Sericomyrmex saussurei Sericomyrmex burchelli Sericomyrmex impexus S. urichi maracas Revision of the fungus-farming ant genus Sericomyrmex Mayr (Hymenoptera, Formicidae, Myrmicinae) Jesovnik, Ana Schultz, Ted R. ZooKeys 2017 670 1 109 6YJSL Emery, 1894 Emery 1894 Insecta Formicidae Sericomyrmex CoL Animalia Sericomyrmex saussurei Hymenoptera 81 82 Arthropoda species saussurei    SericomyrmexsaussureiEmery, 1894: 223. Holotype worker: BRAZIL, Mato Grosso, [-13, -56], ANTC25804, 1886, P. Germain (MSNG: 1w, USNM00445513).  Sericomyrmex burchelli= Forel, 1905: 183. syn. n. Type material examined: BRAZIL, Goias[-15.9, -50.3], W. J. Burchell (MHNG: 1q, USNM00445563; 1m, USNM00445564).  Sericomyrmex impexus= Wheeler, 1925a: 54. syn. n. Type material examined: GUYANA, Cuyuni-Mazaruni, Kartabo [6.3551, -58.6944], Jul-Aug 1920, W. M. M. Wheeler (MCZ: 2w, MCZ-ENT00021138).  S. urichi maracas= Weber, 1937: 395. syn. n. Type material examined: TRINIDAD AND TOBAGO, San Juan-Laventille, Maracas Valley [10.75, -61.43], 1 Oct 1935, N. A. Weber, NAW373-1 (MCZ: 2w, MCZ23048).   S. saussureiworker diagnosis. Medium-sized species; mandible usually dorsally striate, frontal carina complete; frontal lobe triangular; eye convex, moderately protruding from sides of head, covered with thick white layer; posterior cephalic emargination abruptly to gradually impressed, mesosomal tubercles from low and obtuse to well developed; first gastral tergite with lateral carinae well developed, dorsal carinae weak to well developed.   S. saussureiworker description. Measurements in mm, range (holotype): HWe 0.88-1.23 (0.98) HW 0.88-1.23 (NA) HW1 0.82-1.32 (1) HW2 0.92-1.56 (1.13) HW3 0.55-0.84 (0.7) IFW1 0.59-0.88 (0.67) IFW2 0.19-0.36 (0.24) HL1 0.84- 1.15(0.96) HL2 0.76-1.08 (0.87) SL 0.62-0.86 (0.73) EL 0.12-0.24 (0.14) Om 7-11 (NA) WL 1.1-1.64 (1.35) PL 0.21-0.38 (0.25) PPL 0.15-0.3 (0.2) GL 0.70-1.13 (1.13) HFL 0.75-1.38 (1.13) PW 0.61-0.85 (0.76) CI 94-112 (102) FLI 63-74 (69) SI 65-81 (74) OI 12-23 (15) CEI 4-14 (9) [N=68] Pilosity. Pubescence dense, often lighter than integument, appressed to decumbent. Hairs often curved, darker in color at base, yellow to gray, appressed to suberect, mostly decumbent.  Head. In full-face view slightly broader than long (CI=104 +/-3), posterior corner rounded to angular, posterior cephalic emargination distinct (CEI=9 +/-2), gradually (Figure 7j) to abruptly (Figure 7k) impressed. Vertexal impression and frontal tumuli distinct. Mandible with 7-8 teeth, dorsally glossy and striate, sometimes striation reduced or absent (Figure 56b). Eye medium-sized (OI =15 +/-1), conspicuously convex, protruding slightly from side of head in full-face view, 7-9 ommatidia across largest diameter, always covered with thick, white layer (Figure 6 n-o), which makes discerning individualommatidia difficult. Frontal lobe relatively wide (FLI=69 +/-2), triangular, slightly laterally expanded, with posterior margin shorter than medial. Frontal carina complete, reaching posterior cephalic corner. Antennal scape relatively short (SI=71 +/-2), not reaching posterior cephalic corner. Mesosoma. Mesosomal tubercles from low and obtuse to moderately pronounced. Propodeal carinae low, reduced, sometimes with posterodorsal denticle. Metasoma. Petiole and postpetiole with two low, short, serrate, longitudinal carinae dorsally, in petiole sometimes reduced to low denticles, best seen in dorsolateral view. Postpetiole usually with another pair of low carinae laterally. First gastral tergite with lateral carinae well developed, dorsal carinae weak to well developed.   