Heptagoniodes Carriker, 1936

Heptagoniodes Carriker, 1936: 166 (Type species: H. mirabilis Carriker, 1936, by original designation); Guimarães & Lane

(1937: 7); Kéler (1938: 323); Guimarães (1942a: 16); Carriker (1944: 207).

Kelloggia (Heptagoniodes); Guimarães (1948: 163).

Kelloggia Carriker, 1903 (in part); Hopkins & Clay (1952: 166); Price et al. (2003: 189).

Heptagoniodes contains four known species, plus one described below as new; all of them are restricted to hosts of the genus Tinamus . Our study of specimens of Heptagoniodes of four species held in the MZUSP collection allowed us to give here an emendation of the generic diagnosis presented by Carriker (1936) and Guimarães (1942a, 1948), and a comparison with its morphologically close relatives.

Heptagoniodes is morphologically close to Kelloggia Carriker, 1903 and Ornicholax Carriker, 1903 having each side of the first visible tergo-pleurite (= I+II) entirely surrounded anteriorly by the metanotum and laterally by tergo-pleurites III. The first and second visible tergo-pleurites overlap those sclerites in segment III (Figs 1–2). Species of Ornicholax have well developed coni and the antennae are inserted at mid-point of the head lateral margins, whereas in Heptagoniodes and Kelloggia the coni are absent and the antennae are inserted near the front of the head lateral margins. Both sexes of Heptagoniodes can be promptly distinguished from Kelloggia by the absence of serration in the postero-lateral margin of the pterothorax (Fig. 7), which is quite conspicuous in the latter genus (Figs 6, 8). Species of Heptagoniodes have sexually dimorphic antennae (males have the scapus and pedicel swollen and the first flageromere with a dorsal finger-like projection) and a deep post-ocular emargination (Figs 3–4). The head of Kelloggia males is similar to those of the females (see Fig. 6). Another important character to distinguish both genera is head chaetotaxy: in both sexes of Heptagoniodes, the pns (postnodal seta) and pts (postemporal seta) are developed into distinct setae (Figs 4–5), while in Kelloggia they are like sensilla (Fig. 6); in males of Heptagoniodes four (s3–s6) of the six head sensilla placodea are developed into well-formed setae, while in Kelloggia the s1–s6 are sensilla in all species (Fig. 6). Furthermore, the shape of the mesosome in the male genitalia of both genera is different (compare Fig. 9 vs Figs 10–12).

The head sexual dimorphism of Heptagoniodes is phylogenetically informative as discussed by Guimarães (1948). The male head emargination is an important character to distinguish the genus Heptagoniodes into two main species groups (see Figs 3–4 and key below). The head shape in species of Kelloggia and Heptagoniodes implies different copulation strategies, and this feature alone supports their generic separation (Guimarães 1948: 163).