Sericomyrmex saramama

The fungal cultivar associated with this species, at least where it was collected in Peru, is a member of the diverse clade of generalized higher-attine fungi grown by species of Sericomyrmex and Trachymyrmex, but it occupies a long, separate branch from all other higher-attine cultivars (Ješovnik et al. 2017b). S. saramama grows this cultivar species even when other cultivars are readily available; it was collected at the same locality in which two Sericomyrmex mayri and two S. parvulus nests were growing a different fungal species, the “amabilis-mayri” species, that is widely cultivated by Sericomyrmex species across the range of the genus.

Identification
Ješovnik & Schultz (2017) - Small species; mandibles dorsally smooth and glossy; frontal lobe triangular, weakly directed anterad, with short posterior margin; frontal carina complete; eye without white layer; mesosomal tubercles low; gaster with lateral carinae moderately developed, dorsal carinae weakly to strongly developed.

Sericomyrmex saramama can be separated from the similar Sericomyrmex parvulus and Sericomyrmex opacus by its larger size, complete frontal carinae, larger eyes that lack a white layer, and frontal lobe shape and size. The queen of S. saramama is similar in size to S. opacus and S. parvulus queens, but it can be separated from them by its striate mandibles (smooth in parvulus and opacus).

Within-species variation includes the dorsal gastral carinae, which are robust in the Peru population but hardly visible in the Ecuador population. Sericomyrmex saramama is the sister species of a clade containing Sericomyrmex maravalhas + Sericomyrmex scrobifer, Brazilian cerrado species that are also rarely collected. Together, S. saramama + (S. maravalhas + S. scrobifer) form a clade that is the sister to all remaining Sericomyrmex species. Morphologically, S. saramama resembles opacus more than its sister species.

Distribution
Ješovnik & Schultz (2017) - Colombia, Ecuador, Peru.  Sericomyrmex saramama occurs in forested habitats in Peru, Colombia, and Ecuador, but has never been collected in Amazonian Brazil. No other Sericomyrmex species has a similar distribution, although the known distribution could easily be an artifact of undersampling.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil, Ecuador, Peru.

Castes
Jesovnik and Schultz 2017. Figure 53bdf. Queen (USNMENT00924065). Figure 54. S. saramama worker (USNMENT01125262), SEM images. a Head, full-face view b mandibles c metasoma, lateral view d eye.

Jesovnik and Schultz 2017. Figure 55. S. saramama larva (USNMENT01125266), SEM images. a Lateral view b ventral view c head, frontodorsal view d head, lateral view e mouthparts f anal setae.

Nomenclature

 *  saramama. Sericomyrmex saramama Ješovnik & Schultz, 2017a: 86, figs. 53-55 (w.q.l.) PERU.

Worker
(holotype): HWe 0.9–1.13 (1) HW 0.9–1.13 (0.98) HW1 0.6–1.05 (0.93) HW2 0.9–1.16 (1.02) HW3 0.53–0.76 (0.65) IFW1 0.58–0.78 (0.65) IFW2 0.22–0.35 (0.31) HL1 0.84–1.1 (0.96) HL2 0.78–0.98 (0.87) SL 0.65–0.8 (0.72) EL 0.11–0.18 (0.16) Om 7–9 (8) WL 1.12–1.4 (1.3) PL 0.22–0.38 (0.28) PPL 0.19–0.3 (0.25) GL 0.78–0.98 (0.86) HFL 0.95–1.2 (1.13) PW 0.54–0.74 (0.65) CI 97–109 (104) FLI 61–82 (65) SI 68–78 (72) OI 12–17 (16) CEI 7–12 (9) [N=25]

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

Head. In full-face view slightly broader than long (CI=103 ± 3), posterior corner smoothly rounded to acute, lateral margin of head slightly convex, posterior cephalic emargination distinct (CEI=10 ± 2), gradually impressed. Vertexal impression usually distinct, frontal tumuli faint. Mandible with 7–8 teeth, dorsally smooth and glossy, finely transversely striate only along masticatory margin. Eye medium-sized (OI =15 ± 1), slightly convex, without white layer, 7–9 ommatidia across largest diameter. Frontal lobe moderately wide (FLI=67 ± 3), triangular, weakly directed anterad, posterior margin shorter than medial. Frontal carina not very robust, usually complete, reaching posterior cephalic corner. Antennal scape moderately long (SI=72 ± 3), sometimes almost reaching posterior cephalic corner.

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

Metasoma. Petiole with two low, reduced dorsal denticles; node of postpetiole with two faint, short dorsal carinae, both best seen in dorsolateral view. First gastral tergite with lateral carinae relatively weak, dorsal carinae from barely visible to well developed.

Queen
HWe 1.35 HW 1.4 HW1 1.4 HW2 1.5 HW3 0.95 IFW1 0.93 IFW2 0.38 HL1 1.32 HL2 1.16 SL 0.88 EL 0.22 Om 15 EW 0.11 WL 1.92 PL 0.48 PPL 0.36 GL 1.82 HFL 1.48 PW 1.08 CI 102.27 FLI 68.89 SI 64.81 OI 16 [N=1]

Head. Mandible with 8 teeth, dorsally striate, differing from worker. Preocular carina fading posterior to eye. Eye large, slightly convex, 15 ommatidia across largest diameter. Frontal lobe slightly more robust than in worker.

Mesosoma. Scutum in dorsal view with notauli very reduced, median mesoscutal line absent. Parapsidal lines thin, slightly curved. Scutellum in dorsal view narrowing posteriorly, posterior notch shallow. Propodeal denticles blunt and low, directed posterolaterad.

Metasoma. First gastral tergite with lateral carinae weakly to moderately developed, dorsal carinae absent, anteromedian dorsal groove visible.

Larva
Setae on dorsal and lateral body surfaces and supra-antennal setae absent. Four genal setae on each side. Mandibular apical tooth divided. Labial denticles absent. First thoracic segment ventrally with multiple multidentate spinules, arranged in transverse rows. Numbers of ventral setae: six on each thoracic segment, two on the abdomen (not including anal setae). Single pair of papilliform setae anterior to anal opening.

Type Material
Holotype worker: Peru: Madre de Dios, Tambopata Reserve, -12.8187, -69.3636, 224m, A. Ješovnik, AJ120729-03, primary forest, nest on forest trail. (: 1w, USNMENT00924064). Paratypes: same data as holotype (: 1q, USNMENT00924065; 1w, USNMENT00924070) (: 1w, USNMENT00924068; 1w, USNMENT00924069) (: 1w, USNMENT00924071; 1w, USNMENT00924080), (: 1w, USNMENT00924072; 1w, USNMENT00924073) (, 1w, USNMENT00924074) (: 1w, USNMENT00924077) (: 1w, USNMENT00924078; 1w, USNMENT00924079).

Etymology
This species is named after the Incan goddess of grain, Saramama, because the type locality is in the former Incan Empire (modern-day Peru) and because Sericomyrmex is an ant that practices agriculture. The species name is a noun in apposition.

References based on Global Ant Biodiversity Informatics

 * Jesovnik A., J. Chaul, and T. Schultz. 2018. Natural history and nest architecture of the fungus-farming ant genus Sericomyrmex (Hymenoptera: Formicidae). Myrmecological News 26: 65-80.