Labiotermes orthocephalus (Silvestri) Silvestri, 2006

Constantino, Reginaldo, Acioli, Agno N. S., Schmidt, Karen, Cuezzo, Carolina, Carvalho, Sérgio H. C. & Vasconcellos, Alexandre, 2006, A taxonomic revision of the Neotropical termite genera Labiotermes Holmgren and Paracornitermes Emerson (Isoptera: Termitidae: Nasutitermitinae), Zootaxa 1340, pp. 1-44 : 25-28

Labiotermes orthocephalus (Silvestri) , new combination

Cornitermes orthocephalus Silvestri, 1901: 5 ; Silvestri 1903: 60 –61 [soldier (Pl. Fig. 106), worker]; Desneux 1904: 38 ( Termes ); Holmgren 1912: 50 ( Cornitermes subgenus Labiotermes ); Snyder 1949: 333 ( Paracornitermes ); Araujo 1954: 183 –185 ( Paracornitermes ) [soldier, Fig. 1 , 4 ].

Syntypes: soldiers and workers (DEZA, MCSN), not examined.

Type­locality: Brazil: Mato Grosso, Cuiabá.

New Synonyms:

Paracornitermes hirsutus Araujo, 1954: 187 [soldier]; Mathews 1977: 205 [soldier]. Holotype: soldier (MZSP), examined; type­locality: Brazil: Minas Gerais, Monte Azul.

Paracornitermes caapora Bandeira & Cancello, 1992: 424 [soldier ( Figs. 2–5 ), worker ( Fig. 1 )]. Holotype: soldier (INPA), examined; type­locality: Brazil: Roraima, Ilha de Maracá.

Imago ( Figs. 9 J–M, 12D). Head capsule rounded; fontanelle small and inconspicuous. Eyes nearly rounded, very large, almost touching the lower margin of head capsule; ocelli large, elliptical, larger than antennal socket. Postclypeus moderately arched in profile. Pronotum wider than head without eyes. Mesonotum and metanotum with deeply emarginate hind margins. Left mandible: distance from M3 to M4 shorter than distance from M1 to M3; distance from A to M1 about the same as distance from M1 to M3; M3 conspicuously smaller than M1. Right mandible: distance from A to M1 longer than distance from M1 to M2; M2 small. Antenna with 17–18 articles. Head capsule brown; postclypeus, pronotum and tergites light brown; sternites brownish yellow; wings transparent, brownish. Head, postclypeus and pronotum densely covered with straight bristles; tergites and sternites densely covered with bristles and hairs of variable size; wings densely covered with minute hairs. Measurements in Table 1 .

Comparisons. The imago of L. orthocephalus can be recognized by its large size, inconspicuous fontanelle and numerous, relatively long, hairs on the head and pronotum. The imagos of all other known species have fewer or shorter hairs, and a more conspicuous fontanelle. The imagos of L. emersoni and L. brevilabius have antenna with 16 articles.

Soldier ( Figs. 9 A–I, 11I). Head capsule subrectangular, with nearly parallel sides in dorsal view; sides slightly convex. Frontal tube conspicuous, oriented anteriorly; fontanelle about the same line as antennal sockets. Top of head in profile almost straight. Antenna with 15 articles. Labrum longer than broad; sides convex. Mandibles short, robust and curved. Left mandible: cutting edge between apical and 1st marginal concave; cutting edge between marginal teeth concave. Right mandible with two marginal teeth, about the same size and grouped together near base. Front coxa with a lateral conical projection near base. Head capsule and labrum brownish yellow; thorax and legs lighter than head capsule; tergites and sternites yellowish. Head capsule densely covered with bristles of variable size; postmentum with numerous bristles on anterior half; pronotum with many bristles; tergites and sternites densely covered with bristles and fine hairs. Measurements in Table 2 .

Comparisons. The soldier of L. orthocephalus can be recognized by its large size, hairy head, coxa with a prominent conical projection, mandibles with large marginal teeth and cutting edge of apical tooth of left mandible evenly curved.

