.48; CI = 89; MI = 30; SI = 48

Paratype worker measurements (n=2). HL = 0.41–42 (0.42); HW = 0.36–0.36 (0.36); ML = 0.13–0.13 (0.13); PW = 0.25–0.26 (0.26); SL = 0.19–0.20 (0.20); TL = 1.71–1.73 (1.72); WL = 0.44–0.46 (0.45); CI = 87–89 (88); MI = 30–32 (31); SI = 52–54 (53)

Non-type worker measurements (n=4). HL = 0.39–0.45 (0.42); HW = 0.33–0.4 (0.37); ML = 0.12–0.13 (0.13); PW = 0.25–0.27 (0.26); SL = 0.18–0.19 (0.18); FL = 0.23–0.23 (0.23); HT = 0.29–0.29 (0.29); EL = 0.04– 0.05 (0.05); TL = 1.73–1.83 (1.79); WL = 0.45–0.49 (0.47); CI = 84–90 (87); MI = 28–33 (30); SI = 46–53 (50)

Worker description. Mandibles in full face view and at full closure triangular and tapering apically; MI 28–33 Inner mandibular margin with a series three evenly spaced teeth, incrementally increasing in length distally, with the apices of the basal two teeth failing to meet when the mandibles are fully closed. Apices of mandibles with four teeth arranged vertically: the upper two long and spiniform, and the lower two shorter and triangular, giving a total dental count of seven. Antennal scapes short: SI 46–54. Occipital lobes enlarged, with the lateral margins of the head converging anteriorly and the posterior margin broadly concave in full-face view. Clypeus smooth and shining. Cephalic dorsum with a smooth and shining central strip that is flanked by finely punctate-striolate sculpture, which extends from the border of the clypeus and frontal carinae nearly to the apex of the occipital lobes. Dorsum of head with elongate, fine, tapering setae which curve toward the midline. Compound eye small: diameter less than the maximum width of the antennal scape. In profile view, head with dense punctate sculpture that extends from the apex of the antennal scrobe to postbuccal impression, and uniformly covers the ventral surface of the head capsule.

Mesosoma compact: WL approximately 1.8 times PW. Uniformly smooth and shining except for faint punctae around the propodeal spiracle and lamellae. Dorsal surface with sparse elongate, fine, tapering setae which curve toward the midline.

Petiolar node broad, roughly 2/3 as broad as postpetiole in dorsal view. Petiolar peduncle covered in dense reticulate sculpture, but dorsal surface of petiole and postpetiole smooth and shining. Dorsal surfaces of petiole and postpetiole with long, fine, tapering setae which curve toward the midline.

Basigastral costulae present only on the limbus and the extreme base of the first gastral tergite, the remainder of which is smooth and shining. First gastral tergite with numerous long, fine, tapering setae.

Head, mesosoma, and gaster uniformly dark brown. Appendages light brown.

Distribution and Ecology. This species is known from two localities in the Dominican Republic, both of which were mature forest located in the Cordillera Septentrional, which is found on and near the northern coast of the Dominican Republic. The type locality is lowland mature secondary broadleaf moist forest in the Toro Palomo sector of the Loma Guaconejo Scientific Reserve, near the village of La Peonía. The holotype worker, a dealate gyne, and several paratype workers were collected at Loma Guaconejo from sifted leaf litter extracted via the Winkler method. These specimens were found in two areas slightly more than a kilometer apart. Two additional workers and brood were collected by hand from mid-elevation broadleaf moist forest, under a moss mat covering a small boulder on the summit of Loma Quita Espuela in Duarte province.

Taxonomic notes. Etymology: in the theology of the Caribbean Taíno people who occupied pre-Colombian Hispaniola, zemis were ancestral spirits, typically housed in sculptural objects. By the account of Christopher Columbus’s ethnographer, Fray Ramón Pan, sculptural zemis were buried in Taíno manioc gardens to aid soil fertility. Often these were in the shape of an isosceles triangle, somewhat reminiscent of the head of S. zemi in full-face view. The name is a noun in apposition.

Figures

FIGURE 7. Holotype worker of Strumigenys zemi (MCZ-ENT00036126): a) dorsal view b) profile view c) full-face view. Scale bars 0.2 mm.

FIGURE 8. Paratype dealate queen of Strumigenys zemi (MCZ-ENT00595663): a) dorsal view b) profile view c) full-face view. Scale bars 0.2 mm.