Stigmatogobius yanamensis Rao, 1971

Stigmatogobius yanamensis Rao, 1971 View in CoL

1971. Stigmatogobius yanamensis Visweswara Rao , Journal of the Zoological Society of India, 23:1

2005. Pseudogobius yanamensis Rao, 1971 . Larson, H. K., A revision of the gobiidae genus Stigmatogobius (Teleostei: Gobiidae ), with descriptions of two new species. Ichthyological Exploration of Freshwaters 16:4

Common Name

Barfin fatnose goby

Conservation Status

Not Enlisted (IUCN 3.1) (IUCN Red List)

Material examined

ZSI/SbRC/KN 3353, 1 ex., TL 25mm, SL 20.3mm, Pakhir Dweep near Pakhiralaya, Sunderban Biosphere Reserve (22° 8'49.55"N; 88°51'11.47"E), 25.12.2019, Coll: Arya Sen. ( Figure 2c, d View Figure 2 ). ZSI/SbRC/KN 3133, 1 ex., TL 28mm, SL 23.2mm, Coringa Wild Life Sanctuary (16°49′53″N; 82°20′12″E), 11.12.2020, Coll: Dr. Sreeraj, C.R GoogleMaps .

Diagnostic Characters

1st Dorsal spines 6; 2nd Dorsal spine 1; 2nd Dorsal soft rays 7; Anal spine 1; Anal soft rays 7; Ventral spine 1; Ventral soft rays 5; Pectoral soft rays 15; Caudal soft rays 14. Elongate body. Body rounded in lateral profile anteriorly but laterally compressed posteriorly, snout is rounded at tip. Small teeth in several rows on both jaws. Caudal oblong as head. Opercle scaled. Dorsal profile straight and ventral profile bulges at near pelvic base. Eyes placed dorso-laterally. Small mouth with oblique opening and shorter lower jaw. Tongue anteriorly grooved and pointed at middle. Gill opening restricted before base of pectoral. Pectoral and caudal fin rounded. Pelvic slightly longer than pectoral. Body covered with ctenoid scales, six series of longitudinal rows between base of 2nd dorsal and anal origin.

Body-color of the dorsal and lateral profile is very light green to olivaceous and little silvery ventrally. Scale edges are darker in head region; presence of numerous black dots; presence of distinct 5-7 black bands. Dusky caudal fin.5 dark blotches in a line on the lateral profile. 3 dark blotches in shape of a triangle on the caudal peduncle region ( Figure 2c, d View Figure 2 ). Black stripe on the first dorsal after middle portion. Detailed measurement of the specimen is given ( Table 1).

Habitat

Temporary mangrove mud pools, created inland at the time of low tide having interconnected channels underground. Brackish Water (Salinity: 0-3 ppt)

Distribution

India: Godavari estuary in Andhra Pradesh ( Rao, 1971). Elsewhere: Vietnam, Singapore (Venkateswarlu and Ramarao, 1986; Tan and Lim, 2019).

Remarks

This species can be differentiated from its commonly related species by its distinctive vertical sub-marginal bluish-black bar on the first dorsal fin and four dusky blotches on the side behind the anus, the rearmost blotch is almost joined to two similar blotches at the base of the caudal fin ( Tran et al., 2013). Also, the transparent anal fin, truncated caudal fin and a smaller number of lateral line scales helps in the identification. Study of the specimens Collected from the type locality, i.e., from Coringa Wildlife Sanctuary of Godavary estuary, by the authors also supports the original description of the species and provides the fact of S. yanamensis being a valid species.

The species was described as S. yanamensis by Visweswara Rao from the Godavari estuary in India ( Rao, 1971). Talwar and Jhingran, (1991) discussed this species as a questionable synonym of S. minima Hora, 1923 without any suitable justification. Although the present study as well as the study by Larson and Hammer, (2021), gives justification of S. yanamensis to be a separate valid species. The holotype and six paratypes are held at the Zoology Museum, Andhra University, Waltair ( Fricke et al., 2021). Larson H.K. on the revision of Stigamtogobius placed this species under Pseudogobius Popta, 1922 ; without much justification ( Larson, 2005). Although it seems to be poorly known, the species was again recorded from the Mekong delta in Vietnam ( Tran et al., 2013). From 17 years old survey of mangroves of Singapore, this species has been identified in 2019 ( Tan and Lim, 2019). Recently in 2021, Larson & Hammer in the revision of Pseudogobius , again removed the species from this genus because it has a different setup of sensory canals and pores on its head and does not have the same characteristic corkscrew-shaped intestinal arrangement that is found in Pseudogobius ( Larson et al., 2016) . As well as the S. minima which was previously been confused with S. yanamensis is now placed under the genus Pseudogobius ( Larson and Hammer, 2021) . Still S. yanamensis has been recorded as a synonym of S. minima in World Register of Marine Species, accepted as a Nomen Dubium in Catalogue of Fishes and as a doubtful species from India by Parenti, (2021). Authors suggest that S. yanamensis should be accepted as a valid species following the current study ( Rao, 1971; Larson and Hammer, 2021).