Ernogrammus zhirmunskii Markevich and Kharin, 2011

Yamanaka, Tomoyuki, Abe, Takuzo & Yabe, Mamoru, 2012, First Record of Ernogrammus zhirmunskii (Actinopterygii: Cottiformes: Stichaeidae) from Japan, with a Description and a Revised Diagnosis, Species Diversity 17 (2), pp. 127-133 : 127-132

Ernogrammus zhirmunskii Markevich and Kharin, 2011

[New Japanese name: Yari-gaji]

( Figs 1–4 )

Ernogrammus zhirmunskii Markevich and Kharin, 2011: 59 , figs 1–4 (type locality: Bol’shoy Pelis Island , Peter the Great Bay, Russia, Sea of Japan).

Material examined. Sixteen specimens, 27.8–86.2mm SL: HUMZ 190053, 36.6 mm SL, sex unknown, Volcano Bay near Usujiri (41°56.4′N, 140°57.7′E), Hakodate city, Hokkaido Prefecture, Japan, 10 m depth, rocky area, 21 May 2007; HUMZ 198453, 198454, 2 specimens, female and sex unknown, Usujiri, 9.7 m depth, rocky area, 21 February 2007; HUMZ 198462, 59.7 mm SL, male, Shizugawa Bay (38°39.1′N, 141°29.2′E), Miyagi Prefecture, Japan, 13 February 2007; HUMZ 201217, 81.2 mm SL, male, Usujiri , 10 m depth, rocky area, 27 December 2007; HUMZ 201262, 55.2 mm SL, sex unknown, Shizugawa Bay , 12 m depth, rocky area, 20 December 2007; HUMZ 201312, 60.4 mm SL, female, Shizugawa Bay , 12 m depth, rocky area, 26 November 2007; HUMZ 202084, 43.8 mm SL, sex unknown, Usujiri , 8 m depth, rocky area, 22 April 2008; HUMZ 204499, 64.3 mm SL, female, Usujiri , 10 m depth, rocky area, 29 January 2009; HUMZ 204505, 204510, 2 specimens, 64.0– 66.6 mm SL, male and female, Usujiri , 10 m depth, rocky area, 2 February 2009; HUMZ 205547, 86.2 mm SL, male, Usujiri , 10 m depth, rocky area, 28 July 2009; HUMZ 205739, 51.4 mm SL, Usujiri , 12 September 2009; HUMZ 207106, 207107, 2 specimens, 31.2–38.7 mm SL, sex unknown, Usujiri, 12 m depth, rocky area, 26 February 2010; HUMZ 209646, 50.4 mm SL, female, Shizugawa Bay, 13 February 2007 .

Comparative material. Ernogrammus zhirmunskii (3 specimens, 43.1–73.0 mm SL): HUMZ 156855, 2 specimens, 209111, off Pelis Island, Peter the Great Bay, Primorsky, Russia. Ernogrammus hexagrammus (16 specimens, 27.9–97.5 mm SL): HUMZ 90387, 203224, 204509, 205746, Usujiri; HUMZ 156860, 156975, 2 specimens, Pelis Island; HUMZ 169388, 169389, Okhotsk coast of Kunashir Island , Kuril Islands , Japan; HUMZ 179427, Kholmsk , western coast of Sakhalin Island , Sea of Japan, Russia; HUMZ 179571, 183706, Aniwa Bay , southern part of Sakhalin Island , Russia; HUMZ 198998, 198999, 199101, 199267, Shiretoko Peninsula , eastern Hokkaido Island , Japan; HUMZ 200300, Akkeshi Bay , Pacific coast of Hokkaido Island , Japan . Ernogrammus walkeri: CAS 56198 (holotype), 215.1 mm SL, San Luis Obispo , California, USA . Eumesogrammus praecisus (10 specimens, 103.4–159.5 mm SL): HUMZ 54682, 54690, 60824, 85429, northern part of Sea of Okhotsk, Russia; HUMZ 103290, 103292, 103293, 103294, Terpenia Bay, Okhotsk coast of Sakhalin Island , Russia; HUMZ 123797, Bering Sea , Alaska, USA; HUMZ 203382, Chukchi Sea , Alaska, USA .

Diagnosis. A species of the genus Ernogrammus with the following characters: dorsal fin XL–XLII; anal fin II, 26–27, I–II; pelvic fin I, 3; 4 lateral-line canals (upper, middle, lower, and ventral) present on each side of body, each lateral-line canal with alternating short branches, ventral lateral-line canal unpaired, originating from midline of posterior margin of pelvic fin base and extending to just ahead of anus. Several whitish spots on lower part of head. Pectoral fin base with 2 darkish bands.

