Cobitis lutheri Rendahl, 1935

Vasil’Eva, Ekaterina D., Kim, Daemin, Vasil’Ev, Victor P., Ko, Myeong-Hun & Won, Yong-Jin, 2016, Cobitis nalbanti, a new species of spined loach from South Korea, and redescription of Cobitis lutheri (Teleostei: Cobitidae), Zootaxa 4208 (6), pp. 577-591 : 581-585

Cobitis lutheri Rendahl, 1935

( Figs. 2–4 ; Table 2 )

Cobitis taenia (not of Linnaeus, 1758): Warpachowski & Herzenstein, 1877: 47; Warpachowski, 1892: 153 (partim); Berg, 1907: 438 (partim); Berg, 1909: 169 (partim); Berg, 1916: 355 (partim); Berg, 1923: 328 (partim); Lindberg & Taranets, 1929: 243 (partim); Berg, 1932: 577 (partim); Rozov, 1934: 82 (partim); Lindberg, 1936: 398 (partim); Taranets, 1937а: 81 (partim); Taranets, 1937b: 63 (partim); Berg, 1949: 891 (partim, Fig. 642); Nikolsky, 1956: 382 (partim); Samuylov & Svirskyi, 1976: 89 (partim); Novikov et al., 2002: 154 (partim); Zavertanova, 2007: 45.

Cobitis taenia lutheri Rendahl, 1935: 330 (Khanka Lake basin).

Cobitis lutheri : Vasil’eva, 1988: 1029; Vasil’eva, 1994: 839; Bogutskaya & Naseka, 1996: 48; Vasil’eva, 1998: 97 (partim); Vasil’eva, 1999: 155; Vasil’ev et al., 1999: 355; Tagirova, 2000: 24; Shedko, 2001: 233; Bogutskaya et al., 2001: 44; Zemnukhov et al., 2001: 420; Reshetnikov, 2002: 361 (the characters and the species range are presented with mistakes); Safronov & Nikiforov, 2003: 46; Vasil’eva, 2004: 161; Novomodny et al., 2004: 12, 49; Bogutskaya & Naseka, 2004: 105; Novomodny, 2004: 313; Novomodny, 2005: 103; Tarazanov, 2005: 196 (partim?); Safronov et al., 2005: 172; Vasil’ev & Vasil’eva, 2008a: 1, 2; Vasil’ev & Vasil’eva, 2008b: 51, 52; Bogutskaya et al., 2008: 337; Kolpakov et al., 2008: 52; Kolpakov & Milovankin, 2010: 499; Kottelat, 2012: 26; Parin et al., 2014: 98.

Type material. The original description of C. lutheri was based on five specimens. One specimen initially deposited in the Finnish Museum of Natural History, Zoological Collection ( MZH), collected from the Santakheza River (= Spasovka ), 46.0 mm SL, was indicated as “ typus ” for males, whereas another specimen, in the NRM, from the Odarka River (tributary of the Santakheza River ), 90.0 mm SL, was specified as “ typus ” for females ( Rendahl, 1935). Consequently, no single specimen was designated as name-bearing type (type or holotype), and all specimens in the description are syntypes . The MZH specimen mentioned by Rendahl has been lost ( Risto Väinölä , pers. comm.). The specimens in the NRM collection are bleached (see NRM Ichthyology search). However , the syntype of 64.5 mm SL, male, NRM 10813 ( Fig. 2 ) retains the traces of species-specific color pattern on the head, previously documented on Fig. 4 in Rendahl (1935). Moreover , this specimen defines the other diagnostic characteristics of the species, as the shape of lamina circularis, the snout shape, the position of suborbital spine, and the mandibular barbel length ( Fig. 2 ). We designate this specimen as lectotype of Cobitis lutheri Rendahl, 1935 , to fix the name of the species to an available zoological entity to extend or modify the description in the future for any taxonomic purposes. By that action the other syntypes ( NRM 10810, 64 mm SL, NRM 10811, 90 mm SL, NRM 10812, 63.6 mm SL) become paralectotypes .

