Ruptitermes Mathews

Acioli, Agno Nonato Serrão & Constantino, Reginaldo, 2015, A taxonomic revision of the neotropical termite genus Ruptitermes (Isoptera, Termitidae, Apicotermitinae), Zootaxa 4032 (5), pp. 451-492 : 453

Genus Ruptitermes Mathews

Ruptitermes Mathews 1977: 98 ; Krishna et al. 2013: 1407 –1410 (catalog, synonymy). Type-species: Ruptitermes xanthochiton Mathews 1977 , by original designation.

Imago: Head capsule rounded in dorsal view, short and broad, densely covered with short hairs and scattered bristles. Fontanelle variable, elliptical to rounded, usually conspicuous. Eyes relatively small; ocelli rounded or elliptical, distant from eyes by at least its diameter; ecdysial line (epicranial suture) inconspicuous. Postclypeus relatively small and moderately inflated to large and inflated; depressed at both ends of the midline; midline conspicuous, depressed, and incomplete, vanishing near anterior and posterior margins. Mandibles more elongate than those of workers, with proportionately shorter M1, M2, and M3, and smaller molar plate. Molar plate with or without faint ridges. Pronotum narrowing posteriorly, with convex or nearly straight sides. Posterior points of meso- and metascutellum angular, separated by a short distance; margin between points angular or concave. Antenna with 15 articles. Each tibia with two apical spurs. Wings uniformly covered with irregularly shaped micrasters, with 2–4 arms ( Fig. 20 D); wing surface with very few hairs; dense hairs present only along anterior and posterior borders. Females larger than males.

Worker: Monomorphic (but see comments about R. arboreus ). Head broad and rounded, usually well sclerotized and dark colored (pale colored in a few species); chaetotaxy variable. Fontanelle elliptical to rounded, small to large, of variable color, usually conspicuous. Postclypeus inflated or flattened. Left mandible: A shorter than M1 (except in R. bandeirai , sp.n, where they are about the same length), M3 usually very short (except in R. arboreus and R. bandeirai , sp.n); notch between M1 and M3 always present, but variable in size and shape. Right mandible: molar plate concave, without ridges (except in R. arboreus , which has faint ridges). Antenna with 14 articles. Protibia with one or two irregular rows of spine-like bristles; in most species, procoxa with a curved or elliptical line of spine-like bristles (except R. arboreus and R. bandeirai , sp.n). Each tibia with two apical spurs. Protibia variably inflated, thin and elongate in most species. A pair of rounded, well-developed dehiscent glands present in the anterior part of abdomen, filling up to 1/3 of its volume.

Gut morphology: Crop very small in most species (large only in R. arboreus ); gizzard unarmed; mixed segment short to very short, with the mesenteric lobe moderately inflated distally in some species; Malpighian tubules attached directly to midgut at some distance from the border with P1; P1 long and tubular, about the same diameter as midgut; P2 located dorsally at the right side. Enteric valve with bilateral symmetry, bearing 6 unsclerotized, reticulated ridges (3 longer ones on one side and 3 shorter ones on the other side); spines absent in most species. Connection of P2 with P3 forming a seating with 3 lobes (diverticula) or without lobes ( R. arboreus and R. bandeirai , sp. n.).

Comparisons. The workers of Ruptitermes are easily recognized by the presence of the dehiscent glands, which are usually conspicuous as a whitish mass in the anterior part of the abdomen. These glands are the main synapomorphy of this genus and do not occur in any other termite genus. Workers are usually dark colored, with thin and elongate tibiae (with a few exceptions). Imagoes are larger than most other neotropical Apicotermitinae. The imagoes of Aparatermes Fontes 1985 are the most similar and can be distinguished by the shape of the postclypeus, which is not depressed at the ends of the midline. Imagoes of the R. xanthochiton group, which includes most species, can be distinguished from all other neotropical Apicotermitinae by the very small M3 of left mandible and very small M2 of right mandible.

Remarks. 1) There are two distinct groups of species in Ruptitermes : group arboreus includes forest species which lack several the putative diagnostic characters of the genus presented by Mathews (1977) and Fontes (1982, 1992); group xanthochiton includes all other species, which live mainly in savannas and grasslands and fit into the original diagnosis of the genus. The workers of both groups have well-developed dehiscent glands. 2) Because most species are subterranean, there are very few imagoes in the collections; the imagoes of six species remain unknown; they probably show more morphological variation than we present in this paper. 3) Araujo (1977) included Anoplotermes silvestrii Emerson 1925 in Ruptitermes . Sobotnik et al. (2010), in a brief taxonomic note, synonymized A. silvestrii with Aparatermes cingulatus (Burmeister, 1839) . We have examined specimens of both, including types, and concluded that A. silvestrii indeed does not belong to Ruptitermes . Among other differences, their workers lack the dehiscent glands. However, we also concluded that A. silvestrii is not a synonym of A. cingulatus , although their workers are about the same size and superficially similar. Their imagoes are very different and their geographic distribution is disjunct: A. cingulatus occurs only in the grasslands of Southern Brazil, Uruguay, Paraguay, and Argentina, while A. silvestrii is restricted to lower latitudes and is most common in the Amazon region. A revision of the “ silvestrii ” group is underway and will be published separately.

Figures

FIGURE 20. Imago of Ruptitermes xanthochiton Mathews 1977. A, head in profile; B, head and pronotum in dorsal view; C, pterothorax in dorsal view; D, detail of wing membrane showing micrasters.