Callogobius winterbottomi, Delventhal, Naomi R. & Mooi, Randall D., 2013

Delventhal, Naomi R. & Mooi, Randall D., 2013, Callogobius winterbottomi, a new species of goby (Teleostei: Gobiidae) from the Western Indian Ocean, Zootaxa 3630 (1), pp. 155-164 : 158-162

Callogobius winterbottomi sp. nov.

( Figs. 1–5 , Tab. 1 )

Holotype. ROM 58914, 33.8 mm SL male. Stated locality: Indian Ocean, Comoros, Moheli Bay, on south coast about 3 nautical miles west of Nioumachoua at southwest tip of island at Drondroni River, 12°21’15” S, 43°40’00” E, rotenone, depth 9–17 m, R. Winterbottom, W. Holleman, 27 Nov. 1988.

Paratypes. ROM 92690, 2 specimens (32.2 mm SL male and 22.9 mm SL male). Collected with the holotype.

Other material. SAIAB 0 57357, 1 specimen (37.7 mm SL female). Stated locality: Indian Ocean, South Africa, Aliwal Shoal off Scottburgh, 30°18’01” S 30°48’58” E, 26-28 m, P.C. Heemstra, 7 Feb. 1998.

Diagnosis. Callogobius winterbottomi is distinguished from all other known Callogobius species by the following combination of characters: head pores absent, 23–26 scales in lateral series, and preopercular papillae row (Row 20) not continuous with transverse opercular papillae row (Row 21).

Description. Holotype values are indicated by an asterisk. Parentheses enclose the number of counts in the type specimens with the particular value; counts are made on both sides when applicable or possible. Dorsal fin rays VI, I,9 (3*); anal fin rays I,8(3*); pectoral fin rays 16(2*), 17(4); pelvic fin rays I,5 (6*); segmented caudal fin rays 9+ 7i (1*), i8 + 7i (2); procurrent rays 4 + 4 (3*); scales in lateral series 23(1), 24(3), 26(2*); predorsal scales 8(2), 9(1*); transverse scales 10(1), 11(2*). Counts for these characters in the non-type female fall within the ranges reported for the type specimens.

All scales are large and deciduous, with distinctly outlined centres without circuli ( Fig. 2 ). Scales on the head and anterior half of the body are cycloid; cycloid scales are present in the spaces between the papillae rows on the cheeks, preoperculum and operculum, on the lateral side of the pectoral fin bases, prepelvic and predorsal regions, and on the belly. Scales on the posterior half of the body are ctenoid; ctenoid scales first appear on the midflank region below the 5th or 6th spine of the first dorsal fin. Ctenii are roughly triangular and pointed, and increase in number per scale towards the caudal peduncle. Slightly elongate ctenii occur on scales of the dorsal and ventral edges of the caudal peduncle (near or above the procurrent caudal fin rays) ( Fig. 2 ).

Teeth of upper and lower jaws (based on paratype, ROM 92690, 32.2 mm SL) are conical and slender; outer teeth larger, slightly curved and spaced at a distance of two thirds to twice the height of the tooth. There are 2–3 rows of inner teeth tightly spaced, about half the height of the outer teeth. The tongue is of medium-width with a slightly bilobed tip.

Anterior nostrils are long, slender tubes, reaching almost to the outer edge of the upper lip; the posterior nostrils are very short upright tubes.

Pelvic fins are partially united with the membrane reaching two thirds the length of the fin ( Fig. 3 ). The fifth segmented pelvic-fin ray is about three quarters the length of the fourth ray; all segmented pelvic-fin rays are branched. The pelvic frenum is present, but somewhat weak ( Fig. 3 ).

The male urogenital papilla is very long, slender and darkly pigmented. In the female (SAIAB 057357), the papilla is broad and darkly pigmented with small, distal flaps of skin laterally (E. Heemstra & W. Holleman, pers. comm.).

Head pores are absent. Pore replacement papillae are present in the interorbital, temporal and preopercular regions where pores would normally be found in Callogobius species having sensory canal pores ( Fig. 5 ).

Papillae Row Configuration ( Fig. 5 ): The postnasal rows (Row 2) are long and joined across the midline (3*). The anterior suborbital row (Row 9) is moderately long and does not reach the eye (6*); the mid suborbital row (Row 10) reaches or nearly reaches the eye (4*) or is of moderate length (2). The posterior suborbital rows (Row 11) are short; they may be separate but touch (2*), slightly overlap (2) or be well separated (2). The longitudinal maxillary row (Row 14) is unbroken and extends posteriorly to just below (2) or usually beyond (4*) the transverse cheek row (Row 13), which is short (6*). The longitudinal mandibular row (Row 15) is unbroken (6*). There are approximately 10(1), 11(4*), or 12(1) transverse mandibular rows (Row 16) on each lower jaw. The postorbital rows (Row 17) are short (less than 2/3 the length of the distance from the dorsal mid-line to the bony edge of the cranium) (4) to medium, (more than 2/3 the length of the distance from the dorsal mid-line to the bony edge of the cranium) (2*), and may nearly reach the midline (4*). The preopercular row (Row 20) is positioned anterior to, and not continuous with, the transverse opercular row (Row 21) (6*). The non-type female specimen exhibits papillae row configurations identical to that of the holotype.

