A New Species of Freshwater Eel-tailed Catfish of the Genus Tandanus (Teleostei: Plotosidae) from Coastal Rivers of Mid-northern New South Wales, Australia
Tandanus bellingerensis, new species, is described based on specimens from four river drainages (Bellinger, Macleay, Hastings, and Manning rivers) of the mid-northern coast of New South Wales, Australia. Previously, three species were recognized in the genus Tandanus: T. tropicanus of the wet tropics region of northeast Queensland, T. tandanus of the Murray-Darling drainage and coastal streams of central-southern Queensland and New South Wales, and T. bostocki of southwestern Western Australia. The new species is distinguished from all congeners by a combination of the following morphologic characters: a high count of rays in the continuous caudodorsal and anal fins (range 153–169, mode 159), a high count of gill rakers on the first arch (range 35–39, mode 36), and strongly recurved posterior serrae of the pectoral-fin spine. Additionally, results from previously conducted genetic studies corroborate morphologic and taxonomic distinctness of the new species.

Tandanus bellingerensis, holotype, male, AMS I.47180-001, 439 mm SL, Bellinger River at mouth of Kip Creek on Darkwood Road, approx. 26 km W of Bellingen, NSW, 30°26′39.8″S, 152°37′14.1″E.

Dorsal and ventral body views of Tandanus bellingerensis, holotype, male, 439 mm SL.

Serration of pectoral-fin spine of Tandanus bellingerensis, holotype, male (scale bar = 10 mm, illustration by S. A. Welsh).

Drainage basin locations of Tandanus bellingerensis (Bellinger, Macleay, Hastings, and Manning rivers), T. tropicanus of the wet tropics region (Daintree, Mulgrave-Russell, Johnstone, and Tully rivers, and Five Mile Creek), T. tandanus of the Murray-Darling Basin, T. tandanus from eastern coastal rivers (Fitzroy-Dawson, Burnett, Mary, Brisbane, Tweed, Richmond, and Clarence), and T. bostocki from western coastal rivers (Moore-Hill, Swan, and Serpentine). This figure was adapted from Welsh et al. (2014).

Plot of the second sheared principal component (SPC2) from the morphometric analysis vs. the first principal component (PC1) of the meristic analysis of T. bellingerensis (▪), T. tropicanus (▴), T. bostocki (♦), T. tandanus of the Murray-Darling drainage (•), and T. tandanus from eastern coastal drainages: Brisbane, Burnett, Mary, and Richmond (○), Fitzroy (⋄), Clarence (□), and Tweed (▵).
Contributor Notes
Associate Editor: D. Buth.