Diagnosis. Cobitis lutheri is distinguished by a combination of the following character states: wide poleaxshaped lamina circularis; round scales with slightly-displaced focal zone equal to 61–65% of the scale diameter; short (usually less than 42% of head length) obtuse snout in adults; suborbital spine mostly reaching the center of the eye, and mandibular barbel reaching the anterior edge of the eye in adult specimens; usually fewer than 12 dark brown blotches on the side at the middle of the body; two pronounced spots at the base of caudal fin; commonly several dark streaks on the head, across the eye, suborbital, and two crossed stripes on the opercle; 2n=50 (20 meta- and submetacentrics, and 30 subtelo- and acrocentrics); NF=70.

Description. Dorsal-fin rays iii 7 ½(8), anal-fin rays iii 5 ½, pectoral-fin rays i 7–8 ½, pelvic fin (V) i 5 ½–6(7), caudal-fin rays i (13) 14 i, total vertebrae in five specimens from the Karasik River 41–44. Morphometric characters of adult specimens from the type locality are presented in Table 2 .

Body elongate, rather deep, laterally compressed. Largest adult females, from Amur River, reaching 88 mm SL (ZMMU P-7566, P-7572). Head elongated, compressed, its upper profile convex; eyes large, superiorly located; eye diameter usually (80–100% of adult individuals in sample) greater than 20% of the head length; interorbital space narrow, convex. Snout mostly short, obtuse, its length in males usually (80–100%) less than 42% of head length; specimens with elongated snout observed among large adult females. Suborbital spine bifid, thick, slightly curved, mostly reaching center of eye (see below). Mouth small, inferior, with fleshy lips; lower lip divided in two well developed parts, its mental lobes a little longer than rest of folded portion. Three short pairs of barbels: rostral, maxillary, and mandibular barbels; mandibular barbel often reaches anterior edge of eye or extends further, primarily in adult males (see below). Caudal peduncle obviously shorter than head, well compressed, with poorly developed fleshy keels on dorsal and ventral sides. Pectoral fin elongated in males, its first ray not more elongated than others, not filamentous ( Fig. 3 ). Males with a single lamina circularis (lamina Canestrini) at base of second pectoral-fin ray, broad, branched; plate of lamina circularis wide, poleax-shaped, its external edge crossed by very short dense lines ( Fig. 4 b); end of plate reaching the 2–5th segments of attached ray. Pelvic fin originating posterior to origin of dorsal fin. Body covered with small scales; scales at base of dorsal fin more or less round, with a rather large, slightly-displaced focal zone; diameter of this zone being about 61–65% of scale diameter.

Coloration in alcohol. Background color beige in preserved individuals. Head with small dark brown speckles or stripes on dorsal and lateral sides; apart from typical stripe extending across eye from tip of snout to nape, most specimens in preservative with three well developed stripes: first one (suborbital) below and parallel to aforementioned stripe across eye; second and third crossed stripes on opercle ( Fig. 4 a). Gambetta’s zones of pigmentation ( Gambetta, 1934) nearly complete; first zone, at middle of back, represented by large dark-brown spots of variable shape, surrounded by small brown speckles. Second zone consisting of large brown horizontallyelongated spots partially combined in one line or completely forming a relatively wide streak from head to base of caudal fin in males and some females. Third zone consisting of small dark-brown speckles; fourth zone on side at middle of body represented by large dark-brown blotches (larger than eye), square, round or elongated; their number varying from 8 to 16, usually fewer than 12 (often fewer than 10) (see below). Two spots at base of caudal fin: one elongated vivid black spot at upper part of caudal-fin base, another dark brown or black spot of irregular shape at lower part of caudal-fin base. Specimens with only one (upper) visible spot at base of caudal fin very rare. The faded specimens of C. lutheri from the samples collected more than 30 years ago usually possess only one spot at the upper base of the caudal fin in the surface layer sensu Saitoh & Aizawa (1987), but both spots are visible in the deeper layer, in the connective tissue surrounding the base of fin rays. Dorsal fin with dark brown pigmentation along its rays; caudal fin with elongated brown speckles along its rays, forming usually four transverse lines; small brown scattered speckles on pectoral, pelvic, and anal fins ( Fig. 3 ).

* based on eight examined specimens

Sexual dimorphism. Females with larger, slenderer body than males. Males with lamina circularis at base of second pectoral-fin ray, elongated pectoral and pelvic fins, usually shorter snout ( Table 2 ); during spawning season, dark spots and blotches in second and fourth Gambetta’ zones in adult males usually merging with each other, forming two broad dark stripes ( Shedko (2001) noted that these stripes split into series of independent spots or blotches during late autumn, as were observed in the specimens in aquarium).

