Steirodontina Brunner-Wattenwyl, 1878

Subtribe Steirodontina Brunner-Wattenwyl, 1878

Note. This subtribe consists of two groups of genera which are clearly distinguished from each other. The first group includes the genera Steirodon Serville, 1831 , Cnemidophyllum Rehn, 1917 and Emsleyfolium Cadena-Castañeda, Mendes et Alves-Oliveira, 2016 which are rather diverse in general appearance but characterized by the presence of a pair of rather large lobules on the tenth (last) abdominal tergite in female; also they usually have distinct denticulated or crenulated keels along the dorsolateral edges of the pronotum (these keels run from anterior to posterior edges of the pronotal disc), and often are with widened proximal portions of the middle and hind tibiae. Differences between these genera (except for Emsleyfolium ) are not very clear: for example, no even one general character which may distinguish Steirodon from Cnemidophyllum . But members of these genera are rather diverse and form several subgenera which are more suitable for determination. However, combining these subgenera into a single genus would make such a genus excessively diverse, and raising them to generic rank would make such genera very fragmented. This is a reason why I adopt here the classification of Emsley (1970), where the genera Steirodon and Cnemidopyllum are divided into subgenera, but indicate that some subgenera are very similar and may be synonymized with each other, and that Emsleyfolium may be considered as a subgenus of Cnemidophyllum s. l. (judging by the characteristic ratio of the sizes of their rostral tubercles).

The second group contains the genera Stilpnochlora Stål, 1873 and Nicklephyllum Cadena-Castañeda, 2016 . This group differs from the previous one in the absence of paired lobules on the abdominal tergites in female, in a diverse condition of the pronotal dorsolateral keels (from their almost complete absence to the condition similar to that of Steirodon and Cnemidophyllum ), and in almost unexpanded proximal portions of the middle and hind tibiae. These genera have not yet been divided into subgenera, but Nicklephyllum may be treated as a second subgenus of this genus, because its very large pronotal denticles may have been formed by their enlargement from the condition characteristic of S. incisa Brunner-Wattenwyl, 1878 , and the other differences of this genus from Stilpnochlora (except for reduction of procoxal spine) are within the diversity of the latter genus including the structure of the male cercal apex: in Nicklephyllum , it is with one undivided apical denticle; but in Stilpnochlora , it is with two such denticles, with one partly forked denticle, or sometimes with one undivided denticle.

Thus, the pronotal dorsolateral keels in these groups almost certainly have an independent origin, and for distinguishing this subtribe from similar ones, I can only suggest the characteristic structure of the ovipositor: it is very small, slightly curved, weakly sclerotized, without denticles and with a rounded or narrowly rounded apex (such an ovipositor is probably used only for oviposition on the open surface of branches and leaves). However, similar ovipositors are also developed in some genera of the subtribe Microcentrina . Moreover, one of these genera ( Syntechna Brunner-Wattenwyl, 1878 ) is very similar to Stilpnochlora practically in all other characters of their external structure, except for the absence of even traces of any pronotal keels in Syntechna . So, the latter genus looks as a possible ancestral taxon for Stilpnochlora , and the “second group of Steirodontina ” in reality may be included in Microcentrina or, together with Syntechna and some other genera, may be considered as a separate subtribe of the tribe Steirodontini .