A new species of tadpole-goby, Benthophilus persicus sp. nov. (Teleostei: Gobiidae) from the southern Caspian Sea Author Kovačić, Marcelo 0000-0002-4049-9366 Natural History Museum Rijeka, Lorenzov prolaz 1, HR- 51000 Rijeka, Croatia. marcelo@prirodoslovni.com Author Esmaeili, Hamid Reza Ichthyology and Molecular Systematics Research laboratory, Zoology Section, Department of Biology, School of Science, Shiraz University, Shiraz, Iran. Author Zarei, Fatah Ichthyology and Molecular Systematics Research laboratory, Zoology Section, Department of Biology, School of Science, Shiraz University, Shiraz, Iran. Author Abbasi, Keyvan Inland Waters Aquaculture Research Center, Iranian Fisheries Sciences Research Institute, Agricultural Research, Education and Extension Organization, Bandar Anzali, Iran. Author Schliewen, Ulrich K. 0000-0003-0187-4319 Department of Ichthyology, SNSB - Bavarian State Collection of Zoology, Münchhausenstr. 21, 81247 Munich, Germany. schliewen @ snsb. de; https: // orcid. org / 0000 - 0003 - 0187 - 4319 schliewen@snsb.de text Zootaxa 2021 2021-05-31 4980 1 45 63 journal article 6101 10.11646/zootaxa.4980.1.3 9e5a4897-46e2-4e6f-8dc9-4aad664b979d 1175-5326 4882930 B136A181-ED9A-410D-A9E3-3CEB1F81A4B6 Benthophilus persicus sp. nov. ( Figs 2–10 , Table 1 ) Holotype . ZSM 47595, male, 45.2+ 9.9 mm , Iran , Gilan Province , Anzali , southern Caspian Sea , 37°29’ N 49°29’ E , K. Abbasi & S. Abdolmaleki , 01 Apr. 2004 ( Fig. 4a ). Paratypes . ZSM 47596, female, 45.8+ 9.7 mm , Iran , Gilan Province , Anzali , southern Caspian Sea , 37°31’ N 49°30’ E , K. Abbasi & S. Abdolmaleki , 18 Nov. 2002 . ZSM 47597, juvenile male, 30.4+ 7.6 mm , Iran , Gilan Province , Anzali , southern Caspian Sea , 37°36’ N 49°29’ E , K. Abbasi & M. Tavakoli , 06 Jan. 2004 . ZSM 47599, female, 30.8+7.0 mm, Iran , Gilan Province , Anzali , southern Caspian Sea , 37°36’ N 49°29’ E , K. Abbasi & M. Tavakoli , 05 Jan. 2004 ( Fig. 4c ) . ZSM 47598, juvenile female, 27.5+ 6.4 mm , Iran , Gilan Province , Anzali , southern Caspian Sea , 37°36’ N 49°29’ E , K. Abbasi & S. Abdolmaleki , 01 Nov. 2002 . FIGURE 2. Benthophilus persicus sp. nov. Reversibly stained paratype, PMR VP4679, male, 43.3+10.0 mm, Iran, Gilan Province, Chaboksar, southern Caspian Sea. Preopercle with dermal ossifications: T – tubercles with spinules on tubercles appear irregularly arranged, G1 - single granule, G2 and G3 - granules grouped two and three together, respectively. Photo by M. Kovačić. FIGURE 3. Benthophilus persicus sp. nov. Reversibly stained paratype, PMR VP4679, male, 43.3+10.0 mm, Iran, Gilan Province, Chaboksar, southern Caspian Sea. Dermal ossifications on anterior dorsal body view: D - dorsal row of tubercles: T1- tubercle with one radial row of spinules and T2 - tubercle with two radial rows of spinules, DL - dorsolateral row of tubercles, G - granules. Photo by M. Kovačić. FIGURE 4. Benthophilus persicus sp. nov. preserved specimens. Holotype, ZSM 47595, male, 45.2+9.9 mm, Iran, Gilan Province, Anzali, southern Caspian Sea: A : lateral view, B : urogenital papilla of adult male (marked by arrow). Paratype, ZSM 47599, female, 30.8+7.0 mm, Iran, Gilan Province, Anzali, southern Caspian Sea: C : lateral view, D : urogenital papilla of adult female (marked by arrow). Photos by M. Kovačić. FIGURE 5. Benthophilus persicus sp. nov. Reversibly stained paratype, PMR VP4679, male, 43.3+10.0 mm, Iran, Gilan Province, Chaboksar, southern Caspian Sea. Dermal ossifications on dorsal view of head, TCO - tubercles along upper cheek, preopercle and opercle, TI - interorbital tubercles, G - granules. Tubercles not present on temporal and occipital head regions, i.e., all dermal ossifications there are definable as granules according to size and shape; and the first tubercles anteriorly to temporal region are located at interorbital space, i.e., anteriorly to rear edge of eyes. Photos by M. Kovačić. FIGURE 6. Benthophilus persicus sp. nov. Dermal fold (DF) and chin barbell (CB). Reversibly stained paratype, PMR VP4679, male, 43.3+10.0 mm, Iran, Gilan Province, Chaboksar, southern Caspian Sea: A : lateral detail of head, B : ventral view of head. Reversibly stained holotype, ZSM 47595, male, 45.2+9.9 mm, Iran, Gilan Province, Anzali, southern Caspian: C : chin close up with barbel. Photo by M. Kovačić. FIGURE 7. Benthophilus persicus sp. nov. Reversibly stained paratype, PMR VP4679, male, 43.3+10.0 mm, Iran, Gilan Province, Chaboksar, southern Caspian Sea. A : Dermal ossifications on lateral view of head, TCO - tubercles along upper cheek, preopercle and opercle, G - granules. B : Dermal ossifications on posterior dorsal body view: D - dorsal row of tubercles, DL - dorsolateral row of tubercles, T - tubercle, G - granules. C : Dermal ossifications on anterior lateral body view, D - dorsal row of tubercles, DL - dorsolateral row of tubercles, V - ventral row of tubercles, T - tubercles. D : Dermal ossifications on posterior lateral body view, D - dorsal row of tubercles, DL - dorsolateral row of tubercles, V - ventral row of tubercles, T - tubercles. Photos by M. Kovačić. ZM-CBSU 5003-128, female, 30.9+ 8.2 mm , Iran , Gilan Province , Anzali , southern Caspian Sea , 37°36’ N 49°29’ E , K. Abbasi & S. Abdolmaleki , 09 Jan. 2004 . ZM-CBSU 5001-1, female, 35.1+8.1, Iran , Gilan Province , Anzali , southern Caspian Sea , 37°29’ N 49°29’ E , K. Abbasi & S. Abdolmaleki , Nov. 2002 . ZM-CBSU 5003-60, juvenile female, 25.4+ 6.1 mm , Iran , Gilan Province , Anzali , southern Caspian Sea , 37°31’ N 49°30’ E , K. Abbasi & S. Abdolmaleki , Nov. 2002 . ZM-CBSU 5022-23, female, 26.0+5.9, Iran , Gilan Province , Chaboksar , southern Caspian Sea , 37°01’ N 50°34’ E , K. Abbasi & S. Abdolmaleki , 18 Nov. 2015 . ZM-CBSU 5024-1, female, 23.7+ 5.3 mm , Iran , Gilan Province , Chamkhaleh , southern Caspian Sea , 37°30’ N 49°55’ E , K. Abbasi & S. Abdolmaleki , 09 Nov. 2002 . ZM-CBSU 5003-77, female, 25.1+ 6.3 mm , Iran , Gilan Province , Anzali , southern Caspian Sea , 37°29’ N 49°29’ E , K. Abbasi & S. Abdolmaleki , 01 Nov. 2002 . PMR VP4679 male, 43.3+10.0 mm, Iran , Gilan Province , Chaboksar , southern Caspian Sea , 37°01’ N 50°34’ E , K. Abbasi & A. Sarapnah , 01 Mar. 2005 . PMR VP4680 , male, 47.0+ 8.6 mm , Iran , Gilan Province , Anzali , southern Caspian Sea , 37°31’ N 49°30’ E , K. Abbasi & S. Abdolmaleki , 09 Mar. 2003 . PMR VP4681 male, 35.1+ 8.5 mm , Iran , Gilan Province , Anzali , southern Caspian Sea , 37°29’ N 49°29’ E , K. Abbasi & S. Abdolmaleki , 01 Mar. 2003 . PMR VP4682 , female, 30.4+ 7.4 mm , Iran , Gilan Province , Anzali , southern Caspian Sea , 37°29’ N 49°29’ E , K. Abbasi & S. Abdolmaleki , 17 Sep. 2002 . PMR VP4683 , female, 34.2 mm , caudal fin damaged, Iran , Gilan Province , Anzali , southern Caspian Sea , 37°35’ N 49°29’ E , K. Abbasi & A. Sarapnah , 01 Jan. 2004 . Additional material . ZM-CBSU S003-17, 21 specimens , 31.7–47.3 mm SL, 37°37’46.71” N 49°33’55.10” E , K. Abbasi & S. Abdolmaleki , 09 Mar. 2003 . ZM-CBSU S003-112–113, ZM-CBSU S003-115, 3 specimens , 38.2–40.1 mm SL, 37°37’46.71” N 49°33’55.10” E , K. Abbasi & S. Abdolmaleki , 05 Jan. 2004 . ZM-CBSU S003- 134–135, 2 specimens , 33.5–40.8 mm SL, 37°37’46.71” N 49°33’55.10” E , K. Abbasi & S. Abdolmaleki , 10 Jan. 2004 . All additional material was collected from Iran , Gilan Province , Anzali , southern Caspian Sea . Diagnosis . Benthophilus persicus is distinguished from all other congeneric species by: (1) dermal fold behind jaws well-developed, large, rectangular, (2) chin barbel of moderate size, 1/3–2/3 of eye diameter, (3) maximum body width 15.1–22.9% of SL, (4) mouth width 36.3–55.8% of head length, (5) second dorsal fin I+7–8; (6) origin of anal fin in front of vertical through origin of second dorsal fin, (7) dermal tubercles present, clearly larger than granules, with two posterior rows of spinules forming an acute, always less than right angle, (8) dorsal row of tubercles complete, 22– 29, (9) ventral row of tubercles 22–25, (10) ventrolateral row of tubercles absent, (11) tubercles not present on temporal and occipital head regions, (12) granules not present on flanks, (13) transversal suborbital row 6i below posterior end of row b , (14) anterior interorbital transversal row pa with one or two papillae and anterior interorbital transversal row pp with two or three papillae, and (15) body with 20–22 transversal ltm rows starting anteriorly behind pectoral axilla and alternating anteriorly with three longitudinal llm rows (characters presented in the order of appearance in the description). Each of the selected diagnostic characters differentiate the new species from between 4 to 15 Benthophilus species. Considering only these selected fifteen diagnostic characters, the new species differs from congeneric species in a range from at least five characters (from B. durrelli Boldyrev & Bogutskaya, 2004 , B. mahmudbejovi Ragimov, 1976 and B. pinchuki Ragimov, 1982 ) up to eleven differential characters (from B. kessleri Berg, 1927 ). Description ( Fig. 4 ). All morphometric and meristic values in the text are presented first for the holotype for the paratypes in parentheses. Morphometric data are provided in Table 1 . Particularly large variability of some features may be based on sex, developmental stage or size dimorphism and is highlighted in the Table 1 and further explained in the Discussion. General morphology. Head rounded in vertical view, i.e., triangular with well-rounded lateral sides ( Fig. 5 ). Head large, long and wide, length 2.8 (2.6–3.0) in SL, width 1.0 (1.0–1.2) in head length. Head depressed (dorsoventrally compressed), head depth in head width 1.9 (1.7–2.2), head depth 1.8 (1.6–2.4) in head length, wider than body, head width 0.7 (0.5–0.6) in maximum body width. Snout gently rounded, broad and moderately long, larger than eye diameter, 0.5 (0.6–0.8) in eye diameter, 3.6 (3.6–4.2) in head length. Eye small, horizontal diameter 7.1 (4.6–7.1) in head length. Interorbital distance 6.8 (5.2–10.9) in head length. Eye diameter and interorbital width both size-dependent, i.e., eye diameter negatively correlated and interorbital distance positively correlated with the body size. Dermal fold behind end of jaws well-developed, large, rectangular, elongate ( Figs. 6a and 6b ). Dermal fold depth in length 2.4 (2.5–3.7), with more or less rounded angles, along edge undulate or straight. Dermal fold of variable size to eye diameter, length of its base 0.9 (0.8–1.6) in eye diameter, 6.0 (4.9–8.2) in head length. Chin barbel of moderate size, 0.6 (0.4–0.7) in eye diameter, 12.0 (10.4–13.7) in