Doiichthys

Alexandre P. Marceniuk & Naércio A. Menezes, 2007, Systematics of the family Ariidae (Ostariophysi, Siluriformes), with a redefinition of the genera., Zootaxa 1416, pp. 1-126 : 57-60

Doiichthys Weber, 1913

Doiichthys Weber, 1913: 532. Type species: Doiichthys novaeguineae Weber, 1913. Type by monotypy. Gender: masculine.

Diagnosis. Doiichthys can be differentiated from all other ariid genera by an extensive list of exclusive (1 to 10) and shared (11 to 21) characters: (1) nasal irregularly shaped; (2) presence of five infraorbitals; (3) premaxillary very wide its length more than 4 times in its width; (4) ceratohyal very long (fig. 46); (5) epihyal unusually long (fig. 46); (6) urohyal medial process very long (fig. 47); (7) first and second epibranchials straight for entire length (fig. 48); (8) first pharyngobranchial located at end of first epibranchial (fig. 48); (9) pharyngeal tooth plates long and narrow (fig. 49); (10) mesial portion of first epibranchial very compressed and wide (fig. 48); (11) mesethmoid medial notch allege and shallow (fig. 50) (shared with Bagre , Cinetodus , Cryptarius , Galeichthys , Ketengus and Pachyula ); (12) mesethmoid unusually very large at median portion (fig. 50) (shared with Bagre , Batrachocephalus , Brustiarius , Carlarius , Cochlefelis , Sciades couma , S. emphysetus , S. guatemalensis , S. herzbergii , S. leptaspis , S. passany and S. proops ); (13) lateral horn of lateral ethmoid very long and posteriorly directed [shared with Arius (with the exception of Arius caelatus ), Plicofollis (with exception of P. platystomus and P. tenuispinis ) and Potamarius ]; (14) lower crest of occipital process restricted to base of process [shared with Arius , Batrachocephalus , Brustiarius , Carlarius , Cochlefelis , Cryptarius , Galeichthys , Genidens , Ketengus , Neoarius , Netuma , Notarius , Osteogeneiosus , Plicofollis , Potamarius , Potamosilurus and Sciades (with the exception of S. platypogon )]; (15) face for articulation between palatine and lateral ethmoid on anterior portion of former bone (shared with Bagre ); (16) metapterygoid twice as high as long (shared with Bagre and Galeichthys ); (17) first external branchiostegal ray thin at proximal portion [shared with Arius caelatus , Bagre , Batrachocephalus , Brustiarius , Carlarius , Cochlefelis , Galeichthys , Ketengus , Neoarius , Netuma , Notarius (with exception of N. planiceps ), Osteogeneiosus , Sciades emphysetus , S. passany and S. proops ]; (18) second external branchiostegal ray less than half width of first ray (shared with Amphiarius , Arius , Aspistor , Bagre , Brustiarius , Carlarius , Cinetodus , Cochlefelis , Genidens , Hemiarius , Nemapteryx , Neoarius , Netuma , Notarius , Osteogeneiosus , Pachyula , Plicofollis , Potamarius , Potamosilurus and Sciades ); (19) tip of urohyal medial process bifid (fig. 47) (shared with Bagre ); (20) third pharyngobranchial mesially not angulated, shaped like an hourglass (shared with Ketengus and Potamarius grandoculis ); (21) crest associated with neural spine of third vertebra weakly developed [shared with Arius , Batrachocephalus , Brustiarius , Carlarius , Cochlefelis , Cryptarius , Galeichthys , Genidens , Ketengus , Neoarius , Netuma , Notarius , Osteogeneiosus , Plicofollis , Potamarius , Potamosilurus and Sciades (with exception of S. platypogon )].

Supplementary morphological characters. Cephalic shield granulated visible under the skin; lateral ethmoid and frontal limiting a very conspicuous large fenestra visible under the skin; medial groove of neurocranium limited by frontals and/or on supraoccipital absent; posterior cranial fontanel well differentiated, very large and oval shaped; fenestra limited by supraoccipital, pterotic and sphenotic absent; fossa limited by pterotic, supracleithrum and extrascapular relatively large; epioccipital not invading dorsal portion of cephalic shield; occipital process triangular, very long and narrow, narrower toward its posterior part; anterior and median nuchal plates fused and indistinct, forming a structure of semi-lunar aspect; vomerine tooth plates absent; accessory tooth plates small, vertically elongate, bearing conical teeth; maxillary barbel fleshy and cylindrical; two pairs of mental barbels; base of adipose fin moderately long, about half as long as anal-fin base; lateral line not bifurcated at caudal region, reaching base of caudal-fin upper lobe; cleithrum narrow, second dorsal process located on its upper portion; posterior cleithral process short and distinct from second dorsal process of cleithrum.

Distribution and habitat. Southern New Guinea, brackish waters.