Leucos albus Marić, 2010

Bianco, Pier Giorgio & Ketmaier, Valerio, 2014, A revision of the Rutilus complex from Mediterranean Europe with description of a new genus, Sarmarutilus, and a new species, Rutilus stoumboudae (Teleostei: Cyprinidae), Zootaxa 3841 (3), pp. 379-402 : 391-392

Leucos albus Marić, 2010

( Fig. 2 E)

Rutilus albus Marić, 2010: 153 (type locality, Lake Skadar, Montenegro).

Examined materials. IZA 0 421, 2, Montenegro, R. Moraca at the confluence with R. Zeta, D. Maríc and P.G. Bianco, 11 November 1999 (specimens also tested molecularly by Ketmaier et al. (2008).- IZA 0 469, 7, 58, Republic of Montenegro, R. Zeta, 13 November 1999, P.G. Bianco and D. Marić.

Diagnosis. This species was recently described by Marić (2010). Here we provide a short diagnosis according to our materials from the Moraca-Zeta river system, which flows into the Lake Skadar; the species is not reported for that rivers ( Marić, 2010). Leucos albus can be distinguished from L. basak , its closest relative genetically (see Fig. 1 B), for the number of LL pored scales (41–44 in Leucos albus 37–39 in L. basak ) and for the modal number of branched rays in the D (9 in L. basak , 8 in L. albus ). Flanks are silvery, without lateral bands as observed in L. aula .

Description. A small-medium sized species, not exceeding 190 mm SL, usually 80–120 mm SL. Body uniformly silvery without longitudinal band; color of eye in living fish, yellowish; fins yellowish or pale grayish in preserved specimens; snout pointed, pre-orbital distance near equal to the horizontal diameter of the eye; lips smooth; mouth opening oblique, the corner of maxillae slightly protruded and at level with the vertical crossing of the anterior border of the orbit; mouth slightly inferior; profile of dorsum convex; paired and unpaired fins yellowish; free margin of dorsal and anal fins concave; caudal fin forked; peritoneal membrane blackened by several melanophores addensed and fused; head length more than 3.8–4.0 times in the SL; body deep about 3.6–3.8 times in the SL; origin of the D at same level of the insertion of the P2; LL complete, and extending from the margin of opercular membrane, to the end of caudal peduncle; 41–44 pored scales, usually 41–42; 7.5 above and 3.5 below the LL; constantly 3 un-branched rays followed by 8 branched rays in the D; constantly 3 un-branched and usually 8 branched rays in the anal fin; P1s with 1 un-branched and 14–15 branched rays; P2 with 1 unbranched ray and constantly 8 branched rays; usually 8–9 total GR; in adult males prominent or vestigial tubercles absent. The specimens from River Moraca differ from those from Lake Skadar for a more pointed snout and slender body. For additional description and shape, see Fig. 2 E and Tables 1, 2.

Distribution. L. albus is originally described from Lake Skadar ( Montenegro): it is quite rare in the lake, but seasonally frequent in submerged springs ( Marić, 2010). We also found the species in Zeta and Moraca river system, both flowing into Lake Skadar. The species was found together with Salmo sp, Telestes montenegrinus and Phoxinus phoxinus , all cold-water adapted species. The species, which seems riverine adapted, is steadily declining both in rivers Moraca and Zeta mainly due to illegal fishing of trout (Drago Marić, pers. comm.). The scarce material we obtained (nine specimens) is the result of extensive sampling efforts by electro fishing between 9 and 13 November 1999.

Remarks on ecology, biology and conservation. According to Maríc (2010), the preferential habitats are the sub-lacustrine springs of Lake Skadar, where large numbers of fish gather during the winter period. We found also a riverine sample. Leuco albus coexists with L. basak in Lake Skadar. The proportion between Leucos albus and L. basak is 20: 1 in favor of the second. Spawning season starts in January but in February females have spent gonads. Leucos albus spawns earlier in the season than L. basak . Still not evaluated by IUCN International commission, but according to the IUCN (2012) category, it satisfy to the point B of the “Endangered Category”, as the area of occupancy is less than 500 km 2 and the species is known only from one basin (Lake Skadar and the river flowing into it), which continues to decline as a result of habitat alteration ( Marić, 2010).

Figures

FIGURE 2. Native species of the Rutilus complex in southern Mediterranean Europe: A) Leucos aula, 115 mm SL, R. Bacchiglione, northern Italy, April 1996 (IZA 0425); B) Leucos basak, 95 mm SL, Lake Ohrid, FYROM, August 1987, (IZA 0429); C) Leucos ylikiensis, 120 mm SL, Lake Yliki, April 1987 (IZA 8733); D) Leucos panosi, 130 mm SL, canal to Lake Trichonis, May 1987 (IZA 8766); E) Leucos albus, 98 mm SL, River Moraca, Montenegro, November 1999 (IZA 0421); F) Sarmarutilus rubilio, 100 mm SL, River Ofanto, southern Italy, February 2002 (IZA 02183); G) Rutilus pigus, 230 mm SL, Lake Major, northern Italy, (IZA 0474); H) Holotype of Rutilus stoumboudae new species, 148 mm SL, October 1998, Lake Volvi, Greece (IZA 02107).

FIGURE 1. A) Collecting localities (L. = lakes, R. = rivers) of Rutilus complex species. 1, R. Thames; 2, R. Danube (Slovakia); 3, R. Danube (Romania); 4, L. Como; 5, L. Maggiore; 6, R. Arno and R. Serchio; 7, R. Albegna and R. Cecina; 8, R. Ombrone and R. Fiora; 9, R. Tiber and R. Mignone; 10, L. Trasimeno; 11, R. Liri and R. Garigliano; 12, R. Volturno and R. Sele; 13, R. Pescara and R. Tavo; 14, R. Trigno; 15, R. Tronto; 16, R. Livenza; 17, L. Pernica; 18, R. Sava; 19, L. Drusino; 20, R. Krupa (R. Neretva basin); 21, L. Besanka (R. Neretva basin); 22, R. Moraca and R. Zeta; 23, L. Skadar; 24, L. Dojran; 25, L. Horid; 26, L. Prespa and L. Micraprespa; 27, L. Vegoritis; 28, L. Volvi; 29, L. Joannina; 30, L. Yliki and L. Paralimni; 31, L. Ambrakia; 32, L. Trichonis. Bold numbers are the different peri-Mediterranean ichthyogeographic districts described in Bianco (1990). B) A schematic temporal reconstruction of the diversification of the genus in southern Mediterranean Europe based on cyt- b is shown (modified from Ketmaier et al., 2008). For each taxon the corresponding number of the district of origin is shown; triangles indicate that multiple populations were analyzed. Numbers at nodes are divergence times in million years; all labeled nodes were robustly supported in the phylogenetic reconstructions (see Ketmaier et al., 2008 for further details).