S. saussureiqueen description. Measurements in mm, range: HWe 1.3-1.38 HW 1.27-1.4 HW1 1.4-1.46 HW2 1.49-1.56 HW3 0.9-0.93 IFW1 0.95-1 IFW2 0.35-0.4 HL1 1.27-1.33 HL2 1.18-1.25 SL 0.9-0.96 EL 0.23-0.29 Om 20-24 EW 0.08-0.1 WL 2-2.16 PL 0.43-0.56 PPL 0.25-0.3 GL 1.83-1.95 HFL 1.22-1.6 PW 1.15-1.2 FWg 7.04-7.37 HWg 4.73-4.73 CI 98-106 FLI 70-75 SI 65-72 OI 17-21 [N=6]. Head. Mandible with 8-9 teeth, dorsally glossy and smooth, finely transversely striate only along masticatory margin. Preocular carina fading posterior to eyes. Eye large (OI=19 +/-2), convex, partially covered with white layer, layer thinner than in workers, 20-24 ommatidia across largest diameter. Frontal lobe as in worker, antennal scape not reaching posterior cephalic corner. Mesosoma. Scutum in dorsal view notauli faint, median mesoscutal line visible only anteriorly. Parapsidal lines thin, slightly curved. Groove separating axillae in dorsal view weakly transversely costate. Scutellum in dorsal view narrowing posteriorly, posterior margin medially with wide, shallow V-shaped notch. Propodeal carinae low, posteriorly diverging, with posterodorsal denticles. Metasoma. First gastral tergite with lateral carinae strongly developed, dorsal carinae weak, anteromedian groove visible.   S. saussureimale description. Measurements in mm, range: HWe 0.74-0.9 HW 0.62-0.7 IFW1 0.3-0.32 IFW2 0.16-0.19 HL1 0.66-0.68 SL 0.65-0.74 EL 0.25-0.3 Om 23-26 EW 0.13-0.14 WL 1.6-1.72 PL 0.28-0.38 PPL 0.18-0.22 GL 1.18-1.4 HFL 1.52-1.78 PW 0.74-0.88 IOD 0.56-0.61 FWg 4.73-5.23 HWg 3.15-3.4 CI 112-133 FLI 34-41 SI 79-91 OI 32-36 [N=6] Head longer than broad (CI=125 +/-7), eye large (OI=34 +/-1) and convex, 23-26 ommatidia across the largest diameter. Preocular carina long, extending posteriorly almost to lateral ocellus, slightly curved medially before fading. Notauli and mesoscutal line well developed, integument surrounding parapsidal lines sometimes darker colored, groove between axillae sometimes with one short costa. Propodeum smooth, without protuberances except small spiracular tubercle. Petiole with lateral and dorsal serrate carinae, postpetiole with reduced lateral denticles.   S. saussureilarva. Around eight setae on each side of lateral and dorsal body surfaces (i.e., ~16 total). Supra-antennal setae absent. Four genal setae on each side. Mandibular apical tooth divided. Labial denticles present anterior to sericteries. First thoracic segment without multidentate spinules. Numbers of ventral setae: two on T1, twoon T2, three on T3, and around 10 on abdomen (not including anal setae). Single pair of setae anterior to anal opening.   S. saussureigeographic range. Bolivia, Brazil, Ecuador, French Guiana, Guyana, Peru, Suriname, Trinidad and Tobago, Venezuela. Map: Figure 21, Figure 60.   