Sericomyrmex mayri Forel, 1912

Jesovnik, Ana & Schultz, Ted R., 2017, Revision of the fungus-farming ant genus Sericomyrmex Mayr (Hymenoptera, Formicidae, Myrmicinae), ZooKeys 670, pp. 1-109 : 54-63

Sericomyrmex mayri Forel, 1912 Figures 36, 37, 38(Worker); Figure 39(Queen and male); Figure 40(Larva); Figure 41 (Map)

Sericomyrmex mayri Forel, 1912: 194. Lectotype worker (here designated): BRAZIL, Rio de Janeiro, Niterói, [-22.8751, -43.2775], ANTC31816, A. Forel, (MHNG: 1w, CASENT0909370). Paralectotypes: same data as lectotype (MHNG: 1w, USNMENT00445567; 3m, USNMENT00445580).

Sericomyrmex urichi = Forel, 1912: 193. syn. n. Type material examined: TRINIDAD AND TOBAGO, ANTC31818, F. W. Urich (MHNG: 3w, CASENT0909372).

Sericomyrmex luederwaldti = Santschi, 1925: 15. syn. n. Type material examined: BRAZIL, Minas Gerais, Pirapora, [-17.355, -44.9447], ANTC35978, ANTC25817, E. Garbe (NHMB: 5w, CASENT0912516) (MSNG: 1w, CASENT0904989).

Sericomyrmex moreirai = Santschi, 1925: 16. syn. n. Type material examined: BRAZIL, Rio de Janeiro, [-22.8751, -43.2775], ANTC35979, Moreira (MCZ: 2w, MCZ 1-2 21140) (NHMB: 3w, CASENT0912517; 2w, USNMENT01126231; 2q, USNMENT01126232).

Sericomyrmex harekulli = Weber, 1937: 398. syn. n. Type material examined: GUYANA, East Berbice-Corentyne, Oronoque River, [2.75, -57.4167], NAW598, 27 Jul 1936, N. A. Weber (USNM: 1w, USNMENT00529483) (MCZ: 2w, USNMENT00924104; 2w, USNMENT00924105)

Sericomyrmex harekulli arawakensis = Weber, 1937: 399. syn. n. Type material examined: GUYANA, Cuyuni-Mazaruni, Mazaruni River, Forest Settlement, [6.39733, -58.6781], 10 m, NAW 277, 15 Aug 1935, N. A. Weber (MCZ: 2w, MCZ 23051; 2w, 1q, USNMENT00924106)

S. mayri worker diagnosis.

Large species; head broad; frontal lobe narrow, directed anterad; mandible usually striate; frontal carina often reduced, incomplete; eye flat to mildly convex; posterior cephalic margin shallow, abruptly to gradually impressed; posterior cephalic corner usually angled; mesosomal tubercles low and obtuse, first gastral tergite with lateral carina well developed, dorsal carinae absent or faint.

S. mayri worker description.

Measurements in mm, range (lectotype): HWe 1.05-1.60 (1.4) HW 1.05-1.64 (1.43) HW1 1.02-1.68 (1.44) HW2 1.12-1.8 (1.6) HW3 0.74-1.12 (1.05) IFW1 0.66-1.00 (0.93) IFW2 0.24-0.40 (0.35) HL1 1.02-1.52 (1.33) HL2 0.93-1.36 (1.21) SL 0.74-1.08 (0.99) EL 0.15-0.35 Om 10-13 WL 1.27-2.2 (1.84) PL 0.24-0.47 (0.4) PPL 0.18-0.35 (0.32) GL 0.92-1.42 (1.24) HFL 1.15-1.7 (1.58) PW 0.68-1.2 (1.05) CI 101-115 (105) FLI 59-68 (66) SI 61-76 (71) OI 11-26 CEI 5-19 (9) [N=103]

