|Psammogobius pisinnus Allen, 2017|
A new miniature species of gobiid fish, Psammogobius pisinnus n. sp., is described from West New Britain Province, Papua New Guinea on the basis of 10 specimens, 10.8–17.9 mm SL. Diagnostic features include dorsal-fin rays VI + I,9 (rarely I,10), the third dorsal-fin spine sometimes with a short, filamentous extension; anal-fin rays I,9 (rarely I,8); pectoral-fin rays 16–19 (usually 17); the pelvic fins reaching the anal-fin origin; the pelvic frenum weakly developed; longitudinal scales 25–28; the tongue distinctly bilobed, and a live color pattern that is generally light gray to whitish with three broad brown saddles on the dorsal half of the body. The new species differs from the three previously described species of Psammogobius (P. biocellatus, P. knysnaensis, and P. viet) on the basis of its tiny adult size (less than 20 mm vs, about 70–80 mm SL), fully marine habitat (vs. brackish estuaries and tidal streams), possession of cheek and opercular scales (scaleless in other species, except P. biocellatus with scales on the upper portion of the opercle), only 5–7 predorsal scales (vs. 10–16), and color pattern. The new species is also reported from the northern Great Barrier Reef of Australia on the basis of a single specimen.
Key words: taxonomy, systematics, ichthyology, coral-reef fishes, Indo-Pacific Ocean
|Figure 3. Psammogobius pisinnus, underwater photographs, approx. 13–17 mm SL, all West New Britain Province, Papua New Guinea (G.R. Allen), except lower right taken at Flynn Reef, Great Barrier Reef, Australia (M. Onishi).|
Psammogobius pisinnus, n. sp.
Diagnosis. A species of Psammogobius with the following combination of characters: dorsal-fin rays VI+I,9 (rarely I,10), third dorsal-fin spine sometimes with short filamentous extension; anal-fin rays I,9 (rarely I,8); pectoral-fin rays 16–19 (usually 17); pelvic fins reaching anal-fin origin; pelvic frenum weakly developed; longitudinal scales 25–28; predorsal scales 5–7; cheek and opercle scaled; tongue distinctly bilobed with a deep cleft between lobes; small maximum size of less than 20 mm SL. Color in life light gray to whitish with three broad brown saddles on dorsal half of body, the anteriormost darkest and positioned below first dorsal fin; operculum and cheek mottled dark brown; whitish streak on middle pectoral-fin rays. Inhabits sand slopes near coral reefs.
Etymology. The species is named pisinnus (Latin: small or little) with reference to the exceptionally small maximum size in comparison to congeners.
Gerald R. Allen. 2017. Psammogobius pisinnus, A New Species of Reef Goby (Teleostei: Gobiidae) from Papua New Guinea and Australia. Journal of the Ocean Science Foundation. 26, 80–85. DOI: 10.5281/zenodo.571211