Labiotermes labralis Holmgren

Labiotermes labralis (Holmgren)

Cornitermes labralis Holmgren, 1906: 553 –557, 657–658 [imago (Fig. N), soldier (Fig. O), worker (Fig. P), nest]; Holmgren 1909: 175, 193 [morphology, Fig. 65]; Holmgren 1912: 50 (Cornitermes subgenus Labiotermes); Sjöstedt 1926: 150 (Eutermes); Emerson & Banks 1965: 12 (Labiotermes) [imago, soldier, Fig. 2–4]; Mathews 1977: 207 –208 [nest (Pl. 45), enteric valve (Pl. 48)]; Noirot 2001: 439 [enteric valve, fig. 7­D].

Lectotype: soldier, designated by Emerson & Banks 1965: 19 (NHRS), not examined.

Type­locality: Peru: Chaquimayo.

Synonym: Labiotermes labralis boreus Emerson (in Snyder 1949: 334); Emerson 1925: 363–365 (as Cornitermes labralis) [imago, soldier, Fig. 47]. Holotype: soldier (AMNH). Type­locality: Guyana, Kartabo. Synonymized by Emerson & Banks 1965: 12, 18–19.

Imago. Described and illustrated by Emerson & Banks 1965: 13–15. Additional measurements are presented in Table 1.

Soldier (Figs. 4 A–B, 11D). Described by Emerson & Banks 1965: 15–18. Additional measurements are presented in Table 2.

Comparisons. The soldier of L. labralis can be recognized by the small number of hairs on the head, absence of a projection on the front coxa and the very large and sclerotized labrum with two bristles near tip. The head capsule is also more rounded than in the other species.

Worker (Figs. 4, 13 D, 14B, 15G–H, 16D). Head capsule with very few, sparse bristles. Postclypeus with 2 bristles. Pronotum with a row of bristles on anterior margin and no bristles on posterior margin. Mesonotum without bristles. Front coxa without a lateral projection near base. Antenna with 15–16 articles. Fontanelle large and oval. Enteric valve with 4 ridges, 3 large and a very small one, covered with short spines. Mixed segment with two elongate mesenteric lobes; large one with a broad tip; small lobe about half the length of the large one. Measurements in Table 3.

Comparisons. The worker of L. labralis can be recognized by the small number of hairs on the head and the absence of a projection on anterior coxa. The most similar species in external morphology is L. guasu, which is conspicuously larger. The enteric valve is also distinct from all other species, with 3 large ridges and one small.

Remarks. Mathews (1977: 207–208) mentions only 3 plates in the enteric valve of L. labralis. However, the small plate is visible in his figure (page 233, Plate 48), and is also clearly visible in Noirot’s (2001: 439) figure.

Habits. L. labralis occurs only in rainforest. It builds a large, dark, arboreal nest of irregular shape, made with a mixture of soil and fecal material. The internal surface is sculptured in a peculiar pattern, described and illustrated by Mathews (1977: 208 and plate 45). Martius & Ribeiro (1996) report a density of 10 nests/ha near Manaus.

Geographical distribution. L. labralis occurs in the whole Amazon region, and is also found in Trinidad and in the Brazilian Atlantic forest as far south as 21S (Fig. 19). The absence of records from Ecuador is probably due to lack of collecting. The distribution is apparently disjunct between the Amazon and the Atlantic forest.

Material examined

BRAZIL. Amapá. Curiau: s., w., 18.x.1989, R. Constantino (MPEG­3176). Mazagão: s., w., 20.x.1989, R. Constantino (MPEG­3179). Oiapoque: s., w., im., 01.v.1979, A.G. Bandeira (MPEG­0653). Amazonas. Anavilhanas: s., w., 17.iv.1981, A.E. Mill (MZSP­ 10467). Humaitá: s., w., 13.ix.1990, R. Constantino (MPEG­3682). Manaus: s., w., 07­ 08.ix.1978, P. Howse (MPEG­485, 489); s., w., 06.iv.1979, A.G. Bandeira (MPEG­609); s., w., 06.x.1998, R.L. Abreu (UnB­2629). Manaus, Reserva Ducke: s., w., im., 01.ix.1990, F.B. Apolinário (UnB­3630). Manaus, Rodovia ZF­3: s., w., 09.x.1999, T. Miura (UnB­ 1593). Rio Negro: s., w., no date, H.R. Coles (UnB­1076). Itacoatiara, Fazenda Aruanã: s., w., im., 23­30.iv.1977, A.G. Bandeira (MPEG­091, 163, 260). Bahia. Ilháus: w., 16.xi.2000, E.M Cancello (MZSP). Monte Pascoal: s., w., 08.viii.1974, R.L. Araujo (MZSP­5460). Espírito Santo. Linhares: s., w., im., 28.i.1993, E.M. Cancello (MZSP­ 9811). Mato Grosso. Ique­Juruena: s., w., 27.ix.1980, A.E. Mill (MZSP­10463). Juruena, Rohden Lignea: s., w., 03.vii.2002, R. Constantino (UnB­3331). Minas Gerais. Viçosa: s., w., 19.ii.2002, C. Galbiati (UnB­5552). Pará. Cachoeira do Arari: s., w., 09.iii.1989, R. Constantino (MPEG­3025). Paragominas: s., w., 27.vi.1990, R. Constantino (MPEG­ 3515). Parque Nacional da Amazonia: s., w., 19.viii.1978, A.G. Bandeira (MPEG­394). Oriximiná, Porto Trombetas: s., w., 30.vii.2000, A.N.S. Acioli (UnB­5518). Novo Progresso, Serra do Cachimbo: s., w., im., 18.ix.2003, R. Constantino (UnB­3892). Serra dos Carajás: s., w., 01.viii.1985, C.R.F. Brandão (MZSP­8709). Taperinha: s., w., 03.ii.1968, unknown collector (MZSP­1888). Tucurui: s., w., im., 21.iv.1979, A.G. Bandeira (MPEG­0628). Paraíba. Areia: s., w., 28.xii.1998, A. Vasconcellos (DSEC­ 1216). João Pessoa: s., w., 08.x.1993, J.C.D. Pereira (DSEC­142). Quebrangulo: s., w., im., 26.i.2001, A. Vasconcellos (DSEC). Pernambuco. Caruaru: s., w., 20.ix.1997, A. Vasconcellos (DSEC­1048). Recife: s., w., im., 29.i.1980, E.M. Cancello (MZSP­8019). Rondonia. Guajará­Mirim: s., w., 18.i.2001, D.L. Bernardo (UnB­2728, 2729). Pimenta Bueno: s., w., 17.vii.2000, O. Kitade (UnB­2600). Vilhena: s., w., 27.vii.2000, R. Constantino (UnB­2567). Roraima. Ilha de Maracá: s., w., im., 19.xi.1978, A.G. Bandeira (MPEG­448); s., w., 21.xi.1978, A.G. Bandeira (MPEG­469); s., w., im., 19.xi.1978, A.G. Bandeira (UnB­3536). FRENCH GUIANA. Saül: s., w., 27.v.1997, J.S. Ashe (UnB­2848, 2849, 2852). PERU. Huánuco. Tingo María: s., w., no date, W. Weyrauch (MZSP­1889). VENEZUELA. Amazonas. Alto Orinoco, Motorema: s., w., im., 10.v.1998, M.G. Paoletti (UnB­508, 509). San Pedro: s., w., 23.viii.1981, J.L. Garcia (MZSP­10425).