head length, triangular, widened at base, triangle narrower in larger specimens, broader in smaller fish ( Figs. 6b and 6c ). Mouth relatively wide, mouth width 2.0 (1.8–2.8) in head length. Mouth corner below anterior eye margin. Anterior nostril tube without process from rim, reaching upper lip; posterior nostril with raised rim. No medial groove present on temporal and occipital head regions. Body deepest at first dorsal-fin origin or slightly in front of it, depth decreasing towards caudal-fin base. Greatest body width at middle between pectoral-fin bases, 4.4 (4.4–6.6) in SL, strongly decreasing towards caudalfin base. Caudal peduncle laterally compressed, caudal peduncle width 1.3 ( 1.2–1.5 in depth), shallow, its depth 17.4 (15.0–19.3) in SL, and narrow, its width 22.2 (20.2–25.9) in SL. Maximum size 55.6 mm in total length. Fins. The poor condition of fins in some cases prevents exact counts. D1 IV (III: 1, IV: 14), D2 I+7 (I+7: 7, I+8: 7; in paratype ZM-CBSU 5001-1 positive count was not possible), A I+8 (I+7: 6, I+8: 8; in paratype ZM-CBSU 5001-1 positive count was not possible), C branched rays 10 (10: 7, 11: 3, 12: 2; in three paratypes count was not possible), segmented 13 (13: 12; in three paratypes count was not possible), P 16 on both sides (16: 20, 17: 9, both sides counted; in paratype PMR VP4681 positive count was not possible on left side), V I+5/5+I (V I+5/5+I: 15). First dorsal fin low, its height 11.7 ( 10.5–11.9 in adult males, 13.5–21.3 in other individuals) in SL, lower than second dorsal fin, 7.8 (6.5–8.8) in SL. Origin of anal fin in front of vertical through origin of second dorsal fin. Anal-fin height 9.7 (8.4–10.4) in SL. Pectoral fin long, reaching backwards halfway between the first and second dorsal fins when folded back. Pelvic disc complete and oval with well-developed anterior membrane, anterior membrane with straight edge. Pelvic disc long, 3.2 (3.1–3.8) in SL, reaching to anal-fin origin. Caudal fin rounded. Dermal ossifications. Granules present only on head (on snout, between eyes, on temporal and occipital head regions, and around eye in a circle), on predorsal area and between dorsal and dorsolateral rows of tubercles below the first dorsal fin and below interdorsal space ( Figs. 3 and 5 ). No granules on eyes. No granules on gill covers, dorsal body and posterior flank, around pelvic disc, and only a few granules on posterior dorsal part of caudal peduncle ( Fig. 7 ). Granules tiny, simple-structured bumps, sometimes grouped two or three together, small specimens with comparatively large granules ( Figs. 2 and 3 ). Tubercles distinctively larger than granules ( Figs. 2 and 3 ). Tubercles on head appear more or less randomly scattered. Head with a few small tubercles on snout, 2–4 tubercles present between eyes and 10–12 well-developed tubercles on upper cheek, preopercle and opercle ( Figs. 5 and 7a ). Tubercles not present on temporal and occipital head regions, i.e. all dermal ossifications are definable as granules according to size and shape; and the first tubercles anteriorly to temporal region are located at interorbital space, i.e. anteriorly to rear edge of eyes ( Fig. 5 ). Tubercles on trunk are arranged in longitudinal rows: dorsal, dorsolateral and ventral rows ( Figs. 7 b-d). Dorsal row complete, with 22–29 tubercles, including 2–4 tubercles in front of the first dorsal fin. Several anterior tubercles of dorsal row in front and along the first dorsal fin smaller than remaining tubercles and with one radial row of spinules instead of two. Dorsolateral row with 20–26 well developed tubercles, starting above pectoral-fin base, ending at posterior part or end of D2, decreasing in size posteriorly. No ventrolateral row ( Fig. 7c ). Ventral row anteriorly curved upwards with 2–3 tubercles above others, 22–25 tubercles including the 2–3 anterior upper tubercles. Tubercle bodies poorly defined, dominated by spinules. Tubercles of body rows and of head possess two posterior rows of spinules forming an acute angle, always less than right angle. Exceptions are the anterior tubercles of dorsal row, with one radial row of spinules instead of two ( Fig. 3 ), and tubercles on preopercle and opercle, where spinules look disorganised ( Fig. 2 ). Lateral line system ( Fig. 8 ). No head canals present. Number of papillae in rows are strongly specimen size depending, with larger rows of sensory papillae irregularly doubled or tripled in larger specimens (e.g., suborbital transversal rows or row ot ) ( Figs. 2 and 6a ). Some rows or parts of rows as ridges with papillae along top, e.g., row e ( Fig. 9 ). Rows with range of number of sensory papillae in parentheses as follows: (1) preorbital : snout with four median preorbital series, vertical row r (3–5) slightly above horizontal level of posterior nares, horizontal row s 1 (3–5) below horizontal level of posterior nares, horizontal row s 2 (3–4) n the level of anterior nares and below s 1 and vertical s 3 (2–4) more medially above upper lip. Lateral series c in four parts: superior c 2 as two horizontal rows between anterior and posterior nostril (2+4 – 4+8); middle c 1 (3–6) starting at anterior nostril; inferior rows, upper horizontal c 2 (5–10) and lower horizontal c 1 (3–6) starting anteriorly at upper lip. (2) suborbital : seven transverse suborbital rows ( 1–7 ) of sensory papillae: rows 1–4 begin distant from orbit, row 4 from anterior end of row b downwards to posterior end of row d ; superior segments rows 5s and 6s and row 7 close to eye, inferior sections of rows 5 and 6 well developed, row 5i below middle of row b , row 6i below posterior end of row b , both ending downwards below row d in the level and behind dermal fold ( 1 : 10+23, 2 : 8–15, 3 : 8–21, 4 : 8– 15, 5s : 4–8, 5i : 10– 16, 6s : 4–7, 6i : 12–19, 7: 1–2). Longitudinal row b (10–16) extending forwards above row 5i to upper end of row 4 not reaching below eye. Longitudinal row d (9+8 – 15+11) discontinuous with large gap between supralabial and cheek parts from suborbital row 2 to row 3. (3) preoperculo-mandibular : external row e (27+22 – 44+34) divided into anterior and posterior sections; internal row i continuous (40–62), mental row f (6–14) as cluster in front of chin barbel ( Fig. 9 ). (4) oculoscapular : vertical row tra (1–3) behind lower posterior eye edge with one additional papilla behind it, longitudinal row x¹ placed posteriorly above opercle (1+3 – 5+3), divided by vertical row trp (3–5) in two parts, vertical row q (2–5) behind and below row x¹, with one or two additional papillae behind it. Longitudinal row x² (2–3) placed above opercular posterior edge, with transversal row y (2–3) below it. Axillary vertical rows as 1 (3–7), as 2 (4–7), as 3 (6–12) present, row la 1 (2–4) above as 2 , row la 2 (3–5) above between as 2 and as 3 . (5) opercular : transverse row ot (23–48); superior longitudinal row os (10–24); and interior longitudinal row oi (3–5). (6) anterior dorsal : anterior row n longitudinal (1–3) behind upper eye, transverse row o (1–4) distant from fellow in dorsal midline; longitudinal row g (3–4) distant behind row o , longitudinal row m and longitudinal row h not visible. (7) interorbital : two pairs of interorbital transversal rows, anterior pa (1–2) and posterior pp (2–3). Body with 18–22 transversal ltm rows starting anteriorly behind axilla and as rows, alternating anteriorly with three longitudinal llm rows making anterior beginning pattern of -II-I-I ( Fig. 10 ). Three transversal lv rows at lower anterior body. Two longitudinal lc rows, one along midline of caudal fin, the second above it. Osteology. Vertebral column: 9 (8–10) precaudal and 19 (19–20) caudal vertebrae (including urostyle); total vertebral count: 28 (28–30). D1 pterygiophore insertion pattern: 3–22 1*01*1*1* (only from holotype ); number of anal pterygiophores anterior to the first haemal spine 0 (0–1). Crest-like remaxillary process present on posterior third of premaxialla, sloping with a steep angle on anterior rim and gently towards posterior tip of premaxialla. Five branchiostegal rays. One epural. Number of C rays inserting in hypural 5: 2 (1–2), 3+4 (fused): 5 (5–6), hypural 1+2 (fused): 4 (4–5) and parhypural: 1 (0–1), total number of C rays inserting in hypurals, and parhypural: 12 (12; fused hypural 1+2 and 3+4 separated by a large gap, which does not support any branched caudal ray. Coloration. No live coloration recorded. Color of preserved specimens ( Fig. 4 ): body opaque fawn, irregularly scattered melanophores present on upper head and body, and also on dorsal, caudal and pectoral fins. In some specimens remaining pigmentation almost invisible. Some specimens with three whitish saddles on back: at D2 anterior beginning, D2 posterior end and on caudal peduncle, and with four pigmented blotches on caudal fin longitudinally arranged. Etymology . The species is named for Persia . Distribution and habitat . Southern Caspian Sea basin ( Fig. 1 ). Benthophilus persicus inhabits brackish waters and is abundant on sandy bottoms in coastal areas of the southern Caspian Sea. Capture depth ranges from 6 to 70 m . However, no specimens have yet been collected in the eastern part of southern Caspian Sea. Remarks . Boldyrev & Bogutskaya (2007) tentatively assigned 20 recognized species of the genus Benthophilus to four phenotypic groups. The most prominent differences of the new species as compared with members of the four different species groups are as follows. The new species clearly differs from group I members comprising B. granulosus Kessler, 1877 , B. grimmi Kessler, 1877 , B. kessleri Berg, 1927 , B. leptorhynchus Kessler, 1877 and B. svetovidovi Pinchuk & Ragimov, 1979 by having tubercles on the body ( vs. bony plates rather than tubercles on body). Benthophilus persicus differs from B. baeri Kessler, 1877 and B. spinosus Kessler, 1877 of group IV by having comparatively small dorsal tubercles with body poorly defined, dominated by clearly visible spinules ( Figs. 2 and 3 ) ( vs. very large dorsal tubercles with clear polygonal conical erected body with small or hardly visible spinules, Figure 4 in Boldyrev & Bogutskaya (2007)) , 22–25 tubercles in ventral row ( vs. 9–20), numerous tiny simple structured granules, sometimes grouped two or three together ( vs. large and sparse granules with spinules), a few granules present on the posterior dorsal part of the caudal peduncle ( vs. granules restricted to the upper head surface, gill covers and anterior part of the back). Benthophilus persicus cannot be unambiguously assigned to phenotypic groups