Issidius PUTON , 1898

E, Werner, M, Atlas & P, Western, 2019, A new genus and three new species of Nogodinidae from North Africa (Insecta, Hemiptera, Auchenorrhyncha, Fulgoromorpha), Linzer biologische Beiträge 51 (2), pp. 933-948 : 934

On Issidius PUTON, 1898 and Rileyopsis BERGEVIN, 1917

According to LETHIERRY & PUTON (1887), the type specimen of Issidius rotundiceps is a male specimen, short-winged and 6 mm long, collected in " Biskra " by "Dr. Ch. Martin". A female is also mentioned as "variété", originating from " Batna ", "D. Ch. Martin", length 5 mm. In contrast, the specimen in MNHN Paris labelled as "Type" of Issidius rotundiceps is a female from Biskra, with a total body length of 6.7 mm (see Fig 1 ). It is doubtful for me if this specimen is indeed the holotype.

Another generic name from this region is Rileyopsis BERGEVIN, 1917 . It was described by BERGEVIN (1917) for a single species, R. peyerimhoffi BERGEVIN, 1917, from Djebel Haouas near El Djelfa, Algeria. Four years later, Ernest de BERGEVIN (1921) published a note on this taxon and name: In this paper, he stated, that R. peyerimhoffi was conspecific with Issidius rotundiceps (and, subsequently, considered Rileyopsis as a younger subjective synonym of Issidius ). He was of the opinion, that this species occurs as small, short-winged morph in the Atlas Mts. (" Issidius rotundiceps var. peyerimhoffi ") and as long-winged morph in the lowland Sahara desert. So, according to BERGEVIN (1921), Rileyopsis BERGEVIN, 1917 is a younger synonym of Issidius PUTON, 1898 and Rileyopsis peyerimhoffi BERGEVIN, 1917 is a younger synonym of Issidius rotundiceps LETHIERRY in PUTON & LETHIERRY, 1887. But, at the time Bergevin published this synonymy, he was neither aware of the importance of (inner male and female) genitalia structures for species identification nor of the enormous species diversity revealed only by studying these structures. So, in fact, the conspecifity of the types should be verified by contemporary methods.

CHINA (1938) described the genus Philbyella , type species P. arabica , but gave no characters to distinguish it from Issidius / Rileyopsis . Studying Nogodinidae specimens from Algeria, where Issidus and Rileyopsis occur, it seems quite probable that in fact Philbyella arabica is congeneric with Issidius and/or Rileyopsis . As the types were untraceable (for me), I compared Philbyella arabica with the descriptions of PUTON (1898) and BERGEVIN (1917). At least two diagnostic characters can be found, that might justify the presence of different genera: BERGEVIN (1917) states, that the hind tibia in Rileyopsis has 3-4 large lateral spines and presents a drawing with 4 spines ( BERGEVIN 1917: 311, Fig 5 ). Philbyella has only 2-3 spines; the only other Nogodinidae genus in Western Palaearcic realm with 4 spines is Iranissus DLABOLA, 1980 . A second characters is the position of the CuA fork in the fore wing: According to the drawings of Rileyopsis in BERGEVIN (1917), the CuA vein is divided into CuA1 and CuA2 clearly distal of the middle of the wing. In Philbyella , this fork is in the middle of the wing or slightly basad of the middle. In the presumptive type of Issidius rotundiceps , a distinct fork is not visible at all ( Fig. 1 ). Until a solution of this problem is found (i.e. the types of Issidius and Rileyopsis are properly identified), I propose to keep the usage of Philbyella as previous authors did (e.g. DLABOLA 1980, LINNAVUORI 1989, GNEZDILOV 2017b).

Figures

Fig 1: Issidius rotundiceps LETHIERRY in PUTON & LETHIERRY, 1887, female specimen from MNHN Paris, labelled as "type". A-C: habitus from dorsal (A), lateral (B) and frontal (C); D: labels of the specimen; E-F: tip of abdomen from caudal (D) and lateral (E); G: habitus sketch from dorsal. Photos Gernot Kunz, (c) MNHN Paris.

Fig 5: Philbyella gnezdilovi nov.sp., holotype: Head and fore body in lateral (A), frontal (B) and dorsal (C) view; left fore wing (D). Drawings by M. Stöckmann.