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

Head. In full-face view broader than long (CI=108 ± 3), posterior corner angular to acute, lateral margin of head straight, sometimes slightly convex. Posterior cephalic emargination distinct, shallow, usually abruptly, sometimes gradually impressed, variable within species and within colonies. Vertexal impression relatively deep, pronounced, sometimes extending anterad to include frons (Figure 36a), frontal tumuli often distinct. Mandibles with 7-8 teeth, dorsally glossy, usually striate. Frontal carina straight to slightly curved laterally, usually fading before reaching posterior cephalic corner, sometimes complete. Eye small to medium-sized (OI=14 ± 1), flat to slightly convex, lacking white layer, 10-13 ommatidia across largest diameter. Frontal lobe triangular, narrow (FLI=63 ± 2), posterior margin much shorter than medial, lateral margin long, directed anterad. Antennal scape short (SI=68 ± 3), never reaching posterior cephalic corner.

Mesosoma. Mesosomal tubercles low and obtuse. Propodeal carinae low, without posterodorsal denticles, or denticles low and weak.

Metasoma. Petiole and postpetiole each with two low, short, serrate, longitudinal carinae dorsally, on 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 absent or faint.

S. mayri queen description.

Measurements in mm, range: HWe 1.44-1.64 HW 1.48-1.68 HW1 0.52-1.76 HW2 1.64-1.84 HW3 1.03-1.2 IFW1 0.98-1.13 IFW2 0.36-0.45 HL1 1.4-1.56 HL2 1.24-1.4 SL 0.96-1.09 EL 0.24-0.3 Om 16-21 EW 0.08-0.13 WL 2.12-2.5 PL 0.45-0.65 PPL 0.25-0.4 GL 1.76-2.21 HFL 1.5-1.85 PW 1.24-1.46 FWg 6.56-8.03 HWg 4.29-5.28 CI 100-109 FLI 64-72 SI 62-70 OI 16-19 [N=15]

Head. Mandible with 8-9 teeth, dorsally striate. Preocular carina fading posterior to eye, rarely (in one queen from Ecuador) 1-3 supraocular carinae also present, not reaching posterior cephalic corner. Eye large (OI=18 ± 1), convex, sometimes mildly notched posteriorly, 16-21 ommatidia across largest diameter. Frontal lobe as in worker, antennal scape not reaching posterior cephalic corner.

Mesosoma. Lateral pronotal tubercles low and obtuse. Scutum in dorsal view with notauli faint, median mesoscutal line sometimes anteriorly developed into weak costa, posteriorly with shallow longitudinal impressions on each side. Parapsidal lines thin, slightly curved. In dorsal view scutellum short, narrowing posteriorly, posterior notch shallow, sometimes continuing into median impression that divides scutellum in two lateral parts. Propodeal denticles reduced, low.

Metasoma. Petiole in frontodorsal view with two pointed, distinct dorsal denticles, and two smaller, lateral denticles. Postpetiole with two dorsal and two lateral short, low carinae, sometimes reduced to small denticles. First gastral tergite with lateral carinae strongly developed, dorsal carinae weak, anteromedian groove distinct.

S. mayri male description.

Measurements in mm, range: HWe 0.84-1.02 HW 0.71-0.84 IFW1 0.32-0.38 IFW2 0.15-0.27 HL1 0.72-0.8 SL 0.77-0.85 EL 0.31-0.36 Om 24-32 EW 0.13-0.16 WL 1.88-2.05 PL 0.35-0.56 PPL 0.24-0.33 GL 1.32-1.8 HFL 1.9-2.2 PW 0.87-1.12 IOD 0.65-0.74 FWg 5.4-6.25 HWg 3.79-4.29 CI 105-131 FLI 34-42 SI 78-96 OI 31-42 (N=8)

Head in full-face view longer than broad (CI=124 ± 8). Eye large (OI=36 ± 3), convex, 24-32 ommatidia across largest diameter. Preocular carina long, extended posteriorly beyond lateral ocellus, slightly curved medially before fading. Notauli and mesoscutal line well developed, surrounding integument usually lighter colored, often reticulate, groove between axillae with 1-4 transverse keels. Propodeum smooth, without any protuberances except spiracular tubercles. Petiole with two lateral and two dorsal low, serrate carinae, postpetiole with reduced lateral denticles.