II or III of Boldyrev & Bogutskaya (2007) since it features a mix of characters that were used to distinguish these two groups. The new species has tubercles with two posterior rows of spinules forming an acute angle ( vs. almost right angle of two rows of spinules on dorsal tubercules in group III), tubercles present between eyes ( vs. tubercles absent between eyes in group III), a complete dorsal row ( vs. dorsal row incomplete in group III), and a low count of 22–29 dorsal row tubercles ( vs. two out of four species of group III, B. pinchuki Ragimov, 1982 and B. ragimovi Boldyrev & Bogutskaya, 2004 , having higher counts of dorsal row tubercles). However, it has no tubercles on temporal and occipital head regions ( vs. usually four tubercles in row on each side of head in temporal and occipital regions of head, one unpaired temporal tubercle in group II) and no blotches on body in a preserved state ( vs. blotches on body in group II, except B. abdurahmanovi Ragimov, 1978 ). The phenotypic groups II and III of Boldyrev & Bogutskaya (2007) appear less well defined morphologically than the other two groups. Therefore, the new species is here compared with each of the 13 recognized species of groups II and III in alphabetic order: FIGURE 8. Head sensory papillae pattern of lateral line system of Benthophilus persicus sp. nov. Paratype, PMR VP4679, male, 43.3+10.0 mm, Iran, Gilan Province, Chaboksar, southern Caspian Sea. Terminology in text. Drawing by M. Kovačić. FIGURE 9. Benthophilus persicus sp. nov. Sensory papillae pattern of lateral line system in reversibly stained paratypes, anterior part of preoperculo-mandibular rows in PMR VP4680, male, 47.0+8.6 mm, Iran, Gilan Province, Anzali, southern Caspian Sea. Terminology in text. Photo by M. Kovačić. FIGURE 10. Benthophilus persicus sp. nov. Sensory papillae pattern of lateral line system in reversibly stained paratypes, sensory papillae rows on anterior flank in PMR VP4681, male, 35.1+8.5 mm, Iran, Gilan Province, Anzali, southern Caspian Sea. Sensory papillae rows marked, terminology text. The transversal ltm rows starting anteriorly behind axilla, alternating with three longitudinal llm rows making anterior beginning pattern of -II-I-I. Photo by M. Kovačić. Benthophilus persicus differs from B. abdurahmanovi Ragimov, 1978 by having origin of anal fin in front of vertical through origin of second dorsal fin ( vs. under origin of the second dorsal fin), tubercles present, clearly larger than granules, with two posterior rows of spinules forming an acute angle ( vs. tubercles slightly larger than granules, with weakly developed spinules), no ventrolateral row of tubercles ( vs. present), no tubercles on temporal and occipital head regions ( vs. weak tubercles present there), no granules on flanks ( vs. present), transversal suborbital row 6i below posterior end of row b ( vs. below middle of row b ), and the anterior interorbital transversal row pa with 1–2 papilla ( vs. 3–5 papillae). Benthophilus persicus differs from B. casachicus Ragimov, 1978 by having the dermal fold rectangular large ( vs. triangular large), the origin of anal fin in front of vertical through origin of second dorsal fin ( vs. under origin of the second dorsal fin), tubercles present with two posterior rows of spinules forming an acute angle ( vs. tubercles with numerous radial rows of spinules), no tubercles on temporal and occipital head regions ( vs. weak tubercles present on head), anterior interorbital transversal row pa with 1–2 papillae ( vs. 3–5 papillae), body with 18–22 transversal ltm rows starting anteriorly behind axilla and alternating anteriorly with three longitudinal llm rows, having a total of 21–25 lm rows ( vs. 17–18 lm rows in total), and a maximum body width 15.1–22.9% of SL ( vs. 23.2–27.8%). Benthophilus persicus is different from B. ctenolepidus Kessler, 1877 in having the dermal fold rectangular large ( vs. curved large), origin of anal fin in front of vertical through origin of second dorsal fin ( vs. under origin of the second dorsal fin), tubercles present with two posterior rows of spinules forming an acute, always less than right, angle ( vs. about right angle), dorsal row of tubercles complete, 22–29 ( vs. incomplete dorsal row), transversal suborbital row 6i below posterior end of row b ( vs. below middle of row b ), and second dorsal fin with I+7–8 rays ( vs. second dorsal fin I+9–10). Benthophilus persicus differs from B. durrelli by being distributed in southern Caspian Sea ( vs. distribution in the Taganrog Bay of the Sea of Azov and Don River from mouth upstream to the upper stretch of Tsymlyansk Reservoir) and by having no ventrolateral row of tubercles ( vs. large tubercles present), no tubercles on temporal and occipital head regions ( vs. present in two radial rows), no granules on flanks ( vs. sparsely scattered but present), transversal suborbital row 6i below posterior end of row b ( vs. below middle of row b ), and the anterior interorbital transversal row pa with 1–2 papillae ( vs. 3–5 papillae). Benthophilus persicus differs from B. leobergius Berg, 1949 in having the dermal fold rectangular ( vs. triangular), origin of anal fin in front of vertical through origin of second dorsal fin ( vs. origin of anal fin under origin of the second