Giuris charpini, Keith & Mennesson, 2020

Keith, Philippe & Mennesson, Marion I., 2020, Review of Giuris (Teleostei: Eleotridae) from Indo-Pacific islands, with description of three new species, Cybium 44 (4), pp. 331-349 : 340-341

Giuris charpini n. sp. Keith & Mennesson

( Figs 1 , 3 , 10 ; Tabs III-IV)

Material examined

Eight specimens from New Caledonia and Vanuatu, totaling 5 males and 3 females; size range 78-120 mm SL, largest male 120 mm SL, largest female 105 mm SL.

Holotype. – MNHN 2019-0250 , 1 male (120 mm SL), Kû Bwéné , New Caledonia, 8 Jul 2019, Charpin coll.; speci 5, tag 12600.

Paratypes. – MNHN 2005-1893 , male (114.7 mm SL), Gaua Is., Vanuatu, Kirilou riv., 18 Jul. 2005, Keith et al. coll . MNHN 2019-0246 , 1 male and 1 female (92.2- 102.8 mm SL), Fausse Yaté , 29 Nov. 2018, New Caledonia, Charpin coll.; tags 6847, 6846 . MNHN 2011-0125 , female (78.2 mm SL), Santo Is., Vanuatu, Jordan riv., 16 Nov. 2005, Keith et al. coll . MNHN 2019-0248 , 1 female and 2 males (105-120 mm SL), Kû Bwéné , New Caledonia, 8 Jul. 2019, Charpin coll.; tags 12596 to 12598 .

Diagnosis

The new species has 13-14 pectorals rays, a medium body depth at anus (20-24% SL), 8-10 scales around the eye, and 13-14 scales in transverse forward series.

Description

The scale and ray counts are given in table III and morphometrics in table IV. Below, the holotype counts are given first, followed in brackets, if different, by the paratypes’ counts.

The body is more ovoid than elongated. The body depth at anus is 23 (20-24% SL), at first dorsal fin 23 (19-25% SL), and the caudal peduncle depth is 16 (13-16% SL). Predorsal length 44 (43-44% SL) and preanal length 64 (59-65% SL).

The head 33 (31-33% SL) is depressed, the snout is convex. The anterior nostrils are short, not reaching upper margin of upper lip. The mouth and jaw length 10 (10-11% SL) are small. Inwardly curved teeth set on both jaws and larger on outer row; caniniform teeth in lower jaw. Posterior end of maxillary extending to below around anterior margin of eye. Lips with numerous internal short papillae. No external papillae on mentum, snout, inferior lip and between nostrils. Eye diameter 5 (5-7% SL) and interorbital length 13 (12- 14% SL).

Dorsal fins VI-I,8 with no filamentous rays. The first dorsal fin is with second, third, fourth and fifth rays longer. Anal fin I,8-9 directly opposite to the second dorsal fin. The caudal fin is with 13-14 branched rays and its posterior margin is rounded. Pelvic fins separate, I,5. Pectoral fins 13 (13-14), with the posterior margin rounded. Lateral scales 29 (27-29), with ctenoid scales on flanks and caudal peduncle. Cycloid scales from snout to top of head and anterior part of D1, on operculum, on base of pectoral fins and on belly extending to anus. Scales on top of head and back bigger than those of belly. Scales in transverse back series 10 (9-11), in transverse forward 14 (13-14), in predorsal 15 (13-15) and in zigzag 9 (8-9). 8 (8-10) scales around the eye (ENO). 25 vertebrae.

Absence of oculoscapular canal and supratemporals and presence of a short preopercular canal with the pores N’ and O’.

Cephalic sensory papillae system developed as described by Akihito et al. (1988).

Males with a rounded/triangular urogenital papilla with distal tip rounded. The females have bulbous urogenital papilla with fimbriate projections around distal opening.

Colour in preservation

Males. – Background of body entirely brownish and covered with numerous greyish spots including the two dorsal and the caudal fins. Three thick brown stripes rows radiate from the eye to the cheeks and operculum. The belly is whitish. The anal fin is brownish at the distal part with a whitish base. The caudal fin is brown. The upper part of the first and second dorsal fins is greyish, with a brownish base with white spots.

Females. – Background of body brownish to beige on the back. Top of head brownish, lateral part greyish with 3 thin brown stripes radiating from the eye to the cheeks and operculum, the upper one continuing on the pectoral base. Several small alternating greyish rounded patches along the flanks from pectoral base to hypural base. Belly whitish. Base of caudal fin with 3 brown spots. The first dorsal fin is greyish with white basal part. Pectoral fins greyish. Pelvic fins greyish as the anal and caudal fins.

