Cobitis erkakanae, Freyhof & Bayçelebi & Geiger, 2018

Freyhof, Jörg, Bayçelebi, Esra & Geiger, Matthias, 2018, Review of the genus Cobitis in the Middle East, with the description of eight new species (Teleostei: Cobitidae), Zootaxa 4535 (1), pp. 1-75 : 55-58

Cobitis erkakanae , new species

( Fig. 42–44 )

Holotype. ZFMK ICH-98958 , 49 mm SL; Turkey: Adıyaman prov.: river connecting Lakes Gölbaşı and Azaplı west of Gölbaşı , 37.790 37.626.

Paratypes. FSJF 2510 , 16 , 34–65 mm SL; same data as holotype .

Material used in molecular genetic analysis. FSJF DNA-982 ; Turkey: Adıyaman prov.: river connecting Lakes Gölbaşı and Azaplı west of Gölbaşı , 37.790 37.626. (GenBank accession numbers: KJ 552949 , KJ552977 , KJ 553235 ) .

Diagnosis. Cobitis erkakanae is distinguished from other Cobitis species in the Anatolian Mediterranean basin by a combination of characters, none of them unique. It is distinguished from C. evreni from the adjacent Ceyhan River drainage by having a small, roundish or comma-shaped black spot at the upper caudal-fin base (vs. absent) and the blotches in Z2 and Z4 being well separated, horizontally elongate and often fused to adjacent once but not forming a stripe (vs. Z2 and Z4 formed by one continuous stripe on the anterior flank).

Cobitis erkakanae is distinguished from C. aliyeae , C. anabelae and C. levantina by having horizontally elongated blotches in Z2 and Z4, often fused to adjacent once, (vs. blotches in Z2 and Z4 usually well distinct from each other, roundish, or squarish, not elongate), a yellow background colour (vs. silvery or whitish), pigmentation in Z1 well separated from Z2 along its complete length (vs. Z1 and Z2 usually fused into a mottled pattern in C. levantina ), the flank yellowish in life (vs. silvery greyish) and the caudal fin with 4–6 wide, regularlyshaped bands (vs. many, very narrow and irregularly-shaped bands in C. aliyeae , C. anabelae and C. levantina ).

Cobitis erkakanae is distinguished from C. battalgilae and C. phrygica by having one series of horizontally elongate blotches in Z4 (vs. blotches in Z4 usually roundish, squarish or vertically elongate, often very densely set, dissociated in many individuals, especially in C. phrygica , forming a wide band or field of small, irregularlyshaped blotches and spots), usually lacking flank pigmentation below Z4 (vs. present in most C. phrygica and in some C. battalgilae ), having a small, roundish or comma-shaped black spot at the upper caudal-fin base (vs. absent in C. phrygica ), a bifurcate suborbital spine (vs. simple in C. phrygica ), a greater prepelvic (57–61% SL vs. 54–56 in C. battalgilae ), preanal distance (82–85% SL vs. 74–80) and a narrower dorsal-fin depth (16–19% SL vs. 21–22 in C. battalgilae ; 19–21 in C. phrygica ).

Cobitis erkakanae is distinguished from C sipahilerae by having 3–5 brown, large and roundish blotches on the back anterior to the dorsal-fin origin (vs. back plain cream-brown, except few individuals with 1–3 narrow, squarish, brown bars) and a series of distinct blotches in Z4 (vs. a dark-brown stripe in Z4 reaching from above the pectoral-fin base until the dorsal-fin base or beyond).

It is distinguished from C. linea by having large, well separated, usually horizontally elongate blotches in Z4, often fused to each other (vs. very small and roundish or comma-shaped, very densely set, often fused into stripes or dissociated into a field of several rows of blotches). Cobitis erkakanae is distinguished from C. elazigensis by the blotches in Z2 and Z4 being usually horizontally elongate and often fused to each other forming short stripes (vs. blotches in Z2 and Z4 roundish, very widely spaced and not fused to each other), 3–5 dark-brown blotches on the back anterior to the dorsal fin-origin (vs. 5–9) and being much smaller, no female was found to be larger than 83 mm SL (vs. female growing up to 160 mm SL in C. elazigensis ).

Description. See Figures 42–44 for general appearance and Table 6 for morphometric data of the holotype and 16 paratypes. Greatest body depth at or slightly anterior to dorsal-fin origin, decreasing towards caudal-fin base. Head profile slightly convex, head length 1.2–1.6 times in body depth. Snout pointed, its length 0.7–0.9 times in postorbital length. Eye diameter 0.3 times in head depth at eye, 1.4–2.2 times in interorbital width. Caudal peduncle 1.0–1.5 times longer than deep

Pelvic axillary lobe present or absent. Margin of dorsal and anal fins convex. Caudal fin truncate or slightly rounded. A shallow dorsal and ventral keel on caudal peduncle. External part of the suborbital spine bifurcate, reaching slightly beyond centre of eye. Largest recorded specimen 67 mm SL.

Dorsal fin with 3 unbranched and 6½ (15) branched rays. Anal fin with 3 unbranched and 5½ (14) and 6½ (1) branched rays. Caudal fin with 6+6 branched rays in the one male, 7+ 7 in other males, 8+ 7 in the two females. Pectoral fin with 7 (1), 8 (10), 9 (3) and 10 (1) branched rays and pelvic fin with 4 (1) and 5 (14) branched rays. Body completely covered by embedded scales, except on belly and breast. Scales small. Focal zone in subdorsal scales about less than 1/3 or 1/5 of vertical scale diameter. Lateral line short, with 5–9 pores or absent. Lips ( Fig. 54 ) thin and mental lobes of lower lip long, usually well separated from lower lip, produced into a short barbel-like process in few individuals. Rostral barbel reaching base of mandibular barbel. Mandibular barbel reaching to or slightly beyond vertical of nostril. Maxillary barbel reaching vertical of front border or middle of eye.