S. mayri larva description.

Two to four setae on each side of lateral body surfaces, none dorsally. Supra-antennal setae present. Six 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 hairs: ten to fourteen on T1, six on T2, four to six on T3, two to eight on abdomen (not including anal setae). Single pair of setae anterior to anal opening, no additional setae laterally.

S. mayri geographic range.

Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, Trinidad and Tobago, Venezuela. Map: Figure 41.

S. mayri notes.

S. mayri can be separated from both S. amabilis and S. saussurei by its large size, broad head, narrow frontal lobes, and gaster lacking anteromedian dorsal carinae. In addition, saussurei has eyes covered with a thick white layer, which is never the case in mayri . Sericomyrmex lutzi is similar in size, but lutzi has a characteristic, much deeper cephalic emargination and smooth mandibles. In addition to worker characters, the S. mayri queen can be separated from the sympatric S. saussurei queen by its more pronounced petiolar denticles.

Variation within S. mayri includes the scape length, the head shape, and mandibular striation (Figure 37). As with S. amabilis and saussurei , two other species with striate mandibles, some individuals or populations of S. mayri have smooth or faintly striate mandibles. These alternative states are encountered less commonly in mayri than in the other two species, mostly in populations from Trinidad and Tobago (Figure 37a). Intermediate-state workers (i.e., those with faint mandibular striation) were collected at the same locality and, indeed, were found within the same nest as workers with typically striate mandibles. A callow worker of mayri studied with SEM had smoother, faintly striate mandibles (Figure 6i), so some observations of smooth mandibles may be due to sampling of recently eclosed workers, but this is unlikely to explain smooth-mandibled foragers.

The presence/absence of the anteromedian dorsal gastral carinae and robustness of the lateral gastral carinae are also variable in mayri . Typically, both carinae are present, but in some specimens the anteromedian carinae are very faint or absent, while lateral carinae can be weak to robust. The posterior cephalic emargination can be very shallow, so that the posterior margin of the head appears almost straight (e.g., specimens from Minas Gerais, Uberlandia, Brazil, and the type series of S. moreirai ). The shape of the head varies to some extent, from distinctly broad in some specimens to more narrow in others (the CI range is wide: 101-115).

We studied variation in the morphology of S. mayri with reference to the molecular phylogeny (Suppl. material 1), in which there is high statistical support for four subspecific clades within S. mayri , in order to investigate whether any of these separate, well-supported subclades could represent separate species. We found no consistent morphological differences between those four molecular clades (Figure 5c). Geographical separa tion can explain those clades to some extent (Figure 42), although the distribution ranges of two of the populations overlap in Brazil. Further, one specimen collected in Lençios, Brazil, has a COI sequence that differs from those of the other samples collected in that same locality, instead grouping with the other Brazilian S. mayri population. This could indicate the presence of two genetically distinct, sympatric populations, which would be consistent with a hypothesis of two separate Brazilian species or of introgression between two incipient species. However, we do not have UCE data for this sample and a previous comparative study of UCE and COI data for Sericomyrmex ( Ješovnik et al., 2017) indicates that COI is inadequate for delimiting species, especially in the mayri and bondari clades. Further, these two populations are morphologically indistinguishable (Figure 5c). Therefore, based on our morphological studies and inconclusive molecular evidence, we currently regard S. mayri as a single, widespread species with molecularly and geographically distinct populations. We find S. mayri interesting in terms of population structure, and we report these inconclusive data to encourage further research. Population study of S. mayri with finer geographic sampling could be important for understanding speciation and population genetics in attine ants.