Description. Proportional measurements and counts given in Table 1. Body cylindrical, gradually compressed posteriorly, and covered with minimal cycloid scales. Head without scales, cirri, or dermal crest, and subconical and slightly depressed in shape. Snout short, rounded. Anterior nostril with nasal tube; posterior nostril small, without any appendage. Jaws about equal in length, posterior margin of upper jaw situated approximately as far posteriorly as rear margin of pupil. Upper and lower jaws with thickly set conical teeth. Anterior part of lower jaw with 2 pairs of relatively robust conical teeth. Upper lip separated from snout. Palatine and vomer with minute conical teeth forming narrow band. Interorbital space almost flat. Eye rounded, moderate in size. Sensory canal on head well developed, with relatively large pores. Infraorbital canal with 3 pores on inner side, 8 pores on outer side ( Fig. 2 : middle). Posterior occipital canal well developed, its posterior tip extending to near origin of dorsal fin ( Fig. 2 : upper). Branchiostegal membranes on both sides narrowly united with each other and free from isthmus. Pseudobranch present. Gill rakers comb-like. Posterodorsal part of opercle forming siphon. Four lateral-line canals (upper, middle, lower, and ventral) on each side of body, composed of short, troughlike tubules and covered by skin; each canal with short, alternately placed dorsally and ventrally directed branches, and each branch with single pore at distal tip. Upper lateral-line canal originating at posterior end of postorbital canal, extending to near base of caudal fin, and larger dorsal branch missing. Middle lateral-line canal originating above pectoral fin base, extending to mid-height of caudal fin base, with a few pores extending onto caudal fin. Vertical branches connecting upper and middle lateral-line canals absent. Lower lateral-line canal originating from anterior part of pelvic fin, canals on each side not connected to each other at anterior margin of pelvic fin base, extending in parallel on lower side of body along base of anal fin to near base of caudal fin. Ventral lateral-line canal unpaired, originating from midline of posterior part of pelvic fin base and extending to just ahead of anus, there splitting to connect with lower lateral-line canals on each side above anus. Dorsal fin originating above pectoral fin base, its spines gradually becoming more rigid posteriorly. Anteriormost dorsal pterygiophore inserted between first and second vertebrae. Posteriormost dorsal pterygiophore supporting 2 spines. Membrane narrowly connecting posteriormost dorsal fin spine and caudal fin. Anal fin with 2 weak spines in its anteriormost part, second spine longer than first, and 1 spine (rarely 2, in 1 of 17 specimens) in its posteriormost part, this latter being more robust than anterior spines; posterior spine and posteriormost soft ray supported by last anal pterygiophore (in case of 2 posterior spines both supported by this pterygiophore) ( Fig. 3 ). Anal fin separated from caudal fin. Pectoral fin ovoid. Pelvic fin with single slender spine; innermost ray longest. Caudal fin rounded.

Coloration when fresh. Body and head light to dark brown or darkish gray, sometimes with whitish markings on side of body; single whitish mark on occipital area; 8–10 whitish marks below dorsal fin or whitish band along dorsal fin base. Head darker than body. Several whitish spots on lower part of head. Ground color of dorsal and anal fins almost same as that of body, both fins edged whitish. Dorsal fin with blackish ellipsoidal blotch on anterior part, irregular blotches on posterior part. Anal fin with several yellowish stripes. Pectoral fin translucent with 2 darkish bands on base, anterior band more distinct than posterior one; posterior part of fin with several irregular transverse bands. Pelvic fin whitish with slightly darker base. Caudal fin translucent with darkish band on base, posterior part of fin with several irregular transverse bands.

Coloration when alive (based on underwater photograph, specimen not collected; Fig. 4 ). Head and body brown, slightly purplish, with single irregular whitish band on dorsal surface of head and along dorsal fin base. Several whitish spots on lower part of head. Both lips with several irregular whitish bands. Single white blotch anterior to dorsal fin origin, another on upper part of pectoral fin base, and another above pectoral fin. Several whitish spot along anal fin base. Ground color of dorsal and anal fins almost same as color of whitish band along dorsal fin base, with some blackish irregular blotches surrounded by translucent margins. Coloration of pectoral and caudal fins almost same as when fresh.

Coloration in alcohol. Almost same as when fresh, except for disappearance of yellow stripe on anal fin and whitish band along dorsal fin base.

Distribution. Currently known from Peter the Great Bay, Sea of Japan, Russian Far-East; Volcano Bay, Pacific coast of Hokkaido, Japan; and Shizugawa Bay, Miyagi Prefecture, Pacific coast of the northern Honshu, Japan.

Habitat. This species is found under stones in sandy gravelly areas or in cracks in rocky substrates, at depths of 5– 20 m.

Remarks. Ernogrammus zhirmunskii was originally described on the basis of 10 specimens from Peter the Great Bay, Russia. Markevich and Kharin (2011) reported E. zhirmunskii to be easily distinguished from the congeneric species E. hexagrammus and E. walkeri in having the lateral-line canal on the ventral side of body originating from the posterior margin of the pelvic-fin base and extending to just ahead of the anus, and a rigid spine on the posteriormost part of the anal fin (versus a pair of parallel ventral lateral-line canals, and no posterior anal-fin spine). The present 16 specimens, collected from Hokkaido and Miyagi Prefectures, Japan, are easily distinguished from all other species of the Stichaeinae in having the above mentioned diagnostic characters of E. zhirmunskii (e.g., Lindberg and Krasyukova 1975; Hatooka 2002; Mecklenburg et al. 2002; present study). The other morphological features of these specimens almost fully agree with those of E. zhirmunskii as described by Markevich and Kharin (2011) ( Table 1), with some exception.

