Mugilogobius tigrinus Larson, 2001

Sreeraj, Chemmencheri Ramakrishnan, Sen, Arya & Raghunathan, Chelladurai, 2024, Report of two euryhaline goby fishes (Family: Gobiidae) from Coringa Wildlife Sanctuary, Andhra Pradesh, Records of the Zoological Survey of India 124 (3), pp. 265-272 : 269-270

Mugilogobius tigrinus Larson, 2001

2001. Mugilogobius tigrinus Larson [H. K.] A revision of the gobiid fish genus Mugilogobius ( Teleostei: Gobioidei), and its systematic placement. Records of the Western Australian M useum Suppl. No. 62: i-iv + 1-233 (Mangrove Creek, Sungei Pandan, Singapore).

Common Name : Tiger mangrove goby

Conservation Status: Not Evaluated (IUCN Red List 3.1)

Economic Importance: Commercially not important ( India)

Material examined: India: Andhra Pradesh, Coringa Wildlife Sanctuary , (16°52’55.39”N; 82°14’54.50”E), 2 exs., 11.XII.2020, Coll: Sreeraj C. R., (Reg. No ZSI/SbRC/ KN3132) .

Diagnostic Characters: First dorsal spine 6; Second dorsal spine 1; Second dorsal soft rays 7; Anal spine 1; Anal soft rays 7; Pectoral Soft rays 15; Ventral Spine 1; Ventral soft rays 5; Caudal soft rays 16 (Segmented); Longitudinal scales 27; Transverse scales 9; Pre-dorsal scales 9. Slender body with an overall compressed profile but the anterior portion is somewhat rounded. Head length is almost one-third of the standard length. Head pores absent. Eyes placed dorsolateral at the uppermost part with a ridge at the top. The nape is somewhat concave after the first dorsal. Mouth oblique and subterminal. Jaws reaching below the middle of the eye. Anterior nose trills are tube-like, small and positioned just at the top of the upper lip. Lips are fleshy and smooth and the lower lip is free at the side. Scales at the anterior is enlarged. Body scales are ctenoid. Pre-dorsal scales are the same size as the body scales. Half of the operculum is covered with cycloid scales. The first spine of the first dorsal is enlarged having double length of normal spine length. First dorsal is low and triangular. Pectoral fins are semi-rounded and with pointed ends. Caudal fin with a semi-rounded edge.

Live specimen colouration is mainly transparent with a light yellowish dorsal profile and light pinkish ventral profile. Four full dark black bands, two dark half bands and one elongated circular black spot appear over

Report of two euryhaline goby fishes (Family: Gobiidae ) from Coringa Wildlife Sanctuary, Andhra Pradesh the body. This elongated spot almost covers the upper half of the base of the caudal with a yellowish margin. A triangular black spot at the base of the Operculum. Both dorsal margins with black bands just after a white patch. The lower part of the head and lips are black. One pigmented narrow black patch is present just after the eye up to the operculum. Each scale on the side of the body up to the caudal peduncle has a dusky margin. The elongated dorsal spine is transparent. Most of the fin membrane and fin rays are transparent. Eye socket edges are pigmented black. ( Figure 4 ). Detailed morphometric measurements of this specimen are given in Table 1.

Distribution: Peninsular Thailand, Malaysia, Singapore, Sri Lanka, India (Andamans, Kerala on the west coast) ( Larson, 2001; Larson & Lim, 2005; Larson et al., 2008; Ott, 2011; Praveenraj et al., 2017; Sreeraj et al., 2023). The species is reported here for the first time from the Indian mainland east coast; thus a significant range extension is reported here.

Habitat: Small mangrove mud pools, created temporarily during the time of low tide having interconnected channels underground (intertidal). Mud pools are associated with the base of tree trunks and pneumatophores in shady areas of the mangrove. The specimen was collected using a small aquarium net and it was well camouflaged in a muddy base with very little movement in the water; Brackish Water (Salinity: 9-15 ppt, Water temperature:

27.7°C – 39.1°C, Mud Temperature – 22.9°C – 26.2°C, pH: 8.1 – 8.3) ( Figure 3 ).

Comments: The key characteristics of this species include an average lateral scale count of 26, four bands encircling the body, and a black stripe running from the eye to the mouth. The cryptic behaviour of these species and the selection of this specialized kind of microhabitat (Mud Pools), body colouration, and small size are the characteristics that made this species easily overlooked during a field survey. One specimen is observed in a single pool and two different specimens have been collected from two different pools. Another dominating group in this mud pool was Oryzias sp. This species cannot survive outside of water for a long period.

The species was collected from the mangrove creek of Sungei Pandan, Singapore for the first time and was identified as M. tigrinus by Larson (2001). According to Larson (2001), this species is closely associated in appearance with M. fasciatus Larson, 2001 which occurs in the western Pacific. But more or less M. tigirinus can be easily differentiated by the presence of four bands on the body and the presence of black bands behind the eye, whereas in the case of M. fasciatus five bands are present over the body and the bands behind the eye are white.

Figures

Figure 3. Collection habitat of Hemigobius hoevenii (Bleeker, 1851) & Mugilogobius tigrinus Larson, 2001 in Coringa Wildlife Sanctuary.

Figure 4. Live Specimen picture of Mugilogobius tigrinus Larson, 2001.