An integrative revision of the genus Isognathotermes (Termitidae: Cubitermitinae) with description of seven new species and four new subspecies

Cubitermitinae species whose workers have enteric valves of the fungifaber and finitimus patterns were previously gathered into the genus Isognathotermes. Here, we revise this genus, combining the morphological and anatomical features of all castes, as well as the species’ chorological, ecological, and phylogenetic (mitogenome) characteristics in an integrative taxonomic approach. In addition to the genetic signature, the best morphological criteria for generic recognition are found in the workers’ EVA (enteric valve architecture) and the spinosity of the fore coxae of the workers, and the best criteria for specific recognition are found in (a) the valve and caecum of the workers, (b) the caecum, dimensions of the head, and curvature of the mandibles of the soldiers, and (c) the dimensions of the head and the relative dimensions of eyes and ocelli of the imagines. After revision, only eight of the 22 known taxa remain valid, 14 known taxa become junior synonyms, and one is considered as incertae sedis; six new morphologically recognizable species, one cryptic species and four new subspecies are described. The mitogenome of 12 out of the 15 valid species have been sequenced. The following described species are considered valid: I. bulbifrons (Sjöstedt, 1924), I. finitimus (Schmitz, 1916), I. fungifaber (Sjöstedt, 1896), I. minitabundus (Sjöstedt, 1913), I. planifrons (Sjöstedt, 1924), I. severus (Silvestri, 1914), I. ugandensis (Fuller, 1923) and I. zenkeri (Desneux, 1904). The following species are described as new: I. acristatus Josens & Deligne sp. nov., I. modicus Josens & Deligne sp. nov., I. magniplanifrons Josens & Deligne sp. nov., I. phallicaecalis Josens & Deligne sp. nov., I. phalloides Josens & Deligne sp. nov., I. rectimalatus Josens & Deligne sp. nov., and I. similifinitimus Josens & Deligne sp. nov. Four new subspecies of I. ugandensis are recognized: I. ugandensis burundii Josens & Deligne subsp. nov., I. ugandensis kenyae Josens & Deligne subsp. nov., I. ugandensis malawii Josens & Deligne subsp. nov., and I. ugandensis ugandensis Josens & Deligne subsp. nov. The following species are considered junior synonyms: I. antennalis (Sjöstedt, 1924), I. banksi (Emerson, 1928), I. comstocki (Emerson, 1928), I. fungifaber var. elongata (Sjöstedt, 1924), I. gaigei (Emerson, 1928), I. gibbifrons (Sjöstedt, 1924), I. heghi (Sjöstedt, 1924), I. kemneri (Emerson, 1928), I. loubetsiensis (Sjöstedt, 1924), I. modestior (Silvestri, 1914), I. schmidti (Emerson, 1928), I. silvestrii (Sjöstedt, 1925), I. speciosus (Sjöstedt, 1924), and I. subarquatus (Sjöstedt, 1926). Are considered as incertae sedis: I. bredoi (nomen nudum), I. congoensis (Emerson, 1928), an “I. aff. planifrons” (undescribed), and an unknown Isognathotermes from Malawi (undescribed). GenBank accessions: see Suppl. file 3 and ‘Material examined’ of each chapter.