Gorogobius stevcici, Ić, Marcelo Kova Č & Schliewen, Ulrich K., 2008

Ić, Marcelo Kova Č & Schliewen, Ulrich K., 2008, A new species of Gorogobius (Perciformes: Gobiidae) from São Tomé Islands, Zootaxa 1686, pp. 29-36 : 30-34

Gorogobius stevcici sp. nov.

( Fig. 1a ,b,c)

Holotype ( Fig 1a ,b). Male, 33.0+ 6.9 mm, SMNS 23053, Rolas Island, São Tomé Group, south of São Tomé Island, August, 2002, collected P. Wirtz.

Paratypes. Four females, 23.3+ 6.3 mm, 22.4+ 6.3 mm, 21.1+ 4.6 mm, 19.5+ 4.7 mm, SMNS 23054, Rolas Island, São Tomé Group, south of São Tomé Island, collected P. Wirtz.

Diagnosis. The new species is distinguished from G. nigricintus by (1) presence of pore β; (2) row g anteriorly ends more or less in front of row o; (3) transverse interorbital row p present; (4) snout with four vs. three median preorbital rows; (5) 37–41 vs. 29–33 longitudinal scale rows; (6) 22–24 vs. 18 predorsal scales; (7) 9 vs. 10–11 anal fin rays; (8) 17 vs. 18–20 pectoral fin rays; (9) body overall light reddish-brown, with or without faint brown vertical bands vs. dark brown bars contrasting strongly with light ground on flanks, fins, eyes, head and lips.

Description. Morphometric values are given in Table 1. Body moderately elongate, laterally most intensively compressed at caudal peduncle. Head not markedly depressed. Snout moderately oblique and convex in lateral view, rounded in dorsal view, shorter than eye. See “Generic description” for nostrils, eyes, mouth, jaws, lips, branchiostegal membrane, dentary and tongue.

Sex Male Females

n 1 4

standard length (mm) 33.0 19.5–23.3

% standard length, head length 28.8 28.7–31.6 (30.0) head width 20.6 14.4–18.6 (16.5) head depth 17.3 14.8–17.7 (16.3) distance from snout to origin of first dorsal fin 36.1 37.8–40.7 (38.8) distance from snout to origin of second dorsal fin 54.5 57.4–59.0 (58.0) distance from snout to anus 53.0 51.3–56.5 (54.6) distance from snout to vertical of anal fin origin 56.7 57.4–60.9 (59.1) distance from snout to vertical of pelvic fin origin 31.5 33.3–35.5 (34.6) caudal peduncle length 23.9 22.9–28.7 (25.5) first dorsal fin base 19.7 17.2–20.4 (18.5) second dorsal fin base 27.0 24.7–26.2 (25.5) anal fin base 19.4 18.2–19.5 (19.1) caudal fin length 20.9 20.1–20.9 (20.6) pectoral fin length 25.2 26.8–29.3 (27.6) pelvic fin length 24.5 23.9–26.0 (25.1) body depth at at pelvic fin origin 24.2 21.5–24.2 (22.7) body depth at anal fin origin 24.5 19.6–24.2 (21.8) body width at anal fin origin 13.9 10.5–14.3 (11.8) caudal peduncle depth 13.9 11.8–13.4 (12.6) distance from pelvic fin origin to anus 21.5 22.0–23.1 (22.3)

% caudal peduncle length, caudal peduncle depth 58.2 43.3–58.5 (50.2)

% head length, snout length 20.0 16.1–19.7 (18.0) eye diameter 31.6 33.8–35.7 (34.4) postorbital length 45.3 42.3–47.5 (45.3) cheek depth 18.9 16.1–18.3 (16.9) head width 71.6 49.2–60.6 (54.8)

% eye diameter, interorbital width 26.7 22.7–30.4 (27.8)

% lateral preorbital distance, upper lip width 50.0 50.0–100.0 (73.3)

% distance from pelvic fin origin to anus, pelvic fin length 116.9 106.7–117.6 (112.3) First dorsal fin VI; second dorsal fin I/11; anal fin I/9; caudal fin with 13–15 branched rays (13:3, 14:1, 15:1), 16–17 segmented rays (16:1, 17:4); 17 pectoral rays (both sides), pelvic fin I/5 + 5/I. First dorsal fin spines I and II longest. All first dorsal fin spines reaching at least base of second dorsal fin when fin folded down. Second dorsal fin of almost uniform height. Interdorsal spaces membranous. Anal fin commences approximately below 1st segmented ray of second dorsal fin, with last ray approximately below vertical of 9th segmented ray of second dorsal fin. Caudal fin rounded. Pectoral fin with uppermost rays enclosed by finmembrane, reaches beyond vertical through origin of second dorsal fin. Pelvic fin elliptical, with truncate rear edge, reaching anus; anterior membrane well developed, its caudal margin ending at approximately 3/4 length of fifth segmented ray.