Synonymy. The examined syntypes of S. luederwaldti , S. harekulli , and S. harekulli arawakensis conform to typical S. mayri morphology. Their original authors ( Santschi 1925, Weber 1937) focus on slight differences in mesosomal tubercles, head shape, and scape length, all of which are variable within mayri . The moreirai syntypes have the cephalic emargination less pronounced than in the mayri lectotype, but this difference is encompassed by the range of variation in mayri as here defined. In his description of S. moreirai , Santschi (1925) calls it the “neighbor” of mayri , but says it is "much more stocky." He also compares moreirai with urichi and reports small differences in pilosity and mesosomal tubercles, both of which fall within the variation observed in S. mayri . The syntypes of urichi we examined, unlike the mayri lectotype, have almost completely smooth mandibles, but, as discussed above, smooth mandibles are encountered in some mayri populations, especially those from Trinidad and Tobago, the type locality of urichi . In all other characters and measurements, urichi clearly agrees with S. mayri . In his description Forel (1912) distinguished mayri and urichi by complete versus incomplete frontal carinae and by the depth of the cephalic emargination, but he does not mention striate vs. smooth mandibles. Again, the cited differences (depth of the emargination, length of the frontal carinae, and degree of mandibular sculpture) fall within the range of observed intraspecific variation in S. mayri as here defined.

Material examined.

