Alburnoides manyasensis (Actinopterygii, Cyprinidae), a new species of cyprinid fish from Manyas Lake basin, Turkey

Abstract Alburnoides manyasensis, sp. n., is described from the Koca Stream (Lake Manyas drainage, Marmara Sea basin) in Anatolia. It is distinguished from all species of Alburnoides in Turkey and adjacent regions, Alburnoides tzanevi (Rezovska [Rezve], Istranca and Terkos streams in the western Black Sea drainage), Alburnoides cf. smyrnae (Banaz Stream, a drainage of Büyük Menderes River, Aegean Sea basin), Alburnoides fasciatus (streams and rivers in the eastern Black Sea drainage) and Alburnoides eichwaldii (Kura and Aras rivers [a drainage of Kura River], Caspian Sea basin) by a combination of the following characters (none unique to the species):marked hump at nape, especially in specimens larger than 60 mm SL; partly developed ventral keel between pelvic fin and anal fin, scaleless 1/2 to 2/3 its length; body depth at dorsal-fin origin 29−32% SL; caudal peduncle depth 11−12% SL; 45–52+ 2–3 lateral-line scales; 9–12 scale rows between lateral line and dorsal-fin origin; 4–5 scale rows between lateral line and anal-fin origin, 10½–12½ branched anal-fin rays; 40–42 total vertebrae.

The genus Alburnoides is widely distributed in Turkey in rivers and streams of basins of the Marmara, Black and Aegean seas from tributaries of Büyük Menderes River in the west, Euphrates and Tigris river drainages in the east and south-east, and Kura River drainage in the east, being absent only from the Mediterranean Sea basin (Kuru 1975, Erk'akan 1983, Kutrup 1994, Turan 2003, Kuru 2004, Geldiay and Balık 2009. The populations of Alburnoides from streams and rivers in the eastern Black sea coast of Turkey were identified as A. fasciatus, and populations from Kura as A. eichwaldii (Bogutskaya et al. 2010).
In order to understand the Alburnoides diversity in Turkey, we sampled at 105 localities throughout the country between 2004 and 2012. In this paper we shall only discuss Alburnoides distributed in the Manyas Lake drainage in Marmara sea basin of Turkey (Fig. 1). After comparison with the other Alburnoides species of Turkey, including Kura River (Caspian Sea basin), Menderes River (Aegen Sea basin), also rivers Terkos, Istranca, Çoruh and İyidere (Black Sea basin), we concluded it is a distinct unnamed species which we describe herein as A. manyasensis.

Materials and methods
Fish were caught by pulsed DC electrofishing equipment and killed by over overanestization, fixed in formaldehyde and stored in ethanol. Material is deposited in: FFR, Recep Tayyip Erdoğan University Zoology Museum of the Faculty of Fisheries (Former Fisheries Faculty of the city of Rize). Counts and measurements follow Hubbs and Lagler (1947) except as follows. Head width 1 : the distance between the anterior eye margins; head width 2 : the distance between the posterior eye margins; head width 3 : the head width at the nape; head depth 1 : the head depth through the eye; head depth 2 : the head depth at the nape; snout width: measured at level of the nostrils. The lateral-line scales are counted from the anteriormost scale (the first one to touch the shoulder girdle) to the end of the hypural complex. The scales on the caudal fin itself are indicated by '+'. The last two branched dorsal and anal rays articulating on a single pterygiophore are counted as 1½. The number in parentheses after a count indicates the frequency of occurrence of the count. Vertebral counts were obtained from radiographs and counted as total, predorsal, abdominal and caudal vertebrae following Bogutskaya and Coad (2009). Predorsal vertebrae include the Weberian vertebrae and abdominal vertebrae anterior to the first dorsal-fin pterygiophore. Abdominal vertebrae were counted from the first Weberian vertebra to the one just anterior the first caudal vertebra. The first caudal vertebra is that with its haemal spine fully developed (Fig. 2). The count of total and caudal vertebrae includes the last complex vertebra bearing hypurals.
The morphometric characters of the five species of Alburnoides from Turkey were compared by Principal Component Analysis (PCA) using a covariance matrix on logtransformed measurements and counts with the software package PAST version 1.8 (Hammer et al. 2001).
Sexual dimorphism. There are small tubercles on rays of anal fins in male. The length of the paired fins does not display any statistically significant difference in males and females as it often occurs in other Alburnoides species.
Coloration. Formalin preserved adults and juveniles brownish on back and upper part of flank, yellowish on lower part of flank and belly. Caudal and dorsal fins light grey; pectoral, pelvic and anal fins yellowish. Spots along lateral line above and below pores slightly distinct in anterior part of body but indistinct in posterior part. Dark grey stripe (its width approximately equal to eye diameter) on upper part of flank from posterior margin of operculum to caudal peduncle, slightly distinct in anterior body part but clearly distinct in posterior part. No or few dark pigment dots on each scale pocket below lateral stripe.
Etymology. The name of the species, an adjective, is derived from the name of Lake Manyas.

