Workers and queens occur in samples of sifted leaf litter from the forest floor.
Brazil (type locality), Costa Rica. Costa Rica: widespread in lowland wet forest, including the Osa Peninsula, San Vito area at 1200m, Manuel Antonio, Carara, La Selva Biological Station and surrounding Atlantic slope sites to 600m, Penas Blancas Valley, and the Pitilla area of Guanacaste Conservation Area.
Taxonomic history
See also: Feitosa & Brandão, 2008 PDF: 34.Figures 14, 19
Lachnomyrmex plaumanni Borgmeier , 1957: 125, fig. 47. Syntypes, BRAZIL: Rio de Janeiro: Itatiaya, i.1956, Dr. Barth col. (2 workers and 1 gyne) [ MZSP ] (examined); Santa Catarina: Nova Teutonia, iv.1954, F. Plaumann col. (3 workers and 1 gyne) [ MZSP ] (examined, 1 worker here designated lectotype in order to improve nomenclatural stability); same locality, xi.1954, F. Plaumann col. nos. 66111/64824 (1 worker and 1 gyne) [ USNM ] (examined); same data (1 worker) [ MZSP ] (examined); same data (2 workers) [ MCZC ] (not examined).
Worker diagnosis. Body sparsely covered by short, fine rugae; promesonotum elevated minimally above propodeum level; apex of propodeal spines curved downwards; teeth of propodeal lobes swollen and extremely reduced; dorsum of postpetiole with about six long hairs; first tergite of gaster entirely devoid of long flexuous hairs.
FIGURE 13. Holotype worker of Lachnomyrmex platynodus from Mt. Ayanganna, Guyana: A, head in full face view; B, lateral view; C, dorsal view. Image by Michele Esposito, specimen CASENT0173881.
Lectotype measurements. HL 0.65; HW 0.63; ML 0.19; SL 0.38; EL 0.11; WL 0.71; PSL 0.14; PL 0.30; PPL 0.14; GL 0.79; TL 2.77; CI 97; SI 60; OI 17.
Worker measurements (n=58). HL 0.57-0.69; HW 0.57-0.68; ML 0.17-0.20; SL 0.35-0.42; EL 0.09- 0.14; WL 0.61-0.80; PSL 0.13-0.15; PL 0.25-0.35; PPL 0.11-0.14; GL 0.68-0.93; TL 2.51-3.07; CI 96-101; SI 56-65; OI 14-22.
Gyne measurements (n=20). HL 0.58-0.71; HW 0.58-0.71; ML 0.17-0.25; SL 0.36-0.44; EL 0.13- 0.19; WL 0.73-0.91; PSL 0.13-0.16; PL 0.30-0.39; PPL 0.13-0.16; GL 0.79-1.02; TL 3.45-2.70; CI 97-102; SI 58-62; OI 21-28.
Worker description. Color light reddish-brown to dark brown, with appendages lighter. Body sparsely covered by irregular short rugae, somewhat longer and longitudinal on head dorsum; mandibles with short longitudinal striae restricted to basal portion; petiole and postpetiole finely and irregularly rugose. Abundant pilosity on head and promesonotum dorsum; dorsum of petiolar node and postpetiole with about four and six long hairs, respectively; first gastral tergite entirely devoid of long flexuous hairs.
Head as long as broad, with vertexal margin strongly convex; frontal lobes laterally rounded; eyes with about six facets on maximum diameter. Promesonotum moderately convex in profile, only discretely higher than level of propodeum; metanotal groove shallow to virtually obsolete; apex of propodeal spines distinctly curved downwards; teeth of propodeal lobes swollen and reduced, with less than one-third of propodeal spines length. Petiolar node moderately elevated, dorsally rounded, and with the posterior face weakly sloped in lateral view; postpetiole feebly convex dorsally and without ventral processes.
Gyne. Differing from worker by the larger eyes, with around 12 facets at maximum diameter; propodeal spines relatively wider basally and with the apexes only minimally curved downwards.
Etymology. Father Thomas Borgmeier (1957) named this species in honor of the Lithuanian entomologist, Fritz Plaumann (1902-1994), collector of the L. plaumanni type-series and known for his exhaustive work on the insect fauna of the state of Santa Catarina, Brazil. Plaumann is considered the most important insect collector of Latin America in the 20th century.
Comments. Lachnomyrmex plaumanni is one of the smallest species in the genus and can be immediately recognized by the combination of sparse sculpturation, propodeal spines curved downwards, and dorsum of postpetiole with about six long hairs.