S. saussureinotes. The species most similar to S. saussureiis its sister species S. amabilis, but amabiliscan easily be distinguished by its more or less flat eyes lacking the white layer, and usually by geography (Figure 21). S. mayri, which, like S. saussureihas striate mandibles, is larger, has a wider head, and flat eyes without a white layer. The smaller species S. parvulusand S. opacusmay have a similar white layer over the eyes, but their eyes are small and flat, and the white layer is thinner than in saussurei, sometimes incomplete and with individual ommatidia still distinguishable (Figure 6 l-m). Also, both parvulusand opacushave smooth mandibles. The white layer is not as distinct in the queen of S. saussurei, but the combination of body size, pilosity, and frontal lobe shape are enough to separate the S. saussureiqueen from those of the sympatric mayri, bondari, and parvulus. Several populations of S. saussureihave faintly striate or completely smooth mandibles. The atypical smooth-mandibled state was in at least one case consistent within an entire nest; all individuals in a colony collected in Vicosa(Brazil) have smooth mandibles. Individuals with intermediate states are sometimes encountered, with mandibles faintly or partly striate. Smooth-mandibled saussureiare distributed more or less across the entire range of the species, but are more concentrated in eastern Brazil (Figure 60). However, in the molecular phylogeny the two forms cluster into two imperfect subclades in which some striate-mandibled forms mix with predominantly smooth-mandibled forms and vice versa, and a similar pattern is observed in principal component analyses of the morphological measurement data (Figure 5h). More data are clearly needed to determine if the smooth-mandibled variant represents a separate species. Here we choose to include both forms in a single species because they are morphologically very similar, the molecular evidence is indecisive, and this character is generally plastic (e.g., both amabilisand mayri, which typically have striate mandibles, likewise have a few populations with smooth or smoother mandibles).  Interestingly, the white layer on the eyes of saussureiis exceptionally consistent compared to character-state distributions in other Sericomyrmexspecies. In fact, it is among the most consistent of all morphological characters across all Sericomyrmexspecies. In all specimens of S. saussureiexamined, from across a large geographic range (Figure 21), the eyes are convex and covered with a thick white layer. Similar white layers are also seen in parvulusand opacus. In those species, however, the layer itself is thinner and often incomplete, and the eyes are generally smaller and flat, creating a distinctly different appearance (Figure 6 l-m). Also, in both parvulusand opacusthe layer is completely absent in some individuals or populations. In the remaining species of Sericomyrmexthe eyes are uncoated, without a white layer. It would be interesting to determine the biological significance of this layer and to analyze its chemical properties. Based on our SEM images it seems to be an extension of the waxy, crystal-like cuticular layer found on the integuments of workers and queens in all Sericomyrmexspecies (Figure 6 b-c), but which is absent in males and in callow workers (Figure 6 d-f), as well as in some individuals of S. maravalhas. Why this layer extends to and completely covers the eyes in some species but not others remains unknown. Synonymies. No character states in S. impexusand S. urichi maracasdistinguish them from S. saussurei. The two examined syntypes of impexusare only slightly larger in size than the single saussureitype specimen, but