dorsal fin), no tubercles on temporal and occipital head regions ( vs. tubercles present), transversal suborbital row 6i below posterior end of row b ( vs. below middle of row b ), anterior interorbital transversal row pa with 1–2 papilla ( vs. 3–5 papillae), maximum body width 15.1–22.9% of SL ( vs. 24.5–31.1%), and mouth width 36.3–55.8% of head length ( vs. 65.3–71.3%). Benthophilus persicus differs from B. leptocephalus Kessler, 1877 in having the dermal fold large and rectangular ( vs. dermal fold absent), a moderate chin barbel, 1/3–2/3 of eye diameter in length ( vs. very small barbel, hardly visible or absent), tubercles present with two posterior rows of spinules forming an acute, always less than right, angle ( vs. nearly right angle), a complete dorsal row of tubercles, 22–29 ( vs. incomplete dorsal row), anterior interorbital transversal row pp with 2–3 papillae ( vs. single papilla), and second dorsal fin with I+7–8 rays ( vs. second dorsal fin rays I+9–11). Benthophilus persicus differs from B. macrocephalus (Pallas, 1787) in having a moderate chin barbel, 1/3–2/3 of eye diameter ( vs. large barbel, about equal eye diameter), the origin of anal fin in front of vertical through origin of second dorsal fin ( vs. under origin of the second dorsal fin), no tubercles on temporal and occipital head regions ( vs. tubercles present), no granules on flanks ( vs. thorn like granules on flanks), transversal suborbital row 6i below posterior end of row b ( vs. below middle of row b ), anterior interorbital transversal row pa with 1–2 papillae ( vs. 3–6 papillae), and mouth width 36.3–55.8% of head length ( vs. 56.2–67.8%). Benthophilus persicus is distinguished from B. magistri Iljin, 1927 by its distribution in southern Caspian Sea ( vs. distribution in the eastern part of the Sea of Azov) and by having the origin of the anal fin in front of vertical through origin of second dorsal fin ( vs. origin of anal fin under origin of the second dorsal fin), no ventrolateral row of tubercles ( vs. large tubercles present), no tubercles on temporal and occipital head regions ( vs. very small tubercles present), no granules on flanks ( vs. granules present), transversal suborbital row 6i below posterior end of row b ( vs. below middle of row b ), and the anterior interorbital transversal row pa with 1–2 papillae ( vs. 3–5 papillae). Benthophilus persicus differs from B. mahmudbejovi by lacking a ventrolateral row of tubercles ( vs. present with large tubercles), no tubercles on temporal and occipital head regions ( vs. tubercles present), granules not present on flanks ( vs. granules present), transversal suborbital row 6i below posterior end of row b ( vs. below middle of row b ), and the anterior interorbital transversal row pa with 1–2 papillae ( vs. 3–5 papillae). Benthophilus persicus differs from B. nudus Berg, 1998 by its distribution in southern Caspian Sea ( vs. distribution in the lagoons, lakes and rivers of the north-western Black Sea) and by having the dermal fold rectangular and large ( vs. dermal fold roughly triangular, large), origin of anal fin in front of vertical through origin of second dorsal fin ( vs. behind vertical through the origin of the second dorsal fin), no ventrolateral row of tubercles ( vs. present with large tubercles), no tubercles on temporal and occipital head regions ( vs. tubercles present), no granules on flanks ( vs. granules present), and transversal suborbital row 6i below posterior end of row b ( vs. below middle of row b ), anterior interorbital transversal row pa with 1–2 papillae ( vs. 3–5 papillae). Benthophilus persicus differs from B. pinchuki in having the dermal fold well developed, rectangular ( vs. dermal fold triangular, small), origin of anal fin in front of vertical through origin of second dorsal fin ( vs. origin of anal fin under origin of the second dorsal fin), tubercles present with two posterior rows of spinules forming an acute, always less than right, angle ( vs. nearly right angle), dorsal row of tubercles complete, 22–29 ( vs. dorsal row complete, 31–33 tubercles), and a second dorsal fin with I+7–8 rays ( vs. second dorsal fin rays I+9–10). Benthophilus persicus differs from B. ragimovi in having the dermal fold rectangular, large ( vs. triangular, small), the origin of anal fin in front of vertical through origin of second dorsal fin ( vs. under origin of the second dorsal fin), tubercles present with two posterior rows of spinules forming an acute, always less than right angle ( vs. nearly right angle), dorsal row of tubercles 22–29 ( vs. 30–33), no ventrolateral row of tubercles ( vs. present, large), and the second dorsal fin with I+7–8 ( vs. I+9–10). TABLE 1. Benthophilus persicus sp. nov. Morphometric characters as % of standard length or as % of head length. Characters are sorted as in Boldyrev & Bogutskaya (2007) with the new introduced characters added at the end in alphabetic order. The morphometric character and the related values of dimorphic characters with non-overlapping ranges of groups marked with ^ for adult males vs. the immature male and all females, with * for all males and the large female vs. small mature and immature females, and with ˜ for adult males and the large female vs. smaller females and the immature male, see Discussion.

