Glossogobius callidus ( Smith, 1937 )

Zarei, Fatah, Sithole, Yonela, Schliewen, Ulrich, Bills, Roger & Chakona, Albert, 2025, Integrative systematics of the taxonomically complex gobiid genus Glossogobius Gill, 1859 (Teleostei: Gobiidae) from the south-western Indian Ocean, with a description of a new species, Zoological Journal of the Linnean Society 203 (4) : -

Glossogobius callidus ( Smith, 1937)

( Figs 5–7, 8A–E)

Gobius gulosus Smith 1936: 49 (Bushman’s River, Alicedale; preoccupied).

Gobius callidus Smith 1937: 197 (replacement for Gobius gulosus Smith ).

Glossogobius callidus — Skelton 1993, 2001, 2024; Maake et al. 2013 in part (Lineage 1).

Holotype: SAIAB 305 , male, 91 mm TL, Bushman’s River , Alicedale, Cape Province, South Africa, collected by A. Cruden, Esq., date of collection unknown.

Topotypes (N = 16): SAIAB 130800 , 2 males, 2 females, 61.1– 65.7 mm SL, Bushman’s River near Alicedale, Cape Province, South Africa, –33.38916, 26.05, collected by S. Torne, 14 February 2007 ; SAIAB 235532 , 8 males, 4 females, 32.1– 59.1 mmSL, Bushman’sRiveratweirinAlicedale, CapeProvince , South Africa, –33.32916, 26.0772, collected by A. Chakona, W. Kadye, and U. Schliewen, 17 March 2022 (GenBank: COI: PQ761154, PQ761155 ) .

Additional materials, included in the description and analyses (N = 59): SAIAB 76359 , 2 males, 2 females , 43.6–57.3 mm SL, Kat River at Amhurst Farm , Kat River, Great Fish System, South Africa, –32.62110137, 26.6849002838, collected by E . R. Swartz and A.H. Bok, 13 May 2005 (GenBank: COI: PQ761162 ) ; SAIAB 88618 , 6 males, 2 females , 22.2–54.7 mm SL, bridge at Siyadla , Siyadla, Kosi, South Africa, –27.081194, 32.78675, collected by P. Maake, E . R. Swartz , and B. Kramer, 25 October 2009 (GenBank: COI: PQ761166 ) ; SAIAB 88629 , 2 males, 3 females , 58.1–80.8 mm SL, bridge in Manguzi , Mahlampane River, Kosi River system, South Africa, –26.993416, 32.742861, collected by P. Maake, E . R. Swartz , and B. Kramer, 27 October 2009 (GenBank: COI: PQ761167 ) ; SAIAB 88638 , 5 males, 1 female , 45.8–56.2 mm SL, bridge on the way to Manguzi , Nkanini, South Africa, –26.949416, 32.777527, collected by P. Maake, E . R. Swartz , and B. Kramer, 28 October 2009 (GenBank: COI: PQ761168 ) ; SAIAB 88650 , 1 male, 1 female , 60.1–65.8 mm SL, Kosi Bay Nature Reserve , Mpungwune River, Kosi River system, South Africa, –26.957305, 32.82994, collected by P. Maake, E . R. Swartz , and B. Kramer, 29 October 2009 (GenBank: COI: PQ761169 ) ; SAIAB 88656 , 2 males, 2 females , 24.1–41.2 mm SL, Lake Mgobozeleni outside the Sodwana Park, Mgobozeleni, South Africa, –27.53516, 32.660194, P. Maake, E . R. Swartz , and B. Kramer, 30 October 2009 (GenBank: COI: PQ761165 ) ; SAIAB 96557 , 4 males, 2 females , 34.2–48.8 mm SL, Nseleni River—Nature Reserve— Richards bay , Nseleni, South Africa, –28.699416, 32.001283, collected by O. Weyl, B. Ellender , R.W. Jones, and R. Karsing , 23 May 2010 (GenBank: COI: PQ761163 ) ; SAIAB 97176 , 7 males, 4 females , 31.3–44.7 mm SL, first pool above barrier, Kirkwood , Klein Uie, Sundays, South Africa, –33.33025, 25.492016, collected by O. Weyl, 9 September 2009 (GenBank: COI: PQ761156 ) ; SAIAB 97357 , 1 male, 1 female , 33.1–37.6 mm SL, Groendal Wilderness , Swartkops, South Africa, –33.7146, 25.29953, collected by B. Ellender, 14 April 2010 (GenBank: COI: PQ761159 ) ; SAIAB 99444 , 1 male , 35.2 mm SL, Martin Swart Farm— Lower Kirkwood , Sundays, South Africa, –33.40919, 25.48417, collected by N. Mazungula, D. Woodford, and T. Bellingan , 26 August 2011 (GenBank: COI: PQ761157 ) ; SAIAB 203776 , 4 males, 1 female , 44.9–62.8 mm SL, bridge upstream of the dam, Lourie River , Gamtoos system, South Africa, –33.8506944, 25.0388194, collected by A. Chakona and B. Motshegoa, 18 January 2016 (GenBank: COI: PQ761160 ) ; SAIAB 210314 , 3 males, 2 females , 44.9–58.1 mm SL, Makat Farm in Jamela , Mbabe, Nseleni, South Africa, –28.65516, 32.030194, collected by A. Chakona, N. Mazungula, and B. Motshegoa, 4 September 2015 (GenBank: COI: PQ761164 ) .