well within the size range for the species. When describing impexus Wheeler (1925a)only distinguishes it from urichiand lutzi. Likewise, in his description of urichi maracas Weber (1937)simply lists differences from urichi, to which this species is not very closely related ( S. urichiis a junior synonym of S. mayri). S. burchelli, described only from a queen and a male, can be recognized as belonging to saussureibased on morphological measurements, and in the queen also by a thin white layer partially covering the eye. Forel (1905)separates the queen of burchellifrom saussureiby its sparser hair, more developed petiole and postpetiole, and less developed metanotal tubercles. However, this comparison must have been made to a saussureiworker, because the queen of S. saussureiwas unknown prior to the present study. Consequently,  Forel's(1905)differences are due both to differences between the worker and queen castes as well as to observed within-species variation.  Material examined. BOLIVIA: Santa Cruz: 10 km NW Terevinto, -17.6667, -63.45, 380m, 9 Dec 1993, P. S. Ward; Aserradero Moira, -14.5667, -61.2, 180m, 27 Nov 1993, P. S. Ward; BRAZIL: Amazonas: Floresta de Tapaua, km 4, -6.01, -63.1, 69m, 13 Oct 2013, I. O. Fernandes; Manaus, Br 174, Km.70, [-2.26, -60.04], 95m, 30 Aug 1995, H. Vasconcelos; Pres. Figueredo, I. Pe Inchado, [-2.02, -60.02], 26 Aug 1994, Queiroz; Bahia: CEPLAC, arboreto, -14.7535, -39.2313, 11 Oct 2013, J. H. C. Delabie; Ilheus, Ponta do Ramo, Cacau 02, -14.5294, -39.0619, 28 Aug 1998, J. R. Maia; Itabuna, Ferradas A27, -14.8258, -39.4044, 21 Sep 2000, J. R. M. Santos; Itororo, -14.9744, -40.0502, 11 Aug 2000, J. R. M. Santos; Marau, Fazenda AguaBoa, -14.5847, -39.2672, 1 Jul 1997, J. R. M. Santos; Salvador, [-12.9833, -38.5167], 1 Oct 2012, T. S. Melo; Urucuca, -14.5847, -39.2672, 16 Dec 1997, J. R. M. Santos; Goias: Cavalcante, Serra da Contenda, -13.4951, -47.5504, 15 Oct 2004, R. R. Silva, B. H. Dietz; Niquelandia, -14.0166, -48.3, 24 Sep 1995, R. Silvestre, B. H. Dietz, C. R. F. Brandao; Maranhao: Bom Jardim, REBIO Gurupi Parcela 01 A2, -3.9258, -46.7712, 19 Sep 2014, A. Y. Harada; Estreito, Fazenda Itaueiras, -6.5317, -47.3711, 1 Jun 2005, R. R. Silva, R. M. Feitosa; Estreito, JoaoLisboa, -6.5317, -47.3711, 1 Jun 2005, R. R. Silva, R. M. Feitosa; Minas Gerais: Camacan, Serra Bonita, -15.3907, -39.5634 +/-6m, 789m, 20 Mar 2009, J. Sosa-Calvo; Serra de Ricardo Franco State Park, -14.9076, -60.0646, 200m, 7 Feb 2014, J. Maravalhas; Vicosa, Mata do Seu Nico, -20.7833, -42.8333, 8 May 2013, R. Jesus, J. Chaul; Vicosa, UFV Mata da Biologia, -20.7578, -42.8636, 10 Oct 2015, J. Chaul, S. Epifanio; Para: Alter do Chao, -2.4607, -54.926 +/-6m, 39m, 27 Jan 2009, J. Sosa-Calvo; Goianesia, Faz. Rio Capim, [-3.8384, -49.0986], 16 Jun 2003, A. M. Elizabeth; Gurupa, [-1.197, -51.7], 18 Oct 2003, J. M. S. Vilhena; Marituba, Cacau, [-1.3666, -48.3333], 16 Oct 2004, J. R. M. Santos; Melgaco, Caxiuana, ECFPn IV Transecto 9-100) Winkler #5, -1.7248, -51.4230, 27 Jun 2003, A. Y. Harada; Paranapuebas Palmares, Lote BPR Mensa Ponto: 35583, -5.8072, -49.8325, 9 Apr 2008, M. Martins; Tailandia, Faz. Marupiara, Parcela 05, -2.8121, -48.5122, 25 Apr 2013, M. Tavares, A. Palmeira; Rio de Janeiro: Nova Iguacu, ReBio Tingua, -22.5705, -43.4141, 2 Feb 2002, A. Mayhe, S. Veiga-Ferreira; Restinga da