Specimen	ZSM 47595 holotype	ZSM 47596 paratype	ZSM 47597 paratype	ZSM 47599 paratype	ZSM 47598 paratype	ZM - CBSU 5003 - 128 paratype	ZM - CBSU 5001-1 paratype	ZM - CBSU 5003-60 paratype	ZM - CBSU 5022-23 paratype	ZM - CBSU 5024-1 paratype	ZM - CBSU 5003- 77 paratype	PMR VP4679 paratype	PMR VP4680 paratype	PMR VP4681 paratype	PMR VP4682 paratype	PMR VP4683 paratype
Sex	male	female	juvenile male	female	juvenile female	female	female	juvenile female	female	female	female	male	male	male	female	female
Standard length (SL) inmm	45.2	45.8	30.4	30.8	27.5	30.9	35.1	25.4	26.0	23.7	25.1	43.3	47.0	35.1	30.4	34.2
% ofSL
Maximum body depth*	22.2*	19.8*	21.0*	14.6	14.6	17.6	16.7	16.9	15.6	17.0	16.5	19.7*	20.7*	22.8*	16.6	14.6
Maximum body width*	22.6*	22.9*	20.9*	16.7	16.0	15.1	18.0	18.5	17.6	17.5	18.9	19.2*	20.0*	21.9*	18.4	17.2
Depth of caudal peduncle	5.8	6.3	6.7	5.7	5.4	5.3	6.0	5.9	5.5	5.6	5.5	6.5	6.3	5.4	5.7	5.2
Width of caudal peduncle	4.5	4.3	4.6	3.9	3.9	3.9	4.2	5.0	4.0	4.0	3.9	4.3	4.2	4.0	4.3	3.9
First predorsal distance	40.1	42.3	42.8	39.8	39.3	40.7	41.3	39.3	39.5	39.7	39.6	39.9	41.1	41.2	38.9	42.7
Second predorsal distance	67.1	68.0	61.7	63.2	62.1	63.0	65.1	62.1	62.0	60.4	61.9	66.6	65.0	66.2	63.3	64.3
Caudal peduncle length	18.0	17.9	19.9	20.5	19.5	19.4	20.3	20.0	19.1	18.2	20.7	18.1	20.3	19.2	19.0	19.6

...Continued on the next page TABLE 1. (Continued)

Specimen Depth of	ZSM 47595 holotype	ZSM 47596 paratype	ZSM 47597 paratype	ZSM 47599 paratype	ZSM 47598 paratype	ZM - CBSU 5003- 128 paratype	ZM - CBSU 5001-1 paratype	ZM - CBSU 5003-60 paratype	ZM - CBSU 5022-23 paratype	ZM - CBSU 5024-1 paratype	ZM - CBSU 5003-77 paratype	PMR VP4679 paratype	PMR VP4680 paratype	PMR VP4681 paratype	PMR VP4682 paratype	PMR VP4683 paratype
first dorsal fin^ Length	8.5^	7.2	6.9	6.3	5.7	7.3	6.9	4.7	5.5	5.1	6.9	9.5^	9.0^	8.4^	7.4	7.1
of second dorsal fin base	17.4	16.7	18.3	18.5	18.8	19.9	17.3	18.6	16.7	18.4	17.9	18.5	19.8	20.1	16.7	17.7
Depth of second dorsal fin	12.9	12.0	15.3	13.2	11.3	13.2	12.1	12.3	12.2	12.7	11.6	13.4	12.4	14.0	12.1	12.7
Length of anal-fin base	19.8	23.1	20.4	19.5	19.5	20.7	20.2	22.1	21.6	19.2	20.8	21.5	21.9	22.3	23.8	19.7
Depth of anal fin	10.3	10.3	11.1	10.7	9.9	10.2	11.4	10.9	9.6	11.0	10.2	10.5	10.7	10.1	11.5	11.9
Preanal distance	62.8	57.4	60.2	59.9	57.2	59.7	59.6	57.1	58.9	60.2	59.2	57.6	60.4	60.7	58.3	58.6
Prepectoral distance	36.5	37.1	39.9	35.4	32.9	38.4	36.8	37.9	33.2	35.6	34.6	35.5	37.4	37.6	37.7	38.7
Prepelvic distance*	32.2*	35.1*	32.1*	31.0	29.1	31.6	30.8	30.6	31.6	30.7	29.7	32.5*	35.9*	35.2*	28.8	27.2
Pelvic disc length	31.1	28.6	31.4	29.4	30.2	32.1	damaged	29.3	29.4	29.4	26.2	29.8	28.2	28.7	29.9	27.0
Lateral head length Body depth	35.3	35.1	37.8	35.4	33.4	36.1	37.6	36.8	33.4	33.2	33.9	37.0	36.0	38.1	35.4	36.9
at anal-fin origin* Body width	13.8*	13.8*	13.2*	11.7	11.1	12.2	12.0	12.7	12.4	12.7	11.8	13.0*	13.4*	12.9*	12.7	11.5