Additional material not included in the description and analyses but eoamined and confirmed morphologically to map the geographic range of the species: SAIAB 54636 , 2 specimens, 53.3–53.9 mm SL, Groendal , Blindekloof, Swartkops System, South Africa, –33.7057991, 25.2961006165,collectedbyR.BillsandD. Naran, 28 March 1997 ; SAIAB 64950 , 14 specimens, 19.5–68.0 mm SL, catle watering spot above road bridge, Reit River , Reit System, South Africa, –33.55389022, 27.0063896179, collected by R. Bills , K . T. Kleophas , and E. Qonya, 9 November 2001 ; SAIAB 64961 , 14 specimens, 26.4–66.1 mm SL, low bridge on the Bathurst-Martindale Rd , W Kleinemond River, W Kleinemond System, South Africa, –33.49750137, 26.930, collected by R. Bills and E. Qonya, 14 November 2001 ; SAIAB 68409 , 1 specimen, 53.3 mm SL, Bloukrans River , Kowie System, South Africa, –33.50444412, 26.7447223663, collected by R. Bills , J. Msibi, M. Fakudze, N. Khumalo , R. C. Boycot, and D. Tweddle, 19 June 2002 ; SAIAB 79445 , 8 specimens, 38.8–64.3 mm SL, Gqudushe , Keiskama River, Keiskama System, South Africa, –32.8683, 26.946, collected by D. Weeks, 12 October 2005 ; SAIAB 74937 , 2 specimens, 31.0– 42.8 mm SL, KwaNxamkwane Stream draining Potsdam town, Buffalo System, South Africa, –32.98527908, 27.6388893127, collected by P. Maseti, 7 April 2003 ; SAIAB 83600 , 10 specimens, 27–39 mm SL, by road bridge, Mzimayi River , South Africa, –30.73683, 30.0, collected by H.K. Larson, 18 November 2005 ; SAIAB 88609 , 10 specimens, 30.4–64.5 mm SL, Zotsha River Estuary, South Africa, –30.78099, 30.42329, collected by H.K. Larson, 19 November 2005 ; SAIAB 128178 , 13 specimens, 29–64 mm SL, national road bridge at entrance of Diep River , South Africa, –34.05, 24.575, collected by A.H. Bok and M. King, 11 May 1982 ; SAIAB 128291 , 15 specimens, 22.6–33.2 mm SL, at bridge west of Alicedale , Bushmans, South Africa, –33.3083, 26.0538, collected by P.H. Skelton and M. King, 8 September 1982 ; SAIAB 128622 , 3 specimens, 20–37 mm SL, causeway on Vaalkrans Farm , Alicedale Road, Bushmans, South Africa, –33.3838, 26.0272, collected by J. Olivier and S. Torne, 19 February 1983 ; SAIAB 133445 , 8 specimens, 42–53 mm SL, bridge 50 m above guaging weir, Mntafufu , South Africa, –31.49416, 29.527, collected by A.H. Bok and J.A. Cambray, 1 November 1996 ; SAIAB 134138 , 2 specimens, 59–70 mm SL, below Ticor Factory , Mhlatuze, Okula, South Africa, –28.712, 31.87861, collected by M. Coke, 18 May 2002 ; SAIAB 134407 , 2 specimens, 48.3–56.8 mm SL, Mhlongwana , Durban, South Africa, –30.2, 30.77361, collected by R. Karssing , 30 March 2006 ; SAIAB 191032 , 10 specimens, 72–80 mm SL, Sundays dams, South Africa, –33.58115, 25.66436, D. Woodford , T. Bellingan , and L. Mofu, 15 August 2013 ; SAIAB 191097 , 12 specimens, 20–59 mm SL, Coffee Bay , Umdumbi, South Africa, –31.98472, 29.14694, collected by P.C. Heemstra and E. Heemstra, 30 April 2002 ; SAIAB 200858 , 1 specimen, 51 mm SL, under Van Stadens River bridge on old Cape Road, Van Stadens, South Africa, –33.901916, 25.18538, E . R. Swartz and H. Roos, 18 June 2015 ; SAIAB 208849 , 3 specimens, 26.4–49.4 mm SL, main channel, between Cambria and Komdomo, Gamtoos, South Africa, –33.69527, 24.60361, collected by E . R. Swartz , date unknown ; SAIAB 211000 , 7 specimens, 35–43 mm SL, Mona River confluence, Tongati, South Africa, –29.53, 31.0894, collected by M. Coke, 18 March 2005 .