BOLIVIA: Beni: Vaca Diez, nr. Reserva Ecológica El Tigre, [-10.8667, -65.75], 172m, 1 Jul 1999, R. Dunn; BRAZIL: Amapá: Oiapoque, [3.8333, -51.8333], 1 May 1979, W. L. Overal; Amazonas: Manaus, Rs2303, [-3.1133, -60.0253], 30 Sep 1993, A. B. Casimiro; Manaquiri, Br 319, km100, [-3.4, -60.4], 10 Oct 2010, F. Baccaro; Manaus, Reserva Ducke, [-2.917, -59.983], 9 Aug 1992, T. R. Schultz; Pres. Figueredo, I. Pe Inchado, -1.8971, -59.4865, 23 Aug 1993, Queiroz; Reserva Campina, EEST km 44, [-2.67, -60.03], 18 Aug 1992, T. R. Schultz; Bahia: Andaraí, Mata Carrasco (castanha), [-12.8055, -41.3312], 13 Dec 1990, C. R. F Brandão, Diniz, Oliveira; NP Chapada Diamantina - Mucugê, -12.9053, -41.5005, 1032m, 6 Sep 2009, E. Borges; Lençóis, nr. NP Chapada Diamantina, -12.5598, -41.3708 ± 5m, 530m, 9 Nov 2008, J. Sosa-Calvo; Una, Fazenda Ararauna, -15.3071, -39.1626, 80m, 9 May 2014, I. O. Fernandes; Espírito Santo: Aracruz, [-19.8156, -40.3244], 10 Dec 1980, E. Campinos, D. R. Smith; Parque Sooretama, Linhares, -19.0725, -39.9491, 31 Mar 2004, J. H. C. Delabie; Goiás: Campo Limpo, Faz. Conceição, -16.3308, -49.1636, 20 Jan 2005, R. R. Silva, R. M. Feitosa; Colinas do Sul, Serra da Mesa, -14.0166, -49.2, 2 Dec 1995, B. H. Dietz, Campaner; Fazenda Pau Brasil, Reserva 19, -15.5813, -51.3987, 310m, 8 Apr 2008, S. E. Solomon; Ouro Verde, Faz Boa Vista, -16.3308, -49.2118, 1 Jul 2005, R. R. Silva, R. M. Feitosa; Maranhão: Bom Jardim, REBIO Gurupi Parcela 01 08, -3.9258, -46.7712, 20 Sep 2014, A. Y. Harada; Estreito, Fazenda Itaueiras, -6.5317, -47.3711, 1 Jun 2005, R. R. Silva, R. M. Feitosa; Mato Grosso: Chapada dos Guimarães, Cachoeira Pedra Furada, [-15.4671, -55.7363], 15 Feb 1985, J. C. Trager; Hwy to Santo Antônio do Leverger, 10 km S Cuiabá, [-15.780, -56.0638], 16 Feb 1985, J. C. Trager; Mata São João, Reserva Sapiranga, -12.5581, -33.0431, 21 Jun 2001, R. R. Silva, R. M. Feitosa, C. R. F Brandão; Xingu, [-10.5233, -53.5264], 1 Nov 1961, Alvarenga & Werner; Minas Gerais: Cachoeira da Fumaça (district of Novo São Joaquim), -14.697, -52.312, 288m, 5 Nov 2011; Panga, Uberlândia, -19.1831, -48.4014, 813m, 19 Oct 2012, A. Ješovnik; Serra de Ricardo Franco State Park, -14.9076, -60.0646, 200m, 11 Feb 2014, J. Maravalhas; Unaí, Fazenda Santo Antônio, -16.7544, -46.4825, 1 Feb 2014, L. N. Paolucci; Pará: Baixo Amazonas, [-1.4256, -48.3906], 1 Feb 1949, C. R. Gonçalves; Goianésia, Faz. Rio Capim, [-3.8384, -49.0986], 1 Jun 2003, A. M. Elizabeth; Melgaço, Caxiuanã, -1.7248, -51.4230, 10 Oct 2006, A. Y. Harada; Nova Ipixuna, Fazenda Bom Retiro, -4.8412, -49.218, 12 Jun 2012, M. Tavares, A. Palmeira; Parauapebas, FL Nacional de Carajás, Parque Zoobotânico, -6.0629, -50.0571, 626m, 2 Oct 2014, A. Ješovnik; Viseu São Jose do Gurupi, Parcela 3, -1.5718, -46.2672, 10 Aug 2014, A. Y. Harada; Pernambuco: Recife, [-8.096, -34.904], 1 Jan 1988, L. Lima Castro; Tapera, [-9.4272, -40.7218], B. Pickal; Piaui: Rio Uruçuí-Preto, [-7.3431, -44.6168], 20 Feb 1976, R. Negrett; Rio de Janeiro: Belford Roxo, [-22.7631, -43.3991], 15 Jun 1936, C. R. Gonçalves; Rio de Janeiro DF, [-22.8751, -43.2775], 1 Mar 1940, C. R. Gonçalves; Nova Iguaçu, ReBio Tinguá, -22.5705, -43.4141, 2 Feb 2002, A. Mayhe, S. Veiga-Ferreira; Represa Rio Grande Guanabara, [-22.9167, -43.4167], F. M. Oliveira; São Bento, [-21.9167, -41.1167], 25 Apr 1946, A. Silva; Rondônia: Fazenda São Sebastião, [-10.5336, -63.5457], 7 Oct 2008, S. E. Solomon; Ilha Pedras, km1, subparcela 