Worker ( Figs. 9 N–Q, 13I, 14F, 15Q–S, 16I). Head capsule and postclypeus with numerous straight bristles. Pronotum with numerous bristles on anterior and posterior lobes. Mesonotum with numerous bristles near posterior margin. Front coxa with a conspicuous lateral conical projection near base. Antenna with 15 articles. Fontanelle large and rounded. Enteric valve with 6 ridges of unequal size and irregular shape, covered with fine spines. Mixed segment with two mesenteric lobes; large lobe oval, proximal part very narrow; small lobe rounded and inflated. Measurements in Table 3 .

Comparisons. The worker of L. orthocephalus is the most similar species are L. laticephalus and L. emersoni , which are in the same size range and have a conical projection on the front coxa. The enteric valve armature of L. orthocephalus is distinct (see description above and Fig. 16 I).

Geographical distribution. L. orthocephalus occurs in the Cerrado, the Brazilian Atlantic Forest, and in Amazonia ( Fig. 22 ).

Remarks. P. hirsutus is clearly an eastern geographical form of L. orthocephalus . Araujo (1954) based his description of P. hirsutus on samples from Minas Gerais, which have larger and more hairy soldiers than typical L. orthocephalus from Mato Grosso. Soldiers from Goiás are intermediate and there is a clear East­West gradient of soldier size and number of hairs on soldier head. Soldier mandibles show considerable intraspecific variation. The imagos are identical, as well and all the other diagnostic characters. P. caapora was described based on a single sample with a few soldiers and several workers.

Compared to larger series from several localities, the differences mentioned in its original description are not consistent and soldiers from its type series are nearly identical to some soldiers of P. orthocephalus from central Brazil.

Material examined

BRAZIL. Amazonas. Humaitá: s., w., 20.ix.1990, R. Constantino (MPEG­3802). Bahia. Eunápolis: s., w., 26.vi.1974, R.L. Araujo (MZSP­5566). Ceará. Crato: s., w., 17.x.2004, A. Vasconcellos ( DSEC). Distrito Federal. Brasília: s., w., 01.xii.1971, K. Kitayama (MZSP­7064). Espírito Santo. Linhares: s., w., 28.i.1993, E.M. Cancello (MZSP­9810). Rebio Sooretama: s., w., 31.viii.1966, H. Reichardt (MZSP­2018). Vila Velha: s., w., 31.v.1954, R.L. Araujo (MZSP­4190). Goiás. Alvorada do Norte, Fazenda Paraná: s., w., 25.viii.2003, D.L. Bernardo (UnB­4040, 4058). São Domingos, Monte Alto: s., w., 02–05.ix.2003, D.L. Bernardo (UnB­4278, 4300, 4325, 4329, 4361). Parque Nacional das Emas: s., w., 06.iv.1984, IQUSP (MZSP­8424). Minaçu, Serra da Mesa: s., 23–28.ii.1997, R. Constantino (UnB­234, 239, 240). Mato Grosso. Chapada dos Guimarães, Rio Manso: s., w., 12.i.1999, R. Constantino (UnB­0782). Chapada dos Guimarães: s., w., 10.ii.1976, R.L. Araujo (MZSP­6636). Cuiabá: s., w., 17.ii.1976, R.L. Araujo (MZSP­2019). Juruena: s., w., 06.vii.2002, R. Constantino (UnB­3429). Utiariti: s., w., 01.viii.1961, K. Lenko (MZSP­8096). Mato Grosso do Sul. Campo Grande: s., w., 20.ii.1976, R.L. Araujo (MZSP­6568). Costa Rica: s., w., 01.ii.1986, IQUSP (MZSP­ 9289). Rondonia. Vilhena: s., w., im., 07–09.xi.1998, R. Constantino (UnB­684, 691, 692, 726). Minas Gerais. Bocaiúva: s., 26.xi.1998, N.R.A. Castro (UnB­1785). Bom Sucesso: s., w., im., 12.xi.1972, R.L. Araujo (MZSP­5793). Capitão Eneias: s., w., 15.vii.1975, R.L. Araujo (MZSP­6247). Curvelo: s., w., im., 13.xi.1972, R.L. Araujo (MZSP­5781, 6234). Francisco Sá: s., w., 18.vii.1975, R.L. Araujo (MZSP­6143). Montes Claros: s., w., 16.xi.1972, R.L. Araujo (MZSP­5610, 5641). Rio Pomba: s., w., 01.vii.1975, R.L. Araujo (MZSP­6092, 6180). Teófilo Otoni: s., w., 26.xii.1976, R.L. Araujo (MZSP­7262). Rio de Janeiro. Rio de Janeiro: s., w., 06.i.1966, R.L. Araujo (MZSP­377, 2019). Seropédica: s., w., im., 11.x.2001, R. Constantino (UnB­2127). Roraima. Ilha de Maracá: s., w., paratypes of P. caapora , 22.x.1987, A.G. Bandeira (INPA­ 222). Tocantins. Paranã, Fazenda São João: s., w., 12–17.ix.2003, D.L. Bernardo (UnB­ 4874, 4905, 4922, 4947, 4966).