Among the features that are inconsistent with those described in the original description, Markevich and Kharin (2011) reported E. zhirmunskii to have I, 28–30, I anal fin rays, but the present specimens have II, 26–27, I–II anal fin rays. We re-counted the anal fin rays of all specimens in the type series of E. zhirmunskii from radiographs, and found that they have II, 26–28, I (II, 27, I in the holotype). The present single specimen (HUMZ 205739, 51.4 mm SL) with two spines in the posteriormost part of the anal fin ( Fig. 3B ) is recognized as conspecific with the others because it is consistent in all other characters.

Markevich and Kharin (2011) reported the number of cephalic sensory pores of E. zhirmunskii as follows: supraorbital canal 6, infraorbital 4, postorbital 4, preoperculo-mandibular 4, preopercular 7, occipital 6; however, the method of counting the pores was not clearly stated and it is unclear which cephalic sensory pores were counted with in each category. We counted the cephalic sensory pores following Makushok (1958) based on the diagrammatic drawing of the holotype of E. zhirmunskii in Markevich and Kharin (2011), and found that the holotype of E. zhirmunskii has three nasal pores, nine interorbital pores, eight occipital pores and five pores on posterior occipital canal, 11 infraorbital pores, six preopercular pores, four mandibular pores, and 13 postorbital pores. These pore counts agree with those of the present specimens from Japan ( Table 1).

Additionally, Markevich and Kharin (2011) described E. zhirmunskii as having one spine and three branched soft pelvic fin rays, but they indicated I, 4 pelvic fin rays in their Table 1. Our own re-counting of the pelvic fin rays of the holotype based on an X-ray photograph revealed one spine and three branched soft rays, which agrees well with all our Japanese specimens.

As for coloration, Markevich and Kharin (2011) noted that live specimens of E. zhirmunskii have two wide black stripes near the base of the pelvic fin, divided by a narrow white stripe, but their color photographs (their fig. 2) clearly show the two black stripes associated instead with the base of the pectoral fin, while the color of the pelvic fin base is indistinct. All our specimens have two darkish bands on the base of the pectoral fin and no distinct markings on the pelvic fin base.

Because no significant differences were found between the type specimens of E. zhirmunskii and the 16 Japanese specimens, we conclude that our material is conspecific with E. zhirmunskii . This species was previously known only from Peter the Great Bay , and the present specimens of E . zhirmunskii represent the first confirmed records of this species from Japan ( Hatooka 2002; Markevich and Kharin 2011).

Markevich and Kharin (2011) recognized E. zhirmunskii as a member of the genus Ernogrammus because of the characteristic pattern of lateral-line canals, viz., three longitudinal lateral-line canals on each side of the body; each canal with short branches and a single pore at the tip of each branch; the upper lateral line-canal extending nearly to the caudal fin base; and the middle lateral-line canal separated from the upper one. Additionally, uniquely in the genus E. zhirmunskii has a spine in the posteriormost part of the anal fin. This peculiar condition has been recognized hitherto as a diagnostic feature of Eumesogrammus praecisus (KrØyer, 1836) , distinguishing it from all other stichaeine fishes ( Jensen 1944; Andriyashev 1954; present study). Therefore, to clarify the systematic position of E. zhirmunskii , further studies on the phylogeny and systematics of the Stichaeinae are needed.

Figures

Fig. 1. Ernogrammus zhirmunskii, HUMZ 205547, 86.2mm SL, Volcano Bay, Pacific coast of Hokkaido, Japan. Upper: line drawing; lower: fresh specimen.

Fig. 2. Cephalic sensory system of Ernogrammus zhirmunskii, HUMZ 205547, 86.2mm SL. na, nasal pores; it, interorbital pore; if, infraorbital pores; oc, occipital pore; poc, pores on posterior occipital canal; po, postorbital pores; pr, preopercular pores; mn, mandibular pores; uc, upper lateral-line canal; mc, middle lateral-line canal; lc, lower lateral-line canal; vc, ventral lateral-line canal. Dotted lines separate abovenamed sections of sensory canals. Scale bars 5mm.

Fig. 3. Posterior anal fin spines of Ernogrammus zhirmunskii. (A) HUMZ 205547, 86.2mm SL, with a single spine (arrow); (B) HUMZ 205739, 51.4mm SL, with two spines (arrows). Scale bars 2mm.

Fig. 4. Underwater photograph of Ernogrammus zhirmunskii taken by Nagaaki Sato at Sizugawa Bay, Miyagi Prefecture, Japan; specimen not collected.