Body and head with ctenoid scales. Entire predorsal area to eyes and pore κ scaled. Scales on cheek extending forwards variably: in larger specimens scales well developed below anterior edge or at least to central level of pupil, and extended downwards below level of posterior angle of jaws; in smaller specimens scales on cheek weakly developed in the anterior part and barely visible. Opercle and breast with ctenoid scales. 37–41 longitudinal scale rows (both sides: 37:1, 38:1, 39:4, 40:3, 41:1), 13–14 scales in transverse series (both sides: 13:6, 14:4), 22–24 predorsal scales (22:2, 23:1, 24:2).

Head lateral-line system with anterior oculoscapular canal, carrying pores σ, λ, κ, ω, α, β, ρ respectively. The relative size of pores variable, with pores σ, λ, κ being usually the largest pores and β, ρ being the smallest ones. Rows and the number of sensory papillae ( Fig. 2 ): (I) preorbital: snout with four rows in median preorbital series: upper row r (5–9) between pores σ and λ. Upper row s1 (3–6) below pore σ, lower s2 (3–7) transversal, and s3 short, longitudinal above upper lip (3–5). Lateral series c in four parts: superior (c2) below PN (7–14) in two or three longitudinal rows; middle transversal c1 (3–5) close to AN; inferior upper c2 (6–10) longitudinal above lips; and lower c1 (2–5) between lips and row 1. (II) suborbital: six transverse (1–7) and two longitudinal rows (b, d) of sensory papillae on cheek. Rows 1–5 before longitudinal row b; row 6 above row b, with no inferior sections, row 7 represented by one papilla near α; (1: 7–9, 2: 6–11, 3/4: 5–8, 5: 10–18, 6s: 4– 8, 7: 1). Rows 1–5 begin at similar distance from orbit. Row 1 ending downwards near row d above the upper lip; row 2 ending on row d or below level of d, row 3/4 ending near d; row 5 passing d. Longitudinal row b (5– 12) extending forwards below rear part of eye, meeting row 5. Longitudinal row d (15–23) long, continues (the paratypes 23.3 mm and 22.4 mm, SMNS 23054) or separated by the lower end of transverse row 2 into two more or less distant parts (the holotype 33.0 mm, SMNS 23053, and paratypes 21.1 mm and 19.5 mm, SMNS 23054), not reaching row 5 posteriorly. (III) preoperculo-mandibular: external row e distinctly divided into anterior (e1: 14–22), and posterior sections (e2: 16–32); internal row i begins anteriorly before e, also distinctly divided into anterior (i1: 8–10), and posterior sections (i2: 9–11); mental row f longitudinal (6–12). (IV) oculoscapular: four longitudinal rows (x1, x 2, la1, la2) and seven transversal rows (z, q, tr, y, as1, as2, as3). Anterior longitudinal row x1 (11–13) extending forwards above or slightly in front pore β, ending backwards between rows q and tr; posterior longitudinal row x2 (4–9) above row y; row z (3–10) beginning between pores β and ρ; row q (6–19) beginning behind pore ρ, transversal, long, extending above level of row x¹ (the paratype 21.1mm, SMNS 23054 with well-developed row q visible on just one side); transversal rows tr (5– 12) and y (4–9) present; two single papillae present, the first between q and tr, below x¹, the second between tr and y, in the level of x¹; transversal axillary rows as1 (11–22), as2 (7–13), as3 (10–25) long, longitudinal rows la1 (3–6) and la2 (3–6) present above rows as. (V) opercular: transverse row ot (16–27); superior longitudinal row os (5–11); and inferior longitudinal row oi (5–8). (VI) anterior dorsal: long anterior dorsal row n (18–31) behind orbit and pore ω, extending behind pore α onto upper cheek; transversal rows o (5–7) well developed and separated; longitudinal row g (7–12) ends anteriorly more or less in front row o, longitudinal row m (3–7) behind and below posterior part of row g; longitudinal row h (10–15) continuous. (VII) interorbital: transverse interorbital row p present (2–4).

