Trimma christianeae, a new species of goby (Teleostei: Gobiidae) from Milne Bay Province, Papua New Guinea

A new species of gobiid fish, Trimma christianeae, is described from 11 specimens, 9.8–18.9 mm SL, collected in 1–4 m depth near the town of Alotau in Milne Bay Province, Papua New Guinea. Diagnostic features include: dorsal-fin elements VI+I,9, second dorsal-fin spine usually with a short filament, extending to the base of the first to fourth segmented dorsal-fin ray when adpressed; anal-fin elements I,7; the fifth segmented pelvic-fin ray with sequential branching consisting of three branch points, its length about 75–90% (mean 83%) length of fourth ray; the basal membrane of the pelvic fin fully developed; well-developed interorbital and postorbital trenches; no scales present on the opercle; the posterior naris large and adnate to the orbital rim; the gill rakers on the first arch 3–4+12–13; color in life mainly orange to brownish red with diffuse brown scale margins forming a reticulated pattern; 6 indistinct narrow white or gray bars (sometimes branching) along the back and dorsalmost part of caudal peduncle; and the pectoral-fin base with a distinctive orange to reddish-brown medial area with large white spots dorsally and ventrally. The new species is most similar in appearance to T. mendelssohni, from the western Indian Ocean, which differs in having scales present on the upper opercle, a pair of small, fleshy lappets on the dorsal surface of the nape, and the absence of upper-limb gill rakers. The general color pattern and well-developed interorbital and postorbital trenches indicate a possible relationship to the Trimma caesiura complex.