Sericomyrmex lutzi Wheeler, 1916

Jesovnik, Ana & Schultz, Ted R., 2017, Revision of the fungus-farming ant genus Sericomyrmex Mayr (Hymenoptera, Formicidae, Myrmicinae), ZooKeys 670, pp. 1-109 : 45-48

Sericomyrmex lutzi Wheeler, 1916 Figures 28, 29(Worker); Figure 30(Queen and male); Figure 31 (Map)

Sericomyrmex lutzi Wheeler, 1916: 9. Lectotype worker (here designated): GUYANA, Roraima, Kauwa creek [5.223, -60.73], 13 Aug 1911, A. Crampton, AC3097 (MCZ: 1w, MCZ 12-14 21139, topmost worker on the pin). Paralectotypes: same data as lectotype (MCZ: 2w, MCZ 12-14 21139, lower two specimens on the pin) (MCZ: 2w, 1q, MCZ 9-11 21139) (AMNH: 1w, 1q, 1m, USNMENT01126226).

S. lutzi worker diagnosis.

Large species; posterior cephalic emargination deep, gradually impressed; mandible dorsally smooth and glossy; frontal lobe triangular, relatively narrow; mesosomal tubercles low; first gastral tergite with lateral carinae weak, dorsal carinae absent.

S. lutzi worker description.

Measurements in mm, range (lectotype): HWe 1.12-1.35 (1.21) HW 1.12-1.35 (1.21) HW1 1.08-1.27 (1.2) HW2 1.21-1.46 (1.32) HW3 0.86-0.90 (0.86) IFW1 0.70-0.88 (0.78) IFW2 0.27-0.33 (0.32) HL1 1.16-1.30 (1.16) HL2 0.96-1.12 (0.96) SL 0.80-0.93 (0.86) EL 0.14-0.19 (0.16) Om 9-11 (11) WL 1.38-1.68 (1.55) PL 0.3-0.44 (0.3) PPL 0.22-0.26 (0.26) GL 0.9-1.18 (0.99) HFL 1.20-1.40 (1.33) PW 0.73-0.94 (0.83) CI 100-104 (104) FLI 63-68 (65) SI 67-73 (71) OI 12-15 (13) CEI 14-17 (17) [N=7]

Pilosity. Pubescence dense, lighter than integument, appressed to decumbent. Hairs curved, darker in color at base, yellow to gray, appressed to suberect, mostly decumbent.

Head. Head in full-face view slightly broader than long (CI=103 ± 2), posterior corner acute, lateral margin of head convex, posterior cephalic emargination distinct, very deep (CEI=15 ± 1), gradually impressed. Vertexal impression relatively deep, frontal tumuli distinct. Mandibles with 7-9 teeth, dorsally smooth, glossy, finely transversely striate along masticatory margin. Frontal carina straight to slightly curved laterally, complete. Eyes medium-sized (OI =14 ± 1), weakly convex, 9-11 ommatidia across largest diameter. Frontal lobe triangular, relatively narrow (FLI=64 ± 2), posterior margin shorter than medial. Antennal relatively short, scape not reaching posterior cephalic corner (SI=71 ± 2).

Mesosoma. Mesosomal tubercles low and obtuse. Propodeal carinae low, reduced, sometimes with posterodorsal denticles.

Metasoma. Petiole and postpetiole each with two low, short, serrate carina dorsally, on petiole sometimes reduced to low denticles, best seen in dorsolateral view. First gastral tergite with lateral carinae weakly developed, dorsal carinae absent.

S. lutzi queen description.

Measurements in mm: HWe 1.4 HW 1.4 HW1 1.32 HW2 1.52 HW3IFW1 0.9 IFW2 0.34 HL1 1.36 HL2 1.16 SL 0.92 EL 0.25 Om 18 EW 0.1 WL 2.08 PL 0.44 PPL 0.28 GL 1.72 HFL 1.56 PW 1.18 1 FWg 6.82 HWg 4.6 CI 103 FLI 64 SI 66 OI 18 [N=1]

Head. Mandibles with nine teeth, dorsally glossy and smooth, finely transversely striate only along masticatory margin. Preocular carina fading posterior to eye. Eye large, convex, 18 ommatidia across largest diameter. Frontal lobe as in worker, antennal scape not reaching posterior cephalic corner.

Mesosoma. Scutum in dorsal view with notauli and median mesoscutal line reduced. Parapsidal lines faint, slightly curved. Scutellum in dorsal view narrowing posteriorly, posterior notch shallow. Propodeum with two low, reduced denticles.

Metasoma. First tergite of gaster with lateral carinae strongly developed, dorsal carinae absent, anteromedian groove distinct in dorsal view.

S. lutzi male.

Measurements in mm: HWe 0.9 HW 0.74 IFW1 0.27 IFW2 017 HL1 0.7 SL 0.74 EL 0.29 Om 30 EW 0.13 WL 1.74 PL 0.4 PPL 0.22 GL 1.4 HFL 1.67 PW 0.80 IOD 0.58 FWg 5.21 HWg 3.55 CI 128 FLI 30 SI 83 OI 32 [N=1]

Head in full-face view longer than broad (CI=128). Eyes large (OI=32), 30 ommatidia across largest diameter. Preocular carina extending posterior to median ocellus, medially curved before fading. In dorsal view scutum with notauli well developed, mesoscutal line distinct, with dark-brown reticulation, best seen in frontodorsal view. Groove between axillae with one transverse, short costa medially. Propodeum devoid of protuberances or carinae except for spiracular tubercles. Petiole with weak lateral carinae; postpetiole simple, smooth, without denticles or carinae.

S. lutzi geographic range.

Guyana. Map: Figure 31.

S. lutzi notes.

Based on morphology, S. lutzi seems to be most closely related to S. mayri , but mayri has a much shallower posterior cephalic emargination; striate mandibles; narrower, anterad-directed frontal lobes; and often at least faint anteromedian dorsal gastral carinae.

S. lutzi was originally described from a handful of specimens collected on Mt. Roraima, a mountain plateau (tepui) on the border of Guyana, Venezuela, and Brazil. The only other specimens of this species were collected on the slopes of the eastern-most tepui in Guyana, Mt. Ayanganna. It is very likely that this species has a restricted distribution and is endemic to the tepuis of the Guiana Highlands, an area known for its endemic flora and fauna ( Brown 1975, Steyermark 1987, Berry et al. 1995, LaPolla et al. 2007).

S. lutzi material examined.

GUYANA: Cuyuni-Mazaruni: Mt. Ayanganna base camp, 5.3344, -59.9248, 732 m, 8 Oct 2002, T. R. Schultz.