Schismatogobius mondo, Keith & Lord & Larson, 2017

Keith, Philippe, Lord, Clara & Larson, Helen K., 2017, Review of Schismatogobius (Gobiidae) from Papua New Guinea to Samoa, with description of seven new species, Cybium 41 (1), pp. 45-66 : 58

Schismatogobius mondo , new species

( Figs 1-2B , 4 , 7 ; Tabs I-III)

Material examined. – Two specimens from Solomon Islands with a size range of 18-20.1 mm SL .

Holotype. – MNHN 2016-0297 , male (20.1 mm SL); Mondo River, Ranongga Island , Solomon Islands, 26 Oct. 2015, coll. Keith, Lord, Boseto and Hevalao; tag 10598.

Paratype. – MNHN 2016-0298 , female (18.0 mm SL); Dae River , Ranongga Island, Solomon Islands, 24 Oct. 2015, coll. Keith, Lord, Boseto and Hevalao; tag 10585 .

Diagnosis

14-15 pectoral rays; pectoral fins partly crossed by broad black band and few rows of black spots. First dorsal fin membrane posterior to spine 6 not connected to base of spine of second dorsal fin. Anal fin I,9. Three transverse black bands on the body. Ventral surface of head and frenum in male blackish. Ventral surface of head in female whitish with a blackish border.

Description

A small sized Schismatogobius (average size <22 mm SL). Body naked, slender, almost circular in cross-section. Head rounded, snout rather pointed. Mouth oblique, tip of lower lip anteriormost. Jaw lengths in male much greater than in female; jaw length 47% of HL in male holotype and 36% of HL in female paratype. Lower jaw reaching vertical of 1/3 of the eye in female and exceeding (for 1/3 of eye diameter) a vertical of posterior margin of eye in male. Eyes high on head, close together; interorbital width about equal to half eye diameter. Anterior nostril in short tube.

Dorsal fins VI-I,9, membrane in first dorsal fin posterior to spine 6 not connected to base of spine of second dorsal fin. D1 with all spines about equal in length. Anal fin I,9, slightly behind or approximately below second dorsal fin origin. Caudal fin with 12 branched rays, posterior margin rounded. Pectoral fins oblong with posterior margin pointed and 14(1)-15(1) rays ( Tab. I), ventralmost ray unbranched. Pelvic fins always I,5, with both fins joined together for their entire length between fifth rays to form a strong cup-like disc and a well developed and lobed frenum between spines, fins not extending beyond anus. Morphomeristic data given in table III.

Tongue (anterior tip) bilobed. Teeth in upper jaw (16- 20) in two or three rows, teeth conical and slightly recurved. Teeth in lower jaw (7-12) in two rows anteriorly and single row laterally, all teeth conical with outer row teeth only slightly enlarged and somewhat recurved.

Cephalic sensory pore system always with pores B, D, F, K, L, N and O, pore D singular with all other pores paired; oculoscapular canal absent between pores F and K. Anterior interorbital extension of anterior oculoscapular canal with double terminal pores B slightly posterior to posterior nostril. D pore at rear of interorbital. Posterior extension of anterior oculoscapular canal terminating laterally on each side of head at pore F, just behind posterior edge of eye. Posterior oculoscapular canal with 2 terminal pores, K and L; preopercular canal with 2 pores, N and O. Cutaneous sensory papillae not well developed but similar to pattern described by Akihito et al. (1988).

Sexual dimorphism fairly well developed with male having jaws longer than female and a different colour pattern on ventral surface of head. Urogenital papilla broadly rounded in female and slightly pointed in male.

Colour in preservation ( Fig. 7B )

Three vertical black bands in dorsal and lateral views; first band below first dorsal fin, second below second dorsal fin and third one at hypural crease. Head black. These lateral body black markings alternate with 3 vertical white to grey stripes. In male, ventral surface of head and frenum black, with pelvic fins brownish to black ( Fig. 2B ). Ventral surface of head in female slightly pigmented with a blackish border ( Fig. 2B ); belly whitish; breast whitish. First dorsal fin with large black basal band. Second dorsal fin mostly cream with rows of black spots on rays. Caudal fin black and white, with black spot at centre of hypural crease and two white spots posteriorly. Anal fin mostly cream. Pectoral fins with a large triangular transverse black band.

Colour in life ( Fig. 7A )

Female with three vertical black bands, lateral and dorsal parts of body between vertical black bands are cream with rose to orange mottling, pinkish towards the nape becoming darker on the posterior part of the body. Head pinkish dorsally with a few brown markings; cheeks with numerous tight brown spots. Ventral surface of head white. First dorsal fin translucent with wide black basal band. Second dorsal fin translucent with rows of small dark dots on rays. Caudal fin barred black and white, with large black blotch beginning at hypural crease and extending on first half fin toward two white oval spots. Anal fin translucent. Pectoral fins translucent with a couple of rows of black spots.

Figures

Figure 1. – Bayesian phylogenetic reconstruction, based on the partial COI barcode region (636 bp). The posterior probability values are given at each node. Following each species name is the country the specimen comes from; the numbers following the species are the numbers given on the field.

Figure 2. – A-F: Schematic drawings of the ventral surface of head of Schis- matogobius species from Papua New Guinea to Samoa. A: 13-14 pectoral rays.

Figure 4. – Distribution area of Schismatogobius species from Papua New Guinea to Samoa.

Figure 7. – A: Schismatogobius mondo n. sp., paratype, MNHN 2016-0298, female, 18.0 mm SL (Photo P. Keith). B: Schismatogobius mondo n. sp., holotype, MNHN 2016-0297, male, 20.1 mm SL (Photo P. Keith).