Discussion
We compared the material from the Koca Stream in the Marmara Sea basin with Alburnoides fasciatus from streams and rivers in the eastern Black Sea basin, Alburnoides eichwaldii from Kura and Aras rivers (Kura River drainage) and Alburnoides tzanevi from Rezovska (Rezve), Istranca and Terkos streams in the western Black Sea basin.
No specimens were collected from the type locality of A. bipunctatus var. smyrnae although we checked it (Melel Stream, Aegean Sea basin) as well as some streams and rivers near İzmir (ancient Smyrna, Aegean Sea basin, Turkey). Thus, we failed to catch any specimens from the population which is known to exist quite sparsely in the province of İzmir where the habitat is heavily degraded. Instead, we examined 8 specimens of Alburnoides from Banaz Stream, a tributary of Büyük Menderes River, Aegean Sea basin. The Banaz Stream population exibits character states similar to those known in A. bipunctatus var. smyrnae such as the numbers of lateral-line scales and anal-fin branched rays. They have 41-46 total lateral line scales according to Pellegrin (1928: 86) and 42-47 in our material, and 13-15 branched anal-fin rays according to Pellegrin (1928: 86) and 12½-14½ in our material. The population from the Büyük Menderes River is most probably conspecific with A. bipunctatus var. smyrnae. Therefore we identify them as Alburnoides cf. smyrnae (Fig. 4) and suppose it is a distinct valid species. It is distinguished from all species of Alburnoides in Turkey and adjacent watersheds by fewer total lateral-line scales (42-47, vs. 47-57, except for A. tzanevi) and a longer caudal fin (length of the upper caudal-fin lobe 28-31% SL, vs. 21-28, see Table 1). Besides characters mentioned, Alburnoides cf. smyrnae differs from A. tzanevi by having a deeper body (28−30% SL, mean 28.6, vs. 24−27, mean 25.4).
The type locality of Alburnoides bipunctatus tzanevi is Rezovska River in Bulgaria, Black Sea drainage. We consider it to be a valid species because it can be easily distinguished from all species of Alburnoides in Turkey and adjacent area by a more slender body (the body depth at dorsal-fin origin about equal to the head length, vs. the body depth at dorsal-fin origin commonly greater than the head length), a considerably pointed snout (vs. slightly pointed or rounded). The detailed metric and meristic characters of A. tzanevi are given in Tables 1 and 3.
Besides the differences given above, Alburnoides manyasensis is distinguished from A. tzanevi by the presence of a hump at nape in specimens larger than 60 mm SL (vs. absent) and a deeper caudal peduncle (11-12% SL, mean 11.5, vs. 9-11, mean 9.9). In A. manyasensis, pigmentation of the lateral line is slightly distinct in anterior part of the body but indistinct in posterior part of body (Fig. 3) and the snout length is markedly shorter than interorbital distance in contrast to A. tzanevi (Fig. 5) with the lateral line clearly distinct in both the anterior and posterior parts of the body and the snout length about equal to the interorbital distance.
Alburnoides manyasensis differs well from A. fasciatus by the presence of a hump at nape in specimens larger than 60 mm SL (vs. absent) and in having fewer branched anal-fin rays (10½-12½, vs. 13½-15½) and fewer predorsal vertebrae (13-14, mode 14, vs. 14-15, mode 15). It is further distinguished from A. fasciatus by a more slender body (29-32% SL, mean 29.4, vs. 25-30, mean 27.8), a narrower head (head width at the anterior eye margin 8-10% SL, mean 8.8, vs. 10-11, mean 10.1) and a longer caudal peduncle (20-25% SL, mean 22.2, vs. 17-21, mean 19.1). In A. manyasensis, the eye diameter is longer than both the snout length and the interorbital width, while in A. fasciatus the eye diameter is smaller than both the snout length and the interorbital width (Table 2). In A. manyasensis, pigmentation of the lateral line is slightly distinct in the anterior part of the body but indistinct in the posterior part (Fig 3) in contrast to A. fasciatus (Fig. 6) with the lateral line clearly distinct in both the anterior and posterior parts of the body.