Colour in Preservative ( Fig. 1 ): General colour pattern consists of brown dusky bars and mottling on a pale yellow-brown head and body. Head markings are poorly defined, consisting of lateral dusky blotches and a more evenly pigmented region from the snout through the post-orbital region, dorsally. The ventral region of the head is lightly pigmented. Papillae rows are more distinctly pigmented than surrounding regions. A wide dusky bar extends dorsally over the operculum and pectoral-fin base towards the first dorsal-fin spine; the ventral region of this bar may be darker than the remainder. The trunk has a wide bar extending below the first dorsal fin, reaching to, but not across, the belly. The belly is pale. A narrow, irregular, mottled bar or partial bar may be visible between the dorsal fins, particularly in the smallest specimen; this marking is more defined ventrally. A wide, slanted bar extends from the second dorsal fin to the posterior edge of the anal fin and around the anterior portion of the caudal peduncle. A wide bar encircles the posterior caudal peduncle, the edge of the hypural plate and the proximal regions of the caudal fin. The fins are pigmented with a darker brown; the first and second dorsal fins have irregular rows of pale spots and/or bands; the outermost edges are mostly pale. The pectoral fins are darkly mottled; there is greater pigment concentration medially. The pelvic and anal fins are evenly dark, except for the margins, which are pale. The caudal fin is dark, with fine, irregular and indistinct vertical bands. The urogenital papilla is dark.

Etymology. Named in honour of Rick Winterbottom who, along with Wouter Holleman, collected the type series. Rick has made substantial contributions to the systematics of gobies and other Indo-Pacific fishes, and to the development of both authors’ respective careers. Suggested vernacular name: Winterbottom’s flapheaded goby.

Distribution and habitat. Known only from the Comoros (3 specimens, the type series) where the field station was described as “base of vertical wall with numerous caves” at 9–17 m, and South Africa (1 specimen), collected at a depth of 26– 28 m.

Comparisons. Only three other described Callogobius species lack all head pores: C. hastatus , C. crassus and C. clarki . C. winterbottomi can easily be distinguished from C. hastatus and C. clarki by lower lateral scale counts (23–26 vs 32–37 in C. hastatus and 33–41 in C. clarki ). C. winterbottomi differs from C. crassus by higher lateral scale counts (23–26 vs 19–21) and papillae row configuration (preopercular row not continuous with transverse opercular row, longitudinal maxillary row and longitudinal mandibular row not broken in C. winterbottomi vs preopercular row continuous with transverse opercular row, longitudinal maxillary row and longitudinal mandibular row broken and displaced in C. crassus ). We are aware of at least two undescribed species of Callogobius lacking head pores, but these both differ from C. winterbottomi in having the preopercular row (Row 20) continuous with the transverse opercular row (Row 21).

In the Western Indian Ocean, C. winterbottomi may also be confused with C. maculipinnis , C. sclateri , C. bifasciatus , C. flavobrunneus or C. plumatus . These species develop head pores by the time they reach 14 mm but may be more difficult to distinguish as juveniles. C. winterbottomi differs from small C. maculipinnis by having 10 or more transverse mandibular rows (vs 3–4) and the fifth segmented pelvic fin ray shorter than the fourth (vs. fifth pelvic fin ray as long or longer than the fourth); from C. sclateri by having a pelvic frenum and connecting membrane between the fifth segmented pelvic fin rays (vs. pelvic frenum and connecting membrane absent) and by pectoral fin darkest medially (vs. pectoral fin with dark upper edge in small C. sclateri ); from C. bifasciatus and C. flavobrunneus by lateral scale counts (23–26 in C. winterbottomi vs. 37–48 in C. bifasciatus and 34–38 in C. flavobrunneus ); and from C. plumatus by having preopercular row not continuous with transverse opercular row (vs. continuous) and by having the anterior nostril longer than the posterior nostril (vs. shorter).

Remarks. SAIAB 0 57357 was not assigned type status because of the difference in collection locality. Although this specimen is slightly larger and darker than the Comoros specimens (cf Figs. 1 , 4 ), these differences are unlikely to be of taxonomic or biological significance. SAIAB 0 57357 is a female and all three type specimens are males, but we have not observed sexual dichromatism or dimorphism in other Callogobius species, except in the shape of the urogenital papilla, and do not expect them in C. winterbottomi .

Figures

FIGURE 1. Left lateral views of type specimens of Callogobius winterbottomi. (a) Holotype, ROM 58914, 33.8 mm SL male. (b) Paratype, ROM 92690, 32.2 mm SL male. (c) Paratype, ROM 92690, 22.9 mm SL male. Scale bar = 5 mm.

FIGURE 2. Scale morphology in Callogobius winterbottomi, illustrated from male paratype, ROM 92690, 32.2 mm SL. Left, entire mid-lateral scale from region below last spine of first dorsal fin showing distinctly outlined centre and single row of ctenii of normal length. Circuli are not illustrated, although note that they do not occur within the outlined centre. Right, slightly elongate ctenii of postero-dorsal caudal peduncle scale for comparison. Scale bar = 1 mm.

FIGURE 3. Ventral view of pelvic fins of Callogobius winterbottomi, illustrated from male paratype, ROM 92690, 32.2 mm SL. F—weak frenum; M—extent of membrane uniting pelvic fins, about two thirds length of fins (reconstructed, membrane damaged in all specimens available); S—pelvic spine. Scale bar = 2 mm.

FIGURE 4. Right lateral view of Callogobius winterbottomi, SAIAB 0 57357, 37.7 mm SL female. Scale bar = 5 mm.

FIGURE 5. Sensory papillae pattern in Callogobius winterbottomi paratype, ROM 92690, 22.9 mm SL, male. (a) Lateral view. Arrow indicates anterior extent of gill opening. (b) Dorsal view. Numbers refer to Akihito & Meguro’s (1977) sensory papillae system (see Table 2). Scale bar = 2 mm.