Diagnosis: Head and body pigmented and eyes present (vs. head and body devoid of pigment and eyes absent in G. ankaranensis ); predorsal area on top either naked or with up to eight scales in midline, not extending over opercle; sides of predorsal area scaled to mid-opercle or behind it (vs. predorsal area fully scaled to above preopercular margin in G. tenuiformis , and fully scaled to behind eyes in G. giuris clade B, with a distinct naked patch usually present); all suborbital papillae lines (Lines 7–11) and those on underside of head (Lines 12–13) in single rows (vs. suborbital lines 9–10 and Line 13 on underside of head doubled or tripled in G. giuris clade B); anterior half of papillae Line 5 below eye doubled anterior to the mid-eye, and single row posteriorly (vs. Line 5 in single row in G. tenuiformis and G. giuris clade B). It further differs from G. tenuiformis and G. giuris clade B in having a distinct predorsal blotch (vs. predorsal blotch absent), and a doubled blotch on caudal-fin base, with both blotches rounded and the posterior one being slightly larger (vs. triangular in both G. tenuiformis and G. giuris clade B, with a distinct unpigmented gap posteriorly in the former species). Glossogobius callidus s.s. differs from its closest relative, G. hanisii sp. nov., in the number of pectoral-fin rays (14–17, usually 16 vs. 18–20, usually 18–19) and, if expressed, having a darker head and body and more midlateral blotches (5–8 blotches, usually 6–7 vs. 5–6 blotches, usually 5) (dark pigmentation and midlateral blotches may be less pronounced in live specimens).

