Nedystoma
Creators: name: Alexandre P. Marceniuk
name: Naércio A. Menezes
Publisher: name: Zenodo
Year: 2007
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Siluriformes
Ariidae
Nedystoma

description: Nedystoma Ogilby, 1898
(fig. 63)
Nedystoma Ogilby, 1898: 32. Type species: Hemipimelodus dayi Ramsay & Ogilby, 1886. Type by original designation and also monotypy. Gender: neuter.
Diagnosis. Nedystoma can be distinguished from all other members of the Ariidae through the combination of exclusive (1 to 3) and shared (4 to 9) characters: (1) premaxillary anterior margin fringed; (2) third external branchiostegal ray in form of a spatula; (3) pharyngeal tooth plates very long and narrow (fig. 64); (4) accessory tooth plates absent (shared with Cephalocassis borneensis, Ketengus, Pachyula, Potamarius izabalensis and Potamosilurus velutinus); (5) opercle anterior part trapezoid shaped, long and narrow (shared with Bagre, Cinetodus and Galeichthys); (6) upper hyomandibular crest short and high (shared with Amphiarius, Arius, Aspistor, Batrachocephalus, Cathorops, Hemiarius, Ketengus, Notarius, Osteogeneiosus, Plicofollis platystomus and Potamosilurus); (7) contact face between first epibranchial and first pharyngobranchial very conspicuous [shared with Arius arius, A. gagora, A. madagascariensis, Brustiarius, Osteogeneiosus, Plicofollis (with exception of P. platystomus) and Potamosilurus]; (8) lateral face of third pharyngobranchial conspicuous and acute (shared with Arius, Brustiarius, Neoarius, Netuma, Plicofollis and Potamosilurus); (9) transversal crest of neural spine of fourth vertebra very high (shared with Amphiarius, Bagre, Batrachocephalus, Cathorops, Cinetodus, Cryptarius, Ketengus, Hemiarius, Nemapteryx, Notarius planiceps, Osteogeneiosus, Pachyula and Sciades platypogon).
Supplementary morphological characters. Cephalic shield granulated visible under the skin; lateral ethmoid and frontal delimiting a large fenestra clearly visible under the skin; medial groove of neurocranium limited by frontal bones and/or on supraoccipital absent; posterior cranial fontanel well differentiated, 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, progressively narrower toward its posterior part; anterior and median nuchal plates fused and indistinct, forming a structure of semi-lunar aspect; tooth plates associated with vomer absent; accessory tooth plates absent; 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, with second dorsal process on its upper portion; posterior cleithral process short and distinct from second dorsal process of cleithrum.
Distribution and habitat. Southern New Guinea, predominantly freshwaters.
description: Published as part of Alexandre P. Marceniuk & Naércio A. Menezes, 2007, Systematics of the family Ariidae (Ostariophysi, Siluriformes), with a redefinition of the genera., pp. 1-126 in Zootaxa 1416 on page 73