Goby expert Helen Larson has revised the goby genus Redigobius, naming two new species from Fiji, Australia and New Guinea in the process.
Redigobius is a group of estuarine and freshwater gobies found throughout the Indo-Pacific. The revision is published in the most recent issue of the journal Ichthyological Exploration of Freshwaters, naming the two new species Redigobius lekutu and R. nanus.
Redigobius lekutu is a freshwater species known from two river systems in Vanua Levu, Fiji. It is distinguished from congeners in having a midlateral dark band formed by seven to eight brown blotches and a series of narrow vertical dark bands along the sides of the body. 7 first dorsal-fin spines, low and rounded first dorsal fin, usually I,7 second dorsal- and anal-fin rays, 15-17 pectoral-fin rays, 8–9 transverse scale rows backwards, 26–29 longitudinal scales, 7–10 predorsal scales, and 12 circumpeduncular scales.
The species is named after the river system (Lekutu) in which this species was first obtained. Redigobius lekutu has been collected in rivers with clear, darkly-stained water flowing over rough fused rock, where it was observed to form mid-water schools or rest on the substrate.
Redigobius nanus is an estuarine species known from northern Australia and southern New Guinea. It is distinguished from congeners in having a small adult size when adult (less than 3 cm standard length), indistinct lateral dark speckling and dorsal saddles on the body, scale margins narrowly outlined in dark brown, bright blue pale flecks and spots over brown markings on head, body and fins in living fish, pointed first dorsal fin, I,7 dorsal-fin rays, I,6 anal-fin rays, 16–17 pectoral-fin rays, 7–10 transverse scale rows backwards, 20–25 longitudinal scales, 6–10 predorsal scales, and 12 circumpeduncular scales.
The species is named after its small adult size (Latin nanus=dwarf). Redigobius nanus is usually associated with mangroves in muddy or sandy-muddy estuarine habitats.
Besides the two new species, ten other valid species are recognised in the study: R. balteatus, R. bikolanus, R. chrysosoma, R. dewaali, R. dispar, R. leveli, R. macrostoma, R. oyensi. R. penango, and R. tambujon.
For more information, see the paper: Larson, HK (2010) A review of the gobiid fish genus Redigobius (Teleostei: Gobionellinae), with descriptions of two new species. Ichthyological Exploration of Freshwaters 21, pp. 123–191.