Cyphonethes biseriatus ( Verhoeff, 1900 ) Karaman & Horvatović, 2018

Karaman, Ivo M. & Horvatović, Mladen, 2018, Revision of the genera Cyphonethes Verhoeff, 1926 and Titanethes Schioedte, 1849 (Isopoda: Oniscoidea: Trichoniscidae) with a description of a new genus and three new taxa, Zootaxa 4459 (2), pp. 261-284 : 263-265

Cyphonethes biseriatus ( Verhoeff, 1900) comb. nov.

Figs 1–2

Titanethes biseriatus: Tabacaru, 1996

Titanethes biseriatus: Schmalfuss, 2003

Microtitanethes licodrensis: Pljakić, 1977 syn. nov.

Microtitanethes licodrensis: Tabacaru, 1996

Microtitanethes licodrensis: Schmalfuss, 2003

Material examined: Serbia: Krupanj, Lipenovići, Lukića pećina cave, 7.4.2008, leg. I. Karaman & M. Horvatović, 1♀ ; ibid. 24.5.2008, leg. I. Karaman & M. Horvatović, 1♂ ; Sjenica, Vranjina pećina cave, 4♂, 7♀ ; Sjenica, 17.4.1973 , 1♂, 3♀. Montenegro: Rožaje , Bać , vrelo (fountainhead), 2.8.1972, leg. M. Pljakić, 2♀; ibid. 13.2.1974 , leg. M. Pljakić, 3♂, 2♀. Bosnia and Herzegovina: Republika Srpska, East Herzegovina, Fatničko polje, Lepirnica cave, 18.6.2003 , leg. I. Karaman, 2♂, 3♀. Macedonia: Skopska Crna Gora Mt, Banjani, Monastery Sveti Ilija, 17.4. 2000 , leg. I. Karaman, 1♀; Skopska Crna Gora Mt, Blace, Fuše špela cave, 27.2.2007, leg. I. Karaman, 11♂, 28♀ ; Skopje, Rašće, Dona Dupka cave, 7.10.2009, leg. I. Karaman, 1♀.

Diagnosis. Medium sized species (up to 4.4 mm long) without tegumental sexual gland-piliferous organ. Cephalon with three rows of small and low tubercles; Pereon tergites smooth with two transversal rows of small, low tubercles. Exopodite of pleopod 1 with widely rounded distal margin ( Fig. 1 ); medial margin of pleopod 2 exopodite with distinct curvature toward its distal end ( Fig. 2 ).

Remarks. The distribution of these species includes an unusually wide area of the central part of the Balkan Peninsula, where it occurs only sporadically ( Fig. 3 ), in isolated and mutually remote karstic regions. The species is described on the basis of a single female specimen from a cave in the vicinity of the town of Trebinje in the eastern part of Herzegovina. Strouhal (1939c) mentioned two additional cave localities in the wider surroundings of Trebinje from which three female specimens of this species were collected. According to the position of the localities and listed fauna of the remaining cave isopods, we believe that these findings are reliable and that certainly relate to this species. In any case the species is recognizable in the local fauna of cave isopods by two transversal rows of tubercles on pereon tergites and by its body dimensions. Over our long term biospeleological investigations on terrestrial isopods on the terrain of Eastern Herzegovina (including Trebinje vicinity and a cave that could be the Vučja pećina cave—locus typicus of C. biseriatus ) we found this species only on one occasion, in a cave located about 35 km north of Trebinje. This best illustrates the fact that C. biseriatus is very rare. However, the fact that adults of C. biseriatus by size resemble juvenile specimens of the genus Alpioniscus and Cyphonethes herzegowinensis (that are otherwise frequent and numerous in the caves of this area) should not be neglected. Therefore, during the selective collection of cave isopods they could easily be overlooked.

Distribution of C. biseriatus covers territories that do not share congruent fauna, particularly where cryptobionts are concerned. This can be explained only by its possible dispersion during the Pleistocene, when there had to be adequate corridors of substrate saturated with moisture which provided for the expansion of this species, especially to the east. We found specimens of T. biseriatus , in a small and relatively dry cave in West Serbia (the northernmost point of the species known areal—loc.typ of Microtithanethes licodrensis syn. nov.), deep in the crevices of cracked clay in a very humid part of the cave. However, the appearance of this species of real troglobite—without pigment and with reduced eyes, its unusual distribution and finding outside caves from the localities of Bać ( Pljakić 1977) and our finding of a specimen on Skopska Crna Gora Mt ( Macedonia), suggest it is more likely to be an element of MSS (Mesovoid Shallow Substratum) fauna with specific requirements for high humidity. Such conditions in the past could have provided littoral along river and stream flows of primarily karstic terrains that most likely allowed wide dispersion of this species (then as epigean), as is the case with the Carpatho- Balkan isopod species Mesoniscus graniger (Frivaldsky, 1865) . These findings of specimens of this species outside a cave, in an ambient that is more suitable for organisms inhabiting MSS, speaks about the true nature of this species, i.e. it is a species that has relatively recently settled underworld. We mainly found specimens of this species in small numbers and always in the deeper parts of caves where real troglobionts are present.

It is worth noting that in a cave (Kovačevića pećina cave) near the cave with C. biseriatus in West Serbia (Lukića pećina cave), two interesting troglobite/troglophile species were found ( Kličković et al. 2007): the pselaphid species Bryaxis blacensis (Karaman, 1954) and the julid diplopod species Apfelbeckia insculpta (L. Koch, 1867) . Bryaxis blacensis was described from a cave near Blace at Skopska Crna Gora Mt in Macedonia (close to the cave where we found C. biseriatus ). The two listed caves, far from each other, are the only known findings of this species up till now. The julid diplopod A. insculpta is often a characteristic troglophile for south diniaric caves where C. biseriatus is also present. This finding is the most remote finding of this species to the north; the same holds true for C. biseriatus . Thus, the mentioned species are connecting distant and faunistically remarkably different regions, as a testimony to past invasions of some faunal elements in certain areas, but also as an expression of the zoogeographical closeness of these regions in the past.

In most cases we found C. biseriatus sympatrically with other cave isopod species. On the southern part of its distribution (east Herzegovina) it appears together with Cyphonethes herzegowinensis and some species from the genus Alpioniscus ( Alpioniscus (I.) heroldii Verhoeff, 1931 or A. (I.) herzegowinensis Verhoeff, 1931 ). In the Dona Dupka cave (Rašće, Macedonia) it appears together with Cyphoniscellus (Vardaroniscus) tetraceratus (Buturović, 1955) . At localities in Serbia we found them together with the species Mesoniscus graniger (which was more numerous), that by size and body shape does not differ, so it is possible to overlook the presence of this species when found in mixed populations.

Figures

FIGURE 3. The geographical distribution of the genera: Titanethes, Cyphonethes and Cetinjella n. g. (ITA–Italy; AUS– Austria; SLO–Slovenia; CRO–Croatia; BIH–Bosnia and Herzegovina; HUN–Hungary; ROM–Romania; SRB–Serbia; MNE– Montenegro; ALB–Albania; MK–Macedonia).

FIGURES 1–2. Cyphonethes biseriatus, male. 1, pleopod 1. 2, pleopod 2. Scale bar = 0.5 mm.