Sexual dimorphism. Male have a longer pectoral fin than female (17–20% SL vs. 13–17) and two laminae circularis (vs. absent).

Colouration. Background colour yellowish with a dark-brown pigmentation pattern organised in one middorsal and four lateral zones. Mid-dorsal pigmentation consisting in a series of 9–12, elongate blotches, often very closely set or slightly fused. Pigmentation in Z1 well developed, with many very small to medium sized spots narrower than Z2, not reaching dorsally to interspaces of mid-dorsal blotches, fused with Z2 on postdorsal flank. Spots in Z2 about eye size or larger, often fused to adjacent spots, fused to short stripes in two males. Spots in Z2 usually well distinguished until caudal peduncle. Pigmentation in Z4 formed by 3–6 predorsal, 1–2 subdorsal and 5–9 postdorsal blotches, blotches elongate, anterior most and posterior most blotches often roundish. A single, usually indistinct black spot at upper caudal-fin base, less than eye diameter. Upper part of head, opercle and snout covered by large spots. A dark-brown stripe between eye and snout. Fins hyaline. Caudal fin with 4–7 and dorsal fin with 4–6 dark-brown, sometimes irregular shaped bars. Few dark-brown spots in paired fins. Barbels whitish.

Etymology. Named for Füsun Erk’akan (Ankara) for her contribution to the exploration of the species diversity of Cobitis . A noun in genitive, indeclinable.

Distribution. Cobitis erkakanae has only been found at one place in the Gölbaşı lakes basin.

Remarks. The finding of a third species of Cobitis in the Ceyhan River drainage is an unusual situation. All three species occur in allopatry within the Ceyhan River drainage but we are not aware of a biogeographic background explaining, why the Gölbaşı lakes have an own fish fauna, isolated from the Ceyhan River. Not only C. erkakanae is (likely to be) endemic to the Gölbaşı lakes, Geiger et al. (2014) also show molecular data indication that the populations of A. mento and Pseudophoxinus zekayi are isolated from those in the Ceyhan. While the water from the Gölbşı lakes flows to the Ceyhan today, we postulate, that this was an endorheic basin for a while and was connected only recently to the Ceyhan.

Molecular data ( Fig. 1 ) place C. erkakanae in the C. linea species group ( C. linea , C. aliyeae , C. anabelae , C. elazigensis , and C. levantina ). Based on DNA barcoding it is well separated from all other included Cobitis , and by a minimum K2P distance of 5.5% to C. elazigensis . It is also supported by the PTP approach as distinct entity.

Figures

FIGURE 1. Maximum likelihood estimation of the phylogenetic relationships based on the mitochondrial COI barcode region (TN93 model, discrete Gamma distribution for rate differences with 3 categories +G parameter = 0.3792. Nucleotide positions with less than 95% site coverage were eliminated, resulting in 590 analysed positions. Numbers of major nodes indicate bootstrap values from 1000 pseudoreplicates from the ML, NJ and MP method. A star denotes highest possible support from all three methods. Solid bars right to the specimen labels indicate species delimitation results from PTP followed by the results of the mPTP approach as dashed bars. Except to the outgroups and the branch to the right part of the figure, the tree is drawn to scale with branch lengths depicting number of substitutions per site.

FIGURE 42. Cobitis erkakanae, left column from the top: males, ZFMK ICH-98958, holotype, 46 mm SL; paratypes, FSJF 2510, 49 mm SL, 49 mm SL; right column from the top: females: FSJF 2427, 67 mm SL, 68 mm SL, 60 mm SL; Turkey: river connecting Lakes Gölbaşı and Azaplı.

FIGURE 43. Cobitis erkakanae, left column from the top: males, ZFMK ICH-98958, holotype, 46 mm SL; paratypes, FSJF 2510, 49 mm SL, 49 mm SL; right column from the top: females: FSJF 2427, 67 mm SL, 68 mm SL, 60 mm SL; Turkey: river connecting Lakes Gölbaşı and Azaplı.

FIGURE 44. Cobitis erkakanae, FSJF 2510, female, about 65 mm SL; Turkey: river connecting Lakes Gölbaşı and Azaplı.

FIGURE 54. Upper row: Cobitis afifeae, FSJF 3022, paratype, 76 mm SL; Turkey: Büyük Menderes River; C. aliyeae, FSJF 2427, paratype, female, 65 mm SL; Turkey: Seyhan River; C. anabelae, ZFMK ICH-98633, holotype, male, 53 mm SL; Turkey: Karasu River; C. emrei, FSJF 1960, paratype, female, 77 mm SL; Turkey: Lake Sapanca basin; Lower row: C. erkakanae, FSJF 2510, paratype, female, 68 mm SL; Turkey: canal at Lake Gölbaşı; C. joergbohleni, ZFMK ICH-97624, holotype, female, 60 mm SL; Turkey: spring Soysallı; C. pirii, FSJF 2474, paratype, female, 95 mm SL; Turkey: streams Çayköy; C. troasensis, FSJF 2383, paratype, female, 72 mm SL; Turkey: stream Tuzla.