Colour in life

Males. – ( Fig. 3A ) Male with background of body entirely reddish and covered with numerous silver, yellow or bluish spots including the two dorsal and the caudal fins. Three thick red stripes and three spotted silver rows radiate from the eye to the cheeks and operculum, the upper red one continuing on the pectoral base, which is red-brown. The belly is whitish. The anal fin is reddish at the distal part with yellowish to whitish spots at the base. The caudal fin is red-brown with a bright red basal part. The upper part of the first dorsal fin is hyaline, with a median yellow to white line and a reddish base with white spots. The upper part of the second dorsal fin is hyaline, with sometimes a median yellow spotted line, base reddish with white spots and a thin distal white line. The pectoral fin is translucent with a red brown-base followed by a thin white stripe. Pelvic fins are hyaline with a yellow base and a distal white band.

Females. – Two patterns (1) Background of body brownish to red on the back and flanks. Lateral part of head with whitish spots and 3 reddish stripes radiating from the eye to the cheeks and operculum, the upper one continuing on the pectoral base. Nine to ten large alternating reddish to bluish rounded patches along the flanks from pectoral base to hypural base. Numerous whitish spots along midline and around patches. The belly is greyish to whitish. First and second dorsal fins hyaline, with a median yellow to white line and a reddish base with white spots. Pectoral fins hyaline to greyish. Pelvic fins hyaline to greyish with a white distal stripe. The anal fin is reddish with a yellowish basal line. The caudal is red-brown fin with 3-5 brown spots at the base, and numerous yellowish dots along the rays ( Fig. 3B ). (2) Background of body brownish to beige on the back. Top of head dark brown, lateral part brownish to yellowish with 3 thin red stripes radiating from the eye to the cheeks and operculum, the upper one continuing on the pectoral base. Nine to eleven small alternating brownish to yellowish rounded patches along the flanks from pectoral base to hypural base. Belly whitish to greyish. Base of caudal fin with 3 brown spots. The first dorsal fin is hyaline with a yellow median to basal part as the second dorsal, which has a thin white stripe at the distal tip. Pectoral fins greyish to yellowish. Pelvic fins greyish to yellowish with a thin white stripe at the distal tip. The anal and caudal fins are greyish to yellowish.

Ecology

Giuris charpini occurs in estuaries and lower parts of coastal streams, usually in riverbank vegetation and in shelters over rocky or gravel bottoms. It is omnivorous and feeds on small shrimps, aquatic insects and fish. It is thought to be amphidromous as some other species of the family ( Marquet et al., 2003; Keith et al., 2010).

Distribution

Giuris charpini is known from New Caledonia and Vanuatu.

Etymology

The new species is dedicated to Nicolas Charpin for all his work for the improvement of knowledge and the protection of the freshwater fauna of New Caledonia.

Comparison

Giuris charpini differs from the other species sequenced by having a high percentage of divergence in COI gene (3.2- 13%) (Tab. II), by having fewer scales in lateral series (27- 29 (mean 28) vs. 28-32 (Mean> or = 29)) and by the colourful pattern of the male. Moreover it differs from G. yahayai (present paper) in having fewer scales in transverse forward series (13-14 vs. 17-20), a smaller body depth at anus (20- 24 vs. 26-36% SL) and a smaller body depth at first dorsal fin (19-25 vs. 26-39% SL). It differs from G. tolsoni in having more scales around the eye (8-10 vs. 6-9), a greater body depth at anus (20-24 vs. % SL 16-22) and 13 or 14 pectorals rays vs. always 14 rays. It differs from G. margaritaceus in having 13-14 pectorals rays vs. 14 or 15 rays and fewer scales in zigzag series (8-9 vs. 9-10). It differs from G. viator in having fewer scales in transverse back series (9-11 vs. 11-12), fewer scales around the eye (8-10 vs. 10-13) and 13 or 14 pectorals rays vs. always 14 rays. It differs from G. aporocephalus in having 13-14 pectorals rays vs. 15 rays and more scales in transverse forward series (13-14 vs. 11-13), and from G. caussei (present paper) in having 13-14 pectorals rays vs. 14-15 rays and more scales in transverse forward series (13-14 vs. 11-12). It differs from G. laglaizei in having 13-14 pectorals rays vs. always 15 and more scales around the eye (8-10 vs. 6-8).

Figures

Figure 1. – Bayesian tree of the cytochrome c oxidase subunit (COI – 495 bp) for sequenced specimens of Giuris. Numbers at each node represent posterior probabilities.

Figure 3. – A: Giuris charpini n. sp., male; MNHN 2019-0250, holotype, New Caledonia; LS 120 mm (Photo N. Charpin). B: G. charpini n. sp., female; MNHN 2019-0248, paratype, New Caledonia; LS 105 mm (Photo N. Charpin).

Figure 10. – Distribution of Giuris species.