The soldier of R. tinto is the only non-phragmotic kalotermitid worldwide with dark coloration of the anterior head capsule. Aside from head color, it differs from congeneric soldiers in that the anterolateral corners of the frontal ridges project to form acute angles. In other South American (Fig. 4), Central American, and Oceanian Rugitermes, the anterolateral corners of the frontal ridges are either at right or obtuse angles.

Among South American species, the imago of R. tinto, with contrasting coloration of the head and pronotum, is similar to R. bicolor, R. flavicinctus, R. magninotus, and R. nodulosus. Of these, the imago of R. bicolor is larger, while that of R. flavicinctus is smaller than R. tinto and the head/pronotum coloration of the former two are similar to R. magninotus. The imago of R. magninotus has a brown head and a yellow pronotum while the imago of R. tinto has a black head and a brownish pronotum. The distribution of R. nodulosus is known only from southern Brazil (Minas Gerais).

Imago (Fig. 2A, B). Single female damaged: distal half of left wings torn, right wings absent. Head capsule black; pronotum brownish orange. Compound eye small, nearly circular. Ocellus very small, circular, black; difficult to see as there is no contrast with head capsule cuticle; ocellus well removed from eye margin. Head vertex and frons not depressed; frons with faint rugosity; covered with dozens of erect setae ca 0.15-mm-long. Pronotum slightly wider than head capsule; anterior margin slightly incised; posterolateral corners evenly rounded, posterior margin narrowly concave. Pronotum pilosity congruent with vertex. Antennae with at least 16 articles, basal article relative lengths 1>2=3>4. Forewing anterior half as per genus; median vein very short, joins radial 0.9 mm from wing scale. Wing scale covered with about 20 setae of similar length and density as those on head and pronotum. Wing membrane smokey brown, covered with darker nodules. Legs dark brown. Arolium present. Measurements (maximum, mm): head width 1.31, pronotum width 1.43, eye diameter 0.32, ocellus diameter 0.01, and body length 7.9.

Figure 2. 

Rugitermes tinto sp. nov. A Dorsal B lateral views of head and thorax of imago C dorsal D frontal views of anterior soldier head capsule (white arrows mark frontal flange, yellow arrows mark frontolateral ridge, and black arrows mark protuberance of frontolateral ridge).

Soldier (Figs 2C, D, 3). Head capsule, in dorsal view, dark castaneous brown from posterior margin of postclypeus to posterior one fourth; posterior one fourth grading from dark reddish brown to brownish orange at occiput. In ventral view, head capsule coloration grades gradually from dark castaneous brown to brownish orange with exception of postmentum which remains dark reddish brown at posterior. Pronotum yellowish with reddish interior, in obvious contrast with head capsule coloration. Head capsule long, rectangular; lateral margins very slightly concave in middle, covered with a few setae except at frons where setae are denser. Pronotum much wider than long; with scattered setae, denser along lateral margins; anterior margin weakly incised. In dorsal view, the frontal flange forms a weak hemispherical border surrounding the frons. The frontal flange forms a 30° angle with plane of vertex. Frons finely rugose. In dorsal view (Fig. 2C), frontolateral ridges form shelves on each side of the frons almost in-line with posterior margin of postclypeus. The outer margins of each ridge are adorned with protuberance forming acute angles of ca 65°. In frontal view, the ridges rise slightly at their protuberances; dorsal margins of antennal carinae (“sockets”) positioned well below ridges. Eye spots small, concolorous with head capsule. Third antennal article club-shaped, about twice as long as second and fourth articles. Mandibles about half length of head capsule; outside margin of each blade curving gradually, with very slight hump at base. Measurements in mm [mean (range, N = 6)]: Head length lateral base of mandibles: 2.83 (2.47–2.99), max. head width 1.72 (1.52–1.90), max. head height with postmentum 1.42 (1.29–1.47), max. pronotum width 1.86 (1.58–2.04), max. pronotum length 0.90 (0.86–0.95), third antennal article length 0.19 (0.18–0.20).

Figure 3. 

Rugitermes tinto sp. nov. soldier head and pronotum. A Dorsal B lateral C ventral view.

Holotype (soldier). Colombia: Risaralda, Pereira (4.810, -75.695); 1410 meters a.s.l., 11APR1998, J. Navarro, A. Arevalo; two soldiers (one labelled holotype), one damaged female imago University of Florida Termite Collection (UFTC) no. CO919, subsample from Colección Entomológica Forestal Universidad Distrital “Francisco José de Caldas” (CEFUDFJC) no. 009942 of which remains one soldier and three pseudergates.

Colombia: Cundinamarca, Villeta (5.017, -74.467); 842 meters a.s.l., no date, A. Moreno; one soldier and two pseudergates; CEFUDFJC no. 009940. Colombia: Risaralda, Pereira (4.810, -75.695); 1410 meters a.s.l., 11APR1998, J. Navarro, A. Arevalo. Same location; two soldiers, three pseudergates; CEFUDFJC no. 009942.

Rugitermes tinto is known from the Cauca River Valley montane ecoregion (Pereira) which has a mesic climate (Olson et al. 2001) and from the higher slopes of the Magdalena River Valley ecoregion (Villeta) which is characterized by more xeric forests (Sánchez-Cuervo et al. 2012).

“Tinto” is the Colombian name for plain black coffee which is reminiscent of the dark coloration of the R. tinto soldier head capsule. The type locality of R. tinto, Pereira, is also in the major coffee growing area of Colombia.

Figure 4. 

Anteriodorsal views of Rugitermes soldier heads from South America. Margins of left frontolateral ridges enhanced. A R. bicolor, PU946 B R. flavicinctus, TT88 C R. laticollis, EC1465 D R. magninotus, PU1087 E R. occidentalis, AG380 F R. niger, AG500 G R. nodulosus (modified from fig. 14, Krishna 1961) H R. rugosus PA1186. Accession numbers from UFTC (Scheffrahn 2019b). Scale bars: 1 mm.