Intra- and inter-population variability of diagnostic features. Among 135 specimens examined from ZIN collection, only 6.7% (three females from the Amur River and 6 females from the Tumen’ -Ula River) had none or only a vague dark suborbital stripe on the head. Similarly, 3.0% (three females from the Amur and Tumen’ -Ula rivers and one male from the Tunguska River) lacked the spot at the lower part of the caudal-fin base. All of 40 examined specimens from Khanka Lake basin had a conspicuous suborbital stripe and two spots at the caudal-fin base. Among 17 adult specimens from the type locality in ZMMU collection, only one specimen (male, SL 49.5 mm) had no visible suborbital stripe; all specimens had two spots at the caudal-fin base; the number of blotches in the fourth Gambetta’s zone varied from 8 to 14, most specimens (68.8%) had fewer than 12 blotches; suborbital spine usually reached the center of the eye (58.8%) or extended further (35.3%); the mandibular barbel reached the anterior edge of the eye or extended further in 35.3% of the adults; one male (P-17837) had lamina circularis with an atypical narrow bottle-shaped plate on the right pectoral fin. Only one specimen among 20 completely faded adults from the Lyanchihe River in the ZMMU collection had mandibular barbel not reaching the anterior edge of the eye; in all specimens the suborbital spine reached the center of the eye or extended further. Only two specimens among 34 adults from the Tsukanovka River (ZMMU P-23900) had a poorly visible suborbital stripe; in most specimens (67.7%) the mandibular barbel did not reach the anterior edge of the eye; the suborbital spine did not reach the center of the eye in 50% of specimens; one male had lamina circularis with an atypical narrow plate on the right pectoral fin; all specimens had two spots at the caudal fin base; among 57 adult and juvenile specimens, 47.4% had fewer than 10 blotches in the fourth Gambetta’s zone, the total number of blotches varying from 8 to 16. In 12 specimens from the Razdolnaya River (ZMMU P-20041), 8–12 blotches were observed in the fourth Gambetta’s zone, and specimens with fewer than 10 blotches comprised 48.4%. Large adults (16 males with SL 52.5–58.0 mm, 20 females with SL 64.3–85.0 mm) from the Tygda River (ZMMU P-21545) had 7–12 blotches in the fourth Gambetta’s zone, specimens with 7–10 blotches were predominant (72.2%); only one female had no spot at the lower part of the caudal fin base; one male had suborbital spine not reaching the center of the eye; mandibular barbel not reaching the anterior edge of the eye was observed in six females; the snout length in females varied from 37.9 to 43.5% of the head length (mean 40.9%), in males, from 36.0 to 43.8% (mean 39.4%).

The karyotype is characterized by the total chromosome number (2n) of 50 chromosomes with 12 meta-, 8 submeta- and 30 subtelo- and acrocentrics and NF=70 ( Table 1 ) (Vasil’ev & Vasil’eva, 2008a, b).

Geographical distribution. Cobitis lutheri occurs in the lower and middle Amur River drainage (up to Blagoveshchensk), including the Ussuri River and Khanka Lake systems, rivers flowing into Amur and Ussuri bays in Primorye, and adjacent parts of the East Sea /Sea of Japan (e.g., Tumannaya River at Russia / North Korea border), and in rivers in northern Sakhalin Island ( Fig. 1a ). Shedko (2001) found this species in rivers of the central part of Primorye coast, namely Kievka, Chernaya, Margaritovka, and Rudnaya. Safronov & Safronov (2002) recorded C. lutheri from rivers of northeastern Sakhalin Island (from Uspenskoye Lake to Lakh River drainages), from the eastern Sakhalin coast (including Tym’ and Poronai rivers), and from the open pits at Gastello village (southeastern Sakhalin). However, the morphological description of the species by Safronov & Safronov (2002) includes features absent in C. lutheri (e.g., “narrow plate” of lamina circularis, and 18 branched caudal fin rays).

Common names. Luther’s spined loach (English); shchipovka Ljutera [щиповка Лютера] (Russia); Ah-murjum-jool-jong-geh [ỌșäḏḵǭNj] (Korea).