150, -9.1744, -64.61222, 86m, 25 Oct 2013, I. O. Fernandes; Ouro Preto do Oeste, Res do INPA No 0078, [-10.2, -61.9], 26 Mar 1985, F. F. Ramos; Tocantins: Aguiarnópolis, -6.6137, -47.4814, 1 Jun 2005, R. R. Silva, R. M. Feitosa; Araguacema, -8.9888, -49.6780, 16 Nov 2005, R. R. Silva, R. M. Feitosa; Aurora do Tocantins, -12.6985, -46.3604, 9 Oct 2004, R. R. Silva, R. M. Feitosa; Gurupi, -12.0111, -48.6783, 30 Sep 2001, R.R. Silva, N.L. Albuquerque; Peixe, Fazenda Galileia, Transecto 1, -11.9788, -48.6591, 30 Sep 2001, R.R. Silva, N.L. Albuquerque; Recursolândia, Mata Ciliar Rio Mateiros, -8.7579, -47.0388, 9 May 2005, R. R. Silva, B. H. Dietz; COLOMBIA: Meta: San Martín, El Caduceo Reserve, 3.6694, -73.6585, 374m, 30 Sep 2007, T. R. Schultz; San Martín, El Caduceo Reserve, 3.6292, -73.6256, 364m, 1 Oct 2007, J. Sosa-Calvo; Putumayo: PNN La Paya Cabaña La Paya, -0.0333, -75.2, 330m, 15 Dec 2001, E. Lozano; PNN La Paya Cabaña Vivano Cocha, -0.1166, -74.9666, 320m, 30 Nov 2001, R. Cobete; Valle del Cauca: PNN Farallones de Cali, Anchicayá, [3.4333, -76.8], 730m, 20 Jul 2000, S. Sarria; Vichada: Cumaribo, Cgto. Santa Rita, PNN El Tuparro, 5.3555, -68.0244, 135m, 1 Feb 2004, I. Quintero, E. Gonzales; Cumaribo, Cgto. Santa Rita, PNN El Tuparro, 5.3316, -67.8908, 135m; ECUADOR: Napo: Tiputini, La Selva, Chorongo trail, -0.6382, -76.1493, 16 Jun 2003, A. Little; Orellana: Estación Chiruisla-Petrobras, Río Huiririma, -0.6438, -75.9124, 18m, 10 Sep 2005, D. Donoso; FRENCH GUIANA: Cayenne: Kaw Mt., Amazon Nature Lodge, 4.55, -52.2, 950m, 20 Jul 2005, T. R. Schultz; Nouragues Field Station, XII trail, 4.09, -52.6768, 75m, 27 Jul 2005, T. R. Schultz; Paracou Experimental forest, 5.2808, -52.9465, 10 Jul 1999, S. Durou; Régina: Nouragues Field Station, XII trail, 4.09, -52.6768, 75m, 27 Jul 2005, T. R. Schultz; GUYANA: Cuyuni-Mazaruni: Mabura Hill, camp at the end of Rd. to Lethem, 5.1552, -58.6997, 64m, 30 Oct 2002, J. S. La Polla; Mazaruni River, Forest Settlement, 6.3973, -58.6781, 1 Aug 1935, N. A. Weber; Potaro-Siparuni: Iwokrama, Kurapakari base Camp, [4.6698, -58.6854], 60m, 7 Apr 1996, T. R. Schultz, U. G. Mueller; Upper Takutu-Upper Essequibo: Annai-Georgetown Rd., nr. Essequibo Riv., [3.93, -59.27], 9 Apr 1996, T. R. Schultz, U. G. Mueller; Karanambo, [3.36, -59.78], 5 Apr 1996, T. R. Schultz, U. G. Mueller; Kusad Mountains, 2.8120, -59.8668, 135m, 26 Oct 2013, J. A. Helms; Upper Essequibo, CI concession, BBC camp, 3.5059, -58.2334, 11m, 21 Nov 2011, A. Ješovnik; Acarai Mountains, nr. Romeo’s camp, 1.3833, -58.9333, 282m, 7 Oct 2010, T. R. Schultz; PERU: Madre de Dios: Pakitza, PN Manu, [-11.95, -71.2833], 13 Feb 1992, R. Cambra, D. Quintero; Puerto Maldonado, Los Amigos Biol. Station, -12.569, -70.1005, 272m, 23 Nov 2005, J. Sosa-Calvo; Tambopata Reserve, -12.8187, -69.3636, 224m, 1 Aug 2012, A. Ješovnik; SURINAME: Brokopondo: Maripaheuvel, near Dam on Sara creek, [4.67, -54.95], 1 Sep 1959, I. v. d. Drift; Poeroe man Kemisa, [4.67, -54.95], 1 Sep 1959, I. v. d. Drift; Sipaliwini: Bakhuis Mountains, 4.7208, -56.726, 249m, 5 Mar 2006, J. Sosa-Calvo; Lely Mts., 4.2529, -54.7561, 619m, 26 Oct 2005, J. Sosa-Calvo; Nassau Mountains, 4.2529, -54.7561, 619m, 26 Oct 2005, J. Sosa-Calvo; TRINIDAD AND TOBAGO: Tunapuna-Piarco: Simla Research Station, [10.6836, -61.2833], 240m, 8 Jan 1995, U. G. Mueller; VENEZUELA: Bolívar: Río Tawadu, Nichare Field Stn., 6.4333, -64.8833, 200m, 9 Feb 1966, D. M. Olson.