Marambaia, [-23.0685, -43.9531], P. S. Meneguete; Teresopolis, PN Serra dos Orgaos, -6.5317, -47.3711, 23 Nov 1999, Racha, B. H. Dietz, Rosa; Rondonia: Jaci-Parana, km 0, subparcela 100, -9.2656, -64.2125, 94m, 27 Jan 2013, I. O. Fernandes; Ji- Parana, -10.7997, -61.5947, 273m, 7 Oct 2008, T. R. Schultz; SaoPaulo: Cananeia, Ilha do Cardoso, -28.0968, -47.9298, 24 Dec 2002, R. R. Silva, C. R. F. Brandao, C. Scott; Jacupiranga, [-24.7055, -48.0167], 1 Nov 1963, F. Plaumann, C. Kempf; Jureia-Itantins, -24.54416, -47.235; Picinguaba, P.E. Serra do Mar, -23.3361, -44.8375, 1 Apr 2001, C. R. F. Brandao; Tocantins: Aguiarnopolis, -6.6137, -47.4814, 14 Jan 2005, R. R. Silva, R. Silvestre; Araguacema, Rio Tiririca, -8.9886, -49.6675, 16 Nov 2005, R. R. Silva, R. M. Feitosa; Babaculandia, -7.0878, -47.8286, 10 Dec 2001, R. R. Silva, N. L. Albuquerque; Goiatins, -7.9413, -47.1586, 3 May 2005, R. R. Silva, B. H. Dietz; Parana, -12.9343, -47.9618, 13 Oct 2004, R. R. Silva, B. H. Dietz; Recursolandia, -8.7579, -47.0388, 9 May 2005, R. R. Silva, B. H. Dietz; COLOMBIA: Amazonas: Leticia, Reserva Forestal Del Rio Calderon, Estac. Biol. El Zafire, -4.0058, -69.9125, 146m, 1 Dec 2007, L.E. Franco, S. Florez; PNN Amacayacu Matamata, -3.6833, -70.25, 150m, 15 Oct 2000, A. Parente; Putumayo: PNN La Paya CabanaViviano Cocha, -0.1166, -74.9666, 350m, 1 Jun 2003, R. Cobete; ECUADOR: Orellana: Tiputini Biodiversity Station, -0.6333, -76.1333, 220m, 14 Feb 2002, K. T. Ryder Wilkie; FRENCH GUIANA: Cayenne: Kourou, 5.096, -52.404, 18 Dec 2014, M. Fichaux, Orivel; GUYANA: Potaro-Siparuni: Iwokrama, Kurapakari base camp, [4.6698, -58.6854], 60m, 9 Apr 1996, T. R. Schultz, U. G. Mueller; Upper Takutu-Upper Essequibo: AcariMountains, nr. Romeo'scamp, 1.3833, -58.9333, 282m, 10 Oct 2006, J. Sosa-Calvo; PERU: Cajamarca: Cajamarca, 32 km W Jaen, -7.1667, -78.5167, 600m, 19 Jan 1955, E. I. Schlinger, E. S. Ross; Madre de Dios: PN Pampas de Heath, RioHeath, -12.8333, -68.8333, 26 Jul 1991, B. L. Fisher; Puerto Maldonado, Los Amigos Biol. Station, trail 3, Huangana, -12.569, -70.1008, 277m, 9 Oct 2004, T. R. Schultz, J. Sosa-Calvo; Tambopata Reserve, -12.8187, -69.3636, 224m, 1 Aug 2012, A. Jesovnik; SURINAME: Sipaliwini: Lely Mountains, 4.4507, -55.2302, 550m, 29 Oct 2005, J. Sosa-Calvo, R. Badal; Nassau Mountains, 4.8172, -54.6067, 514m, 3 Nov 2005, J. Sosa-Calvo; VENEZUELA: Bolivar: RioTawadu, Nichare Field St., 6.4333, -64.8833, 200m, 9 Feb 1966, D. M. Olson.  Figure 56. S. saussureiworker; head, profile, and dorsal view. Striate-mandibled form (USNMENT01125217) (a, c, e). Smooth-mandibled form (USNMENT01125221) (b, d, f).  Figure 57. S. saussureiworker (USNMENT01126237), SEM images. a Head, full-face view b mandibles c mesosoma, lateral view d metasoma, lateral view e eyes completely covered with white layer, individual ommatidia not visible f eyes with thick white layer, ommatidia visible through small holes in the layer.  Figure 58. S. saussureiqueen and male; head, lateral profile, and dorsal view. Queen (USNMENT01125514) (a, c, e) Male (USNMENT01125515) (b, d, f).  Figure 59. S. saussureilarva (USNMENT01126236), SEM images. a Lateral view b ventral view c head, frontolateral view d head, dorsal view e mouthparts f anal setae.  Figure 60. Distribution map of S. saussureiindicating smooth-mandibled (black triangles) and striate-mandibled (red circles) forms.