Figures

FIGURES 1. Labiotermes brevilabius. Soldier: A, head in dorsal view; B, thorax; C, head in profile. Worker: D, head in dorsal view; E, thorax; F, head in profile; G, right front leg. Scale bars = 1.0 mm.

FIGURES 2. Labiotermes emersoni. Soldier from Minas Gerais: A, head in dorsal view; B, pronotum in dorsal view; C, head in profile; D, pronotum in posterior view; E, right front leg; F, postmentum. Soldier from Rondonia: G, head in profile. Imago: H, head in dorsal view; I, pronotum; J, head in profile; K, antenna. Worker: L, head in dorsal view; M, thorax; N, head in profile; O, right front leg. Scale bars = 1.0 mm.

FIGURES 3. Labiotermes guasu, new species. Soldier: A, head in dorsal view; B, pronotum in dorsal view; C, pronotum in posterior view; D, head in profile; E, postmentum; F, right front leg. Worker: G, head in dorsal view; H, thorax; I, head in profile; J, right front leg. Scale bars = 1.0 mm.

FIGURES 4. Labiotermes labralis. Soldier: A, head in dorsal view; B, head in profile. Worker: C, head in dorsal view; C, thorax; D, head in profile; E, right front leg. Scale bar = 1.0 mm.

FIGURES 5. Labiotermes laticephalus. Large soldier: A, head in dorsal view; B, pronotum in dorsal view; C, pronotum in posterior view; D, postmentum; E, head in profile; F, right front leg. Small soldier: G, head in dorsal view; H, pronotum in dorsal view; I, pronotum in posterior view; J, head in profile; K, postmentum. Worker: L, right front leg; M, head in dorsal view; N, thorax; O,

FIGURES 9. Labiotermes orthocephalus. Soldier from Mato Grosso: A, head in dorsal view; B, pronotum in dorsal view; C, head in profile; D, pronotum in posterior view; E, right front leg; F, postmentum. Soldier from Minas Gerais: G, head in dorsal view; H, pronotum; I, head in profile. Imago: J, head in dorsal view; K, pronotum; L, head in profile; M, antenna. Worker: N, head in dorsal view; O, thorax; P, head in profile; Q, right front leg. Scale bars = 1.0 mm.

FIGURES 16. Enteric valve armature of workers. A, Labiotermes brevilabius; B, L. emersoni; C, L. guasu, new species; D, L. labralis; E, L. laticephalus; F, L. leptothrix; G, L. longilabius; H, L. oreadicus, new species; I, L. orthocephalus; J, L. pelliceus.

FIGURES 22. Geographic distribution of Labiotermes orthocephalus. Triangles correspond to Paracornitermes hirsutus and the square to P. caapora, both synonyms of L. orthocephalus. The double symbol indicates the respective type­locality.