General morphology: Body proportions detailed in Table 2: moderately elongate body, depth at pelvic-fin origin 14.6%–21.1% SL, at anal-fin origin 14.2%–19.1% SL, laterally compressed posteriorly, with shallow caudal peduncle (depth 0.3–0.43 times caudal peduncle length). Large head: length 28.3%–36.1% SL, width 53.9%–70.9% head length, and depth 48.6%–63.7% head length and 0.78–1.08 times head width. Nearly straight/slightly convex postorbital profile, short snout (length 0.97–1.79 times eye diameter, 26.8%–36.1% head length). Anterior nostril in erect flared tube with posteriorly elevated rim; posterior nostril pore-like, rim slightly elevated anteriorly. Dorsolateral eyes, large (diameter 19.9%–30.4% head length), elevated orbit. Interorbital 20.9%–73.6% eye diameter. Mouth obliquely upwards, distinctly projecting lower jaw, angle of jaws anterior to pupil. Cheek moderately deep (depth 0.28–0.58 times head depth at eye). Both jaws with conical teeth in outermost and innermost rows, irregular rows of smaller teeth in-between. Broad gill opening, reaching forward to just anterior to posterior margin of preoperculum.

Fins: D1 VI; D2 I/8–I/10 (holotype I/10; other materials: I/8:3, I/9:70, I/10:2); A I/7–I/9 (holotype I/8; other materials: I/7:12, I/8:61, I/9:2); P 14–17 (holotype: 16; other materials: 14:3, 15:13, 16:41, 17:18), V I/5 + 5/I. Morphometric characters are given in Table 2. D 1 dorsal profile triangular, 1st to 2nd spines lengthen progressively, 3rd to 6th spines shorten progressively, 6th spine length 0.6–0.8 times 1st spine length. D1 1st spine length 0.9–1.1 times D2 spine length. D1 and D2 not connected by interdorsal membrane, interdorsal space between D1 VI and D2 I narrow, typically 1 scale or shorter. D2 origin slightly posterior to anus. Anal-fin origin below 1st to 2nd branched rays of D2. Anal-fin last ray below or slightly beyond D2 penultimate ray. D2 and A rays usually do not reach base f uppermost and lowermost caudal-fin rays, except in some large specimens. C lanceolate, 0.78–1.26 in head length. P lanceolate, reaching a vertical at D2 origin. P rays all branched; uppermost rays fused by membrane. V disc complete, oval, below P, significantly anterior to vertical at D1 origin; its length 0.88–1.2 times V origin to anus, usually does not reach or rarely extends to A origin (variability in both sexes). V with well-developed pelvic frenum; edge of pelvic frenum straight.

Squamation: Body mainly with ctenoid scales; cycloid scales on predorsal area, posterior breast, and abdomen. Cheek, opercle, and base of pectoral fins naked. Predorsal area on top naked or with up to eight scales in midline (holotype: 4; other materials: 0:2, 1:11, 2:21, 3:20, 4:14, 5:2, 6:3, 7:1, 8:1), squamation ends posterior to or at predorsal blotch above upper pectoral-fin base; sides of predorsal area scaled to mid-opercle or behind it ( Fig. 9A). LSS 29–33 (holotype: 31; other materials: 29:11, 30:12, 31:18, 32:28, 33:7). TR 9.

Cephalic sensory system: Head pores ( Fig. 10): Anterior oculoscapular canal pores B′, C, D, E, F, G, and H′. Posterior oculoscapular canal pores K′ and L′. Preopercular canal pores M′, N, and O′. All paired except C and D. Sensory papillae ( Fig. 10): Line 1a single row of papillae starting from pore B′; Line 1b, 1–3 papillae above anterior nostril. Line 2a cluster, usually not continuous across snout, rarely connected by single row; Line 2b a single papilla lateral of pore B′. Line 5 below eye, double anteriorly in shape of circle, single posteriorly. Line 6 short, anteriorly joins Line 5 behind mid-eye. Five suborbital longitudinal lines, 7–11, all single rows of papillae. Line 7: slender papillae posteriorly, larger and oval anteriorly, axes in line with axis of papilla line. Line 8: larger oval papillae, axes vertical and perpendicular to axis of papilla line. Lines 9 and 10: single rows of large papillae, axes in line with axis of papilla line. Line 11: single row, large oval papillae, axes vertical and perpendicular to axis of papilla line. Lines 12 on underside of head, single row, continuous. Line 13 on underside of head, single row, continuous, tripled anteriorly. Line 20 transverse single row of papillae on operculum. Line 21 oblique and curved, single row. Line 22 short longitudinal, single row. Chin partly covered with two clusters of papillae. Mental frenum free of papillae. Line 14 short single row behind eye. Line 15 single row from eye to pore K′. A short single row between 14 and 15. Line 17 single row from pore H.:’] l,xxxxxxx to pore K′. Lines 16 and 18 short single rows, parallel, behind pore L′. Line 19 single transverse row, dorsally starts between pores G′ and H, extends downward to just behind or above pore M′.