Comparative remarks. M a l e s o f C. lutheri are easy to distinguish from males of sympatric in the Amur River drainage, C. melanoleuca and C. choii Kim & Son , by the shape of lamina circularis: C. melanoleuca has a narrow bottle-shaped plate, whereas C. choii has a very narrow knife-shaped plate with serrated outer edge. Both males and females of C. melanoleuca and C. choii lack the suborbital stripe and additional stripes on the opercle that are diagnostic features for C. lutheri .

Figures

FIGURE 1 a. The range of Cobitis lutheri covered by the samples from the museum collections marked by mottled sites (a) and sampling localities of Cobitis nalbanti sp. nov. indicated by circles with numbers (b). Locality names in (b) are the following: 1, Cheongmi River, Han River drainage (type locality), 2, Geumdang River, Han River drainage, and 3, Baekgok River, Geum River drainage.

FIGURE 2. The lectotype of Cobitis lutheri — NRM 10813, male, 64.5 mm SL (copyright under Creative Commons License CC BY NC).

FIGURE 3. Male (a) SL 45 mm and female (b) SL 50.5 mm of Cobitis lutheri from the Khanka Lake system, Russia (ZMMU P- 20036) and conspecific male (c) SL 53.5 mm and female (d) SL 74 mm from the Tygda River, Russia (ZMMU P- 21545).

FIGURE 4. Characteristic stripes on the head of Cobitis lutheri (a): 1 — stripe extending across the eye; 2 — suborbital stripe; 3 and 4 — stripes on opercle; lamina circularis (b) in male from the Lyanchihe River, Russia (ZMMU P- 3830).

Tables

TABLE 2. Selected morphometric characters of Cobitis lutheri from the type locality.

Characters	Females (n=6)	Males (n=10)
	Mean (range)	Mean+SD	Range
Total body length (mm)	63.3 (57.5–69.5)	56.9+3.46	50.5–62.3
Standard body length (mm)	55.7 (49.3–61.0)	48.5+3.25	43.0–53.6
In % of standard length
Predorsal length	49.5 (45.9–51.2)	50.1+1.48	46.7–52.5
Postdorsal lenght	38.3 (35.4–40.2)	39.2+1.53	37.0–42.3
Preventral length	50.1 (46.4–51.5)	51.5+2.07	48.9–55.6
Preanal length	76.3 (72.3–80.0)	77.3+1.96	73.0–79.5
Caudal peduncle length	13.3 (12.2–14.3)	14.5+1.41	12.1–17.3
Maximum body depth	13.5 (12.0–15.4)	14.6+2.51	10.6–17.7
Caudal peduncle depth	8.6 (7.6–9.5)	9.0+1.11	7.0–10.4
Maximum body width	9.8 (8.3–10.8)	8.6+3.16	3.6–15.7
Length from pectoral fin base to ventral fin base	30.2 (28.5–31.9)	30.4+1.54	28.3–33.3
Pectoral fin length	14.3 (13.0–15.0)	18.1+1.92	14.4–20.9
Ventral fin length	12.7 (11.8–13.6)	15.3+1.44	13.3–17.4
Length of dorsal fin base	11.6 (10.0–12.5)	11.5+0.97	10.0–12.7
Dorsal fin depth	16.0 (14.5–17.0)	16.3+1.75	13.8–20.0
Length of anal fin base	8.6 (7.3–9.9)	8.8+0.41	8.3–9.6
Head length	20.6 (18.7–21.8)	21.5+1.22	19.8–24.0
In % of head length
Snout length	41.5 (39.2–42.7)	38.3+3.09	30.0–41.2
Eye diameter	22.8 (20.5–25.2)	23.2+2.61	19.8–27.0
Interorbital distance	11.8 (9.2–13.5)	13.9+2.35	9.9–18.0
Head depth	60.0 (55.8–62.7)	57.4+4.39	51.5–63.1
Rostral barbel length	9.0 (4.6–10.8)	9.6*	6.8–11.0
Mandibular barbel length	13.2 (9.1–15.5)	15.8+4.64	8.7–22.0
Caudal peduncle depth in % of its length	65.0 (56.3–74.6)	62.7+11.79	40.2–75.0