This is species has been collected from northern Argentina to southeastern Brazil, along the submontane areas of the Brazilian Atlantic Forest (400-1200m).
Despite the constant presence of L. plaumanni in leaf liter samples from the Atlantic Forest, all attempts to maintain colonies in artificial conditions so far have failed. Gynes and workers usually die a few days after capture. There is a single record of a L. plaumanni worker foraging in the vegetation. It was collected manually in a bromeliad fixed in a high live tree from Serra do Itapeti, state of Sao Paulo, Brazil (M.S. Morini, pers. comm.).
Additional material examined. ARGENTINA: Missiones: 20km SE Pto. Iguazu, 31.xii.1990, S. Peck & J. Peck cols, no. 1660/CASENT0006151 (1 worker, examined by images) [ CASC ]; BRAZIL: Parana: Morretes, P.E. do Pau-Oco, 25°34'05"S48°53'19"W , 6-11.v.2002, R.R. Silva & B.H. Dietz cols, nos. 22/24 (2 workers) [ MZSP ]; Tunas, P. das Lauraceas, 24°51'16"S48°43'00"W , 21-29.ii.2001, R.R. Silva & F. Eberhardt cols, nos. 1/6/19/34/42 (5 workers and 2 gynes) [ MZSP ]; Santa Catarina: Blumenau, P.E. das Nascentes, 27°06'15"S49°09'14"W , 20-27.x.2000, R.R. Silva & F. Eberhardt cols, no. 31 (1 worker) [ MZSP ]; same locality, 27°01-06'S, 49°01-10'W, 10.ii.2001, F. Eberhardt col., no. 10 (1 worker) [ MZSP ]; Chapeco, vii-viii.1960, F. Plaumann col., no. 8333 (5 workers) [ MZSP ]; Concordia, ix.1959, F. Plaumann col., no. 8296 (2 workers) [ MZSP ]; Ibicare, viii.1959, F. Plaumann col., no. 3128 (3 workers) [ MZSP ]; same locality, ix.1960, no. 3619 (2 workers) [ MZSP ]; Linha Facao, v.1957, F. Plaumann col. (1 worker e 1 gyne) [ MZSP ]; Morro do Serro, xii.1958, F. Plaumann col., no. 8318 (1 worker) [ MZSP ]; Nova Teutonia, ix.1954, F. Plaumann col., no. 8216 (8 workers and 1 gyne) [ MZSP ]; same locality, v-xii.1957, F. Plaumann col. (9 workers and 2 gynes) [ MZSP ]; same locality, vii. 1958, F. Plaumann col. (1 worker and 1 gyne) [ MZSP ]; same locality, v.1960, F. Plaumann col. (2 workers and 1 gyne) [ MZSP ]; same locality, vi.1963, F. Plaumann col., no. 3755 (1 worker) [ MZSP ]; same locality, iv.1972, F. Plaumann col., no. 8000 (1 worker and 1 gyne) [ MZSP ]; same locality, vi.1963, F. Plaumann col., no. 3755 (1 worker) [ MZSP ]; same locality, iv.1976, F. Plaumann col., no. 13629 (1 worker) [ MZSP ]; Palhoca, P.E. da Serra do Tabuleiro, 27°44'28"S48°41'50"W , 2-10.vi.2003, R.R. Silva, B.H. Dietz & A .A. Tavares cols, nos. 2/9/10/14 (4 workers) [ MZSP ]; Sao Bento do Sul, A.P.A. Rio Vermelho, 26°21'51"S49°16'16"W , 30.iii-4.iv.2001, R.R. Silva & F. Eberhardt cols, nos. 4/25/29/31/32/33/34/35/38/44/46/48/49 (12 workers and 1 gyne) [ MZSP ]; same data, no. 25 (1 worker) [ INBC ]; same data, no. 29 (1 worker) [ MIZA ]; same data, no. 46 (1 worker) [ MPEG ]; Seara, viii.1958, F. Plaumann col. (3 workers) [ MZSP ]; same locality, v-xii.1998, R.R. Silva col. (4 workers) [ MZSP ]; Sao Paulo: Cananeia, P.E. da Ilha do Cardoso, 18- 24.xi.2002, 25°05'48"S47°55'47"W , R.R. Silva, C.R.F. Brandao & C. Scott cols, nos. 1/7/13/16/18/25/28/34/ 43/48 (8 workers and 3 gynes) [ MZSP ]; same data, no. 7 (1 worker) [ AMNH ]; same data, no. 13 (1 worker) [ BMNH ]; same data, no. 25 (1 worker) [ CASC ]; same data, no. 28 (1 worker) [ CPDC ]; same data, no. 43 (1 worker) [ICNC]; same data, no. 48 (1 worker) [IHVL]; Cunha, P.E. da Serra do Mar, Nucleo Indaia, 23°15'03"S45°00'26"W , 21-22.iv.2001, R.R. Silva & A.A. Tavares cols, nos. 5/11/19/32/43 (7 workers and 1 gyne) [ MZSP ]; Iguape, E.E. Jureia-Itatins, Nucleo Rio Verde, 24°32'39"S47°14'08"W , 5-15.ii.2001, R.R. Silva & A.A. Tavares cols, nos. 4/22/25/27 (3 workers and 1 gyne) [ MZSP ]; Miracatu, Serra do Mar, Clube Pesca & Cia, 4-7.ix.2004, R.M. Feitosa col., nos. 1/9/11/12 (10 workers and 2 gynes) [ MZSP ]; Mogi das Cruzes, P.N.M. da Serra do Itapeti, 20.v.2003, 23°29'22"S46°11'55"W , M.S. Morini col., no. 8 (1 worker) [MSMC]; Praia Grande, P.E. da Serra do Mar, Nucleo Piloes, 23°58'31"S46°32'24"W , 26-27.v.2001, R.R. Silva & A.A. Tavares cols, nos. 5/10/13/24/35/36/39/41 (12 workers) [ MZSP ]; Ribeirao Grande, P.E. Intervales, Barra Grande, 24°18'30"S48°25'10"W , 2.ii.1999, A.A. Tavares col., nos. T1 3/7/16/17/22/23-T2 1/4/7/ 12/ 13/14/15/17/18 (21 workers and 1 gyne) [ MZSP ]; Salesopolis, E.B.B. Boraceia, 23°31'S45°50'W , 2- 6.v.1997, D. Agosti, C.R.F. Brandao & C.I. Yamamoto cols, nos. 5/7/9/15/16 (8 workers and 2 gynes) [ MZSP ]; same data, no. 5 (1 worker) [ MUSM ]; same data, no. 15 (1 worker) [ USNM ]; same data, no. 16 (1 worker) [WMPC]; same locality, 12-17.vi.1997, B.H. Dietz & C.I. Yamamoto cols, nos. 7/10/13/14/16/17/25 (15 workers and 2 gynes) [ MZSP ]; same locality 5-7.vii.1997, C.I. Yamamoto col., no. 9 (2 workers) [ MZSP ]; same locality, 20-26.x.1997, C. Klingenberg & C.I. Yamamoto cols, nos. 10/13/21 (3 workers) [ MZSP ]; Serra dos Agudos Grandes, xi.1963, F. Plaumann col., no. 3865 (1 worker) [ MZSP ]; Tapirai, 24°01'55"S47°27'56"W , 8-14.i.2001, R.R. Silva & F. Eberhardt cols, nos. 1/2/5/8/11/12/13/14/15/16/22/23/ 24/27/29/31/33/34/36/39/40/24/44/47/50 (35 workers and 6 gynes) [ MZSP ]; Ubatuba, P.E. da Serra do Mar, Nucleo Picinguaba, 23°20'10"S44°50'15"W , C.R.F. Brandao et al. cols, nos. 23/24 (2 workers) [ MZSP ]; same locality, 23°18'21"S44°48'25"W , 5.i.2006, C.P. Scott & E.F. Santos cols, nos. 2/7 (3 workers) [ MZSP ]; same locality, 23°17'54"S44°47'49"W , 23.i.2006, C.P. Scott & E.F. Santos cols, nos. 1/7 (5 workers) [ MZSP ]; same locality, 23°17'49"S44°47'31"W , 26.i.2006, C.P. Scott & E.F. Santos cols, no. 9 (1 worker) [ MZSP ]; same locality, 23°17'56"S44°47'13"W , 7.iii.2006, C.P. Scott & E.F. Santos cols, nos. 3/8/9 (6 workers and 1 gyne) [ MZSP ]; Rio Janeiro: Nova Iguacu, ReBio Tingua, 22°34'14"S43°24'51"W , 4.ii.2002, A. Mayhe & S. Veiga-Ferreira cols, no. A32 (1 worker) [ MZSP ]; Sta. Maria Madalena, P.E. do Desengano, 21°58'41''S41°57'00"W , x.2002, A. Mayhe & S. Veiga-Ferreira cols, nos. 1/2/14/18/22 (5 workers) [ MZSP ].