Color pattern in alcohol ( Fig. 1a ). Male: Body overall brownish-grey; with eight more-or- less welldefined vertical narrow pale stripes, beginning at dorsal midline. The first vertical stripe on predorsal area, next two below first dorsal fin, next three below second dorsal fin, and final two on caudal peduncle. Ventral part of body, cheek and operculum beige. Breast whitish. Chin, mouth and snout dark brown to black. First dorsal fin with dark mark between first and fifth spines. The rest of first and second dorsal fins and caudal fin uniformly brownish-grey, more dark at base. Pectoral and pelvic fins uniformly pigmented, pale. Females: Body overall brownish-grey. Two specimens with faint brown vertical bands in the posterior body partition, first three below second dorsal fin, and fourth and fifth on the caudal peduncle, all reaching from the dorsal profile down to about half of the flank; in the other two specimens, no faint bands are discernable; ventral portion of body and head beige; cheek and breast whitish; caudal and second dorsal fin with small brown dots that form irregular lines when fins are expanded; base of anal, first, second dorsal and (in some specimens) lateral edge pelvic fin membrane dusky black; pectoral and pelvic fins otherwise pale; posterior edge of operculum, preoperculum and branchiostegal membrane dark brown; anterior part of lower and upper lip and snout dark brown to black.

Color in life (based on photographs reproduced in Figs. 1 b,c and 3). Male (holotype; Fig. 1 b): Similar to coloration in alcohol, except that anterior flank bands less clearly visible; first dorsal fin mark is clearly visible as a whitish boarded black dot covering the anterior lower half of first dorsal fin; outer margin of first dorsal fin membranes with yellowish margin and dorsal rays basally blackish; iris dark brown without bright metallic yellow coloration as in female specimens; snout, cheek and mouth with yellow-green hue; and lateral part of upper lip metallic whitish, while the posterior part of the the lower lip is black. Female ( Fig. 1 c) and unsexed individuals ( Fig. 3 ): Similar to coloration in alcohol except that dorsal part of eyes, adjacent part of the ligamentous ring and the lateral part of the upper lip are bright metallic yellow; upper iris part directly adjacent to pupil with a thin white circle, the remaining upper part of the iris with a metallic blue-green hue except for a black dot in the lower-posterior quarter of the iris. Overall body coloration rusty red, with the head below the eyes and the area directly posterior to the pectoral base whitish ( Fig. 1 c), or overall body greyreddish ( Fig. 3 ).

Vertebrae, dorsal pterygiophores prehemal spines. Data only for 3 largest paratypes since no x-ray for holotype available: Vertebrae: 11 + 16 = 27; first dorsal-fin pterygiophore insertion pattern: 3-22110; 2–3 prehemal pterygiophores.

Etymology. The new species is named for Zdravko Števčić, colleague carcinologist who encouraged and helped one of us (MK) in the beginning of his work on gobies.

Ecological and geographical distribution. The types were collected between 15 and 25 m depth at Rolas Island (00°00´N, 06°31´E). Otherwise observed at entrances of small caves between 20 and 40 m depth; at Rolas Island small individuals (about 4 cm length) were seen in 20 m depth hovering upside down; animals of approximately twice this size were seen in small caves between 35 to 40 m depth at Diogo Vaz (( 00°19´N, 06°29´E) ( Wirtz et al. 2007). No additional data available.

Figures

FIGURE 2. Gorogobius stevcici sp. nov., head lateral-line sensory papillae and canal pores of holotype, male, 33.0 + 6.9 mm, SMNS 23053. AN, PN, anterior and posterior nostrils; see other terminology in text. Scale = 3 mm.

FIGURE 3. Gorogobius stevcici sp. nov., underwater photograph of three uncollected individuals resting upside-down at the entrance of a small cave (photo courtesy P. Wirtz).

FIGURE 1 a. Gorogobius stevcici sp. nov., holotype (preserved), male, 33.0 + 6.9 mm, SMNS 23053, Scale = 5 mm; 1 b. holotype (shortly after capture; photo courtesy P. Wirtz); 1 c. one of the paratypes (shortly after capture; photo courtesy P. Wirtz).