at anal-fin origin	11.4	12.0	12.0	10.2	10.2	9.6	10.7	10.6	9.7	10.3	9.2	10.1	10.5	10.6	10.9	9.2

...Continued on the next page TABLE 1. (Continued)

Specimen	ZSM 47595 holotype	ZSM 47596 paratype	ZSM 47597 paratype	ZSM 47599 paratype	ZSM 47598 paratype	ZM - CBSU 5003- 128 paratype	ZM - CBSU 5001-1 paratype	ZM - CBSU 5003-60 paratype	ZM - CBSU 5022-23 paratype	ZM - CBSU 5024-1 paratype	ZM - CBSU 5003-77 paratype	PMR VP4679 paratype	PMR VP4680 paratype	PMR VP4681 paratype	PMR VP4682 paratype	PMR VP4683 paratype
Caudal-fin length Length of	21.8	21.3	24.9	22.8	23.4	26.5	23.1	23.8	22.6	22.3	25.0	23.0	18.2	24.1	24.3	damaged
first dorsal- fin base	5.6	4.6	5.4	5.4	4.1	5.3	4.4	4.6	5.1	4.5	5.3	5.8	6.0	5.2	5.9	5.4
Postanal-fin distance	18.0	17.1	17.8	18.0	18.7	17.8	18.2	18.4	18.8	17.6	18.9	17.5	19.7	17.8	17.1	18.6
Postdorsal- fin distance	16.3	17.8	19.0	18.2	18.4	18.5	18.1	17.4	16.4	17.9	18.4	15.2	16.1	17.0	16.9	17.9
% of head length
Head depth*	56.7*	54.7*	55.8*	44.9	46.2	47.0	42.2	43.0	44.8	47.7	49.8	56.5*	61.0*	56.6*	48.2	41.0
Head width* Horizontal	95.8*	101.2*	94.4*	86.8	87.3	90.7	85.8	84.5	86.4	89.1	94.8	103.7*	105.0*	103.7*	89.7	89.1
eye	14.1˜	14.2˜	17.3	17.4	16.7	16.0	16.8	18.9	17.4	21.6	19.7	15.2˜	15.4˜	16.1 ˜	16.4	15.1
diameter˜ Interorbital distance˜	14.8˜	16.5˜	10.5	10.6	11.3	10.7	11.4	9.2	9.5	9.3	9.2	17.3˜	19.3˜	13.8˜	11.9	10.7
Snout length	27.8	25.4	24.6	24.0	26.8	25.2	27.9	24.6	26.0	26.7	24.6	24.3	27.9	26.2	24.4	25.5
Postorbital distance	60.1	59.1	56.8	57.6	54.9	56.6	57.8	54.8	54.5	58.8	54.3	62.5	59.8	59.3	59.4	56.1
Mouth width	50.0*	54.9*	50.7*	37.9	45.8	41.4	39.8	36.3	37.4	41.0	44.5	55.2*	55.8*	49.1*	43.6	38.2
Dermal fold length	16.6	damaged	19.7	15.9	20.5	15.5	13.4	12.2	14.9	18.8	17.7	15.4	17.1	15.5	14.1	14.0
Dermal fold depth	6.8	damaged	6.9	6.1	5.9	6.1	5.0	4.7	5.5	5.6	4.8	5.8	5.3	5.2	5.4	5.2
Chin barbel length	8.3	9.4	9.3	8.6	7.8	9.5	7.4	8.2	9.3	8.0	7.3	9.5	8.9	8.2	9.6	8.6
Lower jaw length	37.6	36.2	37.4	36.3	34.5	33.8	37.6	34.5	33.5	36.2	34.4	37.8	34.7	33.2	38.1	33.6

Benthophilus persicus is distinguished from B. stellatus (Sauvage, 1874) by its distribution in the southern Caspian Sea ( vs. distribution in the Taganrog Bay of the Sea of Azov and Don river from mouth upstream to the upper stretch of Tsymlyansk reservoir) and by having the dermal fold rectangular ( vs. dermal fold roughly triangular), a moderate chin barbel, 1/3–2/3 of eye diameter in length ( vs. large, about equal eye diameter), the origin of anal fin in front of vertical through origin of second dorsal fin ( vs. under origin of the second dorsal fin), no tubercles on temporal and occipital head regions ( vs. tubercles present), transversal suborbital row 6i below posterior end of row b ( vs. below middle of row b ), anterior interorbital transversal row pa with 1–2 papillae ( vs. 3–5 papillae), maximum body width 15.1–22.9% of SL ( vs. 22.8–28.3%), and a mouth width 36.3–55.8% of head length ( vs. 55.8–62.2%).