Glareadessus franzi WEWALKA & BISTRÖM 1998

Ewalka, Pešić, V. & Darvishzadeh, I., 2012, Faunistic notes on some Hydradephaga from the Khuzestan, Hormozgan and Sistan & Baluchestan provinces in Iran, with descriptive notes on the female of Glareadessus franzi WEWALKA & BISTRÖM 1998 (Coleoptera, Dytiscidae, Noteridae), Linzer biologische Beiträge 44 (2), pp. 1057-1070 : 1058-1060

Glareadessus franzi WEWALKA & BISTRÖM 1998

Glareadessus franzi WEWALKA & BISTRÖM 1998: 62 (original description); NILSSON 2012 (distribution).

So far this species was known only from the male holotype ( Fig. 1 ) which is stored in the NMW. The holotype was collected at light ; the label data are: " Iran – 2.5.1974 Manujan [= Manoojān , in Kerman province; ca. 27.4N 57.5E; triangle (3) in Fig. 23], 110 km E Bandarabess (26), leg. Pretzmann, Lichtfang [light trap], Exp. Nat. Hist. Mus. Vind." [printed], a male sex-symbol, " Holotypus, Glareadessus franzi sp.n., Wew. & Bistr. [19]98" [red, printed]. The abdomen, the median lobe and the parameres are glued behind the specimen on the same card. The holotype is rather fragile (and probably slightly immature) and, thus, we did not unglue the specimen to study its underside or other details .

Vladimir Pešić collected two females ( Fig. 2 ) by means of a pump in the river Rudan in the Hormozgan province (= Ostān-e Hormozgān) in south-eastern Iran (triangle (2) in The description of both Glareadessus by WEWALKA & BISTRÖM (1998) is fully appropriate, in particular, they did not report that the male protarsomeres are dilated (compared to those of females). We can confirm that these are not dilated, however, want to add another observation: The first three protarsomeres of the females of G. franzi are provided with setae each of which are distally slightly enlarged to a small sucker cup ("sucking setae"). A few more distally placed setae on the first and second tarsomeres seem to be more strongly enlarged and elongated and reach to the proximal part of the following tarsomere. The sucker cups are imperceptible if the specimens are dry. The protarsomeres must be clean, the specimens kept for a while in water (preferably, afterwards additionally for a while in ethanol) and even then are still difficult to observe. A microscope with high magnification is needed (ca. x 200) and the tarsomeres must be illuminated in an appropriate orientation. We did not study the fragile male holotype of G. franzi , but found similar setae in the females and males of G. stocki , those of the males appearing slightly larger. The cups are too small to be photographed with our equipment. The few specimens which were at our disposal did not allow us to study these structures using an SEM (scanning electron microscope), and the need for wet specimens would really preclude this technique. To our knowledge sucker setae have never been reported for Bidessini (also not in the revision by BISTRÖM 1988) except in LARSON et al. (2000: 101) who state in the case of North-American Bidessini: "Male pro-and mesotarsomeres 1 to 3 narrowly dilated and ventrally bearing several adhesive setae in most species."

We have not been able to find significant differences in extern characters between the male holotype from Manujan and the two females found at Rudan, except the shape of the pronotum. In both sexes it is more or less cordiform because the side margins are sinuate before the posterior angles (in contrast to G. stocki ; cf. Figs 4-5 ), however, these angles are more or less rectangular in both females whereas they are slightly acute in the holotype (cf. Figs 1-2 ). On the other hand the female from Banglayan is larger (and somewhat darker) and has the posterior angles of the pronotum distinctly more acute than the other females (even more than the male holotype), thus, the pronotum appears more cordiform ( Fig. 3 ). We can not exclude the possibility that this specimen belongs to a closely related, but still unknown species. Without having a larger series of specimens, and in particular without males, we refrain from describing a new species at present.

The female genitalia of both Glareadessus have not been figured so far. A gonocoxosternum and a gonocoxa are given in Figs 6 and 7 for G. franzi and in Figs 8 and 9 for G. stocki . It has been rather difficult to prepare these small structures, and, thus, some details may have been overlooked or misinterpreted. Additionally, the shape of the gonocoxosterna seems to be somewhat variable (even those of a single specimen appeared not necessarily identical). The blade of the gonocoxae, however, has been found in all females studied to be longer in G. franzi than in G. stocki . The female genitalia of both species do not deviate considerably from those of other Bidessini studied (cf. the illustrations of the genitalia of members of the Bidessus minutissimus -group given in FERY 1992).

DNA: The DNA of the specimen from Banglayan (voucher number IBE-RA 640) was extracted by colleague I. Ribera (Barcelona, Spain) using commercial column kits. Two fragments of the cytochrome oxydase 1 (cox1) were sequenced: one from the 5' end with primers LCO1490-HCO2198 (the "barcode" fragment, HEBERT et al. 2003), and the second from the 3’ end with primers jerry-pat ( SIMON et al. 1994). Both sequences have been deposited in Genbank with accession numbers HE980448 and HE980449 .

Notes: Whilst so far only four specimens of G. franzi exist in collections, there are many specimens of G. stocki in several collections. This species originally has been described from three localities in Oman (WEWALKA & BISTRÖM 1998: 61), but was recently also found in high number at several localities in the United Arab Emirates [= UEA] (HÁJEK & BRANCUCCI 2011: 132) ( Fig. 23; locus typicus: empty circle; other localities: filled circles; one locality in southern Oman is not included in the map (ca. 800 [!] km SW of the locus typicus, between Şalālah and Mirbāţ, near the border to Yemen); here three paratypes have been found.). The specimens have been collected at the Oman sites in the groundwater of wadis by means of a pump, between gravels in ca. 1 m depth. In the UEA the species was found mostly in light traps, however, also in Malaise and water traps and not in the underground, but in streams and in a pool. Thus, the characterisation of G. stocki as a "predominantly subterranean" (WEWALKA & BISTRÖM 1998: 61) species should be related; possibly, the term "semi-subterranean" is more appropriate. Further collecting actions might reveal that also G. franzi must be treated as a semi-subterranean species.

Notes: The larva of G. franzi so far is unknown, however that of G. stocki has been described by ALARIE & WEWALKA (2001).

Figures

Figs 1-5: Habitus of (1) Glareadessus franzi, male holotype, (2) female from Rudan, (3) female from Banglayan; (4) G. stocki, male, (5) female; both specimens from Wadi Maidaq, UAE.

Figs 6-9: Female genitalia of Glaredessus franzi (6) gonocoxosternum, (7) gonocoxa, and of G. stocki (8) gonocoxosternum, (9) gonocoxa.