Osteology (N = 40): Total vertebrae 26–28 (holotype, Fig. 5B: 27; other materials: 26:3, 27:31, 28:5), precaudal vertebrae 9–11 (holotype: 11; other materials: 9:1, 10:35, 11:3), caudal vertebrae 16–18 (holotype: 16; other materials: 16:6, 17:30, 18:4). D1 pterygiophore insertion patern: 3-22110. Number of anal pterygiophores anterior to first haemal spine: 3.

Coloration: No sexual dichromatism. In life (see Fig. 6: based on three photographs from the Bushman’s and Ntshambili rivers). Head and body greyish to yellowish brown, paler ventrally. Up to eight dark-brown midlateral blotches, forming chevrons or X-shapes; posteriormost blotch on caudal-fin base darkest, double, rounded, with posterior blotch slightly larger. Upper body with numerous, small, irregular greyish to brown spots. A distinct brown blotch anterior to D1 origin, above pectoral-fin base. Dark-brown oblique stripe from front of eye to upper lip, another dark-brown oblique stripe from below eye to jaw. Preoperculum and opercle with various-sized brown spots. Pectoral-fin base with a dark dorsal spot. D1 with a horizontal band, darker and broader posteriorly. D2 with three oblique rows of small brown spots. Caudal fin with six vertical dark bands. In live specimens, dark pigmentation may be less pronounced than in preserved forms. In preservative ( Figs 5, 7, 8A–E): Head and body dark brown; head darker, body paler ventrally. Five to eight dark-brown midlateral blotches along body, usually 6–7, forming narrow chevrons or X-shaped structures; rearmost midlateral blotch on caudal-fin base darkest and double, both blotches rounded, with posterior one larger. Upper body with greyish to dark brown motling and irregular blotches. Dark blotch in front of D1 more or less distinct. Interorbital area and snout usually dark brown. Dark-brown oblique stripe from front of eye to upper lip. Dark-brown oblique stripe from below eye to jaw. Preoperculum and opercle greyish to dark brown with irregular blotches of varying sizes. Pectoral-fin base with distinct brown spot dorsally, extending onto base of pectoral-fin rays. Pectoral-fin rays usually brownish. Mental frenum usually pigmented dark brown. Ventral surface of head and breast variably pigmented, sometimes dark brown to base of pelvic disc. D1 with distinct brown horizontal band on proximal part; outer part with diffuse tiny brown spots on interspinous membranes. D2 with three oblique rows of small brown spots. Caudal fin with 6–11 vertical brown to black bands. Pelvic disc and anal-fin rays and membranes darkly pigmented or grey.

Distribution and habitat: Glossogobius callidus s.s. is abundant in marine habitats, coastal lakes, estuaries, and lower reaches of numerous rivers along the south and east coasts of South Africa, from Pletenberg Bay in Eastern Cape north to Kosi Lake near the South Africa / Mozambique border in KwaZulu-Natal ( Figs 2, 11). Te distribution range of this species overlapping with the southern range of G. hanisii sp. nov. sublineage I. Te materials examined in this study confirm their sympatric occurrence in the Zotsha and Keiskamma rivers.

Seoual dimorphism: Males have a conical urogenital papilla with a pointed posterior edge; females have a wider, trapezoid papilla with a villose posterior edge. Males grow larger (up to 104.1 mm TL) compared to females (max 86.8 mm TL). Morphometric and meristic characteristics overlap.

Etymology: Smith (1937) did not elucidate the origin or rationale behind the specific name.